Hurricane Debby

[wthrmn654]

its over water!

[Windspeed]

non the less very cool looking

*shrug* not close enough to assist in ventilating our newly forming TC. Well, perhaps a small amount of upper-level ventilation to the east, but still pretty minute. Not worth mentioning.

[NJwx85]

Spent the day in the Southern Bahamas, there were easily some 45-50kt gusts associated with rain squalls which began in the afternoon. Sea is angry and the ship has been rocking since yesterday. On our way to the Central Bahamas and Captain said it’s possible we might not be able to dock. Forecast is worse than what we experienced today.

[AccuChris]

Low level center definitely consolidating south of Cuba…future model runs should be interesting

[yoda]

BULLETIN
Tropical Depression Four Advisory Number   3
NWS National Hurricane Center Miami FL       AL042024
1100 PM EDT Fri Aug 02 2024

...TROPICAL DEPRESSION FORMS OFF THE SOUTH COAST OF CUBA...
...EXPECTED TO BECOME A TROPICAL STORM OVER THE SOUTHEASTERN GULF
OF MEXICO BY LATE SATURDAY...


SUMMARY OF 1100 PM EDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...21.4N 79.7W
ABOUT 75 MI...125 KM S OF CAIBARIEN CUBA
ABOUT 260 MI...415 KM SSE OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...WNW OR 285 DEGREES AT 17 MPH...28 KM/H
MINIMUM CENTRAL PRESSURE...1010 MB...29.83 INCHES


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

A Tropical Storm Warning has been issued for the Dry Tortugas.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* The Dry Tortugas
* West coast of the Florida peninsula from East Cape Sable to Boca
Grande

A Tropical Storm Watch is in effect for...
* The Florida Keys south of the Card Sound Bridge
* The southern coast of the Florida peninsula east of East Cape
Sable to the Card Sound Bridge
* The west coast of the Florida peninsula north of Boca Grande to
the mouth of the Suwannee River

A Storm Surge Watch is in effect for...
* Bonita Beach northward to the mouth of the Suwannee River,
including Tampa Bay and Charlotte Harbor

A Tropical Storm Warning means that tropical storm conditions are
expected somewhere within the warning area within 36 hours.

A Tropical Storm Watch means that tropical storm conditions are
possible within the watch area, generally within 48 hours.

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.

Interests elsewhere in Florida and the southeastern coast of the
United States should monitor the progress of this system. Additional
warnings and watches will likely be required for a portion of this 
on Saturday.

For storm information specific to your area, including possible
inland watches and warnings, please monitor products issued by your
local National Weather Service forecast office.


DISCUSSION AND OUTLOOK
----------------------
At 1100 PM EDT (0300 UTC), the center of Tropical Depression Four 
was located near latitude 21.4 North, longitude 79.7 West.  The 
depression is moving toward the west-northwest near 17 mph (28 
km/h).  A turn toward the northwest is forecast on Saturday, 
followed by a slower motion toward the north and then the northeast 
on Sunday and Monday.  On the forecast track, the center of the 
depression will move across Cuba overnight and on Saturday, and then 
move generally northward over the eastern Gulf of Mexico Saturday 
and Sunday, potentially reaching the Florida Gulf coast late Sunday 
or Monday.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts.
Strengthening is forecast during the next several days, and the 
depression is expected to become a tropical storm on Saturday and 
continue strengthening over the eastern Gulf of Mexico through the 
weekend.

The estimated minimum central pressure is 1010 mb (29.83 inches).


HAZARDS AFFECTING LAND
----------------------
WINDS: Tropical storm conditions are expected in the warning area
late Saturday and Saturday night.  Tropical storm conditions are
possible in the watch area in the Florida Keys and the southern
Florida peninsula by Saturday or Saturday night. Tropical storm
conditions are possible in the watch area along the Florida west
coast Saturday night and Sunday.

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...

