ATL: LEE - Advisories

[cycloneye]

Hurricane Lee Discussion Number 21
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Sun Sep 10 2023

Earlier SSMIS and GMI microwave overpasses along with reports from
a NOAA Hurricane Hunter aircraft indicate that Lee has a larger
banded-type eye as compared to yesterday. The ragged eye has
become apparent in visible and infrared satellite images within
the past hour or so. The NOAA aircraft has measured a peak 700-mb
flight-level wind of 106 kt and SFMR winds of 95 kt, and the minimum
pressure has been oscillating in the 956-958 mb range during the
flight. Based on these data, and the recent improvement in
structure, the initial intensity has been raised to 95 kt.

The vertical wind shear over Lee appears to have relaxed some since
yesterday as there has been an expansion of the upper-level outflow
over the southern and southwestern portions of the storm. Most of
the guidance suggests that the shear will decrease more over the
next couple of days, allowing Lee to re-strengthen. The expected
slow motion of the hurricane could cause some upwelling, especially
in the 2-3 day time period when Lee is forecast to be moving at only
around 5 kt. The NHC wind speed forecast calls for steady
restrengthening during the next 24-48 hours, then shows some gradual
weakening after that time due to the potential for upwelling. Later
in the forecast period, increasing southwesterly shear is likely to
cause additional weakening, however Lee is forecast to remain a
strong hurricane through most of this week.

Recent aircraft center fixes show that the hurricane is beginning
to slow down. The initial motion is now west-northwest or 300
degrees at 7 kt. A high pressure ridge to the northwest of Lee is
forecast to build southwestward during the next couple of days,
further slowing Lee's progress. By midweek, a mid-latitude trough
moving into the northeastern United States is expected to weaken
the western extent of the ridge, allowing Lee to turn northward.
There is still significant uncertainty in the global model guidance
regarding the forward speed of Lee later in the forecast period.
The NHC track forecast continues to lie between the faster GFS and
slower ECMWF, close to the various consensus models.


KEY MESSAGES:

1. Lee's core is expected to pass well north of the northern
Leeward Islands, the Virgin Islands, and Puerto Rico during the
next couple of days.

2. Dangerous surf and life-threatening rip currents are affecting
portions of the northern Leeward Islands, the British and U.S.
Virgin Islands, Puerto Rico, Hispaniola, the Turks and Caicos
Islands, the Bahamas, and Bermuda.

3. It remains too soon to know what level of impacts, if any, Lee
might have along the U.S. East Coast, Atlantic Canada, or Bermuda
late next week, especially since the hurricane is expected to slow
down considerably over the southwestern Atlantic. Regardless,
dangerous surf and rip currents are expected along most of the U.S.
East Coast beginning later today and continuing through the week as
Lee grows in size. Users should continue to monitor updates to the
forecast of Lee during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 10/1500Z 21.6N 61.0W 95 KT 110 MPH
12H 11/0000Z 22.3N 62.1W 105 KT 120 MPH
24H 11/1200Z 23.0N 63.3W 110 KT 125 MPH
36H 12/0000Z 23.4N 64.5W 115 KT 130 MPH
48H 12/1200Z 23.8N 65.6W 115 KT 130 MPH
60H 13/0000Z 24.2N 66.5W 110 KT 125 MPH
72H 13/1200Z 24.7N 67.2W 105 KT 120 MPH
96H 14/1200Z 27.3N 67.9W 95 KT 110 MPH
120H 15/1200Z 31.3N 67.7W 80 KT 90 MPH

$$
Forecaster Brown

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 22
NWS National Hurricane Center Miami FL AL132023
500 PM AST Sun Sep 10 2023

...AIR FORCE RESERVE HURRICANE HUNTERS FIND LEE RESTRENGTHENING...
...HAZARDOUS BEACH CONDITIONS EXPECTED TO SPREAD THROUGH THE WESTERN
ATLANTIC DURING THE WEEK...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...22.1N 61.7W
ABOUT 285 MI...455 KM NNE OF THE NORTHERN LEEWARD ISLANDS
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...954 MB...28.17 INCHES



Hurricane Lee Discussion Number 22
NWS National Hurricane Center Miami FL AL132023
500 PM AST Sun Sep 10 2023

Lee has continued to become better organized today. The eye has
become more apparent in both infrared and visible satellite
imagery this afternoon, and reconnaissance aircraft reports
indicate that the eye has contracted today. An Air Force Reserve
Hurricane Hunter aircraft that is currently investigating Lee has
measured peak 700-mb flight-level winds of 112 kt and SFMR winds of
106 kt. Near the conclusion of the earlier NOAA P-3 aircraft
mission an eyewall dropsonde measured mean boundary layer winds in
the lowest 150 m of the sonde of 117 kt, which supported surface
winds of around 100 kt. Based on the improved satellite
presentation and the recent SFMR wind report, Lee's initial
intensity has been raised to 105 kt.

As mentioned this morning, the vertical wind shear over Lee appears
to have decreased as the upper-level outflow has become better
established over the southern and southwestern portions of the
storm. Some further reduction in shear is anticipated during the
next day or so, and Lee is expected to restrengthen during that
time. The NHC intensity prediction calls for steady intensification
during the next 24 hours or so, and Lee is forecast regain category
4 status tonight or early Monday. After that time, the slow
motion of the hurricane could cause the water beneath the hurricane
to cool due to upwelling, which is likely to cause Lee's intensity
to plateau or weaken slight during the middle portion of the
forecast period. By days 4 and 5, increasing southwesterly shear
is likely to cause weakening, however Lee's wind field is expected
to expand by that time, and Lee is forecast to remain a strong
hurricane through most of this week.

Lee is moving west-northwestward or 300 at 7 kt. Lee's is expected
to move slowly northwestward during the next couple of days as its
forward progress is impeded by a high pressure ridge located to the
northwest of the storm. By Wednesday, a mid-latitude trough moving
across the Great Lakes region and into the northeastern United
States should weaken the ridge and allow Lee to turn northward. The
ECMWF model has trended faster with the northward progression of Lee
late in the period and there is a little less spread in the guidance
at day 5. The updated NHC track forecast is very similar the
previous track, but has trended a bit faster later in the period.
Users should be reminded to not focus on the exact forecast track,
especially at the longer range, as the average day 4 and 5 track
errors are about 145 and 200 miles, respectively.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, and
Bermuda through much of this week.

2. Lee could bring wind, rainfall, and high surf impacts to
Bermuda later this week. Although it is too soon to determine the
specific timing and level of those impacts, interests on Bermuda
should monitor the latest forecasts for Lee.

3. It remains too soon to know what level of impacts, if any,
Lee might have along the U.S. East Coast and Atlantic Canada late
this week, especially since the hurricane is expected to slow
down considerably over the southwestern Atlantic. Regardless,
dangerous surf and rip currents are expected along most of the U.S.
East Coast this week as Lee grows in size. Users should continue to
monitor updates to the forecast of Lee during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 10/2100Z 22.1N 61.7W 105 KT 120 MPH
12H 11/0600Z 22.7N 62.7W 115 KT 130 MPH
24H 11/1800Z 23.3N 63.9W 120 KT 140 MPH
36H 12/0600Z 23.8N 65.1W 120 KT 140 MPH
48H 12/1800Z 24.2N 66.2W 115 KT 130 MPH
60H 13/0600Z 24.7N 67.0W 105 KT 120 MPH
72H 13/1800Z 25.6N 67.6W 100 KT 115 MPH
96H 14/1800Z 28.9N 68.0W 90 KT 105 MPH
120H 15/1800Z 33.6N 67.4W 80 KT 90 MPH

$$
Forecaster Brown

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 23
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Sun Sep 10 2023

...LEE GROWING LARGER BUT MAXIMUM SUSTAINED WINDS HAVE NOT YET
INCREASED...
...HAZARDOUS BEACH CONDITIONS EXPECTED TO SPREAD THROUGH THE WESTERN
ATLANTIC DURING THE WEEK...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...22.6N 62.2W
ABOUT 310 MI...500 KM N OF THE NORTHERN LEEWARD ISLANDS
ABOUT 690 MI...1110 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.06 INCHES


Hurricane Lee Discussion Number 23
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Sun Sep 10 2023

There has been a wealth of data to dig though this evening for
Hurricane Lee. Observations from both satellite imagery and this
evening's NOAA-P3 mission indicate the hurricane has become more
symmetric in both its convective pattern and wind field. On
satellite, Lee has once again become more impressive with a warming
eye surrounded by cold -65 to -75C eyewall cloud tops. In response,
the subjective Dvorak estimates have been increasing, both T6.0/115
kt from TAFB and SAB. In addition, a single closed eyewall of 25 n
mi in diameter was reported by the NOAA aircraft, which has also
been observed by the TDR data and an earlier 2151 UTC SSMIS
microwave pass. The surface pressure has also been dropping, with
the most recent dropsonde in the eye reporting 950 mb. However, the
winds have yet to respond to the decreasing pressure, with peak
flight-level winds of 108 kt, SFMR at 103 kt, and surface reduced
TDR data also in the 100-105 kt range. All of the in-situ aircraft
data supports maintaining an initial intensity of 105 kt this
advisory. A Synthetic Aperture Radar (SAR) pass valid at 2213 UTC
also showed a 105-kt peak wind, but with expanding 64-kt wind radii,
which might explain why the winds have yet to respond to the
pressure drop.

Track-wise, Lee continues to move west-northwestward, at 305/6 kt.
This motion is expected to generally continue with a further
slowdown in the forward motion now that the mid-level ridging
influencing the storms steering has shifted more northwest in front
of the hurricane. However, this ridge is expected to then become
eroded by an approaching deep-layer trough, allowing Lee to turn
northward into the weakness produced by the trough. The track
guidance this cycle is in fairly good agreement over the next 5
days, with the largest details still related to the forward motion
of Lee after it turns northward. The NHC track forecast is pretty
much on top of the prior one, continuing to favor the consensus
aids, and is roughly in between the leftward GFS and rightward
ECMWF model solutions. Users should be reminded to not focus on the
exact forecast track, especially given Lee's forecast size at the
longer range, and the average day 4 and 5 track errors are about
145 and 200 miles, respectively.

Data from an earlier NOAA G-IV mission sampling the environment
around Lee indicated that the vertical wind shear that had been
affecting the hurricane has mostly subsided, with the dropsonde data
showing well-established outflow to the north, and a deep-layer of
cyclonic flow to the south associated with Lee's broad and deep
circulation. While it is difficult to predict the inner-core changes
associated with the cyclone, most of the intensity guidance still
suggests Lee will intensify further over the next day or so, with a
120-kt peak predicted in 24 hours. Afterwards, as Lee continues to
slow down, it may then begin to encounter its own cold wake due to
its expanding wind field, and the hurricane is expected to begin
gradually weakening. This weakening should be hastened by increasing
southwesterly vertical wind shear after 72 h as the storm also
traverses already cooled sea-surface temperatures by Franklin and
Idalia last week. However, the model guidance also shows Lee's 34-kt
and 50-kt wind field continuing to expand through the forecast
period even as the hurricane gradually weakens.

KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, and
Bermuda through much of this week.

2. Lee could bring wind, rainfall, and high surf impacts to
Bermuda later this week. Although it is too soon to determine the
specific timing and level of those impacts, interests on Bermuda
should monitor the latest forecasts for Lee.

