ATL: FRANKLIN - Advisories

[cycloneye]

Hurricane Franklin Discussion Number 32
NWS National Hurricane Center Miami FL AL082023
1100 AM EDT Mon Aug 28 2023

Visible, infrared and microwave imagery depict a strengthening major
hurricane with a well-defined eye, a thick eyewall, and very cold
cloud tops. This was further supported by data from the Air Force
Reserve Hurricane Hunters, who have been investigating the storm
this morning. Minimum pressure has decreased from the previous
advisory based on a dropsonde measuring a pressure of 937 mb around
12 UTC. Flight-level, SFMR winds and dropsondes in the eyewall
indicate maximum sustained winds have increased to 125 kt.
Subjective and object satellite estimates also have drastically
increased with this advisory. Given these data, the initial
intensity is raised to 125 kt for this advisory, and Franklin has
rapidly intensified into a Category 4 major hurricane.

The hurricane continues to make a gradual turn northward, with the
latest motion estimate northward at 350/8 kt. A northward then
northeastward motion is forecast during the next 48 hours as
Franklin rounds the western edge of the subtropical ridge. After 48
hours, a deep trough is expected to move off the U.S. northeast
coast and Canada, and has Franklin becoming captured in the
southwesterly flow, with an increase in forward motion to the
northeast. There is better agreement in cross-track guidance
compared to the previous few advisories. However, there is still a
slight difference in the along track guidance with the GFS being
faster, and the ECMWF a little slower. The latest NHC track forecast
is similar to the previous forecast, with only a minor nudge to the
north.

Some additional intensification is possible today, as Franklin
remains in a low shear environment and is over warm sea-surface
temperatures. The latest intensity forecast peaks Franklin as a
strong Category 4 major hurricane. However, inner core changes, such
as eyewall replacement cycles, could occur at any time, making the
peak intensity and short-term forecast a little more challenging.
Some gradual weakening is forecast in about a day or so when models
forecast a slight increase in northwesterly shear. Toward the end of
the forecast period, further weakening is expected as Franklin
encounters increased vertical wind shear and moves over cooler SSTs.
The latest forecast shows the storm becoming a extratropical cyclone
in 120 h, though this could occur sooner.

KEY MESSAGES:

1.Tropical storm conditions are possible on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
coast of the southeast United States. These conditions are
expected to spread northward along the remainder of the U.S.
east coast, Atlantic Canada, and Bermuda during the next couple of
days.


FORECAST POSITIONS AND MAX WINDS

INIT 28/1500Z 27.8N 71.0W 125 KT 145 MPH
12H 29/0000Z 29.0N 71.2W 135 KT 155 MPH
24H 29/1200Z 30.7N 70.8W 130 KT 150 MPH
36H 30/0000Z 32.5N 69.6W 120 KT 140 MPH
48H 30/1200Z 34.5N 67.4W 110 KT 125 MPH
60H 31/0000Z 36.3N 64.1W 100 KT 115 MPH
72H 31/1200Z 38.7N 59.9W 90 KT 105 MPH
96H 01/1200Z 44.5N 49.7W 75 KT 85 MPH
120H 02/1200Z 51.8N 39.8W 65 KT 75 MPH...POST-TROP/EXTRATROP

$$
Forecaster Kelly/Brown

[cycloneye]

BULLETIN
Hurricane Franklin Intermediate Advisory Number 32A
NWS National Hurricane Center Miami FL AL082023
200 PM EDT Mon Aug 28 2023

...LIFE-THREATENING SURF AND RIP CURRENTS ARE OCCURING ALONG THE
COAST OF THE SOUTHEAST UNITED STATES...


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...28.1N 71.1W
ABOUT 455 MI...735 KM N OF GRAND TURK ISLAND
ABOUT 475 MI...765 KM SW OF BERMUDA
MAXIMUM SUSTAINED WINDS...145 MPH...230 KM/H
PRESENT MOVEMENT...N OR 350 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...937 MB...27.67 INCHES

[cycloneye]

Hurricane Franklin Discussion Number 33
NWS National Hurricane Center Miami FL AL082023
500 PM EDT Mon Aug 28 2023

Visible and infrared satellite imagery depicts Franklin remains a
powerful major hurricane this afternoon. The eye has cleared out and
warmed, with a thick symmetric eyewall tightly wrapped around the
center. Subjective and objective satellite estimates have remained
fairly steady throughout the day, around T6.5. Given that the
satellite appearance remains similar to earlier today when we had
aircraft reconnaissance data, the intensity remains at 125 kt for
this advisory. Air Force Reserve Hurricane Hunters will be
investigating the system later this evening.

Franklin is moving northward at 350/8 kt. A northward then
northeastward motion is forecast during the next 48 hours as
Franklin rounds the western edge of the subtropical ridge. In a
couple of days, a deep trough is expected to move off the northeast
coast of the U.S. and eastern Canada, with Franklin becoming
captured in the southwesterly flow, causing an increase in forward
motion to the northeast. The model guidance for this cycle remained
in fairly good agreement except for the ECMWF, which shifted back to
the right. There is still a difference in the a long track guidance,
with the GFS being on the faster side of the model envelope. The NHC
track forecast is fairly similar to the previous, and lies near the
corrected consensus aids.

Some additional intensification is possible as Franklin remains
over warm sea-surface temperatures and low vertical wind shear. The
latest peak intensity is unchanged from the previous forecast,
bringing Franklin to a strong Category 4 hurricane. The short
term forecast is subject to fluctuations in inner core changes, or
eyewall replacement cycles, which could occur at any time, making
the peak intensity forecast a little more challenging. Some gradual
weakening is forecast in about 24 hours as models indicate a
increase in northwesterly shear. Toward the end of the forecast
period, further weakening is expected as Franklin encounters
increased vertical wind shear and moves over cooler SSTs. Models
are in fairly good agreement with the system becoming an
extratropical cyclone around 96 h, and the forecast now
explicitly shows this transition occuring in 96 h.

KEY MESSAGES:

1.Tropical storm conditions are possible on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
coast of the southeast United States. These conditions are
expected to spread northward along the remainder of the U.S.
east coast, Atlantic Canada, and Bermuda during the next couple of
days.


