Tropical Storm Debby Discussion Number  16
NWS National Hurricane Center Miami FL       AL042024
500 AM EDT Tue Aug 06 2024

Debby's center is just inland of the Georgia coast while most of
the deep convection is oriented in a couple of bands over the
Atlantic waters feeding northwestward into South Carolina.
Scatterometer data from late last evening indicated that the
tropical-storm-force wind field had expanded eastward over the
Atlantic waters, and that the maximum sustained winds were near 40
kt.  This was confirmed by a few observations of 35-40 kt sustained
winds along the coasts of Georgia and South Carolina.  The initial
intensity is therefore held at 40 kt.

Debby continues to move northeastward, or 050/6 kt, but the storm
will be trapped in a weak steering regime for the next couple of
days.  The center is likely to move offshore the Georgia coast
later today, but then meander off the coast of South Carolina
through early Thursday.  After that time, a strengthening ridge
over the western Atlantic and an approaching mid-latitude trough
over the upper Midwest should cause Debby to move faster toward the
north across the Carolinas and then into the Mid-Atlantic region
late this week.  The updated NHC track forecast is a bit west of
the previous forecast starting at about 48 hours, trending in the
direction of the HCCA and TVCA consensus aids.

Little change in Debby's intensity is expected today and tonight as
the center moves offshore.  However, some strengthening is forecast
beginning on Wednesday due to the storm being in a low-shear
environment and over very warm waters of about 29 degrees Celsius.
The NHC intensity forecast continues to show a peak intensity of 50
kt in 48 hours, just before the center reaches the coast again,
which is near the top end of the guidance.  Weakening is expected
to begin in 60 hours once the center moves inland.  The cyclone is
likely to merge with a front over the eastern United States in 4 to
5 days.


Key Messages:

1. Potentially historic heavy rainfall across southeast Georgia and
eastern South Carolina through Friday will likely result in areas of
catastrophic flooding. Heavy rainfall will likely result in flooding
impacts from northern North Carolina through portions of
Mid-Atlantic States and southern New England through Sunday
morning.

2. Dangerous storm surge and tropical storm conditions will spread
northward along the southeast U.S. coast from northeastern Florida
to North Carolina through the middle of the week. Storm surge and
tropical storm watches and warnings have been issued for portions of
these areas. Residents in the storm surge watch and warning area
should follow any advice given by local officials.

3. In portions of Florida where Debby has passed, deadly hazards
remain, including downed power lines and flooded areas. Ensure
generators are properly ventilated to avoid carbon monoxide
poisoning.  Exercise caution when using chainsaws and power tools,
and drink plenty of water to avoid heat exhaustion.


FORECAST POSITIONS AND MAX WINDS

INIT  06/0900Z 31.6N  81.6W   40 KT  45 MPH...INLAND
12H  06/1800Z 31.6N  81.0W   40 KT  45 MPH...OVER WATER
24H  07/0600Z 31.7N  79.9W   40 KT  45 MPH
36H  07/1800Z 31.9N  79.4W   45 KT  50 MPH
48H  08/0600Z 32.3N  79.5W   50 KT  60 MPH
60H  08/1800Z 33.1N  79.9W   45 KT  50 MPH...INLAND
72H  09/0600Z 34.1N  80.1W   35 KT  40 MPH...INLAND
96H  10/0600Z 38.5N  77.4W   30 KT  35 MPH...INLAND
120H  11/0600Z 43.4N  67.7W   35 KT  40 MPH...POST-TROP/EXTRATROP

$$
Forecaster Berg