3. It remains too soon to know what level of impacts, if any,
Lee might have along the U.S. East Coast and Atlantic Canada late
this week, especially since the hurricane is expected to slow
down considerably over the southwestern Atlantic. Regardless,
dangerous surf and rip currents are expected along most of the U.S.
East Coast this week as Lee grows in size. Users should continue to
monitor updates to the forecast of Lee during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0300Z 22.6N 62.2W 105 KT 120 MPH
12H 11/1200Z 23.1N 63.1W 115 KT 130 MPH
24H 12/0000Z 23.6N 64.4W 120 KT 140 MPH
36H 12/1200Z 24.1N 65.5W 115 KT 130 MPH
48H 13/0000Z 24.6N 66.4W 110 KT 125 MPH
60H 13/1200Z 25.3N 67.2W 100 KT 115 MPH
72H 14/0000Z 26.5N 67.7W 95 KT 110 MPH
96H 15/0000Z 30.2N 67.9W 85 KT 100 MPH
120H 16/0000Z 35.5N 67.0W 70 KT 80 MPH

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 24
NWS National Hurricane Center Miami FL AL132023
500 AM AST Mon Sep 11 2023

...LARGE LEE REMAINS A MAJOR HURRICANE...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC DURING THE WEEK...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...23.1N 62.6W
ABOUT 340 MI...545 KM N OF THE NORTHERN LEEWARD ISLANDS
ABOUT 650 MI...1045 KM SSE OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...950 MB...28.06 INCHES



TCDAT3

Hurricane Lee Discussion Number 24
NWS National Hurricane Center Miami FL AL132023
500 AM AST Mon Sep 11 2023

The eye of the hurricane became more ragged and less distinct
overnight, but in recent satellite images there appears to be some
warming near the center once again. A 0619 UTC AMSR2 microwave pass
showed the eyewall was open to the south, but a new convective burst
is currently wrapping around the western portion of the eyewall. The
latest objective and subjective satellite intensity estimates have
leveled off due to recent fluctuations in the structure of the
hurricane. The initial intensity is held at 105 kt, which is
consistent with the earlier aircraft data. This intensity also lies
between the latest subjective Dvorak data-T and current intensity
estimates from TAFB and SAB that range from 90-115 kt.

Lee is moving slowly northwestward (310/6 kt) while being steered by
a mid-level ridge over the western and central subtropical Atlantic.
A slow west-northwestward to northwestward motion should continue
for the next day or two before a deep-layer trough moves across the
eastern U.S. and begins eroding the steering ridge by midweek. This
should allow Lee to gradually turn northward by 72 h. The guidance
is in good agreement through midweek with little cross-track spread
noted, and the updated NHC forecast lies just a bit right of the
previous prediction. This takes the core of Lee to the west of
Bermuda, although its expanding tropical-storm-force wind field
could bring some impacts to the island during the latter part of the
week. On days 4-5, Lee should continue moving generally northward
with a ridge positioned to its east. For this portion of the
forecast, the NHC prediction was adjusted slightly west, keeping the
forecast track near the center of the guidance envelope and in best
agreement with the TVCA simple consensus aid.

In the near term, very warm SSTs of 29-30C and weaker deep-layer
shear appear conducive for at least modest strengthening of the
hurricane, although inner-core structural changes and bouts of dry
air entrainment could cause some short-term intensity fluctuations.
Most of the intensity models support an intensity peak within the
next day or so, and this is reflected in the latest NHC forecast.
Thereafter, the large wind field and slow motion of Lee could cause
upwelling of cooler waters. In addition, the hurricane is likely to
encounter increasing southwesterly shear from the aforementioned
trough later in the period, as well as the cool wake left behind by
recent western Atlantic hurricanes (Idalia and Franklin). All of
these factors point toward weakening later this week, and the NHC
forecast follows the IVCN and HCCA trends with gradual weakening
beyond 48 h. Although the peak winds are forecast to decrease, the
outer wind field is expected to expand as the hurricane interacts
with the upper trough and gains latitude over the western Atlantic,
with strong winds extending far from the center of the cyclone.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas, and
Bermuda through much of the week.

2. Lee could bring wind, rainfall, and high surf impacts to
Bermuda later this week. Although it is too soon to determine the
specific timing and level of those impacts, interests on Bermuda
should monitor the latest forecasts for Lee.

3. It remains too soon to know what level of impacts, if any,
Lee might have along the U.S. East Coast and Atlantic Canada late
this week, especially since the hurricane is expected to slow
down considerably over the southwestern Atlantic. Regardless,
dangerous surf and rip currents are expected along most of the U.S.
East Coast this week as Lee grows in size. Users should continue to
monitor updates to the forecast of Lee during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 11/0900Z 23.1N 62.6W 105 KT 120 MPH
12H 11/1800Z 23.5N 63.5W 115 KT 130 MPH
24H 12/0600Z 24.0N 64.8W 115 KT 130 MPH
36H 12/1800Z 24.5N 65.8W 115 KT 130 MPH
48H 13/0600Z 25.1N 66.7W 110 KT 125 MPH
60H 13/1800Z 26.1N 67.3W 100 KT 115 MPH
72H 14/0600Z 27.6N 67.6W 95 KT 110 MPH
96H 15/0600Z 31.8N 67.6W 85 KT 100 MPH
120H 16/0600Z 37.5N 67.0W 70 KT 80 MPH

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 25
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Mon Sep 11 2023

...NOAA HURRICANE HUNTERS INDICATE THAT LEE REMAINS A MAJOR
HURRICANE...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.5N 63.5W
ABOUT 365 MI...590 KM N OF THE NORTHERN LEEWARD ISLANDS
ABOUT 615 MI...985 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...120 MPH...195 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES





Hurricane Lee Discussion Number 25
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Mon Sep 11 2023

Lee has been holding steady in strength this morning. The NOAA
Hurricane Hunters have been investigating Lee and found that the
minimum pressure was around 948 mb while a combination of the
measured flight-level and SFMR winds support holding the initial
intensity at 105 kt. The aircraft data have also shown a clear
indication of concentric eyewalls, which will likely cause
fluctuations, both up and down, in Lee's intensity over the next day
or two.

The major hurricane is moving slowly toward the northwest at about
7 kt. A continued slow motion between west-northwest and northwest
is expected during the next couple of days as Lee continues to be
steered by a mid-level high to its north-northeast. Around the
middle of the week, the ridge is expected to shift eastward as a
mid- to upper-level trough amplifies over the eastern U.S. This
pattern change should cause Lee to turn northward with an increase
in forward speed. The models have generally changed little this
cycle, and only small changes were made to the previous NHC track
forecast. Lee is likely to pass near, but to the west of Bermuda,
late Thursday and Friday and be situated offshore of the
mid-Atlantic states and New England by the end of the forecast
period.

As mentioned above, fluctuations in strength are likely in the
short term due to eyewall replacement cycles, but there is an
opportunity for some strengthening during that time since the
system is expected to remain over very warm waters and in
relatively low wind shear conditions. Beyond a couple of days,
however, progressively cooler waters and a notable increase in
shear should cause Lee to gradually weaken. Although the weakening
is forecast later in the week, Lee is expected to significantly
increase in size and hazards will extend well away from the center
of the storm by the end of the forecast period.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Lee could bring strong winds, rainfall, and high surf impacts to
Bermuda later this week. Interests there should monitor the latest
forecasts.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeast U.S. coast and Atlantic Canada late
this week and this weekend, however, wind and rainfall hazards will
likely extend well away from the center as Lee grows in size. Users
should continue to monitor updates to the forecast of Lee during the
next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 11/1500Z 23.5N 63.5W 105 KT 120 MPH
12H 12/0000Z 23.9N 64.4W 110 KT 125 MPH
24H 12/1200Z 24.4N 65.5W 115 KT 130 MPH
36H 13/0000Z 24.9N 66.5W 110 KT 125 MPH
48H 13/1200Z 25.7N 67.2W 100 KT 115 MPH
60H 14/0000Z 27.0N 67.7W 95 KT 110 MPH
72H 14/1200Z 28.8N 68.0W 90 KT 105 MPH
96H 15/1200Z 33.1N 67.6W 80 KT 90 MPH
120H 16/1200Z 38.9N 67.1W 70 KT 80 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 26
NWS National Hurricane Center Miami FL AL132023
500 PM AST Mon Sep 11 2023

...LEE REMAINS A SLOW MOVING MAJOR HURRICANE...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...23.6N 64.2W
ABOUT 380 MI...610 KM N OF THE NORTHERN LEEWARD ISLANDS
ABOUT 600 MI...970 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES




Hurricane Lee Discussion Number 26
NWS National Hurricane Center Miami FL AL132023
500 PM AST Mon Sep 11 2023

Lee continues to exhibit a double eyewall structure as reported by
the Air Force Hurricane Hunters and seen in recent microwave images.
The inner eyewall is open on the south side, but the outer eyewall
is completely closed and has contracted slightly from the earlier
NOAA P-3 aircraft mission. The minimum pressure is the same as
before, 948 mb, but the initial wind speed is nudged downward to 100
kt based on the aircraft data.

The major hurricane has jogged a little to the left recently, and
the initial motion is estimated to be 290/7 kt. The models are
similar to the previous runs, and no big changes were made to the
NHC track forecast. A continued slow motion between west-northwest
and northwest is expected during the next couple of days as Lee
remains steered by a mid-level high to its north-northeast. Beyond a
couple of days, the ridge is expected to shift eastward as a mid- to
upper-level trough amplifies over the eastern U.S. This pattern
change should cause Lee to turn northward with an increase in
forward speed. Lee is likely to pass near, but to the west of
Bermuda, late Thursday and Friday and then be situated offshore of
the mid-Atlantic states and New England late Friday and Saturday.

Given the current concentric eyewall structure, it seems likely that
Lee will fluctuate in strength in the short term. However, since
the hurricane will remain in generally conducive conditions during
the next couple of days, it could restrengthen if the eyewall cycle
completes. Lee is likely to move over a cool SST wake left behind
by Hurricanes Idalia and Franklin later this week, and cross over
the north wall of the Gulf Stream by the end of the forecast period.
The combination of cooler SSTs, an increase in shear, and dry air
entrainment should cause a steady decay in strength late this week
and over the weekend. The NHC intensity forecast is an update of
the previous one and near the middle of the guidance envelope.

Although Lee is expected to weaken later in the week, it is expected
to significantly increase in size and hazards will extend well away
from the storm center by the end of the forecast period.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Lee could bring strong winds, rainfall, and high surf impacts to
Bermuda later this week. Interests there should continue to monitor
updates to the forecast of Lee during the next several days.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeast U.S. coast and Atlantic Canada late
this week and this weekend. However, wind and rainfall hazards will
likely extend well away from the center as Lee grows in size. Users
should continue to monitor updates to the forecast of Lee during the
next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 23.6N 64.2W 100 KT 115 MPH
12H 12/0600Z 24.0N 65.1W 105 KT 120 MPH
24H 12/1800Z 24.6N 66.1W 105 KT 120 MPH
36H 13/0600Z 25.3N 66.9W 100 KT 115 MPH
48H 13/1800Z 26.5N 67.5W 100 KT 115 MPH
60H 14/0600Z 28.3N 67.8W 95 KT 110 MPH
72H 14/1800Z 30.3N 67.9W 90 KT 105 MPH
96H 15/1800Z 35.4N 67.1W 80 KT 90 MPH
120H 16/1800Z 40.8N 67.0W 65 KT 75 MPH

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 27
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Mon Sep 11 2023

...LEE IS A LARGE MAJOR HURRICANE EXPECTED TO SLOWLY TURN
NORTHWARD LATER THIS WEEK...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...23.9N 64.8W
ABOUT 410 MI...655 KM NNW OF THE NORTHERN LEEWARD ISLANDS
ABOUT 580 MI...935 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 295 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES


Hurricane Lee Discussion Number 27
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Mon Sep 11 2023

This evening, Lee appears to be in the final stages of completing
another eyewall replacement cycle (ERC). A GPM microwave pass at
2201 UTC showed that the outer eyewall remains closed and, while it
remains quite large, continues to contract slowly as the inner
eyewall decays within. The initial intensity is held at 100 kt this
advisory, blending the subjective and objective intensity estimates
this evening. Another Air Force Reserve Reconnaissance mission is
scheduled to investigate the storm overnight, and several saildrones
along Lee's path are also likely to provide additional in-situ
observations in the hurricane over the next day or so.

