Tropical Storm Debby Discussion Number  24
NWS National Hurricane Center Miami FL       AL042024
500 AM EDT Thu Aug 08 2024

Surface observations and satellite imagery suggest that Debby's
circulation has become stretched out to the north and south, but
the center appeared to make landfall around 0600 UTC in the Bulls
Bay area of South Carolina.  A shield of moderate to heavy rain has
spread northward into North Carolina, while a trailing band of deep
convection is located offshore the coast of South Carolina.  An Air
Force Reserve Hurricane Hunter mission that concluded around
midnight measured peak 925-mb flight-level winds of 55 kt and SFMR
winds of 40-45 kt well east of the center, and the current
intensity is therefore estimated to be 45 kt.

Debby's center has not yet made much headway into South Carolina
since the initial motion is northwestward (325 deg) at only 4 kt.
A strengthening ridge over the Atlantic should start giving Debby a
push to the north today, with the center of the cyclone moving
across eastern South Carolina and central North Carolina through
tonight.  A deep-layer trough over the Upper Midwest should then
cause Debby to turn northeastward and accelerate over the
Mid-Atlantic and Northeast U.S. Friday and Friday night and then
over Atlantic Canada on Saturday.  No significant changes were made
to the NHC track forecast compared to the one in the previous
advisory.

Debby is expected to continue weakening as the center moves farther
inland, and global model fields suggest that winds near the coast
should fall below tropical storm force, with the cyclone becoming a
depression, by this afternoon or evening.  Model phase-space
diagrams, and the convective pattern in simulated satellite
imagery, then indicate that Debby will merge with a cold front and
become extratropical over the Mid-Atlantic region on Friday.  Debby
is shown to be dissipated by day 4 based on continuity from the
previous forecast, but it is possible that an area of low pressure
could continue eastward over the north Atlantic for a few more days.


Key Messages:

1. Heavy rainfall across portions of the Carolinas is expected to
persist through today along with areas of considerable flooding.
Heavy rainfall will also result in considerable flooding impacts
across portions of the Mid-Atlantic States and Northeast through
Saturday morning.

2. Tropical storm conditions will continue to affect portions of
the South Carolina and North Carolina coasts today.

3. Coastal flooding due to storm surge is likely along portions of
the South Carolina and North Carolina coastline through today.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0900Z 33.2N  79.7W   45 KT  50 MPH...INLAND
12H  08/1800Z 34.2N  80.1W   35 KT  40 MPH...INLAND
24H  09/0600Z 36.3N  79.7W   30 KT  35 MPH...INLAND
36H  09/1800Z 40.0N  77.3W   30 KT  35 MPH...POST-TROP/EXTRATROP
48H  10/0600Z 44.5N  72.6W   30 KT  35 MPH...POST-TROP/EXTRATROP
60H  10/1800Z 48.7N  65.8W   30 KT  35 MPH...POST-TROP/EXTRATROP
72H  11/0600Z 51.6N  58.7W   30 KT  35 MPH...POST-TROP/EXTRATROP
96H  12/0600Z...DISSIPATED

$$
Forecaster Berg