Hurricane Debby | peak 80mph 979 mb | downgraded, now a Debby Downer

[StretchCT]

NHC has started coverage for PTC 4. Tropical storm warnings and watches are issued for Florida.  90% chance of formation.

Spoiler

NWS National Hurricane Center Miami FL       AL042024
1100 AM EDT Fri Aug 02 2024

...DISTURBANCE LOCATED OVER EASTERN CUBA...
...TROPICAL STORM WARNINGS AND WATCHES ISSUED FOR PORTIONS OF
FLORIDA...


SUMMARY OF 1100 AM EDT...1500 UTC...INFORMATION
-----------------------------------------------
LOCATION...20.9N 76.6W
ABOUT 90 MI...145 KM ESE OF CAMAGUEY CUBA
ABOUT 420 MI...675 KM SE OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...30 MPH...45 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 16 MPH...26 KM/H
MINIMUM CENTRAL PRESSURE...1012 MB...29.89 INCHES


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

A Tropical Storm Warning is now in effect for the southwest coast
of the Florida peninsula from East Cape Sable to Bonita Beach.

A Tropical Storm Watch is now in effect for the Florida Keys south
of the Card Sound Bridge including the Dry Tortugas, the southern
coast of the Florida peninsula east of East Cape Sable to the Card
Sound bridge, and for the west coast of the Florida peninsula north
of Bonita Beach to Aripeka.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT:

A Tropical Storm Warning is in effect for...
* Southwest coast of the Florida peninsula from East Cape Sable to
Bonita Beach

A Tropical Storm Watch is in effect for...
* The Florida Keys south of the Card Sound Bridge including the Dry
Tortugas
* 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 Bonita Beach to
Aripeka

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.

Interests elsewhere in the Florida Peninsula should monitor the
progress of this system. Additional warnings and watches may be
required for a portion of this area tonight and 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 AM EDT (1500 UTC), the disturbance was centered near 
latitude 20.9 North, longitude 76.6 West. The system is moving 
toward the west-northwest near 16 mph (26 km/h).  A turn toward the 
northwest at a slower forward speed is expected tonight or Saturday, 
followed by a turn toward the north on Sunday.  On the forecast 
track, the disturbance is expected to move over Cuba today, cross 
the Straits of Florida on Saturday, and then move near or over the 
west coast of Florida Saturday night through Sunday night.

Maximum sustained winds are near 30 mph (45 km/h) with higher gusts. 
The disturbance is expected to develop into a tropical depression on 
Saturday as it moves across the Straits of Florida, followed by 
intensification into a tropical storm by Saturday night.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 7 days...high...90 percent.

The estimated minimum central pressure is 1012 mb (29.89 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 or 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...

Aripeka, FL to Card Sound Bridge, FL...1-3 ft
Tampa Bay...1-3 ft
Charlotte Harbor...1-3 ft

RAINFALL: Potential Tropical Cyclone 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 near the Southeast U.S.
coast this weekend through Wednesday morning. This rainfall could
result in areas of flash and urban flooding, with isolated river
flooding possible.

For a complete depiction of forecast rainfall and flash flooding
associated with Potential Tropical Cyclone Four, please see the
National Weather Service Storm Total Rainfall Graphic, available at
hurricanes.gov/graphics_at3.shtml?rainqpf


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

$$
Forecaster Beven

Nothing major the next 120hrs, but a lot of uncertainty.  My take is that it can either ramp up quickly off the W coast of Fl, or it could just not organize.  Once it moves over the Atlantic, more development is likely.  But no idea where its going .

Spoiler

Potential Tropical Cyclone Four Discussion Number   1
NWS National Hurricane Center Miami FL       AL042024
1100 AM EDT Fri Aug 02 2024

Satellite imagery and surface observations indicate that the 
tropical wave that NHC has been monitoring for the last several days 
is now over southeastern Cuba, with disorganized convective bands to 
the north and south of a broad vorticity center.  The maximum winds 
are currently near 25 kt, and the minimum pressure based on surface 
observations is near 1012 mb.  Given the potential for development 
once the system moves over water on Saturday, advisories are 
initiated at this time on Potential Tropical Cyclone Four.

The initial motion is 290/14 kt.  A turn toward the northwest and 
north is expected during the next couple of days as the system moves 
into a break in the subtropical ridge caused by a mid-latitude 
trough over the Ohio Valley.  This should be followed by recurvature 
into the westerlies after about 60 h.  On the forecast track, the 
system is expected to move into the Straits of Florida and the 
southeastern Gulf of Mexico on Saturday, followed by a motion near 
the west coast of Florida Saturday night and Sunday.  After that 
time, the system should cross the northern Florida peninsula and 
move over the Atlantic near or offshore of the southeastern coast of 
the United States.  The track guidance is in good agreement with 
this scenario. However, since the forecast track is almost parallel 
to the west coast of the Florida Peninsula and the southeast coast 
of the U. S., only a small change in the track could lead to large 
changes in which land areas receive any landfalls and the biggest 
impacts.