FORECAST POSITIONS AND MAX WINDS

INIT 28/2100Z 28.5N 71.0W 125 KT 145 MPH
12H 29/0600Z 29.7N 71.1W 135 KT 155 MPH
24H 29/1800Z 31.3N 70.3W 130 KT 150 MPH
36H 30/0600Z 33.0N 68.8W 120 KT 140 MPH
48H 30/1800Z 34.9N 66.3W 110 KT 125 MPH
60H 31/0600Z 37.2N 62.0W 100 KT 115 MPH
72H 31/1800Z 39.6N 57.3W 90 KT 105 MPH
96H 01/1800Z 45.6N 48.3W 75 KT 85 MPH...POST-TROP/EXTRATROP
120H 02/1800Z 50.4N 37.6W 60 KT 70 MPH...POST-TROP/EXTRATROP

$$
Forecaster Kelly/Brown

[cycloneye]

BULLETIN
Hurricane Franklin Intermediate Advisory Number 33A
NWS National Hurricane Center Miami FL AL082023
800 PM EDT Mon Aug 28 2023

...FRANKLIN A VERY POWERFUL CATEGORY 4 HURRICANE...
...LIFE-THREATENING SURF AND RIP CURRENTS ARE OCCURING ALONG THE
COAST OF THE SOUTHEAST UNITED STATES...


SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...29.0N 71.1W
ABOUT 440 MI...710 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...150 MPH...240 KM/H
PRESENT MOVEMENT...N OR 360 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...926 MB...27.34 INCHES

[cycloneye]

Hurricane Franklin Discussion Number 34
NWS National Hurricane Center Miami FL AL082023
1100 PM EDT Mon Aug 28 2023

Franklin remains a powerful category 4 hurricane. Satellite images
show a clear and circular eye with a solid and symmetric ring of
deep convection surrounding that feature. The Air Force Hurricane
Hunters have investigated Franklin during the past few hours and
found 700-mb flight-level winds as high as 140 kt and maximum
surface SFMR winds of 128 kt. In addition, the minimum pressure
based on dropsonde data is estimated to be 926 mb. Based on these
data, the initial intensity is set at 130 kt, which is close to the
upper bound of category 4 status.

The major hurricane is now moving due northward at 9 kt. A turn to
the northeast is expected on Tuesday, with a steady increase in
forward speed forecast during the next few days as the hurricane
moves in progressively faster flow between a mid-level ridge
over the central Atlantic and a mid- to upper-level trough over the
northeastern U.S. and eastern Canada. The models are in relatively
good agreement during the next 72 hours, however, they diverge
significantly after that. The GFS shows a continued acceleration
to the northeast with the trough eventually capturing Franklin.
Conversely, the ECMWF shows the trough pulling away, leaving
Franklin behind in weaker steering currents. The NHC track forecast
is roughly between those very different solutions, sticking close
to the various consensus aids.

Franklin should maintain its strength overnight, but a steady
weakening trend should begin on Tuesday as the hurricane moves over
progressively cooler waters and into an environment of higher shear.
Regardless, Franklin is expected to be a significant hurricane
during the next few days. Franklin should complete extratropical
transition in 3 to 4 days when it crosses the northern wall of the
Gulf Stream Current and moves into an environment of very strong
shear. The NHC intensity forecast is a little lower than the
previous one and close to the HCCA and IVCN models.


KEY MESSAGES:

1. Tropical storm conditions are possible on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
coast of the southeast United States. These conditions are
expected to spread northward along the remainder of the U.S.
east coast, Atlantic Canada, and Bermuda during the next couple of
days.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0300Z 29.4N 71.0W 130 KT 150 MPH
12H 29/1200Z 30.5N 70.8W 130 KT 150 MPH
24H 30/0000Z 32.1N 69.7W 120 KT 140 MPH
36H 30/1200Z 33.9N 67.7W 110 KT 125 MPH
48H 31/0000Z 35.8N 64.5W 100 KT 115 MPH
60H 31/1200Z 38.0N 60.3W 95 KT 110 MPH
72H 01/0000Z 40.9N 55.3W 85 KT 100 MPH
96H 02/0000Z 45.8N 45.9W 70 KT 80 MPH...POST-TROP/EXTRATROP
120H 03/0000Z 52.0N 38.5W 55 KT 65 MPH...POST-TROP/EXTRATROP

$$
Forecaster Cangialosi

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 35
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Tue Aug 29 2023

...FRANKLIN REMAINS A FORMIDABLE CATEGORY 4 HURRICANE...
...LIFE-THREATENING SURF AND RIP CURRENTS ONGOING ALONG
THE SOUTHEAST UNITED STATES COASTLINE AND EXPECTED TO SPREAD
UP THE EASTERN SEABOARD...


SUMMARY OF 500 AM EDT...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...30.2N 70.8W
ABOUT 385 MI...615 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...140 MPH...220 KM/H
PRESENT MOVEMENT...NNE OR 15 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...935 MB...27.61 INCHES


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

None.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Watch is in effect for...



Hurricane Franklin Discussion Number 35
NWS National Hurricane Center Miami FL AL082023
500 AM EDT Tue Aug 29 2023

Near the time of the prior advisory, we received a GPM microwave
pass at 0231 UTC, strongly suggesting the initial stages of an
eyewall replacement cycle (ERC) were underway. This observation is
also supported by the recent trends on infrared satellite imagery,
which show the coldest cloud tops relative to Franklin's warm eye
becoming more focused towards outer concentric bands seen earlier on
microwave imagery. Finally, a recently received 0635 UTC AMSR2
microwave pass confirms the ERC is ongoing, with the outer eyewall
already starting to become dominant on the 89-GHz channel. All this
data means is that the hurricane is likely past its peak intensity,
but may be broadening its inner-core wind field as it undergoes this
structural change. Subjective final T-number intensity estimates
were 6.0/115 kt from both TAFB and SAB, with UW-CIMSS ADT also at
T6.0/115 kt. However since the earlier aircraft data showed that
Franklin was stronger than the satellite signature would suggest,
the initial intensity is only being lowered to 120 kt for this
advisory.

Franklin is now beginning to lose longitude again, with the latest
estimated motion at 015/8 kt. A further turn to the northeast is
expected later today as the hurricane becomes caught in the flow
between a subtropical ridge positioned to its southeast and an
approaching mid-latitude trough ejecting out of Canada from the
northwest. Ultimately, this trough is still forecast to capture
Franklin, though the along-track spread remains high beyond the next
48 h. Once again the GFS and ECMWF are book-ending the track
guidance this cycle, with the GFS the fastest and furthest north,
and the ECMWF the slowest and furthest south, missing the trough
connection. The ensemble guidance also continues to exhibit large
spread between these scnerios after the next 48 h. The NHC track
forecast continues to favor a solution closest to the the consensus
aids TVCA and HCCA, which trended a bit slower this cycle. On the
forecast track, Franklin should bypass Bermuda well to the northwest
on Wednesday, but tropical-storm-force winds associated with
Franklin will come much closer to the island due to the hurricane's
large and expanding wind field.