Lee continues to move slowly west-northwestward, with the motion
estimated at 295/6 kt. Lee is expected to continue moving slowly
west-northwest or northwest over the next 24-36 h while mid-level
ridging remains in place centered northwest of the hurricane.
However, the ridge should then become eroded and shift eastward as a
mid- to upper-level trough swings into the northeastern United
States. This pattern change should result in Lee turning northward
and gradually accelerating. The biggest spread in the track
guidance solutions remains in the along-track direction, with the
GFS on the faster end, and ECMWF on the slower end. The NHC track
forecast continues to favor a blend of the simple and corrected
consensus aids, and is very close to the previous forecast track
through 72 h, and is just a touch east of the prior track
thereafter. On this track, Lee is likely to pass near, but west of,
Bermuda late Thursday and Friday and then be situated offshore of
the mid-Atlantic states and New England late Friday and Saturday.

With the pending completion of Lee's ERC, expected over the next
6-12 hours, the NHC intensity forecast continues to show some modest
re-intensification. This seems reasonable given that sea surface
temperatures (SSTs) observed by a saildrone in Lee's south outer
eyewall are still around 29 C. After the next day or so, however,
coupled atmospheric-ocean models suggest the large wind field of Lee
will begin to upwell cooler SSTs, and Lee is still forecast to move
over a cool SST wake left behind by Hurricanes Idalia and Franklin
later this week. In addition, the approaching mid-latitude trough
should also result in an increase in shear, and dry air entrainment,
which should result in more steady weakening later this week and
over the weekend. This trough interaction will also ultimately lead
to Lee transitioning to an extratropical cyclone by the end of the
forecast period as it crosses the north wall of the Gulf Stream. The
NHC intensity forecast is a bit lower than the prior cycle after 72
h but remains close to the consensus intensity aids.

Although Lee is expected to weaken later in the week, it is still
expected to significantly increase in size and hazards will extend
well away from the storm center by the end of the forecast period.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Lee could bring strong winds, rainfall, and high surf impacts to
Bermuda later this week. Interests there should continue to monitor
updates to the forecast of Lee during the next several days.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeast U.S. coast and Atlantic Canada late
this week and this weekend. However, because wind and rainfall
hazards will likely extend well away from the center as Lee grows in
size, users should continue to monitor updates to Lee's forecast
during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0300Z 23.9N 64.8W 100 KT 115 MPH
12H 12/1200Z 24.4N 65.6W 105 KT 120 MPH
24H 13/0000Z 25.0N 66.5W 105 KT 120 MPH
36H 13/1200Z 26.1N 67.2W 100 KT 115 MPH
48H 14/0000Z 27.5N 67.6W 95 KT 110 MPH
60H 14/1200Z 29.4N 67.9W 90 KT 105 MPH
72H 15/0000Z 31.6N 67.8W 80 KT 90 MPH
96H 16/0000Z 37.6N 66.4W 70 KT 80 MPH
120H 17/0000Z 43.0N 66.0W 60 KT 70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 28
NWS National Hurricane Center Miami FL AL132023
500 AM AST Tue Sep 12 2023

...LEE REMAINS A LARGE AND POWERFUL HURRICANE...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...24.0N 65.4W
ABOUT 575 MI...925 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 7 MPH...11 KM/H
MINIMUM CENTRAL PRESSURE...948 MB...28.00 INCHES


WATCHES AND WARNINGS
--------------------
There are no coastal watches or warnings in effect.

Interests in Bermuda should monitor the progress of Lee. Watches
could be required for Bermuda later today.





Hurricane Lee Discussion Number 28
NWS National Hurricane Center Miami FL AL132023
500 AM AST Tue Sep 12 2023

Lee continues to exhibit a concentric eyewall structure in
conventional satellite imagery. This has been confirmed by the Air
Force Reserve Hurricane Hunters that investigated Lee early this
morning, and they reported the outer eyewall had a large diameter of
80 n mi. The maximum 700-mb flight-level wind measured by the
aircraft was 112 kt in the northeast quadrant, while the SFMR winds
peaked around 90 kt. Although the satellite intensity estimates have
fallen a bit this morning, the reduced flight-level winds support
holding the initial intensity at 100 kt for this advisory. The
minimum pressure of Lee remains 948 mb based on dropsonde data.

Lee is still moving slowly west-northwestward (290/6 kt), with
mid-level ridging established to the north and west of the
hurricane. This steering pattern is expected to change during the
next couple of days as a deep-layer trough moves across the eastern
United States and produces a weakness in this ridge. As a result,
Lee is forecast to turn northward and gradually accelerate during
the middle and latter parts of this week. The track guidance
envelope shows little cross-track spread during the first 3 days of
the forecast period, and this portion of the NHC forecast is fairly
similar to the previous one. While the core of the hurricane is
forecast to pass west of Bermuda, the large wind field of the storm
is likely to bring wind impacts to the island later this week, and
tropical storm watches could be required later today. At days 4-5,
there has been a slight westward shift in the guidance envelope, and
accordingly the NHC track forecast was nudged in that direction
toward the HCCA and TVCA aids.

Based on Lee's current satellite structure, as well as its slow
forward motion and large wind field, little near-term strengthening
is expected. Going forward, the large hurricane appears likely to
begin upwelling cooler waters along its path, and in a few days it
will encounter the cool wake left behind by recent western Atlantic
hurricanes. Thus, gradual weakening is forecast through midweek.
Later, the aforementioned trough is expected to produce stronger
deep-layer shear over Lee, and the hurricane is forecast to move
over significantly cooler waters as it passes north of the Gulf
Stream. As a result, more significant weakening is shown at days
4-5, along with completion of its extratropical transition. Despite
the weakening that is forecast, keep in mind that the expanding wind
field of Lee will produce impacts well away from the storm center.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. There is an increasing risk of strong winds, rainfall, and high
surf impacts to Bermuda later this week, and tropical storm watches
could be required for the island later today.

3. It remains too soon to know what level of additional impacts Lee
might have along the Northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 24.0N 65.4W 100 KT 115 MPH
12H 12/1800Z 24.4N 66.2W 100 KT 115 MPH
24H 13/0600Z 25.3N 67.0W 100 KT 115 MPH
36H 13/1800Z 26.6N 67.5W 95 KT 110 MPH
48H 14/0600Z 28.3N 67.9W 90 KT 105 MPH
60H 14/1800Z 30.4N 68.0W 85 KT 100 MPH
72H 15/0600Z 32.9N 67.6W 80 KT 90 MPH
96H 16/0600Z 39.0N 66.7W 70 KT 80 MPH
120H 17/0600Z 44.5N 66.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 29
NWS National Hurricane Center Miami FL AL132023
Issued by the NWS Weather Prediction Center College Park MD
1100 AM AST Tue Sep 12 2023

...TROPICAL STORM WATCH ISSUED FOR BERMUDA...
...HAZARDOUS SURF AND RIP CURRENT CONDITIONS EXPECTED AT BEACHES
ACROSS THE WESTERN ATLANTIC ALL WEEK...


SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...24.3N 65.9W
ABOUT 555 MI...895 KM S OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...WNW OR 300 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...951 MB...28.09 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Bermuda Weather Service has issued a Tropical Storm Watch for
Bermuda.





Hurricane Lee Discussion Number 29
NWS National Hurricane Center Miami FL AL132023
Issued by the NWS Weather Prediction Center College Park MD
1100 AM AST Tue Sep 12 2023

GOES-16 satellite and radar images from the NOAA Hurricane Hunter
indicate that Lee is trying to consolidate into one large eyewall,
but the eye remains obscured with fragments of the old eyewall
structures. Peak 700-mb flight-level winds were about 110 kt, 0.5
km radar estimates were near 121 kt and surface SFMR estimates were
about 90 kt, which could be under sampled with such a large
radius of maximum winds. The initial wind speed is held at 100 kt
as a compromise of the aircraft estimates.

Lee is still moving slowly west-northwestward (300/5 kt), with
mid-level ridging established to the north and east of the
hurricane. This steering pattern is expected to change during the
next couple of days as a deep-layer trough moves across the eastern
United States and produces a weakness in this ridge. As a result,
Lee is forecast to turn northward and gradually accelerate during
the middle and latter parts of this week. The track guidance
envelope shows little cross-track spread during the first 3 days of
the forecast period, and this portion of the NHC forecast is fairly
similar to the previous one. While the core of the hurricane is
forecast to pass west of Bermuda, the large wind field of the storm
is likely to bring wind impacts to the island on Thursday,
prompting the Bermuda Weather Service to issue a Tropical Storm
Watch. The latest NHC track was a compromise between the 6z GEFS
and ECMWF ensembles in the days 4/5 time frame, as it is still too
early to know if any leftward bend will occur as Lee approaches
North America.

No significant change in strength is expected in the near-term with
Lee due to its current structure and large wind field. Going
forward, the large hurricane appears likely to begin upwelling
cooler waters along its path, and in a few days it will encounter
the cool wake left behind by recent western Atlantic hurricanes.
Thus, gradual weakening is forecast through midweek. Later, the
aforementioned trough is expected to produce stronger deep-layer
shear over Lee, and the hurricane is forecast to move over
significantly cooler waters as it passes north of the Gulf Stream.
As a result, more significant weakening is shown at days 4-5, along
with completion of its extratropical transition. Despite the
forecast weakening, it is important to note that the expanding wind
field of Lee will produce impacts well away from the storm center.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. There is an increasing risk of strong winds, rainfall, and high
surf impacts to Bermuda later this week, and a Tropical Storm Watch
has been issued for the island.

3. It remains too soon to know what level of additional impacts Lee
might have along the northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/1500Z 24.3N 65.9W 100 KT 115 MPH
12H 13/0000Z 24.8N 66.6W 100 KT 115 MPH
24H 13/1200Z 25.9N 67.3W 100 KT 115 MPH
36H 14/0000Z 27.4N 67.8W 95 KT 110 MPH
48H 14/1200Z 29.4N 68.2W 90 KT 105 MPH
60H 15/0000Z 31.6N 68.0W 85 KT 100 MPH
72H 15/1200Z 34.3N 67.4W 80 KT 90 MPH
96H 16/1200Z 40.7N 66.6W 65 KT 75 MPH
120H 17/1200Z 45.3N 65.9W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bann/Blake/Gallina

[cycloneye]

Hurricane Lee Discussion Number 30
NWS National Hurricane Center Miami FL AL132023
Issued by the NWS Weather Prediction Center College Park MD
500 PM AST Tue Sep 12 2023

GOES-East satellite and information from an Air Force Reserve
Hurricane Hunter plane indicate a slight recent improvement in the
inner-eye structure with a 5-mb pressure fall noted in the most
recent pass. However, peak 700-mb flight-level winds were lower
than 6 hr ago with SFMR estimates about the same. Given the mixed
signals, we will maintain the initial wind speed at 100 kts for
this advisory. The big change in the aircraft data was the sizable
expansion of the whole wind field in the eastern semicircle
of the hurricane, which was also shown by a late-arriving SAR pass
this morning.

Lee has turned northwestward (315/6 kt) as the mid-level ridging
continues to its north and east. A digging eastern United States
trough remains on track to weaken the ridge during the next few
days. Lee is expected to turn more northward and accelerate by
Thursday as a result of this pattern change. Even though the core
of Lee is expected to be well west of Bermuda, Lee's large wind
field could arrive early Thursday on the island. After day 3,
there is an increase in guidance spread as the hurricane interacts
with an approaching frontal zone, which could cause a small
leftward bend in the track. However, recent guidance has tightened
somewhat, and the official forecast follows a middle-ground
solution similar to the GEFS/ECMWF ensemble means, on the fast side
of the consensus.