Bonita Beach, FL to Suwannee River, FL...2-4 ft
Tampa Bay...2-4 ft
Charlotte Harbor...2-4 ft
Card Sound Bridge, FL to Bonita Beach, FL...1-3 ft
Dry Tortugas...1-2 ft

RAINFALL: Tropical Depression Four is expected to produce rainfall
totals of 4 to 8 inches, with maximum rainfall totals up to 12
inches, across portions of Florida and along the Southeast U.S.
coast this weekend through Wednesday. This rainfall may result in
areas of locally considerable flash and urban flooding, with
isolated river flooding possible.

For Cuba, rainfall amounts of 1 to 2 inches, with localized higher 
amounts, will be possible through Saturday. This may result in 
isolated to scattered areas of flooding.

For a complete depiction of forecast rainfall and flash flooding
associated with Tropical Depression Four, please see the National
Weather Service Storm Total Rainfall Graphic, available at
hurricanes.gov/graphics_at4.shtml?rainqpf

TORNADOES: A tornado or two is possible across the Florida Keys and
the western Florida Peninsula Saturday night through Sunday morning.


NEXT ADVISORY
-------------
Next intermediate advisory at 200 AM EDT.
Next complete advisory at 500 AM EDT.

$$
Forecaster Berg

[yoda]

Tropical Depression Four Discussion Number   3
NWS National Hurricane Center Miami FL       AL042024
1100 PM EDT Fri Aug 02 2024

Shortwave infrared satellite imagery, Cuban radar data, and surface 
observations from Cuba and the Cayman Islands suggest that the 
disturbance has developed a closed circulation, and the center is 
located just off the south coast of Cuba.  Deep convection is still 
a bit fragmented, but there has been a persistent burst near the 
estimated center since earlier this afternoon.  The wind and 
pressure field could still be a little elongated within the 
southern semicircle, but overall the system appears to have enough 
organization to now be designated as a tropical depression.  The 
initial intensity remains 25 kt based on earlier observations.

The depression has not begun to turn yet, and the initial motion is 
west-northwestward, or 285/15 kt.  A turn toward the northwest and 
then north is expected over the weekend due to a break in the 
subtropical ridge caused by a trough over the eastern United 
States.  Since the system has not started to turn yet, this has 
caused all of the track guidance to shift west, and the updated NHC 
forecast is a bit west of the previous forecast along the eastern 
edge of the main cluster of models.  It is important to note that 
because of the forecast track being parallel to the west coast of 
Florida, the location and timing of a potential landfall cannot be 
pinned down at this time.  One additional significant change to the 
forecast is that the models seem to be showing the aforementioned 
trough leaving the cyclone behind early next week, which causes a 
much slower motion while the system is near the coasts of Georgia 
and South Carolina.  As a result, the new NHC forecast is notably 
slower than the previous forecast, particularly on days 4 and 5.

The westward shift to the track forecast now also keeps the system 
over the warm waters of the Gulf of Mexico longer, giving the 
system additional time to potentially strengthen.  In fact, the 
SHIPS guidance and all of the regional hurricane models show the 
cyclone reaching hurricane strength before reaching land in the Big 
Bend region of Florida in 2 to 3 days.  As a result, the new NHC 
forecast brings the intensity to 60 kt at 60 hours as the system is 
reaching land, but if model trends continue, it's possible that 
future forecasts could explicit show the system becoming a 
hurricane before it reaches land.  The intensity forecast is more 
uncertain on days 3 through 5 due depending on if the center moves 
back offshore or stays inland over the southeastern United States.


Key Messages:

1. Heavy rainfall may result in locally considerable flash and urban 
flooding across portions of Florida and the coastal areas of the 
Southeast U.S. this weekend through Wednesday. Isolated river 
flooding will also be possible.

2. Tropical storm conditions are expected Saturday night within the
Tropical Storm Warning area in southwest Florida from East Cape
Sable to Boca Grande and on the Dry Tortugas. Tropical storm 
conditions are possible in the remainder of the Florida Keys on 
Saturday and along the Florida west coast north of Boca Grande to 
Suwannee River Saturday night and Sunday where a Tropical Storm 
Watch is in effect.