With the ongoing eyewall replacement cycle, Franklin is likely past
its peak intensity. It is forecast to continue weakening, especially
as the hurricane also begins to move over cooler waters. In
addition, shear out of the northwest increases markedly in both the
GFS and ECMWF forecasts after 48 hours, which should hasten the
weakening process. The latest NHC intensity forecast is again a bit
lower than the previous cycle, but remains somewhat higher than the
consensus aids which show a slightly faster rate of weakening. There
are still timing differences in the guidance regarding exactly when
Franklin will become extratropical. The day 4 extratropical
transition time frame in the NHC official forecast is a compromise
between the faster GFS and slower ECMWF solutions.

KEY MESSAGES:

1. Tropical storm conditions are possible on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
coast of the southeast United States. These conditions are
expected to spread northward along the remainder of the U.S.
east coast, Atlantic Canada, and Bermuda later today into Wednesday.


FORECAST POSITIONS AND MAX WINDS

INIT 29/0900Z 30.2N 70.8W 120 KT 140 MPH
12H 29/1800Z 31.3N 70.3W 110 KT 125 MPH
24H 30/0600Z 33.0N 68.8W 100 KT 115 MPH
36H 30/1800Z 34.8N 66.3W 95 KT 110 MPH
48H 31/0600Z 36.7N 62.8W 90 KT 105 MPH
60H 31/1800Z 38.6N 58.5W 80 KT 90 MPH
72H 01/0600Z 41.4N 53.1W 75 KT 85 MPH
96H 02/0600Z 48.2N 41.1W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 03/0600Z 59.1N 27.5W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 36
NWS National Hurricane Center Miami FL AL082023
1100 AM EDT Tue Aug 29 2023

...TROPICAL STORM WARNING ISSUED FOR BERMUDA...
...LIFE-THREATENING SURF AND RIP CURRENTS ONGOING ALONG THE
EAST COAST OF THE UNITED STATES...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...30.8N 70.4W
ABOUT 345 MI...555 KM WSW OF BERMUDA
MAXIMUM SUSTAINED WINDS...130 MPH...215 KM/H
PRESENT MOVEMENT...NNE OR 30 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...941 MB...27.79 INCHES


Hurricane Franklin Discussion Number 36
NWS National Hurricane Center Miami FL AL082023
1100 AM EDT Tue Aug 29 2023

Visible, infrared, and microwave satellite imagery indicates that
Franklin is undergoing an eyewall replacement cycle with an outer
concentric band becoming more dominant. The inner eyewall has become
a little more ragged, and has started to collapse on the northern
side. A 1137z 91GHz/37GHz SSMIS microwave pass confirmed the outer
eyewall is becoming more dominant as well. The subjective and
objective Dvorak estimates were in fairly good agreement this cycle,
with a data-T of 5.5 and Final-T of 6.0 from both TAFB and UW-CIMSS
ADT. Given the ongoing inner structural changes and the slightly
weaker appearance on satellite, the initial intensity for this
advisory lowered to 115 kt for this advisory.

Franklin is moving north-northeastward at around 10 kt. A more
northeastward motion is expected later today as the hurricane rounds
the edge of the subtropical ridge and gets caught in the
southwesterly flow ahead of a mid-latitude trough moving off the
northeast U.S. coast and Atlantic Canada. There still remains a good
amount of spread in the track guidance envelope with the GFS faster
and further north, and the ECMWF slower and further south. The NHC
track lies in the middle of the guidance, near the consensus aids
TVCA and HCCA. Even though the center of Franklin is forecast to
pass to the northwest of Bermuda on Wednesday, tropical-storm-force
winds associated with the hurricane are expected to extend well to
the southeast of the center.

The intensity forecast remains similar to the previous forecast.
Franklin is expected to continue weakening, as it begins to move
northward over cooler waters. ECMWF and GFS SHIPS guidance also
forecast the vertical wind shear to increase over the hurricane in
about 36 h. The current NHC forecast has Franklin becoming
extratropical in 4 days. There is some guidance, including the GFS,
that have this transition occurring a little faster, while the
ECMWF is a little slower with this transition.


KEY MESSAGES:

1. Tropical storm conditions are expected on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 29/1500Z 30.8N 70.4W 115 KT 130 MPH
12H 30/0000Z 32.0N 69.6W 110 KT 125 MPH
24H 30/1200Z 33.7N 67.7W 100 KT 115 MPH
36H 31/0000Z 35.3N 64.8W 95 KT 110 MPH
48H 31/1200Z 36.9N 60.8W 90 KT 105 MPH
60H 01/0000Z 39.0N 55.7W 80 KT 90 MPH
72H 01/1200Z 41.3N 50.6W 75 KT 85 MPH
96H 02/1200Z 46.9N 42.9W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 03/1200Z 53.6N 34.4W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Kelly/Brown

[cycloneye]

Hurricane Franklin Discussion Number 37
NWS National Hurricane Center Miami FL AL082023
500 PM AST Tue Aug 29 2023

Franklin has completed an eyewall replacement cycle this afternoon.
This was confirmed by an AMSR microwave pass at 1748Z, showing that
the outer eyewall has now become the dominant feature and the inner
eyewall has completely collapsed. In the last few hours, infrared
imagery has depicted cold cloud tops in the deep convection within
the new eyewall. The subjective and objective satellite estimates
have decreased slightly throughout the day, but still remain around
a T5.5 from TAFB and CIMSS ADT. Given these satellite estimates and
the structure depicted from microwave imagery, the initial intensity
for this advisory will remain 110 kt.

Franklin is moving northeastward at around 10 kt. This northeastward
motion is expected to continue for the next few days with an
increase in forward speed as Franklin rounds the edge of the
subtropical ridge and gets caught in the southwesterly flow ahead of
a mid-latitude trough moving off the northeast U.S. coast and
Atlantic Canada. There still remains a good amount of spread in the
track guidance with both along- and cross-track differences beyond
48 h. The NHC track is near the previous advisory and lies in the
middle of the guidance envelope, close to the consensus aids. Even
though the center of Franklin is forecast to pass to the northwest
of Bermuda on Wednesday, tropical-storm-force winds associated with
the hurricane are expected to extend well to the southeast of the
center.

Franklin could fluctuate in intensity now that it has completed the
eyewall replacement cycle. But, it should gradually weaken in the
near term, as it begins to move northward over cooler waters, with
some increase in northwesterly wind shear. Vertical wind shear is
forecast to increase further in about 36 h, with further weakening
anticipated. The guidance this cycle has come into better agreement
with the timing of extratropical transition in about 72 h, and this
is now reflected in the latest NHC forecast.