The hurricane is expected to gradually weaken over the next few
days while it moves over cooler waters into a higher-shear
environment. Still, all of the guidance keep this system quite
large and at hurricane-strength for the next few days. Once the
circulation reaches the colder water north of the Gulf Stream, more
significant weakening is expected at the day 4-5 period as it
quickly transitions to an extratropical low. Little change was
made to the previous forecast, which is also close to the consensus
aids, and the forward speed north of the Gulf Stream will be
important in the exact wind speed as Lee approaches the mainland.

Note- The 34- and 50-kt wind speed probabilities beyond 36 hours in
the text product and graphics are likely underestimating the risk
of those winds occurring. This is because the forecast wind field
of Lee is considerably larger than average compared to the wind
field used to derive the wind speed probability product.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. There is an increasing risk of strong winds, rainfall, and high
surf impacts to Bermuda later this week, and a Tropical Storm Watch
remains in effect for the island.

3. It remains too soon to know what level of additional impacts Lee
might have along the northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 12/2100Z 24.7N 66.4W 100 KT 115 MPH
12H 13/0600Z 25.4N 67.0W 100 KT 115 MPH
24H 13/1800Z 26.7N 67.6W 95 KT 110 MPH
36H 14/0600Z 28.6N 68.1W 90 KT 105 MPH
48H 14/1800Z 30.7N 68.2W 85 KT 100 MPH
60H 15/0600Z 33.4N 67.6W 80 KT 90 MPH
72H 15/1800Z 36.4N 66.8W 75 KT 85 MPH
96H 16/1800Z 42.8N 66.5W 65 KT 75 MPH
120H 17/1800Z 47.1N 64.5W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Gallina/Blake/Bann

[cycloneye]

Hurricane Lee Discussion Number 31
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Tue Sep 12 2023

Geostationary satellite images show that Lee has a large eye about
40 n mi in diameter surrounded by very cold-topped central
convection. There are numerous convective banding features,
especially over the northern portion of the circulation. The
cirrus-level outflow pattern is fairly symmetric at this time,
suggesting that the vertical wind shear over the system is still
low. The intensity estimate is held at 100 kt for this advisory,
which is a blend of subjective and objective satellite estimates
from TAFB, SAB, and UW/CIMSS. The objective intensity estimates
are generally a little higher than the subjective values.

Lee continues to move on a generally northwestward heading, with a
motion estimate of 320/6 kt, on the southwestern side of a
mid-level anticyclone. Over the next couple of days, a 500-mb
trough moving through the eastern United States should induce a
northward turn with some increase in forward speed. Even though
the predicted track has the center of the hurricane passing well to
the west of Bermuda, Lee's very large wind field should result in
tropical storm conditions spreading over the island by late
Wednesday or early Thursday. In the 3 to 4 day time frame, the
model guidance suggests just a slight leftward bend in the track
while Lee interacts with the trough. There has been little change
to the NHC forecast track, which remains close to the corrected and
simple model consensus predictions. After 96 hours, Lee should
turn northeastward and east-northeastward in the mid-latitude
westerlies.

Gradual weakening is anticipated during the next few days days
while Lee moves over cooler waters and encounters high vertical
wind shear. However the system is likely to remain a large and
dangerous hurricane while it approaches the coast. If Lee moves
faster than forecast over the colder waters north of the Gulf
Stream, it will likely retain more of its strength when it reaches
land. Around 96 hours, simulated satellite imagery from the global
models show the appearance of an extratropical cyclone with
decreased convection and an asymmetric cloud pattern.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text product and graphics are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning Wednesday night or early
Thursday, and a Tropical Storm Warning has been issued for the
island.

3. It remains too soon to know what level of additional impacts Lee
might have along the northeastern U.S. coast and Atlantic Canada
late this week and this weekend. However, since wind and rainfall
hazards will extend well away from the center as Lee grows in size,
users should continue to monitor updates to Lee's forecast during
the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 13/0300Z 25.3N 66.7W 100 KT 115 MPH
12H 13/1200Z 26.1N 67.2W 100 KT 115 MPH
24H 14/0000Z 27.7N 67.8W 95 KT 110 MPH
36H 14/1200Z 29.7N 68.2W 90 KT 105 MPH
48H 15/0000Z 32.1N 67.9W 80 KT 90 MPH
60H 15/1200Z 35.0N 67.1W 75 KT 85 MPH
72H 16/0000Z 38.0N 66.6W 75 KT 85 MPH
96H 17/0000Z 44.0N 66.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
120H 18/0000Z 48.5N 62.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch




Hurricane Lee Discussion Number 32
NWS National Hurricane Center Miami FL AL132023
500 AM AST Wed Sep 13 2023

Lee's structure is very gradually declining in organization. The
hurricane has a ragged but somewhat elliptical 25-30 n mi wide eye,
but deep convection has become eroded a bit within the western
semicircle, possibly due to some moderate westerly shear. In
addition, a 0607 UTC AMSR-2 microwave pass showed that the eyewall
was open on the southwest side at that time. Subjective and
objective satellite estimates range from 90-105 kt, so Lee's
initial intensity remains 100 kt for now.

The hurricane is very slowly making its turn around a west-central
Atlantic mid-level high, with its motion now northwestward at
325/5 kt. The track guidance is tightly clustered during the next
2 days or so, showing Lee turning and accelerating toward the
north-northwest and north between the high and a shortwave trough
swinging across the Great Lakes region. Lee's core is forecast to
pass west of Bermuda in 36-48 hours, but tropical storm conditions
are likely to begin there late tonight or early Thursday due to the
hurricane's large wind field. On days 3 and 4, Lee is expected to
maintain a general northward track offshore the northeastern U.S.
However, the global models are suggesting that the hurricane
will interact with a remnant mid-level trough over the mid-Atlantic
states, causing Lee to possibly bend just west of due north while
it moves across the Gulf of Maine. Under the assumption that the
global models will have a better handle on this mid-latitude
pattern as compared to the regional hurricane models, the NHC track
forecast is close to a consensus of the GFS and ECMWF models (GFEX)
on days 3, 4, and 5, and therefore ends up being a bit west and
then north of the previous prediction on those days.

A number of factors--including Lee's broad structure, increasing
shear, and potential upwelling of cooler waters--are likely to lead
to a very gradual decrease in the hurricane's maximum winds during
the next 3 days or so. In addition, Lee is likely to begin
extratropical transition in 2-3 days, with that process expected to
be complete just before the cyclone's center reaches the coast of
Maine, New Brunswick, or Nova Scotia in about 4 days. That said,
Lee's expected post-tropical transition will not diminish potential
wind, rain, and coastal flooding impacts in New England and Atlantic
Canada due to the system's broad wind field.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text and graphical products are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, and most of the U.S East Coast through much of the week.

2. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning late tonight or early Thursday,
and a Tropical Storm Warning is in effect for the island.

3. There is an increasing risk of wind, coastal flooding, and rain
impacts from Lee in portions of New England and Atlantic Canada
beginning on Friday and continuing through the weekend. Watches may
be required for portions of these areas later today or tonight.
Due to Lee's large size, hazards will extend well away from the
center, and there will be little to no significance on exactly where
the center reaches the coast.


FORECAST POSITIONS AND MAX WINDS

INIT 13/0900Z 25.7N 67.1W 100 KT 115 MPH
12H 13/1800Z 26.6N 67.6W 95 KT 110 MPH
24H 14/0600Z 28.4N 68.1W 90 KT 105 MPH
36H 14/1800Z 30.5N 68.3W 85 KT 100 MPH
48H 15/0600Z 33.0N 68.0W 80 KT 90 MPH
60H 15/1800Z 36.1N 67.4W 75 KT 85 MPH
72H 16/0600Z 39.6N 67.3W 70 KT 80 MPH
96H 17/0600Z 45.2N 67.3W 50 KT 60 MPH...POST-TROP/INLAND
120H 18/0600Z 51.0N 61.4W 35 KT 40 MPH...POST-TROP/INLAND

$$
Forecaster Berg







Hurricane Lee Discussion Number 33
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Wed Sep 13 2023

Lee continues to exhibit concentric eyewalls, but there are some dry
slots between those features. An SSMIS microwave image around 10Z
showed that both eyewalls were open, however, recent infrared
satellite images indicate that the inner eyewall appears to be
becoming better organized during the past few hours. The initial
wind speed is held at 100 kt, but this is near the high end of the
latest satellite intensity estimates. The Air Force Hurricane
Hunters are scheduled to investigate Lee this afternoon, and the
data they collect should provide a better assessment of the
hurricane's intensity and structure.

Satellite images suggest that Lee seems to be beginning its
northward turn on the western side of a subtropical ridge situated
over the central Atlantic. The latest initial motion estimate is
345/6 kt. Lee should gradually increase in forward speed while
moving northward on the west side of the ridge during the next
couple of days, taking the core of the system to the west of Bermuda
Thursday and Thursday night. The combination of a shortwave trough
and a building ridge extending into Atlantic Canada could cause Lee
to turn slightly to the left Friday night and Saturday, which will
likely bring Lee close to southeastern New England before it reaches
Maine and Atlantic Canada later in the weekend. Confidence is
increasing in the forecast track, and the model spread is mostly
along-track, associated with the system's forward speed/timing.
Overall, little change was made to the previous NHC track forecast,
and it remains very near the various consensus models.

Lee is expected to gradually weaken as it moves into an environment
of increasing vertical wind shear, slightly drier air, and over
progressively cooler waters during the next few days. However, the
large size of the system suggests that the weakening process should
be slow. In addition, Lee is expected to grow in size as it gains
latitude during the next few days. The NHC intensity forecast is
largely the same as the previous one and fairly close to the HCCA
and IVCN models. Regardless of the details, there is high
confidence that Lee will be a large hurricane near the coast of New
England Friday night and Saturday.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text and graphical products are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Dangerous surf and life-threatening rip currents will affect
portions of the northern Leeward Islands, the Virgin Islands, Puerto
Rico, Hispaniola, the Turks and Caicos Islands, the Bahamas,
Bermuda, the U.S East Coast, and Atlantic Canada into the weekend.

2. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning early Thursday, and a Tropical
Storm Warning is in effect for the island.

3. There is an increasing risk of wind, coastal flooding, and rain
impacts from Lee in portions of New England and Atlantic Canada
beginning on Friday and continuing through the weekend. Watches
will likely required for portions of these areas later today or
tonight. Due to Lee's large size, hazards will extend well away
from the center, and there will be little to no significance on
exactly where the center reaches the coast.


FORECAST POSITIONS AND MAX WINDS

INIT 13/1500Z 26.4N 67.2W 100 KT 115 MPH
12H 14/0000Z 27.6N 67.7W 95 KT 110 MPH
24H 14/1200Z 29.6N 68.2W 90 KT 105 MPH
36H 15/0000Z 31.8N 68.2W 85 KT 100 MPH
48H 15/1200Z 34.6N 67.6W 80 KT 90 MPH
60H 16/0000Z 37.9N 67.1W 75 KT 85 MPH
72H 16/1200Z 41.1N 67.2W 70 KT 80 MPH
96H 17/1200Z 46.1N 66.6W 50 KT 60 MPH...POST-TROP/INLAND
120H 18/1200Z 52.1N 56.4W 35 KT 40 MPH...POST-TROP/INLAND

$$
Forecaster Cangialosi




Hurricane Lee Discussion Number 34
NWS National Hurricane Center Miami FL AL132023
500 PM AST Wed Sep 13 2023

The Air Force Hurricane Hunters investigated Lee earlier this
afternoon and found that the hurricane has lost some strength. The
initial intensity is lowered to 90 kt based on the aircraft data.
Although the core winds have decreased some, the wind field has
become quite expansive, with the hurricane-force winds now extending
roughly 100 n mi away from the center. The satellite appearance of
Lee has been relatively steady state through the day and there is
still evidence of concentric eyewalls.

