Tropical Storm Debby Discussion Number  10
NWS National Hurricane Center Miami FL       AL042024
500 PM EDT Sun Aug 04 2024

Debby's cloud pattern continues to show increasing organization on
satellite images although there is limited deep convection over the
southwest quadrant of the circulation.  The upper-level
anticyclonic outflow pattern is well-defined.  The latest Air Force
Hurricane Hunter aircraft observations indicated that the central
pressure hadn't changed much and the wind data from the aircraft
continued to support an intensity of near 55 kt.  WSR-88D radar
imagery shows that an eyewall may be trying to close off, and 
another Hurricane Hunter aircraft will be investigating Debby in a 
few hours to assess the strength of the cyclone.

The cyclone has turned toward the north and is now moving at around 
360/10 kt.  Debby should continue to move through a break in the 
subtropical ridge due to a trough over the eastern United States 
for the next day or so, and this motion should bring the center of 
the system to the northeast Gulf of Mexico coast around midday 
tomorrow.  Thereafter, the trough moves eastward, leaving Debby in 
weak steering currents for a few days.  The track guidance shows 
decreasing forward speed and a turn to the east in 24-48 hours.  
Some of the track models show the cyclone moving temporarily over 
the Atlantic in the 72-hour time frame, and so does the official 
forecast.

Debby will continue to move over waters of high heat content 
and remain in an environment of low vertical wind shear into Monday 
morning.  Some dry air intrusion over the southwestern portion of 
the circulation may have temporarily interrupted the intensification 
process.  However, given the favorable oceanic and shear 
conditions, significant strengthening is expected before landfall.
Rapid intensification is especially likely if Debby acquires a 
well-defined inner core.  The official intensity forecast is at the 
high end of the model guidance.  Although weakening will occur 
after landfall, the longer-term strength of the system is 
largely dependent on how long it remains over land.  Currently the 
official forecast shows some re-intensification with Debby moving 
into the Atlantic, but how much the system will restrengthen is 
highly uncertain.


Key Messages:

1. Potentially historic heavy rainfall across southeast Georgia and 
South Carolina through Friday morning will likely result in areas of 
catastrophic flooding.  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.

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. Dangerous storm surge and wind impacts are expected along 
portions of the southeast U.S. coast from northeastern Florida to 
North Carolina through the middle of the week, and storm surge 
warnings and tropical storm watches and warnings have been issued 
for portions of these areas.


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 27.7N  84.4W   55 KT  65 MPH
12H  05/0600Z 29.1N  84.4W   75 KT  85 MPH
24H  05/1800Z 30.5N  83.8W   75 KT  85 MPH...INLAND
36H  06/0600Z 31.3N  83.0W   45 KT  50 MPH...INLAND
48H  06/1800Z 31.7N  82.1W   35 KT  40 MPH...INLAND
60H  07/0600Z 31.7N  81.1W   40 KT  45 MPH...INLAND
72H  07/1800Z 31.9N  80.5W   45 KT  50 MPH...OVER WATER
96H  08/1800Z 32.6N  80.1W   45 KT  50 MPH...INLAND
120H  09/1800Z 34.0N  79.5W   30 KT  35 MPH...INLAND

$$
Forecaster Pasch