KEY MESSAGES:

1. Tropical storm conditions are expected on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 29/2100Z 31.4N 69.9W 110 KT 125 MPH
12H 30/0600Z 32.7N 68.7W 105 KT 120 MPH
24H 30/1800Z 34.3N 66.5W 100 KT 115 MPH
36H 31/0600Z 35.4N 63.5W 95 KT 110 MPH
48H 31/1800Z 36.6N 59.8W 85 KT 100 MPH
60H 01/0600Z 37.9N 55.2W 75 KT 85 MPH
72H 01/1800Z 40.6N 50.2W 70 KT 80 MPH...POST-TROP/EXTRATROP
96H 02/1800Z 46.0N 40.2W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 03/1800Z...DISSIPATED

$$
Forecaster Kelly/Reinhart

[cycloneye]

BULLETIN
Hurricane Franklin Intermediate Advisory Number 37A
NWS National Hurricane Center Miami FL AL082023
800 PM AST Tue Aug 29 2023

...TROPICAL STORM CONDITIONS EXPECTED IN BERMUDA
BEGINNING TOMORROW MORNING...


SUMMARY OF 800 PM AST...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...31.9N 69.4W
ABOUT 275 MI...440 KM W OF BERMUDA
MAXIMUM SUSTAINED WINDS...125 MPH...205 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...947 MB...27.97 INCHES

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 38
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Tue Aug 29 2023

...TROPICAL STORM CONDITIONS EXPECTED IN BERMUDA
BEGINNING TOMORROW MORNING...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...32.3N 69.0W
ABOUT 245 MI...395 KM W OF BERMUDA
MAXIMUM SUSTAINED WINDS...115 MPH...185 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 12 MPH...19 KM/H
MINIMUM CENTRAL PRESSURE...953 MB...28.15 INCHES



Hurricane Franklin Discussion Number 38
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Tue Aug 29 2023

Cloud tops are beginning to warm around Franklin's rather large eye.
A GMI microwave pass at 0136 UTC showed that the southern edge of
the eyewall was beginning to erode. The hurricane passed over NOAA
buoy 41048 around 00 UTC and measured a central pressure of 955 mb
with 20 kt of wind. The initial intensity has been lowered to 100
kt for this advisory and is closest to the TAFB estimate.

Franklin is moving to the northeast at 10 kt. This motion is
expected to continue for the next day or so as the hurricane moves
around the northwest periphery of a subtropical ridge. Beyond 24 h,
Franklin is expected to begin interacting with a trough moving off
the northeast coast of the US and turn to the east-northeast with an
increase in forward speed. However, global model guidance has
significantly decreased the forward motion of the storm and the
along-track position uncertainty remains higher than normal. The
new official track forecast has shifted slightly south of the
previous prediction and has slowed noticeably. Even though the
center of Franklin is forecast to pass to the northwest of Bermuda
on Wednesday, tropical-storm-force winds associated with the
hurricane are expected to extend well to the southeast of the
center.

Franklin appears to be starting a gradual weakening trend. In a
day so, model guidance suggests the vertical wind shear should
increase as it gets caught in the upper-level trough. Franklin is
still expected to complete its extratropical transition around day
3 and dissipate by the end of the forecast period. The NHC
intensity forecast has been lowered slightly from the previous
cycle and remains close the various consensus aids.


KEY MESSAGES:

1. Tropical storm conditions are expected on Bermuda beginning
Wednesday morning, when Franklin is forecast to make its closest
approach to the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0300Z 32.3N 69.0W 100 KT 115 MPH
12H 30/1200Z 33.5N 67.6W 95 KT 110 MPH
24H 31/0000Z 34.7N 65.0W 90 KT 105 MPH
36H 31/1200Z 35.8N 61.7W 85 KT 100 MPH
48H 01/0000Z 36.8N 58.0W 75 KT 85 MPH
60H 01/1200Z 38.3N 53.8W 65 KT 75 MPH
72H 02/0000Z 40.3N 49.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 03/0000Z 45.2N 41.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 04/0000Z...DISSIPATED

$$
Forecaster Bucci

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 39
NWS National Hurricane Center Miami FL AL082023
500 AM AST Wed Aug 30 2023

...FRANKLIN IS A LARGE HURRICANE AND IS PRODUCING SIGNIFICANT SURF
AND RIP CURRENTS ALONG THE EASTERN SEABOARD...
...TROPICAL STORM CONDITIONS ARE EXPECTED IN BERMUDA LATER TODAY...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...33.0N 68.2W
ABOUT 205 MI...325 KM WNW OF BERMUDA
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...NE OR 45 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...956 MB...28.23 INCHES




Hurricane Franklin Discussion Number 39
NWS National Hurricane Center Miami FL AL082023
500 AM AST Wed Aug 30 2023

Franklin has a large eye this morning since completing its eyewall
replacement cycle yesterday. The estimated diameter from satellite
data is about 50 n mi. With that said, there are some subtle signs
that vertical wind shear over the system has begun to increase. The
hurricane's outflow has become restricted in the western side of the
storm, related to the outflow of Idalia spreading quickly towards
it. Intensity estimates have been gradually decreasing, and the
initial intensity was lowered to 95 kt this advisory. This intensity
lies roughly in between the higher TAFB and lower SAB subjective
estimates, and is very close to the most recent ADT and D-MINT
estimates provided by UW-CIMSS.

Franklin appears to be accelerating ever so slightly to the
northeast, with the motion of its large eye estimated at 040/11 kt.
This motion is expected to continue today with a turn to the
east-northeast in about 24-36 h. However, once again the guidance
this cycle has trended much slower compared to the previous
one. The ECMWF, which had been on the slow and south end of the
guidance envelope for days now, related to it missing the
mid-latitude trough capture, is no longer alone, with the latest GFS
forecast substantially slower and also missing an initial trough
capture. The track forecast has thus been slowed down again from the
prior cycle, but since most of this track adjustment was in the
along- and not across-track direction, it actually lies pretty much
on top of the prior NHC track, just slower. This current forecast
may need to be adjusted further in subsequent cycles, as suggested
by the TVCA and HCCA consensus aids. Even though the center of
Franklin is still forecast to pass to the northwest of Bermuda later
today, the large area of tropical-storm-force winds associated with
the hurricane to its southeast are expected to extend near or over
the island, where a tropical storm warning remains in place.