Lee's forward speed is beginning to increase, and it is now moving
north-northwestward at 9 kt. A progressively faster motion to the
north on the west side of a subtropical ridge is forecast during the
next couple of days, taking the core of the system to the west of
Bermuda Thursday and Thursday night. The combination of a shortwave
trough over the Mid-Atlantic States and a building ridge extending
into Atlantic Canada should cause Lee to turn slightly to the left
Friday night and Saturday, which will likely bring Lee close to
southeastern New England before it moves near or over Maine and
Atlantic Canada later in the weekend. The GFS and ECMWF models
have converged, and are now near the previous NHC track forecast.
The new NHC track forecast is again just an update of the previous
one and near the various consensus models.

The environment ahead of Lee is expected to gradually become less
conducive for the hurricane as it moves into a region of higher
wind shear, drier air, and over progressively cooler SSTs. These
conditions favor weakening, but since the system is so large the
weakening process should be slow. The NHC intensity forecast is a
little lower than the previous one, in part due to the initial lower
wind speed, and remains near the HCCA and IVCN guidance.
Regardless of the details, there is high confidence that Lee will be
a large hurricane near the coast of New England Friday night and
Saturday.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text and graphical products are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning early Thursday, and a Tropical
Storm Warning is in effect for the island.

2. Hurricane conditions, heavy rainfall, and coastal flooding are
possible in portions of eastern Maine on Saturday, and a Hurricane
Watch has been issued for that area.

3. There is the potential for life-threatening storm surge flooding
in portions of southeastern Massachusetts, including Cape Cod and
Nantucket, late Friday and Saturday, where a Storm Surge Watch has
been issued.

4. Tropical storm conditions are possible over a large portion of
coastal New England, including Cape Cod, Nantucket, Martha's
Vineyard, and Block Island, where a Tropical Storm Watch has been
issued.


FORECAST POSITIONS AND MAX WINDS

INIT 13/2100Z 27.4N 67.6W 90 KT 105 MPH
12H 14/0600Z 28.7N 68.1W 90 KT 105 MPH
24H 14/1800Z 30.9N 68.2W 85 KT 100 MPH
36H 15/0600Z 33.4N 67.8W 80 KT 90 MPH
48H 15/1800Z 36.4N 67.2W 75 KT 85 MPH
60H 16/0600Z 39.7N 66.9W 70 KT 80 MPH
72H 16/1800Z 42.6N 66.9W 65 KT 75 MPH
96H 17/1800Z 47.7N 63.8W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 18/1800Z 52.3N 52.1W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Cangialosi


Hurricane Lee Discussion Number 35
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Wed Sep 13 2023

Both NOAA and Air Force Reserve Unit Hurricane Hunter aircraft have
been investigating Lee this evening. They found that the central
pressure has not changed much since earlier today, and that the
hurricane still had concentric eyewalls, but these were partially
open over portions of the western quadrant. The Air Force
plane measured 700 mb flight-level winds as high as 105 kt and
the NOAA plane found winds as high as 107 kt at a flight level of
8000 ft. Tail Doppler radar velocities from the NOAA plane were
near 100 kt at elevations of 0.5 km. These observations support
maintaining the intensity at 90 kt for this advisory. Satellite
imagery also suggests that the eyewall is not fully closed but
there is fairly intense inner-core convection.

There has been a (likely temporary) decrease in forward speed and
the initial motion is just west of due north or 350/8 kt. The
steering scenario for the hurricane is essentially unchanged from
the previous few advisories. A 500-mb trough moving into the
northeastern U.S. and a mid-level ridge near eastern Atlantic
Canada should cause Lee to move generally northward at a faster
forward speed during the next couple of days. A slight bend to the
left is likely around 48 hours while the tropical cyclone interacts
with the trough. This will likely bring the center of Lee close to
southeastern New England late Friday before it moves near or over
Maine and Atlantic Canada later in the weekend. The official track
forecast is similar to the previous one and closely follows both the
simple and corrected dynamical consensus guidance.

Over the next couple of days, Lee will encounter significantly
increasing vertical wind shear and somewhat drier mid- to low-level
air. Sea surface temperatures along the projected track decrease
sharply north of around 40N latitude. These conditions should cause
weakening, but since the hurricane has such a large circulation, the
weakening will likely be slow. The NHC intensity forecast is near
or above the highest available model guidance. Notwithstanding,
there is still high confidence that Lee will be a large and
dangerous cyclone when it moves near or over land on Saturday.

It should again be noted that the 34- and 50-kt wind speed
probabilities beyond 36 hours in the text and graphical products are
likely underestimating the risk of those winds occurring. This is
because the forecast wind field of Lee is considerably larger than
average compared to the wind field used to derive the wind speed
probability product.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf are
expected to impact Bermuda beginning early Thursday, and a Tropical
Storm Warning is in effect for the island.

2. Hurricane conditions and coastal flooding are possible in
portions of eastern Maine, southern New Brunswick, and western Nova
Scotia on Saturday, and a Hurricane Watch has been issued for that
area. Heavy rainfall in these areas may produce localized urban
and small stream flooding from Friday night into Saturday night.

3. There is the potential for life-threatening storm surge flooding
in portions of southeastern Massachusetts, including Cape Cod and
Nantucket, late Friday and Saturday, where a Storm Surge Watch has
been issued.

4. Tropical storm conditions are possible over a large portion of
coastal New England, including Cape Cod, Nantucket, Martha's
Vineyard, Block Island, and portions of Atlantic Canada, where a
Tropical Storm Watch has been issued.


FORECAST POSITIONS AND MAX WINDS

INIT 14/0300Z 28.0N 67.7W 90 KT 105 MPH
12H 14/1200Z 29.6N 68.1W 90 KT 105 MPH
24H 15/0000Z 31.9N 68.0W 85 KT 100 MPH
36H 15/1200Z 34.8N 67.2W 80 KT 90 MPH
48H 16/0000Z 37.7N 66.5W 75 KT 85 MPH
60H 16/1200Z 41.0N 66.7W 65 KT 75 MPH
72H 17/0000Z 44.0N 66.3W 60 KT 70 MPH
96H 18/0000Z 49.4N 60.9W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 19/0000Z 53.7N 50.0W 35 KT 40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Pasch



Hurricane Lee Discussion Number 36
NWS National Hurricane Center Miami FL AL132023
500 AM AST Thu Sep 14 2023

Lee's satellite presentation has been a little deceiving early this
morning, as earlier reconnaissance flight-level and dropsonde
surface wind data indicated that the hurricane's center was located
about 15-20 n mi to the west of the satellite eye feature. On the
last couple of passes of the Air Force Reserve C-130 through the
center, the highest 700-mb wind measured was 95 kt, and peak SFMR
readings from both the Air Force and NOAA were 70-75 kt. Accounting
for some undersampling, Lee's initial intensity is reduced slightly
to 85 kt.

The initial motion remains 350/8 kt. A faster northward motion,
with some wobbles, is expected during the next 2-3 days as Lee
moves between a mid-tropospheric high over the west-central Atlantic
and a deep-layer trough over the eastern United States. As noted
in earlier forecasts, a slight bend to the west toward the Gulf
of Maine is likely in 48-60 hours when Lee interacts with the tail
end of the trough over the Mid-Atlantic states. A turn toward the
north-northeast and then northeast is forecast on days 3 and 4,
bringing Lee's center across Atlantic Canada. The NHC track
forecast is nearly on top of the previous forecast, largely due to
consistent and tightly clustered model guidance.

The latest shear analyses suggest that moderate southwesterly shear
has begun to affect Lee, and this is confirmed by the offset of
the aircraft fixes relative to the satellite eye feature. The
shear is forecast to increase further in 24-36 hours, which will
cause Lee to ingest drier and more stable air into its circulation.
In addition, sea surface temperatures along Lee's future path drop
off significantly after 36 hours. Therefore, continued gradual
weakening is forecast, and the NHC intensity forecast is at or
slightly above the intensity consensus aids for much of the
forecast period. Extratropical transition is likely to begin on
Friday as Lee interacts with a frontal boundary moving off the east
coast of the United States, and a good chunk of the guidance
suggests the transition could be complete by 60 hours. In order to
maintain continuity with the previous forecast, Lee is now shown to
be a fully post-tropical cyclone by 72 hours. Regardless of its
designation, Lee will remain a large and dangerous cyclone while it
approaches eastern New England and Atlantic Canada into the weekend.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf are
beginning to impact Bermuda, and a Tropical Storm Warning is in
effect for the island.

2. Hurricane conditions and coastal flooding are possible in
portions of eastern Maine, southern New Brunswick, and western Nova
Scotia on Saturday, and a Hurricane Watch is in effect for that
area. Heavy rainfall in these areas may produce localized urban
and small stream flooding from Friday night into Saturday night.
Tropical storm conditions are possible elsewhere across New England
and Atlantic Canada within the Tropical Storm Watch areas.

3. There is the potential for life-threatening storm surge flooding
in portions of southeastern Massachusetts, including Cape Cod and
Nantucket, late Friday and Saturday, where a Storm Surge Watch is
in effect.


FORECAST POSITIONS AND MAX WINDS

INIT 14/0900Z 29.1N 68.1W 85 KT 100 MPH
12H 14/1800Z 30.7N 68.2W 80 KT 90 MPH
24H 15/0600Z 33.3N 67.7W 80 KT 90 MPH
36H 15/1800Z 36.3N 66.9W 75 KT 85 MPH
48H 16/0600Z 39.5N 66.6W 70 KT 80 MPH
60H 16/1800Z 42.5N 66.7W 60 KT 70 MPH
72H 17/0600Z 45.2N 65.4W 50 KT 60 MPH...POST-TROP/EXTRATROP
96H 18/0600Z 50.2N 58.1W 40 KT 45 MPH...POST-TROP/EXTRATROP
120H 19/0600Z 54.6N 45.8W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Berg



Hurricane Lee Discussion Number 37
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Thu Sep 14 2023

The satellite presentation of Lee has degraded over the past day or
so. An eye is no longer apparent but deep convection continues to
wrap around the eastern and northern portions of the circulation.
Deep convection has waned over the southwestern portions of the
cyclone, likely due to an increase in southwesterly vertical wind
shear and dry air entrainment. An Air Force Reserve reconnaissance
aircraft that has been investigating Lee this morning has measured
peak 700-mb flight-level winds of 96 kt, and the NOAA P-3 aircraft
has found peak 8000 ft flight-level winds of 100 kt. However, peak
SFMR winds from both aircraft have been around 70 kt. Using a blend
of the flight-level and SFMR data, the initial wind speed has been
lowered to 80 kt, but this could be a little generous.

Lee is moving northward at a slightly faster forward speed of 12 kt.
A faster northward to north-northeastward motion is expected during
the next day or so around the western side of a mid-level ridge over
the central Atlantic. A slight bend to the north-northwest toward
the Gulf of Maine is likely late Friday or early Saturday as the
southern extent of mid-latitude trough moves off the Mid-Atlantic
coast. After that time, Lee is forecast to turn northeastward over
Atlantic Canada. The dynamical model guidance is tightly clustered
and only minor adjustments were made to the previous official
forecast. The NHC track is close to a blend of the typically
reliable GFS and ECMWF models.

Southwesterly vertical wind shear is expected to increase over Lee
during the next 24 to 36 hours, and this is likely to lead to
gradual weakening during that time. Sea surface temperatures will
decrease significantly just after 36 hours when Lee moves north of
the Gulf Stream. The global model guidance suggests that Lee will
begin extratropical transition Friday night and this is likely to be
completed within 48 hours, if not a little sooner. The NHC
intensity forecast is a blend of the HFIP corrected consensus and
and the IVCN consensus model. It can't be stressed enough, that
regardless of Lee's designation, it will remain a large and
dangerous cyclone while it approaches eastern New England and
Atlantic Canada.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf will
continue to impact Bermuda through Friday morning, and a Tropical
Storm Warning is in effect for the island.

