ATL: ALBERTO - Post-Tropical

[Aric Dunn]

by the way.. couple ship reports. 45 and 55 mph in that limited convection how accurate they are who knows. but there are few.

[blp]

So looks so far only the decaying LLC we have been watching all day is the one they found.

[tarheelprogrammer]

So, that little swirl is the center? It hasn't moved much. How will this affect the track? It seems to be taking its time leaving the Caribbean.

[Aric Dunn]

So, that little swirl is the center? It hasn't moved much. How will this affect the track? It seems to be taking its time leaving the Caribbean.

It is still within the model forecast. the center is not supposed to be moving north/ north of the yucatan until early tomorrow. so no changes thus far.

Though expect to see something take share near the NE tip of the Yucatan.... slowly

[cycloneye]

SUBTROPICAL STORM ALBERTO FORECAST/ADVISORY NUMBER 2
NWS NATIONAL HURRICANE CENTER MIAMI FL AL012018
2100 UTC FRI MAY 25 2018

CHANGES IN WATCHES AND WARNINGS WITH THIS ADVISORY...

A STORM SURGE WATCH HAS BEEN ISSUED FOR PORTIONS OF THE NORTHERN
GULF COAST OF THE UNITED STATES FROM HORSESHOE BEACH FLORIDA
WESTWARD TO THE MOUTH OF THE MISSISSIPPI RIVER.

A TROPICAL STORM WATCH HAS BEEN ISSUED FOR PORTIONS OF THE NORTHERN
GULF COAST OF THE UNITED STATES FROM INDIAN PASS FLORIDA WESTWARD TO
GRAND ISLE LOUISIANA...INCLUDING LAKE PONTCHARTRAIN...LAKE
MAUREPAS...AND METROPOLITAN NEW ORLEANS.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A STORM SURGE WATCH IS IN EFFECT FOR...
* HORSESHOE BEACH TO THE MOUTH OF THE MISSISSIPPI RIVER

A TROPICAL STORM WATCH IS IN EFFECT FOR...
* TULUM TO CABO CATOCHE MEXICO
* CUBAN PROVINCE OF PINAR DEL RIO
* INDIAN PASS TO GRAND ISLE
* LAKE PONTCHARTRAIN AND LAKE MAUREPAS

A STORM SURGE WATCH MEANS THERE IS A POSSIBILITY OF LIFE-
THREATENING INUNDATION FROM RISING WATER MOVING INLAND FROM THE
COASTLINE IN THE INDICATED LOCATIONS DURING THE NEXT 48 HOURS.
FOR A DEPICTION OF AREAS AT RISK PLEASE SEE THE NATIONAL WEATHER
SERVICE STORM SURGE WATCH/WARNING GRAPHIC AVAILABLE AT
HURRICANES.GOV.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE IN THE YUCATAN AND CUBA PORTIONS OF THE WATCH AREA IN
THIS CASE WITHIN THE NEXT 24 HOURS.

A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE
POSSIBLE IN THE UNITED STATES PORTION OF THAT WATCH AREA WITHIN
48 HOURS.

SUBTROPICAL STORM CENTER LOCATED NEAR 19.4N 86.3W AT 25/2100Z
POSITION ACCURATE WITHIN 30 NM

PRESENT MOVEMENT TOWARD THE EAST OR 90 DEGREES AT 2 KT

ESTIMATED MINIMUM CENTRAL PRESSURE 1005 MB
MAX SUSTAINED WINDS 35 KT WITH GUSTS TO 45 KT.
34 KT.......120NE 100SE 0SW 0NW.
12 FT SEAS..120NE 0SE 0SW 0NW.
WINDS AND SEAS VARY GREATLY IN EACH QUADRANT. RADII IN NAUTICAL
MILES ARE THE LARGEST RADII EXPECTED ANYWHERE IN THAT QUADRANT.

REPEAT...CENTER LOCATED NEAR 19.4N 86.3W AT 25/2100Z
AT 25/1800Z CENTER WAS LOCATED NEAR 19.4N 86.4W

FORECAST VALID 26/0600Z 20.7N 86.0W
MAX WIND 40 KT...GUSTS 50 KT.
34 KT...120NE 100SE 0SW 0NW.

FORECAST VALID 26/1800Z 22.5N 85.7W
MAX WIND 45 KT...GUSTS 55 KT.
34 KT...120NE 100SE 0SW 0NW.

FORECAST VALID 27/0600Z 24.8N 85.6W
MAX WIND 50 KT...GUSTS 60 KT.
50 KT... 50NE 0SE 0SW 0NW.
34 KT...120NE 120SE 0SW 0NW.

