ATL: ALBERTO - Post-Tropical

[robbielyn]

Maybe nhc holding off as long as possible since it’s borderline possibility of a hurricane because of the loss of tourist dollars that would be lost. I know that they won’t endanger others but the want to make real sure first. Since it has gone more east it has more shear and dry air to contend with whereas before it had better conditions to work with if it had gone west to begin with it would have for sure had better chances along with warmer ssts by louisiana, to become a hurricane. now it’s a little iffy.

[jdjaguar]

I think the gusts may be tantamount to spiral bands that are rotating into the storm. The gusts are only in the 30 MPH range along the east coast.

For curiousity I like taking a look at the HRRR mesoscale model to predict conditions within the next 12-18 hours - this may not verify but look at the training bands draped over Southeast FL...

Glad you directed attention to the training bands. IRMA wrapped one of those right over my locale last Sept
That generated 90-95mph gusts. Local weather office at the time was posting max 60-65 expected winds.

One needs to be alert.

[DestinHurricane]

With the GFS forecasting a Cat 1 hurricane at landfall, I expect hurricane watches to be posted on the next advisory.

and HMON, FV3 GFS, nam 12km and nam 32km all show hurricane

[Bocadude85]

Euro Gfs Canadian and Nam all in agreement on extreme NW Florida

The Western Florida panhandle is a good bet, all the models seem locked in on this area.

[SFLcane]

HRRR showing quite the intense outer rain bands training over SFL on Sunday.

[Bocadude85]

HRRR showing quite the intense outer rain bands training over SFL on Sunday.

May be why the latest Euro is showing TS force gusts on the Florida east coast.

[Bocadude85]

With the GFS forecasting a Cat 1 hurricane at landfall, I expect hurricane watches to be posted on the next advisory.

and HMON, FV3 GFS, nam 12km and nam 32km all show hurricane

The 18z run of the NAM’s do not show a hurricane at landfall, most seem to be in the 50kts range.

[cycloneye]

DDHHMM

BULLETIN
Subtropical Storm Alberto Advisory Number 6
NWS National Hurricane Center Miami FL AL012018
400 PM CDT Sat May 26 2018

...ALBERTO EXPECTED TO STRENGTHEN AS IT MOVES NORTHWARD OVER THE
EASTERN GULF OF MEXICO...
...HEAVY RAINFALL CONTINUES TO SPREAD NORTHWARD OVER FLORIDA...


SUMMARY OF 400 PM CDT...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...23.3N 85.1W
ABOUT 95 MI...155 KM N OF THE WESTERN TIP OF CUBA
ABOUT 170 MI...275 KM SW OF THE DRY TORTUGAS
MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H
PRESENT MOVEMENT...N OR 10 DEGREES AT 13 MPH...20 KM/H
MINIMUM CENTRAL PRESSURE...999 MB...29.50 INCHES


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

A Tropical Storm Warning has been issued for the west coast of the
Florida peninsula from Bonita Beach to the Anclote River.

A Tropical Storm Warning has been issued for the northern Gulf Coast
from the Aucilla River westward to the Mississippi/Alabama border.

The Tropical Storm Watch has been discontinued west of the Mouth of
the Pearl River including Lake Pontchartrain and Lake Maurepas.

The Storm Surge Watch has been discontinued to the west of the
Mouth of the Pearl River.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Storm Surge Watch is in effect for...
* Crystal River to the Mouth of the Pearl River

A Tropical Storm Warning is in effect for...
* Cuban province of Pinar del Rio
* Dry Tortugas
* Bonita Beach to Anclote River
* Aucilla River to the Mississippi/Alabama border

A Tropical Storm Watch is in effect for...
* Mississippi/Alabama border to the Mouth of the Pearl River

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 Warning means that tropical storm conditions are
expected somewhere within the warning area.

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 23.3 North, longitude 85.1 West. The storm
is moving toward the north near 13 mph (20 km/h). A slower
northward or north-northeastward motion is expected tonight,
followed by a north-northwest turn on Sunday, and this general
motion should continue into Tuesday. On the forecast track, the
center of Alberto is forecast to move over the eastern Gulf of
Mexico tonight through Sunday night, and approach the northern Gulf
Coast in the warning area on Monday. Heavy rainfall and tropical
storm conditions will likely reach the northern Gulf Coast well
before the arrival of the center of Alberto.

Maximum sustained winds are near 40 mph (65 km/h) with higher gusts.
Gradual strengthening is forecast until the system reaches the
northern Gulf Coast on Monday.