Slow development is possible while the system is over Cuba, and the 
system is likely to become a tropical depression soon after it 
moves offshore. The environment over the Gulf of Mexico is quite
favorable for strengthening with light shear and very warm 
sea-surface temperatures, so subsequent steady strengthening is 
expected.  The two biggest uncertainties in the intensity forecast 
are how long the system will remain offshore of Florida and how 
long it will take to consolidate.  The system is likely to weaken 
as it crosses Florida, with re-intensification likely over the 
Atlantic.


Key Messages:

1. Heavy rainfall may result in flash and urban flooding across 
portions of Florida and the Southeast this weekend through Wednesday 
morning. Isolated river flooding will also be possible.

2. Tropical storm conditions are expected Saturday night within the 
warning area in southwest Florida from East Cape Sable to Bonita 
Beach where a Tropical Storm Warning has been issued. Tropical storm 
conditions are possible in the Florida Keys on Saturday and along 
the Florida west coast north of Bonita Beach to Aripeka Saturday 
night and Sunday where a Tropical Storm Watch is in effect. 

3. Coastal flooding is possible along portions of the west coast of
Florida over the weekend.

4. Interests elsewhere in Florida and along the southeast coast of
the United States from Georgia to North Carolina should monitor the
progress of this system.

INIT  02/1500Z 20.9N  76.6W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  03/0000Z 21.7N  78.3W   25 KT  30 MPH...INLAND
 24H  03/1200Z 23.3N  80.7W   30 KT  35 MPH...TROPICAL CYCLONE
 36H  04/0000Z 25.1N  82.3W   35 KT  40 MPH
 48H  04/1200Z 27.2N  83.0W   45 KT  50 MPH
 60H  05/0000Z 29.2N  82.7W   55 KT  65 MPH...TROPICAL CYCLONE
 72H  05/1200Z 30.7N  81.7W   40 KT  45 MPH...TROPICAL CYCLONE
 96H  06/1200Z 32.0N  80.0W   40 KT  45 MPH...OVER WATER
120H  07/1200Z 33.6N  77.5W   50 KT  60 MPH

 

 

Edited August 9 by StretchCT

[StretchCT]

Shear looks pretty low in the path

as does mid level shear

[StretchCT]

AI Rapid Intensity outlook

[StretchCT]

Upper divergence (yellow), lower convergence (blue) and vorticity (orange) all lined up.

[LiveWire_13]

26 minutes ago, StretchCT said:

Upper divergence (yellow), lower convergence (blue) and vorticity (orange) all lined up.

I think it was TT was pointing out one model stacking the layers and showing a stronger system headed towards FL/Atlantic ocean compared to other models spreading everything out towards LA. Guess we know where things are trending. 

[StretchCT]

Long term spaghetti

 

Short term - note they are in pretty much agreement but because the track is parallel to the FL coast, knowing where it will hit is challenging

Wind field size will be interesting for this one too given the proximity to land. Newly formed storms - do they have tight wind fields or are the winds more dispersed, farther out? I know that as storms start winding down, winds go out... but do they start broad and tighten in?

[StretchCT]

5pm disco has peak at 65mph inland over FL.   Also noted is the challenge of where exactly are the highest winds

Spoiler

Potential Tropical Cyclone Four Discussion Number   2
NWS National Hurricane Center Miami FL       AL042024
500 PM EDT Fri Aug 02 2024

Convection and vorticity associated with the tropical wave, now over
central Cuba, have both increased a little this afternoon.  However,
the circulation is still not well-defined, and the convection is
not yet well enough organized to consider the system to be a
tropical depression.  So, the system remains a potential tropical
cyclone at this time.  A NOAA Hurricane Hunter is currently
investigating the northern side of the wave, and a combination of
its dropsondes and earlier scatterometer data suggest that the
maximum winds remain near 25 kt.

The poorly-defined center has moved more westward since the previous 
advisory.  However the overall motion remains about 290/14 kt. A 
turn toward the northwest and north is expected during the next 
couple of days as the system moves into a break in the subtropical 
ridge caused by a mid-latitude trough over the Ohio Valley.  This 
should be followed by recurvature into the westerlies after 48-60 h. 
On the forecast track, the system is expected to move into the 
Straits of Florida and the southeastern Gulf of Mexico on Saturday, 
followed by a motion near the west coast of Florida Saturday night 
and Sunday.  After that time, the system should cross the northern 
Florida peninsula and move over the Atlantic near or offshore of 
the southeastern coast of the United States.  While the track 
guidance generally agrees with this scenario, there are a couple of 
issues. First, the GFS moves the system much faster northeastward, 
and by 72 h it is forecasting the center to be off of the South 
Carolina coast. Meanwhile, the ECMWF and UKMET still have the 
center over the Gulf of Mexico. Second, due to the track being 
almost parallel to both the west coast of the Florida peninsula and 
the southeastern U. S. coast, small changes in the track could 
cause large differences in potential landfalls and which land areas 
receive the strongest impacts.