2. Hurricane conditions and coastal flooding are possible in
portions of eastern Maine, southern New Brunswick, and western Nova
Scotia on Saturday, and a Hurricane Watch is in effect for that
area. Tropical storm conditions are expected on Cape Cod, Martha's
Vineyard, and Nantucket where a Tropical Storm Warning is now in
effect. Tropical storm conditions are possible elsewhere across New
England and Atlantic Canada within the Tropical Storm Watch areas.

3. Heavy rainfall from Lee may produce localized urban and small
stream flooding across eastern New England and into portions of New
Brunswick and Nova Scotia from Friday night into Saturday night.

4. There is the potential for life-threatening storm surge flooding
in portions of southeastern Massachusetts, including Cape Cod and
Nantucket, late Friday and Saturday, where a Storm Surge Watch is in
effect.


FORECAST POSITIONS AND MAX WINDS

INIT 14/1500Z 30.4N 68.3W 80 KT 90 MPH
12H 15/0000Z 32.2N 68.0W 75 KT 85 MPH
24H 15/1200Z 35.0N 67.2W 70 KT 80 MPH
36H 16/0000Z 38.2N 66.6W 70 KT 80 MPH
48H 16/1200Z 41.5N 66.5W 65 KT 75 MPH
60H 17/0000Z 44.0N 66.1W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 17/1200Z 47.0N 63.6W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 18/1200Z 52.6N 52.2W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 19/1200Z...DISSIPATED

$$
Forecaster Brown




Hurricane Lee Discussion Number 38
NWS National Hurricane Center Miami FL AL132023
500 PM AST Thu Sep 14 2023

There has been little overall change to the satellite presentation
of Lee since the previous advisory. Deep convection continues to
develop near the center, but it is primarily confined to the
northern portion of the circulation. Southwesterly shear and dry
air entrainment is disrupting the convective banding over the
southern portion of the storm. The initial intensity was lowered
to 75 kt on the 1800 UTC intermediate advisory, and was based
on data from the Air Force Reserve reconnaissance aircraft that was
in the storm through midday. The initial wind speed remains at
that value for this advisory. The next reconnaissance mission is
scheduled to investigate Lee this evening. The early aircraft data
along with a couple of fortuitous ASCAT overpasses showed that the
wind field of Lee has continued to expand. The 50-kt wind radii
extend outward up to 170 n mi over the eastern semicircle of the
storm. NOAA buoy 41048 located about 75 miles (120 km) west of the
center of Lee has recently reported a peak one-minute sustained wind
of 58 kt and a gust to 76 kt and wave heights of around 30 ft.
Bermuda, located more than 220 miles east-northeast of the center
has also reported sustained tropical-storm force winds today.

Lee is moving northward at about 13 kt, which is slightly faster
than before. Lee should continue to pick up some forward speed as
it moves northward around the western side of a mid-level ridge
over the central Atlantic during the next 12-24 hours. After that
time a slight bend to the north-northwest is likely late Friday or
early Saturday, and this motion should bring the center of Lee near
or over southwestern Nova Scotia late Saturday. After that time,
Lee is forecast to turn northeastward over Atlantic Canada. The
track guidance is still in good agreement, and no significant
changes to the previous official forecast were required.

Increasing southwesterly vertical wind shear and dry air entrainment
could cause some additional weakening, but baroclinic forcing
during the early stages of Lee's extratropical transition may help
to maintain the cyclone's intensity through Friday. By Friday
night Lee will be moving over significantly cooler sea surface
temperatures, and gradual weakening is expected after that time.
Lee is forecast to complete its transition into an extratropical
cyclone when it nears Atlantic Canada. Regardless of Lee's
designation when it approaches New England and Atlantic Canada, it
will remain a very large and dangerous cyclone through landfall.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf will
continue to impact Bermuda through Friday morning, and a Tropical
Storm Warning is in effect for the island.

2. Hurricane conditions and coastal flooding are possible in
portions of eastern Maine, southern New Brunswick, and western Nova
Scotia on Saturday, and a Hurricane Watch is in effect for that
area. Tropical storm conditions and coastal flooding are expected
to begin in southern New England on Friday afternoon, and spread
northward along the coast of New England through Saturday where
Tropical Storm warnings are in effect.

3. Heavy rainfall from Lee may produce localized urban and small
stream flooding across eastern New England and into portions of New
Brunswick and Nova Scotia from Friday night into Saturday night.


FORECAST POSITIONS AND MAX WINDS

INIT 14/2100Z 31.7N 68.3W 75 KT 85 MPH
12H 15/0600Z 33.8N 67.9W 75 KT 85 MPH
24H 15/1800Z 37.0N 66.9W 75 KT 85 MPH
36H 16/0600Z 40.3N 66.6W 70 KT 80 MPH
48H 16/1800Z 43.3N 66.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
60H 17/0600Z 46.0N 65.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 17/1800Z 48.6N 61.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 18/1800Z 53.7N 48.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 19/1800Z...DISSIPATED

$$
Forecaster Brown

[cycloneye]

BULLETIN
Hurricane Lee Advisory Number 39
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Thu Sep 14 2023

...TROPICAL STORM WARNINGS ISSUED FOR PORTIONS OF ATLANTIC CANADA...
...DANGEROUS SURF AND RIP CURRENT CONDITIONS AFFECTING MUCH OF THE
EAST COAST OF THE UNITED STATES...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...32.9N 67.6W
ABOUT 170 MI...270 KM WNW OF BERMUDA
ABOUT 590 MI...945 KM SSE OF NANTUCKET MASSACHUSETTS
MAXIMUM SUSTAINED WINDS...85 MPH...140 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...957 MB...28.26 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

The Canadian Hurricane Center has issued a Tropical Storm Warning
for New Brunswick from the U.S./Canada border to Fort Lawrence,
including Grand Manan Island, and a Tropical Storm Warning for the
coast of Nova Scotia from Fort Lawrence to Point Tupper.




Hurricane Lee Discussion Number 39
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Thu Sep 14 2023

Observations from an Air Force Reserve Unit Hurricane Hunter
aircraft indicate that Lee's eyewall is not well defined, and this
is also suggested by geostationary satellite and microwave imagery.
Although the peak 700 mb flight-level winds reported by the plane
were near 93 kt, the highest SFMR-observed surface winds were 72 kt.
Thus the winds aloft in the hurricane are not being transported
very effectively to the surface. This is not surprising, since the
central deep convection is no longer very strong. The current
intensity is kept at 75 kt based on the aircraft data, which is
well above the Dvorak satellite estimates.

Lee wobbled a bit to the northeast early this evening, but the
longer-term motion appears to be just east of north, or around
010/12 kt. The system should move generally northward at a faster
forward speed, on the west side of a mid-level ridge, during the
next day or so. A slight bend to the left is likely late Friday as
the cyclone interacts with a mid-level trough. By late Saturday,
Lee should begin to turn toward the north-northeast with the center
passing near or over western Nova Scotia. Then, Lee is forecast to
turn northeastward over Atlantic Canada. The track guidance remains
in good agreement through 72 hours, and the official forecast is
basically an update of the previous one.

South-southwesterly shear is predicted to increase significantly
over Lee during the next couple of days. This, along with cooler
SSTs, particularly after the system moves north of 40N latitude,
should result in weakening. However, baroclinic processes could
help the cyclone maintain its intensity, or at least slow the
weakening rate. The official intensity forecast is above the model
guidance for this reason. In 48 hours, simulated satellite imagery
shows an asymmetric cloud structure characteristic of an
extratropical cyclone. Regardless of when extratropical transition
actually occurs, however, Lee should remain a very large and
dangerous cyclone through landfall.


KEY MESSAGES:

1. Tropical storm conditions, heavy rainfall, and high surf will
continue to impact Bermuda through Friday morning, and a Tropical
Storm Warning is in effect for the island.

2. Hurricane conditions and coastal flooding are possible in
portions of eastern Maine, southern New Brunswick, and western Nova
Scotia on Saturday, and a Hurricane Watch is in effect for that
area. Tropical storm conditions and coastal flooding are expected
to begin in southern New England on Friday afternoon, and spread
northward along the coast of New England and over portions of
Atlantic Canada through Saturday where Tropical Storm warnings are
in effect.

3. Heavy rainfall from Lee may produce localized urban and small
stream flooding across eastern New England and into portions of New
Brunswick and Nova Scotia from Friday night into Saturday night.


FORECAST POSITIONS AND MAX WINDS

INIT 15/0300Z 32.9N 67.6W 75 KT 85 MPH
12H 15/1200Z 35.0N 67.3W 75 KT 85 MPH
24H 16/0000Z 38.4N 66.6W 75 KT 85 MPH
36H 16/1200Z 41.6N 66.6W 65 KT 75 MPH
48H 17/0000Z 44.3N 66.0W 60 KT 70 MPH...POST-TROP/INLAND
60H 17/1200Z 47.0N 63.6W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 18/0000Z 49.6N 59.1W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 19/0000Z 54.5N 42.5W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 20/0000Z...DISSIPATED

$$
Forecaster Pasch

[cycloneye]

Hurricane Lee Discussion Number 40
NWS National Hurricane Center Miami FL AL132023
500 AM AST Fri Sep 15 2023

Lee appears to be in the very initial stages of extratropical
transition. The cloud pattern is becoming increasingly asymmetric,
and scatterometer data from last evening showed a band of strong
winds developing along a boundary to the northwest of the center.
Lee's initial intensity remains 75 kt based on continuity from last
evening's reconnaissance and scatterometer data, but NOAA and Air
Force Reserve Hurricane Hunter aircraft should be in the storm in a
couple of hours to again sample the wind field.

Lee has been wobbling a bit since yesterday afternoon, but the
smoothed motion is northward (010 degrees) at a faster speed of 14
kt. Additional northward acceleration is expected during the next
24-36 hours as Lee moves along the western periphery of a mid-level
ridge, and approaches a trough currently over New England. The
track model guidance continues to be in very good agreement on
bringing Lee's center very near the western end of Nova Scotia by
Saturday afternoon, although the new NHC forecast is a little
faster than the previous prediction. In 2-3 days, Lee is forecast
to turn north-northeastward and northeastward across Atlantic
Canada as it moves between the aforementioned ridge and a mid-level
trough moving across Quebec.

Although southerly shear is forecast to increase markedly through
the day, baroclinic influences during Lee's extratropical transition
are likely to keep the intensity relatively steady for the next 24
hours or so. During that time, the NHC intensity forecast is near
the top end of the guidance suite, closest to the GFS and ECMWF
solutions, and there is some possibility that a band of strong winds
could develop near the front on the western side of the circulation
over the Gulf of Maine. Extratropical transition is forecast to be
complete by 36 hours (although it could be sooner), and Lee is
likely to be weakening--but still near or just below hurricane
force--as it is approaching Nova Scotia due to the continued shear
and much colder ocean temperatures. Lee is expected to continue
weakening while it moves across Atlantic Canada, and global model
fields indicate that it is likely to be absorbed by another
developing area of low pressure near Newfoundland and Labrador just
after 72 hours.


KEY MESSAGES:

1. Hurricane conditions are possible across portions of Down East
Maine, southern New Brunswick, and western Nova Scotia on Saturday
within the Hurricane Watch area. Tropical storm conditions and
coastal flooding are expected to begin in southern New England
within the Tropical Storm Warning area this afternoon, and spread
northward along the coast of New England and over portions of
Atlantic Canada through Saturday. These conditions are likely to
lead to downed trees and potential power outages.

2. Heavy rainfall from Lee may produce localized urban and small
stream flooding across eastern New England and into portions of New
Brunswick and Nova Scotia from tonight into Saturday night.