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

The estimated minimum central pressure is 999 mb (29.50 inches).


HAZARDS AFFECTING LAND
----------------------
RAINFALL: Alberto is expected to produce total rain accumulations
of 10 to 15 inches with isolated totals of 25 inches across western
Cuba. These rains could produce life-threatening flash floods and
mudslides. Rainfall accumulations of 3 to 7 inches with maximum
amounts of 10 inches are possible across the Florida Keys and
southern and southwest Florida. Heavy rains will begin to affect
the central Gulf Coast region into the southeastern United States on
Sunday and continue into the middle of next week as Alberto moves
northward after landfall. Rainfall totals of 5 to 10 inches with
maximum amounts of 15 inches are possible along the track of Alberto
from eastern Louisiana, across much of Mississippi, Alabama, western
Tennessee and the western Florida panhandle. Rainfall totals of 3
to 5 inches with maximum totals of 8 inches are possible from the
southern Appalachians into the coastal southeast United States.

WIND: Tropical storm conditions are expected within portions of the
warning area in Cuba through this evening. Tropical Storm
conditions are expected in the Dry Tortugas and in the warning
area along the west coast of Florida beginning Sunday. Tropical
Storm conditions are expected within the warning area along the
northern Gulf Coast by Sunday night. Tropical Storm conditions
are possible in the watch area along the northern Gulf Coast by
early Monday.

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...

Crystal River to the Mouth of the Pearl 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.

TORNADOES: Isolated tornadoes are possible this evening and
tonight across parts of west-central Florida, including the Keys.

SURF: Swells generated by Alberto are expected to spread
northward along the eastern and northern Gulf Coast through Monday.
These swells are likely to cause life-threatening surf and rip
current conditions. 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 Brown





Subtropical Storm Alberto Discussion Number 6
NWS National Hurricane Center Miami FL AL012018
400 PM CDT Sat May 26 2018

Before departing the storm, the Air Force Reserve Hurricane Hunter
aircraft flew near the low-level cloud swirl that became apparent
in visible satellite imagery over the southeastern Gulf of
Mexico late this morning. Data from the plane indicate that the
center had reformed in that location and that the pressure had
fallen to 999 mb. The aircraft did not sample the area to the east
of the new center, but based on recent satellite classifications and
surface observations the initial intensity remains 35 kt for this
advisory.

The primary mechanism for intensification appears to be a shortwave
trough moving southeastward into the larger negatively tilted trough
over the eastern Gulf, which should cause a cutoff low to form
during the next 24 hours. This is expected to result in deepening
of Alberto while it moves generally northward over the Gulf of
Mexico on Sunday and Sunday night. The shear is forecast to
decrease as Alberto become co-located with the upper-level low and
the system could transition to a more tropical cyclone-like
structure before landfall. The NHC intensity forecast once again
calls for steady strengthening through 36 h, but shows little
strengthening after that time due to the possibility of dry air
intrusion.

The system has moved generally northward during the past 24 hours,
however, the reformation of the center today makes the initial
motion estimate more uncertain than normal. Alberto should move
northward to north-northeastward tonight, and then turn
north-northwestward and decelerate on Sunday and Sunday night as
it moves around the eastern side of the trough/cutoff low. The
dynamical models remain in good agreement on this scenario but
have shifted eastward once again. The interpolated guidance models
lie a bit west of the model fields due to the more northwestward
1800 UTC initial position of Alberto. As a result, the NHC track is
along the eastern edge of the guidance envelope as a compromise
between the ECMWF/GFS model fields and trackers.

The new NHC track forecast has required the issuance of a
Tropical Storm Warning for a portion of the west coast of Florida
and a Tropical Storm Warning for a portion of the northern Gulf
Coast.


KEY MESSAGES:

1. Regardless of its exact track and intensity, Alberto is expected
to produce heavy rainfall and flash flooding over western Cuba,
southern Florida and the Florida Keys. Rainfall and flooding
potential will increase across the central U.S. Gulf Coast region
and over much of the southeastern United States beginning Sunday
and will continue into next week.

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. Residents in the warning and 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 will likely spread
northward along the eastern and northern Gulf Coast through Monday.