FORECAST VALID 27/1800Z 26.8N 86.2W...TROPICAL STORM
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 0NW.
34 KT...130NE 120SE 0SW 80NW.

FORECAST VALID 28/1800Z 29.0N 87.8W...TROPICAL STORM
MAX WIND 55 KT...GUSTS 65 KT.
50 KT... 50NE 50SE 0SW 40NW.
34 KT...130NE 120SE 0SW 80NW.

EXTENDED OUTLOOK. NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 150 NM
ON DAY 4 AND 175 NM ON DAY 5...AND FOR INTENSITY NEAR 15 KT EACH DAY

OUTLOOK VALID 29/1800Z 31.7N 88.6W...INLAND
MAX WIND 30 KT...GUSTS 40 KT.

OUTLOOK VALID 30/1800Z 35.2N 87.6W...INLAND
MAX WIND 20 KT...GUSTS 30 KT.

REQUEST FOR 3 HOURLY SHIP REPORTS WITHIN 300 MILES OF 19.4N 86.3W

NEXT ADVISORY AT 26/0300Z

$$
FORECASTER STEWART


BULLETIN
Subtropical Storm Alberto Advisory Number 2
NWS National Hurricane Center Miami FL AL012018
400 PM CDT Fri May 25 2018

...TROPICAL STORM AND STORM SURGE WATCHES ISSUED FOR THE
NORTH-CENTRAL GULF COAST...
...HEAVY RAINFALL EXPECTED TO AFFECT THE YUCATAN PENINSULA...WESTERN
CUBA...FLORIDA...AND THE NORTHEASTERN GULF COAST THROUGH THE
WEEKEND...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...19.4N 86.3W
ABOUT 85 MI...135 KM SSE OF COZUMEL MEXICO
ABOUT 195 MI...315 KM SSW OF THE WESTERN TIP OF CUBA
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...E OR 90 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES


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

A Storm Surge Watch has been issued for portions of the northern
Gulf Coast of the United States from Horseshoe Beach, Florida,
westward to the Mouth of the Mississippi River.

A Tropical Storm Watch has been issued for portions of the northern
Gulf Coast of the United States from Indian Pass, Florida, westward
to Grand Isle, Louisiana, including Lake Pontchartrain, Lake
Maurepas, and metropolitan New Orleans.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Watch is in effect for...
* Horseshoe Beach to the Mouth of the Mississippi River

A Tropical Storm Watch is in effect for...
* Tulum to Cabo Catoche Mexico
* Cuban province of Pinar del Rio
* Indian Pass to Grand Isle
* Lake Pontchartrain and Lake Maurepas

A Storm Surge Watch means there is a possibility of life-
threatening inundation, from rising water moving inland from the
coastline, in the indicated locations during the next 48 hours.
For a depiction of areas at risk, please see the National Weather
Service Storm Surge Watch/Warning Graphic, available at
hurricanes.gov.

A Tropical Storm Watch means that tropical storm conditions are
possible in the Yucatan and Cuba portions of the watch area, in
this case within the next 24 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible in the United States portion of that watch area within
48 hours.

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 the
United States, please monitor products issued by your national
meteorological service.


DISCUSSION AND OUTLOOK
----------------------
At 400 PM CDT (2100 UTC), the center of Subtropical Storm Alberto
was located near latitude 19.4 North, longitude 86.3 West. The storm
is moving toward the east near 2 mph (4 km/h). A slow and erratic
motion toward the north is expected tonight. From Saturday
afternoon into Sunday, a general northward motion at a faster
forward speed is expected, followed by a turn toward the northwest
on Monday.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Gradual strengthening is forecast during the next 48 hours, with
little change in strength forecast on Monday.

Winds of 40 mph extend outward up to 140 miles (220 km) from the
center.

The estimated minimum central pressure is 1005 mb (29.68 inches)
based on recent data from an Air Force Reserve reconnaissance
aircraft.


HAZARDS AFFECTING LAND
----------------------
RAINFALL: Alberto is expected to produce total rain accumulations
of 10 to 15 inches with isolated totals of 25 inches across the
northeastern portions of the Yucatan Peninsula and western Cuba.
These rains could produce life-threatening flash floods and
mudslides. Rainfall accmumulations of 4 to 8 inches with maximum
amounts of 12 inches are possible across the Florida Keys and
southern and southwestern Florida. Heavy rain will likely begin
to affect the central Gulf Coast region and the southeastern Untied
States later this weekend and continue into early next week.
Flooding potential will increase across this region early next
week as Alberto is forecast to slow down after it moves inland.

WIND: Tropical storm conditions are possible within the watch
area in Cuba and the Yucatan Peninsula through Saturday. Tropical
storm conditions are possible within the United States watch
area beginning on Sunday.

