Official Discussion issued by the National Hurricane Center

Debby (AL042024) DATA RELEASED: 8/5/2024 9:00:00 AM UTC

Copy of official data

Hurricane Debby Discussion Number  12
NWS National Hurricane Center Miami FL       AL042024
500 AM EDT Mon Aug 05 2024

The eyewall of Debby is moving onshore and landfall in the Florida
Big Bend is expected to occur within the next few hours.  Doppler
radar images from Tallahassee indicate that the eye of the hurricane
has become a bit more circular and deep convection remains fairly
well organized over the eastern eyewall, and in bands east of the
center that have spread across portions of northern Florida.  There
have been numerous reports of sustained tropical-storm-force winds,
but the strongest so far is in Horseshoe Beach, where a weather
station recently recorded a sustained wind of 57 kt and a gust to
83 kt.  Data from the Air Force Hurricane Hunters indicate that the
maximum winds are likely near 70 kt, and Debby will likely maintain
that intensity or strengthen a little until it reaches the coast.

After landfall, Debby is expected to slow down and turn
northeastward as the steering currents collapse, taking the system
across northern Florida and southeastern Georgia later today through
Tuesday.  Most of the models show Debby moving off the southeast
U.S. coast late Tuesday and Wednesday before a ridge builds to the
north of the system, which should push it back inland over South
Carolina on Thursday.  Although the details of the track forecast
are unknown, there is high confidence that Debby will move slowly
while near or over the southeastern U.S., which will likely result
in catastrophic flooding in some locations.  The NHC track forecast
is similar to the previous one and in line with the consensus aids.

Rapid weakening is forecast after the center moves inland, and Debby
will likely become a tropical storm over northern Florida this
afternoon.  If Debby does move back offshore of the southeast U.S.,
there could be a little strengthening before it moves inland once
again.  Regardless of the system's strength, the main impact is
expected to be heavy rainfall as mentioned above. The NHC intensity
forecast is generally similar to the previous one and near the HCCA
and IVCN aids.

NHC has begun issuing hourly Tropical Cyclone Updates, and they
will continue through landfall.


Key Messages:

1. Potentially historic heavy rainfall across southeast Georgia and
the coastal plain of South Carolina through Saturday morning will
likely result in areas of catastrophic flooding. Heavy rainfall will
likely result in considerable flooding impacts from portions of
central and northern Florida and across portions of central and
northeast North Carolina through Saturday morning.

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 to
Yankeetown through the morning. Residents in the Storm
Surge Warning area should follow any advice given by local
officials.

3. Hurricane conditions are expected this morning along portions of
the Florida Big Bend region where a Hurricane Warning is in effect.
Tropical storm conditions are expected to continue for several more
hours farther south within the Tropical Storm Warning area 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 are in effect
for portions of these areas.


FORECAST POSITIONS AND MAX WINDS

INIT  05/0900Z 29.5N  83.7W   70 KT  80 MPH
12H  05/1800Z 30.5N  83.1W   55 KT  65 MPH...INLAND
24H  06/0600Z 31.3N  82.1W   45 KT  50 MPH...INLAND
36H  06/1800Z 31.8N  81.1W   45 KT  50 MPH...INLAND
48H  07/0600Z 31.9N  80.2W   45 KT  50 MPH...OVER WATER
60H  07/1800Z 32.1N  79.6W   45 KT  50 MPH...OVER WATER
72H  08/0600Z 32.3N  79.6W   50 KT  60 MPH...OVER WATER
96H  09/0600Z 33.5N  79.6W   40 KT  45 MPH...INLAND
120H  10/0600Z 35.6N  78.9W   30 KT  35 MPH...INLAND

$$
Forecaster Cangialosi