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Tropical Storm Elsa Discussion Number  35
NWS National Hurricane Center Miami FL       AL052021
500 PM EDT Thu Jul 08 2021
 
A NOAA NOS observing site at Wrightsville Beach, North Carolina, 
recently reported a sustained wind of 41 kt, so Elsa's maximum winds 
are now estimated to be 45 kt.  A number of other observing sites in 
the vicinity have also reported sustained tropical-storm-force 
winds.  Elsa's slight strengthening may be the result of baroclinic 
forcing associated with an approaching short-wave trough. The 
system's cloud tops have warmed somewhat during the day, but it is 
still producing some very heavy rains.

Elsa's low-level center is a bit elongated from southwest to 
northeast, but surface synoptic data indicate that it has moved into 
northern North Carolina.  The storm continues to gradually 
accelerate toward the northeast, and the initial motion estimate is 
040/18 kt.  A faster northeastward motion is expected over the next 
1-2 days as the cyclone moves along with the mid-latitude 
southwesterly flow ahead of a broad mid-tropospheric trough over the 
eastern United States and Canada.  Elsa should move near or 
over southeastern New England and Atlantic Canada within the next 
24-48 hours.  The official track forecast remains close to the 
previous one and similar to the multi-model consensus, TVCA.
 
The global models suggest that not much additional strengthening is 
likely.  Simulated satellite imagery from these models show an 
extratropical appearance in 24-36 hours so the official forecast 
shows an extratropical transition by late Friday.  This is also 
supported by cyclone phase analyses of the model fields from 
Florida State University.
 
 
Key Messages:
 
1.As Elsa moves from North Carolina to Virginia today and this
evening, heavy rainfall may result in limited flash and urban
flooding. Heavy rainfall from the Mid-Atlantic into New England
through Friday could lead to considerable flash and urban flooding.
 
2. Tropical storm conditions should continue along portions of the
North Carolina coast this afternoon and spread over the
mid-Atlantic coast later today or tonight.  Tropical storm
conditions are expected in portions of the southern New England
states and New York by Friday.  Gusty winds are expected over
portions of Atlantic Canada Friday night and Saturday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/2100Z 36.3N  78.3W   45 KT  50 MPH...INLAND
 12H  09/0600Z 38.7N  75.1W   45 KT  50 MPH...INLAND
 24H  09/1800Z 42.5N  70.0W   45 KT  50 MPH...OVER WATER
 36H  10/0600Z 47.0N  63.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  10/1800Z 51.5N  54.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
 60H  11/0600Z 56.0N  45.0W   35 KT  40 MPH...POST-TROP/EXTRATROP
 72H  11/1800Z...DISSIPATED
 
$$
Forecaster Pasch
 
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