STORM SURGE: The combination of storm surge and the 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...

Horseshoe Beach to the Mouth of the Mississippi River...2 to 4 ft

The deepest water will occur along the immediate coast. 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.

SURF: Swells generated by Alberto are affecting portions of
the coast of eastern Yucatan Peninsula and western Cuba. These
swells are likely to cause life-threatening surf and rip current
conditions. Hazardous surf conditions are likely to develop along
much of the central and eastern U.S. Gulf Coast this weekend. For
more information, consult products from your local weather office.


NEXT ADVISORY
-------------
Next intermediate advisory at 700 PM CDT.
Next complete advisory at 1000 PM CDT.

$$
Forecaster Stewart

[Aric Dunn]

or convection begins to build with the current circ. the mid and upper levels are beginning to moisten up so who knows.

[cycloneye]

A TROPICAL STORM WATCH HAS BEEN ISSUED FOR PORTIONS OF THE NORTHERN
GULF COAST OF THE UNITED STATES FROM INDIAN PASS FLORIDA WESTWARD TO
GRAND ISLE LOUISIANA...INCLUDING LAKE PONTCHARTRAIN...LAKE
MAUREPAS...AND METROPOLITAN NEW ORLEANS.

A STORM SURGE WATCH HAS BEEN ISSUED FOR PORTIONS OF THE NORTHERN
GULF COAST OF THE UNITED STATES FROM HORSESHOE BEACH FLORIDA
WESTWARD TO THE MOUTH OF THE MISSISSIPPI RIVER.

[chaser1]

Curious, but I thought I noticed a 2 millibar drop at Key West over the last 2 hours

[cycloneye]

The discussion was released late so here it is.

Subtropical Storm Alberto Discussion Number 2
NWS National Hurricane Center Miami FL AL012018
400 PM CDT Fri May 25 2018

The inner-core low-level wind field of Alberto has changed little
since the previous advisory based on recent data from an Air Force
Reserve reconnaissance aircraft, along with land and ship
observations. However, the convective structure of the cyclone has
degraded over the past several hours due a pronounced intrusion of
dry mid-/upper-level air and the cloud pattern continues to exhibit
the structure of a subtropical cyclone. The lowest pressure measured
thus far by the aircraft has been 1006 mb. The initial position is a
little north of the recon position of a pronounced swirl due to the
broad overall nature of the low-level circulation.

The initial motion estimate is 090/02 kt, but this is considered to
be a short-term motion. A gradual turn toward the north should begin
later tonight due to a strong ridge located to the east across the
Greater Antilles. A steadier northward motion is forecast to occur
by Saturday evening and continue into Sunday as a sharp
mid/upper-level trough digging southward into the central Gulf of
Mexico combines with southerly flow around the western portion of a
large subtropical ridge to produce deep-layer southerly flow across
Alberto. By 48 hours and continuing through 72 hours, the developing
mid/upper-level low over the central Gulf should cause the cyclone
to turn northwestward and accelerate until it nears the Gulf Coast
by Monday night. After that, steering currents are forecast to
collapse as a broad weakness develops in the subtropical ridge axis
located along the Gulf coast. Slow but steady recurvature into the
westerlies across the Deep South is expected to begin by 96-120 h.
The new NHC forecast track is similar to the previous advisory,
and closely follows the consensus models TVCN and HCCA, and the
Florida State Superensemble (FSSE) model.

The broad nature of the inner-core wind field, along with strong
westerly wind shear in excess of 20 kt is forecast to continue for
the next 24 hours. The latest model runs actually decrease the shear
sooner than previously forecast, but the ragged nature of the wind
field should prevent any significant intensification until after 48
hours. As a result, only slow but steady strengthening is expected
for the next 3 days, and Alberto could peak around 60 kt around 60
hours when the storm will be in a low wind shear regime and
over SSTs greater than 28 deg C. However, proximity to dry mid-
level air around landfall could hinder any additional strengthening,
and the NHC intensity forecast remains similar to the previous
advisory, closely following a blend of the HCCA and ICON consensus
models and the FSSE model.

The new NHC forecast necessitates the issuance of tropical storm
and storm surge watches for portions of the U.S. Gulf Coast at
this time. Note that if the intensity forecast increases with later
advisories, a hurricane watch could be needed for a portion of the
Gulf Coast.

KEY MESSAGES:

1. Regardless of its exact track and intensity, Alberto is expected
to produce heavy rainfall and flash flooding over the northeaster
Yucatan Peninsula of Mexico, western Cuba, southern Florida and the
Florida Keys. Rainfall and flooding potential will increase across
the central U.S. Gulf Coast region and the southeastern United
States later this weekend and early next week when Alberto is
expected to slow down after it moves inland.