There is little change in the intensity forecast philosophy from the 
previous advisory.  Slow development is possible while the system is 
over Cuba, and the system is likely to become a tropical depression 
soon after it moves offshore on Saturday. The environment over the 
Gulf of Mexico is quite favorable for strengthening with light shear 
and very warm sea-surface temperatures, so subsequent steady 
strengthening is expected.  The two biggest uncertainties in the 
intensity forecast are how long the system will remain offshore of 
Florida and how long it will take to consolidate.  The system is 
likely to weaken as it crosses Florida, with re-intensification 
likely over the Atlantic after 72 h.


Key Messages:

1. Heavy rainfall may result in flash and urban flooding across 
portions of Florida and the coastal areas of the Southeast this 
weekend through Wednesday morning. 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. Tropical storm conditions are possible in 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 later tonight and on Saturday.


FORECAST POSITIONS AND MAX WINDS

INIT  02/2100Z 21.4N  78.3W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 12H  03/0600Z 22.4N  80.1W   25 KT  30 MPH...POTENTIAL TROP CYCLONE
 24H  03/1800Z 24.2N  82.2W   30 KT  35 MPH...TROPICAL CYCLONE
 36H  04/0600Z 26.1N  83.3W   35 KT  40 MPH
 48H  04/1800Z 28.1N  83.3W   45 KT  50 MPH
 60H  05/0600Z 29.7N  82.9W   55 KT  65 MPH...INLAND
 72H  05/1800Z 30.9N  81.9W   40 KT  45 MPH...INLAND
 96H  06/1800Z 32.6N  80.0W   45 KT  50 MPH...NEAR COAST
120H  07/1800Z 34.5N  77.0W   55 KT  65 MPH

 

[1816]

29 minutes ago, StretchCT said:

Long term spaghetti

 

Short term - note they are in pretty much agreement but because the track is parallel to the FL coast, knowing where it will hit is challenging

Wind field size will be interesting for this one too given the proximity to land. Newly formed storms - do they have tight wind fields or are the winds more dispersed, farther out? I know that as storms start winding down, winds go out... but do they start broad and tighten in?

This storm here is like: how can I affect as many people as possible 

[1816]

8 minutes ago, StretchCT said:

The environment over the Gulf of Mexico is quite favorable for strengthening with light shear and very warm sea-surface temperatures, so subsequent steady strengthening is expected. The two biggest uncertainties in the intensity forecast are how long the system will remain offshore of Florida and how long it will take to consolidate.

Anyone want to take bets on how this is gonna go?

Spoiler

 

 

 

[Undertakerson2.0]

[tool483]

Looking healthy even over Cuba, but sure alot of that is land interaction..good spin though

Edited August 2 by tool483

[MaineJay]

36 minutes ago, tool483 said:

Looking healthy even over Cuba, but sure alot of that is land interaction..good spin though

Wonder how the diurnally driven convection over the island will fare once the sun sets

[1816]

1 minute ago, MaineJay said:

Wonder how the diurnally driven convection over the island will fare once the sun sets

Once the coc of the disturbance gets over that hot water we'll find out what kind of storm this wants to be 

[StretchCT]

Ugh.. 18z gfs

 

[LiveWire_13]

26 minutes ago, StretchCT said:

Ugh.. 18z gfs

 

That's the projection for Aug. 9? At least we've got some time to watch it before it potentially gets into NY Metro area. Lot of people up here.

Unfortunately, not sure anyone in FL and southeast is paying attention yet. Feels like this thing is gonna explode in the warm water once it gets coordinated 

[StretchCT]

Where the models are at 72 HR from today at 12z

HAFS A and B

12z Deterministic tracks

 

[1816]

3 minutes ago, StretchCT said:

Where the models are at 72 HR from today at 12z

HAFS A and B

12z Deterministic tracks

 

I kind of have a bad feeling about this. Looking at this just invokes that storm that demolished ft myers not too long ago. 

[clm]

8 hours ago, 1816 said:

Anyone want to take bets on how this is gonna go?

  Hide contents

 

 

 

 

 

[Snow____]

I’m flying out of Jacksonville Monday night to get back home🤦🏽‍♂️🤦🏽‍♂️ praying my flight won’t be delayed or cancelled 

[LiveWire_13]

1 hour ago, Snow____ said:

I’m flying out of Jacksonville Monday night to get back home🤦🏽‍♂️🤦🏽‍♂️ praying my flight won’t be delayed or cancelled 

Can you get a flight Sun night? Looks like TS conditions likely northern FL Monday.