Intensity-wise, Franklin should gradually weaken early on, while
shear remains fairly low, but then more quickly as northwesterly
shear increases to between 20-30 kt from 24-48 h. Based on the
latest forecast track, it may take a bit longer for Franklin to
become an extratropical cyclone, and this is now delayed to day 4 in
the latest NHC intensity forecast. This intensity forecast is in
best agreement with the HCCA consensus aid.


KEY MESSAGES:

1. Tropical storm conditions are expected on Bermuda this morning,
when Franklin is forecast to make its closest approach to the
island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next several days.


FORECAST POSITIONS AND MAX WINDS

INIT 30/0900Z 33.0N 68.2W 95 KT 110 MPH
12H 30/1800Z 34.0N 66.6W 95 KT 110 MPH
24H 31/0600Z 35.0N 63.7W 90 KT 105 MPH
36H 31/1800Z 35.8N 60.6W 80 KT 90 MPH
48H 01/0600Z 37.0N 57.0W 70 KT 80 MPH
60H 01/1800Z 38.0N 53.5W 65 KT 75 MPH
72H 02/0600Z 40.0N 49.5W 60 KT 70 MPH
96H 03/0600Z 44.1N 44.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 04/0600Z 49.0N 43.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

[cycloneye]

BULLETIN
Hurricane Franklin Intermediate Advisory Number 39A
NWS National Hurricane Center Miami FL AL082023
800 AM AST Wed Aug 30 2023

...LARGE FRANKLIN EXPECTED TO BRING TROPICAL STORM CONDITIONS TO
BERMUDA LATER TODAY...
...DANGEROUS SURF AND RIP CURRENT CONDITIONS CONTINUE ALONG THE
EASTERN SEABOARD...


SUMMARY OF 800 AM AST...1200 UTC...INFORMATION
----------------------------------------------
LOCATION...33.3N 67.6W
ABOUT 180 MI...290 KM WNW OF BERMUDA
MAXIMUM SUSTAINED WINDS...110 MPH...175 KM/H
PRESENT MOVEMENT...NE OR 45 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...956 MB...28.23 INCHES

Hurricane Franklin Discussion Number 40
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Wed Aug 30 2023

The large eye of Franklin has become a bit ragged in recent
satellite images. Upper-level outflow from Hurricane Idalia
continues to impinge on the western side of Franklin's circulation,
and recent SSMIS microwave data show a thinner ring of inner core
convection on the western side of the eye, though the eyewall
remains closed. The overall satellite presentation has degraded some
since yesterday, and this is reflected in the latest objective and
subjective satellite estimates. The initial intensity is lowered
slightly to 90 kt, based on consensus T5.0/90 kt Dvorak estimates
from SAB and TAFB and UW-CIMSS ADT and AiDT estimates around 85-90
kt. Radar data from Bermuda reveal an outer band of the hurricane is
passing near the island, and tropical storm conditions are expected
to spread over the area within the next few hours.

The flow between a deep-layer trough over the eastern United States
and Canada and a high pressure ridge over the central Atlantic is
steering Franklin northeastward (50/11 kt). The aforementioned
trough is forecast to move eastward during the next couple of days,
and the flow ahead of this feature should cause Franklin to move
slightly faster toward the east-northeast. Little change was made to
this portion of the forecast. It is still unclear whether or not
Franklin will become completely captured by the trough, which
introduces greater uncertainty in the days 3-5 track forecast. The
GFS favors a faster northeastward motion with greater trough
interaction, while the ECMWF and UKMET keep Franklin on a slower
eastward track before it is steered deeper into the mid-latitudes.
The updated NHC forecast follows the consensus trends and is again
slower than the previous prediction beyond 72 h. Franklin is
forecast to become extratropical by 96 h, although this timing
largely depends on the extent of trough interaction.

Increasing northwesterly shear is expected over Franklin during the
next couple of days. This should induce at least gradual weakening
in the near term, though the tropical-storm-force wind field is
likely to expand as the system accelerates and gains latitude. The
updated track forecast brings Franklin over sub-26C waters in
about 72 h, with extratropical transition forecast to occur by 96
h. Note that this timing largely depends on the extent of trough
interaction that occurs in the coming days, so future adjustments
could be necessary.


KEY MESSAGES:

1. Tropical storm conditions are expected on Bermuda today while
Franklin makes its closest approach to the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next couple of days.


FORECAST POSITIONS AND MAX WINDS

INIT 30/1500Z 33.6N 67.1W 90 KT 105 MPH
12H 31/0000Z 34.4N 65.2W 85 KT 100 MPH
24H 31/1200Z 35.2N 62.2W 80 KT 90 MPH
36H 01/0000Z 36.1N 58.9W 75 KT 85 MPH
48H 01/1200Z 37.2N 55.3W 70 KT 80 MPH
60H 02/0000Z 38.4N 52.0W 65 KT 75 MPH
72H 02/1200Z 40.1N 49.0W 60 KT 70 MPH
96H 03/1200Z 44.5N 44.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 04/1200Z 49.1N 40.0W 45 KT 50 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 41
NWS National Hurricane Center Miami FL AL082023
500 PM AST Wed Aug 30 2023

...OUTER RAIN BANDS OF FRANKLIN SPREADING OVER BERMUDA...
...DANGEROUS SURF AND RIP CURRENT CONDITIONS CONTINUE ALONG THE
MID-ATLANTIC AND NORTHEASTERN UNITED STATES COAST...


SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...34.2N 65.9W
ABOUT 145 MI...235 KM NNW OF BERMUDA
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...NE OR 55 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...961 MB...28.38 INCHES


Hurricane Franklin Discussion Number 41
NWS National Hurricane Center Miami FL AL082023
500 PM AST Wed Aug 30 2023

The cloud pattern of Franklin has become oblong this afternoon,
likely due to increasing westerly shear associated with Idalia's
upper-level outflow. A ring of cold infrared cloud tops still
surrounds the large eye of the hurricane, which is now somewhat
elliptical in shape. The initial intensity is held at 90 kt, which
is supported by a T5.0 Dvorak classification from TAFB and UW-CIMSS
objective estimates between 85-90 kt. Radar images from Bermuda show
an outer rain band is spreading over the island, which will likely
result in gusty winds while it passes over the region.

Franklin is moving northeastward (55/11 kt) between a deep-layer
trough over the northeastern United States and a high pressure ridge
over the central Atlantic. The track guidance remains in good
agreement on the hurricane moving generally east-northeastward and
away from Bermuda during the next couple of days, and little change
was necessary to this part of the forecast. There are still
along-track differences in the global models regarding Franklin's
track at days 3-5 related to its interaction with the upper trough.
But, there is at least general agreement that the cyclone will turn
northeastward after it merges with a frontal system over the
northern Atlantic. The updated NHC track forecast remains relatively
close to the HFIP corrected consensus approach (HCCA) aid during
this period.