2. Tropical-storm-force winds and hazardous storm surge are
possible along portions of the central and eastern U.S. Gulf Coast
beginning on Sunday, including areas well east of the track of
Alberto's center, and tropical storm and storm surge watches have
been issued for portions of these areas. Residents in the watch
areas are encouraged not to focus on the details of the forecast
track of Alberto and should follow any guidance given by their local
government officials.

3. Dangerous surf and rip current conditions are affecting portions
of the Yucatan Peninsula and western Cuba and will likely spread
along the eastern and central U.S. Gulf Coast later this weekend.

FORECAST POSITIONS AND MAX WINDS

INIT 25/2100Z 19.4N 86.3W 35 KT 40 MPH
12H 26/0600Z 20.7N 86.0W 40 KT 45 MPH
24H 26/1800Z 22.5N 85.7W 45 KT 50 MPH
36H 27/0600Z 24.8N 85.6W 50 KT 60 MPH
48H 27/1800Z 26.8N 86.2W 55 KT 65 MPH...TROPICAL STORM
72H 28/1800Z 29.0N 87.8W 55 KT 65 MPH...TROPICAL STORM
96H 29/1800Z 31.7N 88.6W 30 KT 35 MPH...INLAND
120H 30/1800Z 35.2N 87.6W 20 KT 25 MPH...INLAND

$$
Forecaster Stewart

[Aric Dunn]

on a side note.. the current llc.. still has convergence and decent convective bands. I still dont see another vort anywhere. Also convection appears to might be trying to build with the LLC. it has a done a cyclonic loop today and another surge of tropical moisture is coming in from the east. could see some decent convection soon. but all depends on how much the mid levels moisten.

[cycloneye]

From discussion:

The new NHC forecast necessitates the issuance of tropical storm
and storm surge watches for portions of the U.S. Gulf Coast at
this time. Note that if the intensity forecast increases with later
advisories, a hurricane watch could be needed for a portion of the
Gulf Coast.

[stormlover2013]

I wanna wait till tomorrow night to see what models are showing still think this could take a left turn little bit

[CrazyC83]

NHC mentions they may need a hurricane watch, but also that dry air will be a hindrance leading up to landfall. I would it expect it to peak well before landfall, probably 12-24 hours in advance of it.

[RL3AO]

Curious, but I thought I noticed a 2 millibar drop at Key West over the last 2 hours

Looks correct. While the background pressures are dropping, much of that 2 mb pressure drop is apart of the daily cycle of pressure falls in the morning and evening. You can see the pressure min around 6 am and 6 pm local time.

[gatorcane]

UKMET track:

[gatorcane]

Most certainly closed with the LLC north of 20.

https://i.imgur.com/DnzRBK7.png

A bit NE of the 2pm advisory location.

Red circle is roughly where recon found west wind, blue circle roughly 2pm advisory location.

I think your red circle is the mid level circulation and the low level swirl just south and east of your blue circle is the low level center recon found.JMO.

Red circle may be working down to surface bases on latest sat loops, lets see if recon does further sampling of that area.

Red circle moving NE:

http://rammb.cira.colostate.edu/ramsdis ... display=12

[SouthFloridawx]

I wonder if the UKMET, might be the one to go with here.

[psyclone]

Interesting to note that the storm surge watch extends east of the TS watch area to include the very surge prone big bend/forgotten coast region...and for good reason. long timers may recall the gigantic water rise in that area as Dennis made landfall well to the west in 2005. the weather there was fair and yet St Marks got around 10 feet of water rise IIRC. with a protracted southerly flow...even below gale force...along with wave set up...the stage is set for a good bit of water stacking up that way. I wouldn't be surprised if we didn't have some water pile up east of there as well...even down to the cedar key/nature coast area. at least enough to warrant coastal flood headlines. farther south along the west coast beaches some erosion threat may materialize as it often does with southerly flow events.

[PTrackerLA]

FWIW the 18z NAM shifts a little west and goes directly over New Orleans then up towards Baton Rouge.

[blp]

A bit NE of the 2pm advisory location.

Red circle is roughly where recon found west wind, blue circle roughly 2pm advisory location.
[img]https://image.ibb.co/jdvBBT/Alberto.jpg[/]

I think your red circle is the mid level circulation and the low level swirl just south and east of your blue circle is the low level center recon found.JMO.

Red circle may be working down to surface bases on latest sat loops, lets see if recon does further sampling of that area.

Red circle moving NE:

http://rammb.cira.colostate.edu/ramsdis ... display=12

You can definitely see the competing areas. I don't think the blue one can survive because it is too far removed from the main convection but still looks good with a thickening lower cloud deck. The Red has to be the one that takes over for the models to verify.