[StretchCT]

5am disco - Storm should intensify hrs 48-60, possibly reaching hurricane strength, then stall over FL/GA or just offshore as it loses steering currents. After that who knows....

Spoiler

Tropical Depression Four Discussion Number   4
NWS National Hurricane Center Miami FL       AL042024
500 AM EDT Sat Aug 03 2024

Small bursts of deep convection have continued near the estimated 
center of the depression, with some skeletal convective bands over 
the outer portions of the circulation. Earlier scatterometer data 
revealed the strongest winds were occurring to the south and east of 
the center, offshore of the southern coast of Cuba. The overall 
organization of the tropical cyclone has changed little overnight, 
and the initial intensity is held at 25 kt based on the earlier 
scatterometer winds and recent Dvorak estimates from TAFB and SAB.

The estimated motion of the depression is still west-northwestward 
at about 14 kt. The influence of an upper-level trough over the 
eastern United States should cause the cyclone to turn northwestward 
and then northward this weekend as it moves toward a break in the 
subtropical ridge. This motion will bring the system across western 
Cuba this morning, into the eastern Gulf of Mexico later today, and 
toward the Florida Big Bend region on Sunday and Sunday night. There 
is reasonably good confidence in this portion of the track forecast, 
and only slight westward adjustments were made to the NHC prediction 
based on the latest track consensus aids. After landfall, weakening 
steering currents should cause the cyclone to slow down while it 
moves northeastward over parts of northern Florida and Georgia. 
Thereafter, the track forecast becomes highly uncertain as it is 
unclear whether the system will accelerate northeastward ahead 
of an upper trough (GFS) or get left behind and meander over 
the southeastern U.S. or near the coast (ECMWF).

After the system crosses Cuba and emerges over the eastern Gulf of 
Mexico, the environmental and oceanic conditions appear favorable 
for intensification. The latest NHC forecast shows the cyclone 
becoming a tropical storm by tonight, with additional strengthening 
expected while it moves across deep warm waters in a weak shear 
environment. The regional hurricane models and statistical guidance 
continue to indicate some potential for the system to reach 
hurricane strength before it makes landfall in the Florida Big Bend 
region. Although the latest NHC forecast does not explicitly show 
the cyclone becoming a hurricane, note that additional strengthening 
could occur between 48-60 h. Weakening is forecast after landfall 
while the system moves over the southeastern United States. Beyond 
day 3, the intensity forecast remains quite uncertain and highly 
dependent on whether the center stays inland or emerges off the 
Atlantic coast.


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. A Hurricane Watch has been issued for portions of west-central 
Florida and the Big Bend region, where hurricane conditions are 
possible late Sunday. Tropical storm conditions are expected 
farther south along Florida’s west coast, including the Tampa Bay 
area, and across the Dry Tortugas where Tropical Storm Warnings are 
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 Aucilla 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 later today.


FORECAST POSITIONS AND MAX WINDS

INIT  03/0900Z 22.0N  80.7W   25 KT  30 MPH
 12H  03/1800Z 23.4N  82.6W   30 KT  35 MPH
 24H  04/0600Z 25.3N  83.9W   40 KT  45 MPH
 36H  04/1800Z 27.5N  84.3W   50 KT  60 MPH
 48H  05/0600Z 29.1N  83.9W   60 KT  70 MPH
 60H  05/1800Z 30.4N  83.1W   45 KT  50 MPH...INLAND
 72H  06/0600Z 31.2N  82.2W   35 KT  40 MPH...INLAND
 96H  07/0600Z 32.0N  80.5W   45 KT  50 MPH...OVER WATER
120H  08/0600Z 33.0N  79.0W   55 KT  65 MPH

$$
Forecaster Reinhart

Going from FL to SC in three days is slow.  Rain looks to be the main problem at this stage. 

 

[StretchCT]

Looks at some tracks and trends

0z tracks

 

TRENDS

NHC official forecast now on western side

GFS trend west in the Gulf, north off the coast

 

Consensus

Hurricane models are trending west 

 

 

 

Edited August 3 by StretchCT

[StretchCT]

[NJ Snowman]

Models say......🤷‍♂️

[StretchCT]

Estimated center

Tropical Depression Four has become somewhat better organized this 
morning, with the circulation becoming better defined over western 
Cuba and curved convective bands forming close to the center in the 
southern semicircle.  However, the circulation is still somewhat 
elongated with multiple low-level vorticity centers rotating around 
the mean center.  The initial intensity has been increased to 30 kt 
based on surface observations in the Florida Keys and a satellite 
intensity estimate from TAFB.