3. There is a possibility of life-threatening inundation from storm
surge along portions of the west coast of Florida from Bonita Beach
to Suwannee River, including Tampa Bay and Charlotte Harbor, where a
Storm Surge Watch is in effect.

4. Impacts from storm surge, strong winds, and heavy rains are
possible elsewhere in Florida and along the southeast coast of the
United States from Georgia to North Carolina through the middle of
next week, and interests in those areas should continue to monitor
the progress of this system.  Additional watches and warnings will
likely be required on Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0300Z 21.4N  79.7W   25 KT  30 MPH
 12H  03/1200Z 22.6N  81.4W   30 KT  35 MPH...OVER CUBA
 24H  04/0000Z 24.6N  83.3W   35 KT  40 MPH...OVER WATER
 36H  04/1200Z 26.6N  84.1W   45 KT  50 MPH
 48H  05/0000Z 28.4N  84.0W   55 KT  65 MPH
 60H  05/1200Z 29.9N  83.4W   60 KT  70 MPH...INLAND
 72H  06/0000Z 30.8N  82.5W   40 KT  45 MPH...INLAND
 96H  07/0000Z 31.8N  80.9W   45 KT  50 MPH...OVER WATER
120H  08/0000Z 32.8N  79.4W   55 KT  65 MPH

[yoda]

[StantonParkHoya]

If it goes south at origin, the whole cone shifts SW

CHS is actually due for something. OBX catches one every year. Low country gets a get out of jail free.

[Greyhound]

Wife and I supposed to be in Oak Island NC Monday thru Thursday. Glad we bought trip insurance!!!!

[MJO812]

[Floydbuster]

 

[WxWatcher007]

00z GFS verbatim brings it right back into the SC coast early Thursday. Still a lot to be resolved with the steering pattern next week. 

 

Different time stamp but the GEFS are also further west early on. 

[MJO812]

Alot of rain up here as the storm heads north 

[GaWx]

0Z UK: landfall just E of 12Z’s Apalachicola; then goes inland further W into C GA then turns E to CHS, goes up SC coast and then well inland into NC; flooding threat many areas:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 24 HOURS
FORECAST POSITION AT T+ 24 : 23.5N 83.7W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
0000UTC 04.08.2024 24 23.5N 83.7W 1007 28
1200UTC 04.08.2024 36 25.7N 84.8W 1006 34
0000UTC 05.08.2024 48 27.4N 85.5W 1004 43
1200UTC 05.08.2024 60 28.8N 85.3W 1003 42
0000UTC 06.08.2024 72 29.9N 84.4W 1002 35
1200UTC 06.08.2024 84 31.4N 84.2W 1001 36
0000UTC 07.08.2024 96 32.5N 83.3W 997 37
1200UTC 07.08.2024 108 32.5N 81.1W 996 41
0000UTC 08.08.2024 120 32.8N 79.9W 994 43
1200UTC 08.08.2024 132 33.8N 79.5W 996 41
0000UTC 09.08.2024 144 35.3N 78.4W 998 39
1200UTC 09.08.2024 156 36.4N 78.5W 1001 38
0000UTC 10.08.2024 168 37.4N 76.6W 1002 36

[GaWx]

0Z Euro: similar track to 12Z but stronger with it coming back into CHS at 986 mb vs 989 on 12Z; biblical rainfall amts of 20-24” mainly over ~72 hr period SAV-CHS and inland to 50 miles Lowcountry

[Ed, snow and hurricane fan]

19 minutes ago, GaWx said:

0Z Euro: similar track to 12Z but stronger with it coming back into CHS at 986 mb vs 989 on 12Z; biblical rainfall amts of 20-24” mainly over ~72 hr period SAV-CHS and inland to 50 miles Lowcountry

Scrolling, near the 21.57 inch 6 day rainfall I see amounts as high as 30.83 inches.  The only good thing if FFS were correct is S. South Carolina, where the heaviest 6 day totals occurs have offshore winds for much of the storm, or the flooding rivers and streams at least won't be flowing into bays with water levels elevated by onshore flow.  That is a major disaster if it verifies.