3. Tropical storm conditions and high surf will continue to impact
Bermuda through this morning.


FORECAST POSITIONS AND MAX WINDS

INIT 15/0900Z 34.4N 67.5W 75 KT 85 MPH
12H 15/1800Z 36.8N 67.0W 75 KT 85 MPH
24H 16/0600Z 40.3N 66.7W 75 KT 85 MPH
36H 16/1800Z 43.4N 66.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 17/0600Z 46.3N 64.8W 50 KT 60 MPH...POST-TROP/INLAND
60H 17/1800Z 49.3N 61.1W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 18/0600Z 52.2N 55.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 19/0600Z...DISSIPATED

$$
Forecaster Berg

[cycloneye]

Hurricane Lee Discussion Number 41
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Fri Sep 15 2023

Lee remains a very large hurricane over the western Atlantic. The
strongest winds extend out to roughly 70 miles from the center,
hurricane-force winds around 100 miles and tropical-storm-force
winds more than 300 miles. Data from both the NOAA and Air Force
Hurricane Hunters indicate that the core winds have decreased
slightly, and a blend of the latest flight-level and SFMR winds
support an intensity of 70 kt. Satellite images indicate that the
hurricane is asymmetric with most of the convection on the north
side.

The hurricane has been wobbling around, but it has generally been
moving north-northeastward at 16 kt during the past 12-18 hours on
the western side of a subtropical ridge. A northward to
north-northeastward motion at about the same forward speed is
expected until Lee makes landfall in Atlantic Canada in 24 to 36
hours. After landfall, Lee is forecast to accelerate to the
northeast when it moves in the flow on the east side of an
approaching trough. The models are tightly clustered, and no
significant changes were made to the previous NHC track forecast.

Southerly vertical wind shear and dry air are eroding deep
convection on the hurricane's south side. These environmental
conditions are expected to persist while Lee moves over sharply
cooler waters during the next day or so. Therefore, steady
weakening is forecast and Lee will likely become extratropical
around the time it makes landfall. The NHC intensity forecast is a
little lower than the previous one, and fairly close to the GFS
model prediction. Lee is expected to remain a large and dangerous
system over the next couple of days.


KEY MESSAGES:

1. Hurricane conditions are possible across portions southern New
Brunswick, and much of Nova Scotia on Saturday within the Hurricane
Watch area. Tropical storm conditions and coastal flooding are
expected to begin in southern New England within the Tropical Storm
Warning area this afternoon, and spread northward along the coast of
New England and over portions of Atlantic Canada through Saturday.
These conditions are likely to lead to downed trees and potential
power outages.

2. Heavy rainfall from Lee could produce localized urban and small
stream flooding in eastern Maine into portions of New Brunswick and
Nova Scotia from tonight into Saturday night.

3. Tropical storm conditions and high surf will continue to impact
Bermuda during the next few hours.


FORECAST POSITIONS AND MAX WINDS

INIT 15/1500Z 36.0N 66.9W 70 KT 80 MPH
12H 16/0000Z 38.5N 66.4W 70 KT 80 MPH
24H 16/1200Z 41.8N 66.2W 65 KT 75 MPH
36H 17/0000Z 45.1N 65.7W 55 KT 65 MPH...POST-TROP/EXTRATROP
48H 17/1200Z 47.8N 62.8W 45 KT 50 MPH...POST-TROP/EXTRATROP
60H 18/0000Z 50.8N 57.8W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 18/1200Z 53.4N 51.3W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 19/1200Z...DISSIPATED

$$
Forecaster Cangialosi

[cycloneye]

Hurricane Lee Discussion Number 42
NWS National Hurricane Center Miami FL AL132023
500 PM AST Fri Sep 15 2023

Lee remains a very large hurricane over the western Atlantic. ASCAT
data from this morning showed the wind field expanding, with the
hurricane-force winds around 100 miles and tropical-storm-force
winds more than 300 miles outward from the center. New data from
the Air Force Hurricane Hunters indicate that the core winds remain
steady with an intensity of 70 kt. Lee continues to be an
asymmetric hurricane with most of the convection on the north side
of the system.

The hurricane continues to wobble around, but it is generally moving
northward at 17 kt during the last 12-18 hours on the western side
of a subtropical ridge. Lee will continue to move northward around
the same speed until it makes landfall in Atlantic Canada in
approximately 24 to 30 hours. Once Lee makes landfall, it is still
expected to accelerate to the northeast as it moves in the flow on
the east side of an approaching trough. The models remain in quite
good agreement, and the NHC track forecast was only slightly
shifted to the left to follow the new guidance through landfall.
Otherwise, no significant changes were made.

Southerly vertical wind shear and dry air continue eroding deep
convection on Lee's south side. These environmental conditions will
persist while Lee moves over sharply cooler waters when it crosses
the north wall of the Gulf Stream during the next day or so.
Therefore, gradual weakening is forecast and Lee will likely become
a strong extratropical cyclone around the time it makes landfall.
The NHC intensity forecast is slightly lower than the previous one
and continues to be fairly close to the GFS model. However, Lee is
expected to remain a very large and dangerous system over the next
couple of days.

KEY MESSAGES:

1. Hurricane conditions are possible across portions southern New
Brunswick, and much of Nova Scotia on Saturday within the Hurricane
Watch area. Tropical storm conditions and coastal flooding are
expected to begin in southern New England within the Tropical Storm
Warning area this evening, and spread northward along the coast of
New England and over portions of Atlantic Canada through Saturday.
These conditions are likely to lead to downed trees and potential
power outages.

2. Heavy rainfall from Lee could produce localized urban and small
stream flooding in portions of eastern Maine, New Brunswick and
western Nova Scotia Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT 15/2100Z 37.9N 66.7W 70 KT 80 MPH
12H 16/0600Z 40.5N 66.5W 70 KT 80 MPH
24H 16/1800Z 43.5N 66.3W 60 KT 70 MPH
36H 17/0600Z 46.2N 64.7W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 17/1800Z 49.0N 60.9W 40 KT 45 MPH...POST-TROP/EXTRATROP
60H 18/0600Z 51.7N 54.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 18/1800Z 53.9N 47.1W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 19/1800Z...DISSIPATED

$$
Forecaster A Reinhart/Cangialosi

[cycloneye]

Hurricane Lee Discussion Number 43
NWS National Hurricane Center Miami FL AL132023
1100 PM AST Fri Sep 15 2023

Lee remains a very large and dangerous hurricane as it approaches
the northeast United States and Atlantic Canada. The satellite
depiction of Lee shows that the system continues to become more
asymmetric, with most of the convection displaced to the north of
the center. An earlier SSMI/S microwave pass shows thick banding on
the northern and western side of the inner core, which is where the
Air Force Hurricane Hunters found the strongest flight-level and
surface winds. The initial intensity, based on aircraft
reconnaissance data, will remain at 70 kt for this advisory. Air
Force Hurricane Hunters will be investigating Lee again overnight.

Lee continues to wobble as it approaches the northeastern United
States and Atlantic Canada. The past few hours there has been a bit
of a north-northeast jog. Whether this is more of a wobble or a
longer-term motion is still to be determined. Global model guidance
has been hinting that this type of motion would occur as it makes
its approach towards Atlantic Canada, with a slight bend back to the
north-northwest over the next 12-18 h. The track forecast was nudged
to the right given the current motion, but it does show a
north-northwestward motion in the short term. These slight
adjustments on the final approach are minor given the very large
wind field of Lee. Once Lee makes landfall, the system is expected
to accelerate to the northeast as it moves in the flow on the east
side of an approaching trough.

Strong southerly vertical wind shear has displaced the convection to
the northern side of the system. Dry air entrainment is also
inhibiting convection on the southern and eastern side of the
circulation. These hostile environmental conditions will persist as
Lee moves over much cooler waters after it crosses the north wall of
the Gulf Stream on Saturday. Lee is already showing signs of
completing its extratropical transition, with displaced convection
and an elongated center on a recent scatterometer pass, and thus
this transition is now explicitly forecast to occur within the next
12 h. Gradual weakening is forecast throughout the period, the NHC
intensity forecast is similar to the previous, closest to the GFS.

KEY MESSAGES:

1. Hurricane conditions are possible across portions southern New
Brunswick, and much of Nova Scotia on Saturday within the Hurricane
Watch area. Tropical storm conditions and coastal flooding are
expected to begin in southern New England within the Tropical Storm
Warning area very soon, and spread northward along the coast of
New England and over portions of Atlantic Canada through Saturday.
These conditions are likely to lead to downed trees and potential
power outages.

2. Heavy rainfall from Lee may produce localized urban and small
stream flooding in portions of eastern Maine, New Brunswick and
western Nova Scotia Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT 16/0300Z 39.5N 65.8W 70 KT 80 MPH
12H 16/1200Z 41.7N 66.0W 65 KT 75 MPH...POST-TROP/EXTRATROP
24H 17/0000Z 44.5N 65.7W 55 KT 65 MPH...POST-TROP/EXTRATROP
36H 17/1200Z 47.3N 63.3W 45 KT 50 MPH...POST-TROP/EXTRATROP
48H 18/0000Z 50.6N 58.1W 40 KT 45 MPH...POST-TROP/EXTRATROP
60H 18/1200Z 53.0N 50.4W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 19/0000Z 54.3N 41.3W 35 KT 40 MPH...POST-TROP/EXTRATROP
96H 20/0000Z...DISSIPATED

$$
Forecaster Kelly/Brown

[cycloneye]

BULLETIN
Post-Tropical Cyclone Lee Advisory Number 44
NWS National Hurricane Center Miami FL AL132023
500 AM AST Sat Sep 16 2023

...LEE BECOMES POST-TROPICAL AS IT APPROACHES NOVA SCOTIA, BUT IT
IS STILL PRODUCING HURRICANE-FORCE WINDS...
...NHC ADVISORIES WILL CONTINUE...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...41.8N 66.0W
ABOUT 230 MI...365 KM SSW OF HALIFAX NOVA SCOTIA
ABOUT 220 MI...355 KM SSE OF EASTPORT MAINE
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...N OR 355 DEGREES AT 25 MPH...41 KM/H
MINIMUM CENTRAL PRESSURE...965 MB...28.50 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Watch is in effect for...
* New Brunswick from the U.S./Canada border to Point Lepreau,
including Grand Manan Island
* Nova Scotia from Digby to Ecum Secum

A Tropical Storm Warning is in effect for...
* Westport Massachusetts northward to the U.S./Canada border
* Martha's Vineyard
* Nantucket
* New Brunswick from the U.S./Canada border to Fort Lawrence,
including Grand Manan Island
* New Brunswick from Shediac to Tidnish
* Nova Scotia from Fort Lawrence to Point Tupper

A Tropical Storm Watch is in effect for...
* Prince Edward Island
* Magdalen Islands
* New Brunswick from Belledune to Shediac
* Nova Scotia from Tidnish to Aulds Cove
* Nova Scotia from Aulds Cove to Meat Cove to Point Tupper

A Hurricane Watch means that hurricane conditions are possible
within the watch area, in this case later today.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning, in this case today through
Sunday.

For storm information specific to your area in the United States,
including possible inland watches and warnings, please monitor
products issued by your local National Weather Service forecast
office. For storm information specific to your area outside of the
United States, please monitor products issued by your national
meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 500 AM AST (0900 UTC), the center of Post-Tropical Cyclone Lee
was located near latitude 41.8 North, longitude 66.0 West. Lee is
moving toward the north near 25 mph (41 km/h). A northward motion
but at a slower forward speed is expected later today, and the
center of Lee is forecast to reach western Nova Scotia around
midday. Lee is then expected to turn toward the north-northeast and
northeast and move across Atlantic Canada tonight and Sunday.

Data from an Air Force Reserve Hurricane Hunter aircraft indicate
that maximum sustained winds remain near 80 mph (130 km/h) with
higher gusts. Lee is expected to be at or just below hurricane
strength when it reaches Nova Scotia later today. Weakening is
forecast tonight and Sunday while Lee moves across Atlantic Canada.