The satellite structure of Franklin is gradually degrading, and the
increasing shear that is forecast should keep the hurricane on a
weakening trend. The updated intensity forecast is fairly similar to
the previous one, with the most notable change being that Franklin
is now forecast to become a powerful extratropical cyclone by 72 h.
Some of the global guidance suggests this could occur even sooner,
so future forecast adjustments may be necessary. Although weakening
is forecast, the wind field is likely to grow in size as Franklin
moves deeper into the mid-latitudes.


KEY MESSAGES:

1. Tropical storm conditions, mainly in gusts, are expected on
Bermuda into this evening while Franklin passes north of the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next day or two.


FORECAST POSITIONS AND MAX WINDS

INIT 30/2100Z 34.2N 65.9W 90 KT 105 MPH
12H 31/0600Z 34.9N 63.9W 85 KT 100 MPH
24H 31/1800Z 35.8N 60.8W 75 KT 85 MPH
36H 01/0600Z 36.9N 57.4W 70 KT 80 MPH
48H 01/1800Z 38.1N 53.9W 65 KT 75 MPH
60H 02/0600Z 39.7N 50.7W 65 KT 75 MPH
72H 02/1800Z 41.6N 47.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 03/1800Z 45.0N 42.4W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 04/1800Z 50.0N 37.5W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 42
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Wed Aug 30 2023

...TROPICAL-STORM-FORCE WINDS OCCURRING IN BERMUDA AS FRANKLIN
PASSES TO THE NORTH...
...DANGEROUS SURF AND RIP CURRENT CONDITIONS CONTINUE ALONG THE
MID-ATLANTIC AND NORTHEASTERN UNITED STATES COAST...


SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...34.6N 64.5W
ABOUT 160 MI...255 KM N OF BERMUDA
MAXIMUM SUSTAINED WINDS...100 MPH...155 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 14 MPH...22 KM/H
MINIMUM CENTRAL PRESSURE...965 MB...28.50 INCHES

Hurricane Franklin Discussion Number 42
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Wed Aug 30 2023

Satellite imagery indicates the eye of Franklin is beginning to lose
its definition and become cloud-filled. Radar imagery from Bermuda
shows outer rain bands have been crossing the island this evening,
bringing sustained tropical-storm-force winds and gusty conditions.
The initial intensity estimate for this advisory has been lowered to
85 kt based on a blend of the CI and Final T-numbers from both TAFB
and SAB.

Franklin has turned to the east-northeast at an estimated 12 kt,
passing to the north of Bermuda. The hurricane is moving in the
flow between a subtropical ridge over the central Atlantic and a
trough over the northeastern U.S. Track guidance in the first 48 h
remains decently-clustered, showing Franklin continuing generally
east-northeastward with an increased forward speed. By 60 hours
and beyond, there is a larger spread in the guidance as Franklin
turns northeastward while it interacts with the upper-level trough.
The NHC track forecast is similar to the previous prediction and
lies between the simple consensus aid, TVCN, and the corrected
consensus aid, HCCA.

Based on the latest satellite trends, Franklin is continuing to
weaken in an environment of significant northerly vertical wind
shear. Only minor adjustments have been made to the latest official
forecast, which shows gradual weakening through 60 hours as the
vertical wind shear is expected to increase. By day 3, Franklin is
expected to become a strong extratropical cyclone, though this could
occur even sooner.


KEY MESSAGES:

1. Tropical storm conditions, mainly in gusts, are occuring on
Bermuda this evening while Franklin passes north of the island.

2. Life-threatening surf and rip currents are occurring along the
east coast of the United States. These conditions are expected to
continue during the next day or two.


FORECAST POSITIONS AND MAX WINDS

INIT 31/0300Z 34.6N 64.5W 85 KT 100 MPH
12H 31/1200Z 35.3N 62.3W 80 KT 90 MPH
24H 01/0000Z 36.5N 59.0W 75 KT 85 MPH
36H 01/1200Z 37.7N 55.8W 70 KT 80 MPH
48H 02/0000Z 39.2N 52.3W 65 KT 75 MPH
60H 02/1200Z 41.0N 49.1W 60 KT 70 MPH
72H 03/0000Z 42.7N 46.3W 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 04/0000Z 45.9N 41.2W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 05/0000Z 50.1N 35.5W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci

[cycloneye]

Hurricane Franklin Discussion Number 43
NWS National Hurricane Center Miami FL AL082023
500 AM AST Thu Aug 31 2023

Franklin continues to slowly succumb to the increasingly
unfavorable conditions the large hurricane is embedded in. The large
eye that had been evident over the last day or so is no longer
observed on infrared satellite imagery, likely due to 25-30 kt of
northerly shear affecting the convective structure which now favors
the southern side of the storm. This observation is also consistent
with the radar reflectivity returns from the Bermuda radar. With
that said, both the subjective and objective intensity estimates
this morning still support an intensity in the 85-90 kt range. Thus
Franklin's intensity will remain 85 kt this advisory, though this
may be generous.

Franklin continues to move to the east-northeast this morning at an
estimated 070/12 kt. As previously discussed, the hurricane is being
steered by the flow between a subtropical ridge to its southeast and
a trough now ejecting eastward out of the northeastern U.S. After
days of large track spread, the guidance this cycle is in better
agreement this morning, showing a continued east-northeast or
northeastward motion with gradual acceleration. The latest NHC
track forecast is not that much changed from the prior one, though
with a bit more acceleration towards the end of the forecast
period, trending towards the TVCN and HCCA consensus aids.

With continued northerly shear expected to persist another 24 hours,
Franklin should continue to weaken in the short-term. There may be a
brief period between 24-48 h where the shear temporarily decreases
as the hurricane becomes positioned in the right entrance region of
a jet streak as it interacts with a mid-latitude trough. This is why
the intensity forecast shows the weakening trend briefly pausing in
36-48 h. However, this baroclinic forcing will also likely hasten
its transition into an extratropical cyclone, with the latest
forecast now showing this being completed by 60 h, consistent with
simulated-IR imagery from the GFS and ECMWF at that time.

Now that Franklin is moving further away from Bermuda, the
Meteorological Service of Bermuda has discontinued the Tropical
Storm Warning for the island.


KEY MESSAGES:

1. Life-threatening surf and rip currents are occurring along the
east coast of the United States and Bermuda. These conditions are
expected to continue during the next day or two.


