Tropical Storm Debby Discussion Number   9
NWS National Hurricane Center Miami FL       AL042024
1100 AM EDT Sun Aug 04 2024

Hurricane Hunter aircraft observations indicate that Debby
continues to intensify over the eastern Gulf of Mexico.  Satellite
imagery shows that the cloud pattern is becoming better developed
with increasing deep convection near the center of circulation, and
WSR-88D radar data indicate that an eyewall is beginning to form.
The current intensity estimate is estimated to be 55 kt based on a
significant drop in central pressure reported the aircraft. 

The cyclone has been turning gradually to the right and the initial 
motion is north-northwestward or 330/11 kt.  Over the next day or 
so, Debby should move through a weakness in the mid-level 
subtropical ridge over the southeastern United States and reach the 
northeast Gulf of Mexico coast in the Florida Big Bend region on 
Monday.  After the system makes landfall, the steering currents are 
likely to weaken as a trough over the northeastern U.S. moves 
eastward from the area, which should result in a decrease in forward 
speed.  There is significant uncertainty in the track of Debby in 
the 2-5 day time frame.  Much of the track guidance keeps the center 
over the southeastern U.S. for the next several days as a ridge 
builds in over the Carolinas.  The official track forecast is 
similar to the previous one and close to the HFIP corrected 
consensus prediction.  This keeps the slow-moving center near the 
Georgia and South Carolina coast in the 3 to 5 day time-frame. 

Debby will be moving over very warm waters and in a low-vertical 
shear environment prior to landfall.  Therefore significant 
strengthening is likely through tonight, especially if the cyclone 
forms a well-defined inner core The official forecast is near the 
high side of the objective guidance and calls for the system to 
become a hurricane within 12 hours.  The cyclone will weaken after 
it moves inland, but since the system will not be far from the 
coastline for the next few days, it is not predicted to fall below 
tropical storm strength through 72 hours.

Key Messages:

1. Heavy rainfall will likely result in considerable flooding
impacts from the Florida Big Bend region through southeast GA and
the Coastal Plain of the Carolinas through Friday. Potentially
historic heavy rainfall across southeast Georgia and South Carolina
through Friday morning may result in areas of catastrophic 
flooding. Significant river flooding is also expected. 

2. There is a danger of life-threatening storm surge along portions
of the Gulf Coast of Florida, with 6 to 10 feet of inundation above
ground level expected somewhere between Ochlockonee River and
Suwannee River on Monday. Residents in the Storm Surge Warning area
should follow any advice given by local officials.

3.  Hurricane conditions are expected Monday along portions of the 
Florida Big Bend region where a Hurricane Warning is in effect, with 
tropical storm conditions beginning this evening. Tropical storm 
conditions are expected through Monday farther south within the 
Tropical Storm Warning along Florida's west coast, including the 
Tampa Bay area.

4. Impacts from storm surge and strong winds are possible along the
southeast coast from Georgia to North Carolina through the middle of
the week, and storm surge watches and tropical storm watches have
been issued for portions of these areas. Additional watches and
warnings will likely be required later today.


FORECAST POSITIONS AND MAX WINDS

INIT  04/1500Z 27.0N  84.3W   55 KT  65 MPH
12H  05/0000Z 28.3N  84.5W   65 KT  75 MPH
24H  05/1200Z 29.9N  84.1W   80 KT  90 MPH
36H  06/0000Z 30.9N  83.4W   60 KT  70 MPH...INLAND
48H  06/1200Z 31.6N  82.5W   40 KT  45 MPH...INLAND
60H  07/0000Z 31.9N  81.5W   35 KT  40 MPH...INLAND
72H  07/1200Z 32.2N  80.5W   45 KT  50 MPH...OVER WATER
96H  08/1200Z 33.5N  79.5W   40 KT  45 MPH...INLAND
120H  09/1200Z 35.5N  78.0W   30 KT  35 MPH...INLAND

$$
Forecaster Pasch