FORECAST POSITIONS AND MAX WINDS

INIT 26/2100Z 23.3N 85.1W 35 KT 40 MPH
12H 27/0600Z 25.4N 84.9W 45 KT 50 MPH
24H 27/1800Z 27.5N 85.3W 50 KT 60 MPH
36H 28/0600Z 28.9N 86.3W 55 KT 65 MPH...TROPICAL STORM
48H 28/1800Z 30.0N 87.0W 55 KT 65 MPH...TROPICAL STORM
72H 29/1800Z 33.6N 87.9W 30 KT 35 MPH...INLAND
96H 30/1800Z 38.3N 87.5W 20 KT 25 MPH...INLAND
120H 31/1800Z 42.4N 83.4W 15 KT 15 MPH...POST-TROPICAL

$$
Forecaster Brown

[cycloneye]

A Tropical Storm Warning has been issued for the west coast of the
Florida peninsula from Bonita Beach to the Anclote River.

A Tropical Storm Warning has been issued for the northern Gulf Coast
from the Aucilla River westward to the Mississippi/Alabama border.

The Tropical Storm Watch has been discontinued west of the Mouth of
the Pearl River including Lake Pontchartrain and Lake Maurepas.

The Storm Surge Watch has been discontinued to the west of the
Mouth of the Pearl River.

[cycloneye]

A Tropical Storm Warning has been issued for the west coast of the
Florida peninsula from Bonita Beach to the Anclote River.

A Tropical Storm Warning has been issued for the northern Gulf Coast
from the Aucilla River westward to the Mississippi/Alabama border.

The Tropical Storm Watch has been discontinued west of the Mouth of
the Pearl River including Lake Pontchartrain and Lake Maurepas.

[txwatcher91]

With the GFS forecasting a Cat 1 hurricane at landfall, I expect hurricane watches to be posted on the next advisory.

and HMON, FV3 GFS, nam 12km and nam 32km all show hurricane

The 18z run of the NAM’s do not show a hurricane at landfall, most seem to be in the 50kts range.

12z run had it for 3km NAM and 18z run was 982mb which would probably be cat 1.

[Bocadude85]

and HMON, FV3 GFS, nam 12km and nam 32km all show hurricane

The 18z run of the NAM’s do not show a hurricane at landfall, most seem to be in the 50kts range.

12z run had it for 3km NAM and 18z run was 982mb which would probably be cat 1.

Look at the 10m winds, they are not close to hurricane strength.

[cycloneye]

[tarheelprogrammer]

Just an opinion here, and no science included. I think this system will never really get going. It is likely to stay near the intensity it is currently at. It was luck that helped here. A track further west would of been much worse.

Opinions are welcome. So by not really getting going..do you think 65 mph is too high?

Yes. Somewhere near 40. Not close to hurricane strength. Just my dumb opinion lol.

[tolakram]

saved loop, Key West radar.

[Shell Mound]

I think that the reformation of the centre has greatly reduced the threat of a strong tropical storm or hurricane impact to the FL Panhandle. The reformation has placed Alberto on the eastern flank of the cutoff low rather than directly beneath, resulting in stronger vertical wind shear at all levels. The resulting eastward shift in the track also brings the system over cooler shelf waters closer to the west coast of FL, meaning a more stable boundary layer before continental dry air begins to intrude. I'm now thinking that Alberto won't strengthen much beyond what it has already done, given greater-than-expected shear, cooler SSTs, and then dry air near the FL Panhandle, all owing to the reformation of the centre. I think a maximum intensity of more than 50 knots is rather unlikely at this stage, and that the NHC, while logically conservative, may adjust its peak downward in future advisory packages. Plus, NWS forecasts for rainfall over NW FL and S AL now call for peak amounts of up to ten inches, which is significantly less than the point maxima of fifteen to twenty inches being highlighted just a few days ago. Overall, the news is good across the board, though everyone should be ready for Alberto. A typical late-May TS just and a timely reminder in time for the 2018 season...

[tolakram]

I'm going to disagree with the lower estimates. The GFS has had the eastern solution for a while and continues to show LLC re-formations or the LLC being pulled around until well NW of the cooler waters. Both the Euro and GFS show strengthening very close to landfall. I do think it stays just below hurricane strength but I don't think it will stay weak.

[Bocadude85]

I'm going to disagree with the lower estimates. The GFS has had the eastern solution for a while and continues to show LLC re-formations or the LLC being pulled around until well NW of the cooler waters. Both the Euro and GFS show strengthening very close to landfall. I do think it stays just below hurricane strength but I don't think it will stay weak.

Agreed, I think the NHC forecast is spot on. 65mph TS into the panhandle.

[tolakram]

[Kazmit]

Shear is decreasing.