FORECAST POSITIONS AND MAX WINDS

INIT 31/0900Z 34.9N 63.2W 85 KT 100 MPH
12H 31/1800Z 35.8N 60.9W 75 KT 85 MPH
24H 01/0600Z 37.2N 57.6W 70 KT 80 MPH
36H 01/1800Z 38.7N 53.8W 65 KT 75 MPH
48H 02/0600Z 40.8N 49.6W 65 KT 75 MPH
60H 02/1800Z 43.3N 45.2W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 03/0600Z 45.5N 40.0W 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 04/0600Z 47.5N 34.9W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 05/0600Z 50.1N 30.0W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Papin

[cycloneye]

Hurricane Franklin Discussion Number 44
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Thu Aug 31 2023

Satellite imagery indicates that Franklin continues to battle
strong northerly shear associated with the outflow from Idalia.
Recent microwave data confirm its inner core has eroded, with deep
convection confined to the southeastern portion of the circulation.
There is a large spread in the recent intensity estimates, with
higher objective estimates than the consensus T4.5/5.0 Dvorak
classifications from SAB and TAFB. Given this uncertainty, the
initial intensity is held at 85 kt for this advisory.

Some gradual weakening is forecast during the next couple of days
while Franklin contends with the negative impacts of deep-layer
shear. However, the cyclone is expected to remain at or near
hurricane strength while increased baroclinic forcing and
interaction with the upper trough support its extratropical
transition. The GFS and ECMWF show fronts extending into Franklin's
circulation by 48 h, likely signaling completion of this process.
Therefore, the NHC forecast shows Franklin becoming a powerful
extratropical cyclone in 48 h. Thereafter, further weakening is
forecast while the cyclone moves deeper into the mid-latitudes, in
agreement with the latest global guidance.

Franklin is moving east-northeastward (70/12 kt) within the flow
between a deep-layer trough moving off the coast of the northeastern
U.S. and eastern Canada and a subtropical ridge to the east. The
latest track guidance remains in very good agreement that Franklin
will accelerate toward the east-northeast or northeast during the
next couple of days. The NHC track forecast in the near term is
essentially an update of the previous one and remains close to the
TVCN and HCCA aids. Track model solutions diverge beyond day 3
regarding the track and speed of motion for the extratropical
cyclone over the northern Atlantic, and in general the latest NHC
forecast lies between the consensus aids and ensemble means.


FORECAST POSITIONS AND MAX WINDS

INIT 31/1500Z 35.1N 61.6W 85 KT 100 MPH
12H 01/0000Z 36.3N 59.3W 75 KT 85 MPH
24H 01/1200Z 37.8N 55.8W 70 KT 80 MPH
36H 02/0000Z 39.7N 51.7W 70 KT 80 MPH
48H 02/1200Z 42.0N 47.2W 65 KT 75 MPH...POST-TROP/EXTRATROP
60H 03/0000Z 44.2N 43.1W 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 03/1200Z 45.9N 39.1W 50 KT 60 MPH...POST-TROP/EXTRATROP
96H 04/1200Z 48.0N 33.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
120H 05/1200Z 50.5N 28.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

Hurricane Franklin Discussion Number 45
NWS National Hurricane Center Miami FL AL082023
500 PM AST Thu Aug 31 2023

The cloud pattern of Franklin has continued to erode this afternoon.
Deep convection is limited to the southeastern portion of its
circulation, as strong shear continues to negatively affect the
system. Scatterometer data from today show the hurricane is still
producing a very large area of winds greater than 50 kt, though the
resolution limitations of the instrument do not allow for a peak
intensity estimate. The conventional satellite intensity estimates
continue to decrease, and the initial intensity is lowered to 80 kt
based on a blend of the latest objective and subjective estimates.

Franklin is expected to lose tropical characteristics over the next
day or so, with strong shear continuing over the system and
intrusions of drier mid-level air into the circulation as it
accelerates deeper into the mid-latitudes. However, this will not
immediately lead to significant weakening of the system. The GFS and
ECMWF both show an enhancement of hurricane-force winds on the
western side of the storm while the system interacts with a
baroclinic system and begins extratropical transition. Thus, the
near-term intensity forecast shows little change in strength, and
Franklin appears likely to maintain hurricane-force winds through
its extratropical transition in 36 h. Thereafter, a faster weakening
trend is shown through the rest of the forecast period, which is
consistent with the latest multi-model consensus aids.

The initial motion of Franklin is east-northeastward at 65/12 kt. A
northeastward acceleration is forecast during the next couple of
days while the cyclone moves within the flow between a subtropical
ridge over the central Atlantic and a deep-layer trough over
Atlantic Canada. From there, the track guidance generally supports a
continued northeastward motion over the northern Atlantic, and this
forecast shows a slightly faster motion beyond day 3 to reflect the
model consensus trends this cycle.


FORECAST POSITIONS AND MAX WINDS

INIT 31/2100Z 36.0N 60.1W 80 KT 90 MPH
12H 01/0600Z 37.1N 57.7W 75 KT 85 MPH
24H 01/1800Z 38.9N 53.8W 75 KT 85 MPH
36H 02/0600Z 40.9N 49.7W 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 02/1800Z 43.2N 45.3W 60 KT 70 MPH...POST-TROP/EXTRATROP
60H 03/0600Z 45.1N 41.3W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 03/1800Z 46.6N 37.6W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 04/1800Z 49.5N 31.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 05/1800Z 52.5N 27.0W 30 KT 35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart

[cycloneye]

Hurricane Franklin Discussion Number 46
NWS National Hurricane Center Miami FL AL082023
1100 PM AST Thu Aug 31 2023

Convection is separating from the low-level circulation of Franklin
this evening. Infrared satellite imagery show the coldest cloud
tops limited to the southeast quadrant, confirming the cyclone is
experiencing significant vertical wind shear. Subjective and
objective satellite intensity estimates have continued to decrease
and range from 70-77 kt. The initial intensity has been lowered to
75 kt for this advisory.

Franklin is forecast to complete its extratropical transition during
the next day or so. However, global models indicate it will remain
a powerful system despite losing its tropical characteristics.
Therefore, the official intensity forecast shows Franklin gradually
weakening before becoming a hurricane-force extratropical cyclone.
A faster weakening trend is predicted later in the forecast period,
similar to the previous prediction and lies on the higher end of
the guidance envelope.

The hurricane is moving to the east-northeast at 13 kt. The track
reasoning remains unchanged. An acceleration generally
northeastward is expected during the next couple of days as the
hurricane is steered by the flow between a subtropical ridge over
the central Atlantic and a deep-layer trough over the coast of
Atlantic Canada. The track guidance is in good agreement and little
changes have been made to the official forecast.