 

EDIT TO ADD: I quoted a post about the Euro w/ a GFS forecast image.  It is late and I should go to bed soon.

[Windspeed]

I guess I'm going to say it. The intensity forecast seems way underdone. I get the OPs, even the TC models, are keeping the circulation rather broad until the NE GOM, but there is a big caveat here. 1) This does not account for persistent convective blow-ups near the Caymans that have been tugging the COC south of Cuba, and 2) there is literally an MLC rotating S of the broader circulation right now that has ongoing convection. It is worriesome to me that, if this structure persists long enough, eventually, we're going to get a smaller surface vortex that remains over water longer. Naturally, the models will catch up after the fact. I have a hard time convincing myself that this TC is merely a tropical storm landfall in the EGOM and merely a flooding rain event, though, granted, that could be horrible enough. Too much time over water and too much of a swing out over EGOM waters prior to right hook and stall.

[Ed, snow and hurricane fan]

[img]https://media.giphy.com/media/v1.Y2lkPTc5MGI3NjExMWhldzg4ZDk3Z291bnFlcGE0bnBnZ3RmaWMzYm83c205Z2tvYmk1dSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/nZhiqdZ8x1kOBWmgOP/giphy.gif[/img]

OK, I still haven't figured out how to put an animated gif up here without using half my total file size attachment.  I did an extended IR image loop for TT.  Anyway, the center seems to be moving due W or just N of due W.  I can buy the NHC's 285*.  But it needs to turn NW immediately to stay in the center of the forecast cone

[Windspeed]

[img=https://media.giphy.com/media/v1.Y2lkPTc5MGI3NjExMWhldzg4ZDk3Z291bnFlcGE0bnBnZ3RmaWMzYm83c205Z2tvYmk1dSZlcD12MV9pbnRlcm5hbF9naWZfYnlfaWQmY3Q9Zw/nZhiqdZ8x1kOBWmgOP/giphy.gif]

OK, I still haven't figured out how to put an animated gif up here without using half my total file size attachment.  I did an extended IR image loop for TT.  Anyway, the center seems to be moving due W or just N of due W.  I can buy the NHC's 285*.  But it needs to turn NW immediately to stay in the center of the forecast cone

I'll post it for you. But realize that it's the convective burst south of the broader circulation that gives the overall appearance that the system is moving more W of WNW at the moment. Granted, if you read my post above, that is my big worry right now. Eventually, one of these CBs south of the broader surface center is going to go bonkers and form smaller surface vorticity south of the forecast track. A reformation, if you will.

[Stormchaserchuck1]

I agree with you. This could ramp up quickly into a Hurricane. Models remain too far NE with the position of the low pressure, which is also moving a little more W right now than modeled. The only negative is that western tip of Cuba has pretty high elevation. Let's see how far west it can go. 

[NotSureWeather]

It honestly looks like its about to explode.

[cptcatz]

2 hours ago, Stormchaserchuck1 said:

I agree with you. This could ramp up quickly into a Hurricane. Models remain too far NE with the position of the low pressure, which is also moving a little more W right now than modeled. The only negative is that western tip of Cuba has pretty high elevation. Let's see how far west it can go. 

But Cuba is so narrow there a quick moving storm should only spend a couple hours traversing it. Look at Ian... it went over the western part of Cuba and barely made a blip.

[wthrmn654]

[wthrmn654]

[wthrmn654]

[wthrmn654]

 

[wthrmn654]

 

[wthrmn654]

[wthrmn654]

 

[Kevin Reilly]

Waking up to sunny down here in Orlando.  I’m not expecting too many impacts here?  Don’t let your guard down up the coast with what probably will become Debby.  What’s interesting too is I check into Charleston SC on August 11th.  I guess I’ll be checking into the aftermath. We drove down from SE Pa hope the roads are passable in Georgia, SC, NC as I look at the models this morning.