Tropical Storm ELSA Advisory do, 08-07

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Tropical Storm Elsa Discussion Number  32
NWS National Hurricane Center Miami FL       AL052021
1100 PM EDT Wed Jul 07 2021

Doppler radar and surface observations indicate that Elsa is
maintaining its intensity.  However, these winds aren't close to
the center but, rather, in a strong band of convection in the
eastern semicircle of the storm.  The current wind speed is set to
40 kt in accordance with an earlier sustained wind report of 38 kt,
and radar velocities reduced to the surface that would support at
least 40 kt.

Some weakening is expected overnight while a significant portion of
Elsa's circulation remains over land.  However by late Thursday,
more of the storm will be moving over water, and a fair number
of the models suggest re-intensification could take place.
It is a little puzzling why the ECMWF and UKMET models, however,
are showing a strengthening tropical storm close to the
mid-Atlantic states, especially without a significant trough
interaction or warm waters.  I'm getting some deja vu in this case
after working Claudette from a few weeks ago, with those same
models also over-intensifying that storm.  The GFS has been
relatively consistent in showing only a small intensification of
Elsa, and the NHC forecast will continue to be closer to that
model's relatively weaker solution.

The storm has turned north-northeastward tonight and is moving a
little faster, about 14 kt.  Elsa should move northeastward at an
increasing forward speed during the next few days as it becomes
embedded within fast southwesterly flow ahead of a mid-latitude
trough.  No significant changes were made to the previous track
forecast since guidance remains in good agreement.  Elsa is likely
to become absorbed north of Newfoundland by another extratropical
low by day 4.

There is greater confidence tonight that some portion of North
Carolina and the mid-Atlantic coast will receive
tropical-storm force-winds, so the Tropical Storm Watch has been
upgraded to a Tropical Storm Warning in those areas.  Areas to the
north remain less certain, and remain under a Tropical Storm Watch.


Key Messages:

1. As Elsa moves across southeastern Georgia into the Lowcountry of
South Carolina tonight, heavy rainfall may result in considerable
flash, urban, and minor river flooding.  Heavy rainfall, from North
Carolina across the mid-Atlantic and into New England Thursday and
Friday, could lead to isolated flash and urban flooding.

2. Tropical storm conditions are expected along portions of the
coasts of Georgia and South Carolina tonight.  Tropical storm
conditions are also expected along the coasts of North Carolina on
Thursday and the mid-Atlantic by Thursday night.  Tropical storm
conditions are possible in the southern New England states
and New York by Friday.


FORECAST POSITIONS AND MAX WINDS

INIT  08/0300Z 32.1N  82.3W   40 KT  45 MPH...INLAND
 12H  08/1200Z 34.1N  80.7W   35 KT  40 MPH...INLAND
 24H  09/0000Z 37.1N  77.3W   35 KT  40 MPH...INLAND
 36H  09/1200Z 40.4N  72.9W   40 KT  45 MPH...OVER WATER
 48H  10/0000Z 44.5N  67.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 60H  10/1200Z 49.0N  60.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  11/0000Z 54.0N  50.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 96H  12/0000Z...DISSIPATED

$$
Forecaster Blake