FORECAST POSITIONS AND MAX WINDS

INIT 01/0300Z 36.8N 58.6W 75 KT 85 MPH
12H 01/1200Z 38.1N 56.0W 75 KT 85 MPH
24H 02/0000Z 40.0N 51.9W 70 KT 80 MPH
36H 02/1200Z 42.2N 47.5W 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 03/0000Z 44.3N 43.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
60H 03/1200Z 46.0N 39.8W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 04/0000Z 47.3N 36.0W 45 KT 50 MPH...POST-TROP/EXTRATROP
96H 05/0000Z 50.1N 30.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 06/0000Z 53.2N 25.8W 30 KT 35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Bucci

[cycloneye]

BULLETIN
Hurricane Franklin Advisory Number 47
NWS National Hurricane Center Miami FL AL082023
500 AM AST Fri Sep 01 2023

...FRANKLIN EXPECTED TO BECOME AN EXTRATROPICAL CYCLONE
TONIGHT...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION
----------------------------------------------
LOCATION...37.8N 57.0W
ABOUT 580 MI...935 KM NE OF BERMUDA
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...ENE OR 60 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...983 MB...29.03 INCHES





Hurricane Franklin Discussion Number 47
NWS National Hurricane Center Miami FL AL082023
500 AM AST Fri Sep 01 2023

Franklin has a much more asymmetric appearance this morning,
indicative of the increasingly disruptive upper-wind pattern
associated with an approaching mid-latitude baroclinic zone. In
fact, the remaining deep convective mass is about 100 mi southeast
of the surface center. The initial intensity is lowered to 70 kt
and is based on a compromise of the available subjective and
objective intensity estimate techniques.

Franklin is showing signs of losing its tropical characteristics
while drier, more stable mid-level air and increasing northwesterly
shear impedes over the northwest portion of the cyclone.
Consequently, the completion of an extratropical transition is
expected later tonight or early Saturday. However, little change in
strength is forecast, and Franklin should maintain its
hurricane-force sustained winds through the weekend. By early next
week, gradual weakening is expected, which agrees with a blend of
the intensity consensus guidance and the statistical-dynamic SHIPS
models.

Franklin's initial motion is estimated to be east-northeastward or
060/16 kt. An increase in forward speed toward the northeast is
forecast. At the same time, Franklin moves within the mid-latitude
steering flow between high pressure to the east, over the central
Atlantic, and an extensive baroclinic system moving out of the
Canadian Maritimes. Global model spread continues to increase
beyond day 3. Two scenarios are possible. The European models
take a southeastward track while interacting with a larger
cut-off low meandering west of the Iberian peninsula. The other
solution involves the GFS and the regional guidance which gradually
turns the cyclone northeastward to northward over the northeast
Atlantic. The official forecast track indicates a blend of the two
model clusters, lying between both, and is close to the multi-model
consensus aid.

FORECAST POSITIONS AND MAX WINDS

INIT 01/0900Z 37.8N 57.0W 70 KT 80 MPH
12H 01/1800Z 39.1N 54.3W 70 KT 80 MPH
24H 02/0600Z 41.2N 49.8W 70 KT 80 MPH...POST-TROP/EXTRATROP
36H 02/1800Z 43.5N 45.5W 65 KT 75 MPH...POST-TROP/EXTRATROP
48H 03/0600Z 45.7N 41.1W 60 KT 70 MPH...POST-TROP/EXTRATROP
60H 03/1800Z 47.2N 36.6W 50 KT 60 MPH...POST-TROP/EXTRATROP
72H 04/0600Z 48.4N 32.8W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 05/0600Z 50.3N 27.9W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 06/0600Z 51.6N 25.0W 30 KT 35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Roberts

[cycloneye]

Hurricane Franklin Discussion Number 48
NWS National Hurricane Center Miami FL AL082023
1100 AM AST Fri Sep 01 2023

The latest satellite images of Franklin indicate the system is
gradually losing tropical characteristics. The inner circulation of
the system is exposed, with a curved band of deep convection
displaced to the east of its center by strong westerly shear. The
low-level center is also losing definition and appears more
elongated than yesterday. A cold front is racing southeastward
toward Franklin, with rope clouds evident in visible satellite
imagery over the northern Atlantic. Recent scatterometer data shows
peak winds of 55-60 kt to the west of the center, with a larger area
of 34-kt winds in the northwest quadrant due to the approaching
front. Based on these data, the initial intensity is set at 65 kt.

In the short term, Franklin appears likely to remain at or near
hurricane-force intensity due to baroclinic forcing while it merges
with a frontal system over the northern Atlantic. This scenario is
supported by all the global models, which show a narrow band of
strong winds persisting within the western portion of the
circulation during the next 12-24 h (consistent with the
aforementioned ASCAT data). Soon thereafter, the extratropical
cyclone is forecast to weaken as the low moves deeper into the
mid-latitudes and gradually fills. The updated NHC intensity
forecast lies between the GFS and ECMWF in the near term, and then
trends toward the multi-model consensus later in the period.

Franklin is moving northeastward (50 degrees/16 kt) within the flow
between a deep-layer trough over the northwestern Atlantic and a
subtropical ridge over the central Atlantic. A somewhat faster
motion to the northeast is anticipated during the next day or so,
followed by a continued northeastward to east-northeastward motion
into early next week. Through 72 h, the updated NHC forecast lies
close to the previous prediction. As discussed with prior forecasts,
track uncertainty grows beyond day 3 regarding how much interaction
will occur between Franklin and a larger cut-off low meandering over
the eastern Atlantic. The latest NHC track has been adjusted south
of the previous forecast at days 4-5, but future adjustments could
be necessary as it still lies north of the TVCA and HCCA aids.


FORECAST POSITIONS AND MAX WINDS

INIT 01/1500Z 38.7N 55.6W 65 KT 75 MPH
12H 02/0000Z 40.1N 52.4W 70 KT 80 MPH...POST-TROP/EXTRATROP
24H 02/1200Z 42.5N 47.8W 65 KT 75 MPH...POST-TROP/EXTRATROP
36H 03/0000Z 44.7N 43.4W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 03/1200Z 46.5N 39.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
60H 04/0000Z 47.9N 34.5W 45 KT 50 MPH...POST-TROP/EXTRATROP
72H 04/1200Z 48.6N 31.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 05/1200Z 49.0N 28.0W 35 KT 40 MPH...POST-TROP/EXTRATROP
120H 06/1200Z 49.5N 22.0W 30 KT 35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Reinhart