Hurricane-force winds extend outward up to 140 miles (220 km) from
the center and tropical-storm-force winds extend outward up to 390
miles (630 km). A sustained wind of 47 mph (76 km/h) and a gust to
56 mph (91 km/h) was recently reported at Brier Island, Nova
Scotia. A sustained wind of 43 mph (69 km/h) and a gust to 59 mph
(94 km/h) were recently measured at Dennis, Massachusetts.

The minimum central pressure based on dropsonde data is 965 mb
(28.50 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Lee can be found in the Tropical Cyclone Discussion
under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC and on the
web at hurricanes.gov/text/MIATCDAT3.shtml

WIND: Hurricane conditions are possible in the Hurricane Watch
areas in Atlantic Canada later today. Tropical storm conditions
are occurring along the coasts of New England and Nova Scotia and
will spread northward within the Tropical Storm Warning areas today
and tonight. The strong winds are likely to lead to downed trees
and potential power outages.

SURF: Swells generated by Lee are affecting the U.S. Virgin
Islands, Puerto Rico, Hispaniola, the Turks and Caicos Islands, the
Bahamas, Bermuda, the east coast of the United States, and Atlantic
Canada. These swells are likely to cause life-threatening surf and
rip current conditions. Please consult products from your local
weather office.

RAINFALL: Through tonight, Lee is expected to produce rainfall
amounts of 1 to 4 inches (25 to 100 millimeters) over far eastern
Massachusetts, eastern Maine, western Nova Scotia, and New
Brunswick. This may produce localized urban and small stream
flooding.

STORM SURGE: The combination of storm surge and tide will cause
normally dry areas near the coast to be flooded by rising waters
moving inland from the shoreline. The water could reach the
following heights above ground somewhere in the indicated areas if
the peak surge occurs at the time of high tide...

Watch Hill, RI to the U.S./Canada border...1-3 ft
Cape Cod...1-3 ft
Martha's Vineyard and Nantucket...1-3 ft
Boston Harbor...1-3 ft

The deepest water will occur along the immediate coast where the
surge will be accompanied by large and destructive waves.
Surge-related flooding depends on the relative timing of the surge
and the tidal cycle, and can vary greatly over short distances. For
information specific to your area, please see products issued by
your local National Weather Service forecast office.

A dangerous storm surge will produce coastal flooding within the
wind warning areas in Atlantic Canada in areas of onshore winds.
Near the coast, the surge will be accompanied by large and
destructive waves.


NEXT ADVISORY
-------------
Next intermediate advisory at 800 AM AST.
Next complete advisory at 1100 AM AST.

$$
Forecaster Berg

[cycloneye]

Post-Tropical Cyclone Lee Discussion Number 45
NWS National Hurricane Center Miami FL AL132023
1100 AM AST Sat Sep 16 2023

The core of Lee is very near the west coast of Nova Scotia. Data
from the NOAA Hurricane Hunters indicate that the minimum pressure
has been steady at 965 mb, but the surface winds are down a little
to 65 kt. Dropsonde data indicate that winds are notably stronger
just off the surface, so significant wind gusts are likely in areas
of heavy rain and over elevated terrain near the coast. In fact, an
observation on Grand Manan Island in New Brunswick, Canada, recently
recorded a wind gust of 81 kt (150 km/h). Radar data from New
England and Nova Scotia show bands of heavy rain onshore of portions
of coastal New England and Atlantic Canada.

Lee continues to accelerate northward and has jogged to the
left this morning. The core of the cyclone will likely brush the
western portion of Nova Scotia during the next couple of hours and
then move inland near or just east of the U.S./Canada border this
afternoon. After landfall, a faster northeastward motion is
expected as a trough approaches the system, which should take Lee
across portions of Atlantic Canada tonight and Sunday.

Little change in strength is expected before landfall, and the core
winds are likely to come ashore in far down east Maine and western
portions of New Brunswick. Steady weakening is expected after Lee
moves inland, and the system is expected to dissipate by late
Monday.


KEY MESSAGES:

1. Hurricane conditions are possible across portions of southern New
Brunswick and Nova Scotia later today within the Hurricane Watch
areas. Tropical storm conditions and coastal flooding are
occurring across portions of coastal Maine and Atlantic
Canada, and will continue to spread northward within the Tropical
Storm Warning areas. The strong winds are already leading to downed
trees and power outages.

2. Heavy rainfall from Lee may produce localized urban and small
stream flooding in portions of far eastern Massachusetts, eastern
Maine, New Brunswick and western Nova Scotia today.

3. Dangerous surf and life-threatening rip currents will continue
to affect the U.S. East Coast, Atlantic Canada, Bermuda, the
Bahamas, the Turks and Caicos Islands, Hispaniola, Puerto Rico, the
Virgin Islands, and the northern Leeward Islands through the
weekend.


FORECAST POSITIONS AND MAX WINDS

INIT 16/1500Z 43.5N 66.2W 65 KT 75 MPH...POST-TROPICAL
12H 17/0000Z 45.7N 65.8W 50 KT 60 MPH...POST-TROP/EXTRATROP
24H 17/1200Z 48.3N 62.7W 40 KT 45 MPH...POST-TROP/EXTRATROP
36H 18/0000Z 50.8N 57.1W 35 KT 40 MPH...POST-TROP/EXTRATROP
48H 18/1200Z 53.0N 50.1W 35 KT 40 MPH...POST-TROP/EXTRATROP
60H 19/0000Z...DISSIPATED

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Post-Tropical Cyclone Lee Intermediate Advisory Number 45A
NWS National Hurricane Center Miami FL AL132023
200 PM AST Sat Sep 16 2023

...LEE VERY NEAR WESTERN NOVA SCOTIA...
...STRONG WINDS, COASTAL FLOODING, AND HEAVY RAINS ARE OCCURRING IN
PORTIONS OF MAINE AND ATLANTIC CANADA...


SUMMARY OF 200 PM AST...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...43.8N 66.4W
ABOUT 80 MI...130 KM SSE OF EASTPORT MAINE
ABOUT 150 MI...240 KM WSW OF HALIFAX NOVA SCOTIA
MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 22 MPH...35 KM/H
MINIMUM CENTRAL PRESSURE...968 MB...28.58 INCHES


WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY:

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Hurricane Watch is in effect for...
* New Brunswick from the U.S./Canada border to Point Lepreau,
including Grand Manan Island
* Nova Scotia from Digby to Ecum Secum

A Tropical Storm Warning is in effect for...
* Portsmouth northward to the U.S./Canada border
* New Brunswick from the U.S./Canada border to Belledune,
including Grand Manan Island
* All of Nova Scotia
* Prince Edward Island
* Magdalen Islands

A Hurricane Watch means that hurricane conditions are possible
within the watch area, in this case later today.

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning, in this case today through
Sunday.

For storm information specific to your area in the United
States, including possible inland watches and warnings, please
monitor products issued by your local National Weather Service
forecast office. For storm information specific to your area
outside of the United States, please monitor products issued by
your national meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 200 PM AST (1800 UTC), the center of Post-Tropical Cyclone Lee
was located near latitude 43.8 North, longitude 66.4 West. The
post-tropical cyclone is moving toward the north near 22 mph (35
km/h). A northward motion is expected to continue, and the center of
Lee is forecast to make landfall in Atlantic Canada later this
afternoon. Lee is then expected to turn toward the northeast and
move across Atlantic Canada tonight and Sunday.

Maximum sustained winds are near 70 mph (110 km/h) with higher
gusts. Lee is expected to be near hurricane strength when it makes
landfall later this afternoon. Weakening is forecast tonight
and Sunday while Lee moves across Atlantic Canada.

Hurricane-force winds extend outward up to 140 miles (220 km) from
the center and tropical-storm-force winds extend outward up to 390
miles (630 km). An observation in Bangor, Maine, recently
reported a wind gust of 52 mph (84 km/h).

The estimated minimum central pressure is 968 mb (28.58 inches).


HAZARDS AFFECTING LAND
----------------------
Key messages for Lee can be found in the Tropical Cyclone Discussion
under AWIPS header MIATCDAT3 and WMO header WTNT43 KNHC and on the
web at hurricanes.gov/text/MIATCDAT3.shtml

WIND: Hurricane conditions are possible in the Hurricane Watch
areas in Atlantic Canada later today. Tropical storm conditions
are occurring along the coasts of Maine and Nova Scotia and
will spread northward within the Tropical Storm Warning areas today
and tonight. The strong winds are leading to downed trees
and power outages. Tropical-storm-force gusts are likely to
continue on Cape Cod for a couple of more hours.

SURF: Swells generated by Lee are affecting the U.S. Virgin
Islands, Puerto Rico, Hispaniola, the Turks and Caicos Islands, the
Bahamas, Bermuda, the east coast of the United States, and Atlantic
Canada. These swells are likely to cause life-threatening surf and
rip current conditions. Please consult products from your local
weather office.

RAINFALL: Through tonight, Lee is expected to produce rainfall
amounts of 1 to 4 inches, or 25 to 100 millimeters over far eastern
Massachusetts, eastern Maine, western Nova Scotia, and New
Brunswick. This could produce localized urban and small stream
flooding.

STORM SURGE: A dangerous storm surge will produce coastal flooding
within the wind warning areas in Atlantic Canada in areas of
onshore winds. Near the coast, the surge will be accompanied by
large and destructive waves.


NEXT ADVISORY
-------------
Next complete advisory at 500 PM AST.

$$
Forecaster Cangialosi

[cycloneye]

Post-Tropical Cyclone Lee Discussion Number 46
NWS National Hurricane Center Miami FL AL132023
500 PM AST Sat Sep 16 2023

The core of Lee briefly moved across Long Island in Western Nova
Scotia within the past hour or so. Satellite images and surface
observations indicate that the center is now over the Bay of Fundy.
Rain bands continue to spread across portions of Maine, New
Brunswick, and Nova Scotia as seen in radar images. A pair of ASCAT
passes from several ago showed that Lee remains very large, but the
core winds have decreased below hurricane-force. Considering some
undersampling of that data, the initial intensity was lowered to 60
kt on the 1800 UTC intermediate advisory.

The forward motion of Lee is slower than earlier today as it
moves near the west coast of Nova Scotia. However, the storm is
expected to turn northeastward and accelerate late tonight and
Sunday, bringing the system across the Canadian Maritimes. Little
change was made to the previous NHC track forecast.

Strong wind shear, dry air, and land interaction should cause
steady weakening during the next day or so. The global models are
in agreement that Lee should dissipate on Monday, and that is
reflected in the NHC forecast.


KEY MESSAGES:

1. Tropical storm conditions and coastal flooding are occurring
across portions of coastal Maine and Atlantic Canada, and will
continue to spread northward within the Tropical Storm Warning
areas. The strong winds are leading to downed trees and power
outages.

2. Heavy rainfall from Lee could produce localized urban and small
stream flooding in portions of eastern Maine and New Brunswick.

3. Dangerous surf and life-threatening rip currents will continue
to affect the U.S. East Coast, Atlantic Canada, Bermuda, the
Bahamas, the Turks and Caicos Islands, Hispaniola, and Puerto
Rico through Sunday.


FORECAST POSITIONS AND MAX WINDS

INIT 16/2100Z 44.5N 66.1W 60 KT 70 MPH...POST-TROPICAL
12H 17/0600Z 46.5N 64.5W 50 KT 60 MPH...POST-TROP/EXTRATROP
24H 17/1800Z 49.0N 60.3W 40 KT 45 MPH...POST-TROP/EXTRATROP
36H 18/0600Z 51.5N 53.1W 35 KT 40 MPH...POST-TROP/EXTRATROP
48H 18/1800Z...DISSIPATED

$$
Forecaster Cangialosi