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Tropical Storm Elsa Discussion Number  20
NWS National Hurricane Center Miami FL       AL052021
500 AM EDT Mon Jul 05 2021
 
Elsa appears to be holding steady in strength while moving just
south of central Cuba.  Radar data from Cuba and satellite images
show a persistent area of deep convection over the center and some
banding features, especially on the south side of the circulation.
An ASCAT pass from around 0130Z indicated that Elsa was a compact
system with tropical-storm-force winds mostly confined to a region
within about 60 n mi east of the center. Peak winds in the pass were
around 50 kt in the northeastern quadrant, and given the small size
of the cyclone and somewhat course resolution of the ASCAT data, it
seems very reasonable that Elsa has an initial intensity of around
55 kt.  This intensity estimate is also in line with the latest
Dvorak classifications. The NOAA Hurricane Hunters will be
investigating Elsa again shortly, and the data the plane collects
will be valuable in assessing the storm's intensity and wind field.
 
The tropical storm is moving northwestward at about 12 kt on the 
southwestern periphery of a subtropical ridge located over the 
central Atlantic.  A gradual turn to the north is expected over the 
next day or two as Elsa moves in the flow between the ridge and a 
mid- to upper-level low over the northern Gulf of Mexico.  This 
steering pattern should take the core of Elsa across central or 
western Cuba later this morning, near the Lower Florida Keys tonight 
or early Tuesday, and then along or very near the west coast of 
Florida later on Tuesday through early Wednesday.  Most of the 
models show Elsa moving inland over west-central or northern 
Florida, but given the expected parallel motion to the coast, much 
of the west coast of the state will likely see impacts from Elsa on 
Tuesday and into Wednesday.  After Elsa clears Florida, it is 
expected to move faster north-northeastward across coastal Georgia 
and the Carolinas Wednesday and Thursday before moving over the 
western Atlantic.  The new track forecast is just a little to the 
left of the previous one to be in better agreement with the latest 
consensus models.
 
Given the overall favorable environmental conditions, Elsa could
strengthen a little before it reaches the coast of Cuba later this
morning.  Some weakening is expected due to the land interaction
with Cuba, but most of the model guidance suggests that Elsa could
restrengthen slightly before it moves inland over Florida.
Significant strengthening is not anticipated though due to moderate
wind shear.  However, it should be noted that given the expected
track, much of the west coast of Florida will be on the east side of
Elsa, which is where the strongest winds, highest surge, and
heaviest rains are expected to be.  Gradual weakening is forecast
while Elsa moves across portions of the southeast U.S., but some
restrengthening is possible again when the storm moves over the
western Atlantic.  The NHC intensity forecast is a little higher
than the previous one while Elsa is expected to be over the Gulf of
Mexico, and it lies near the high end of the model guidance.
 
 
Key Messages:
 
1. Heavy rain will impact the Cayman Islands and Cuba today 
resulting in significant flooding and mudslides over Cuba. As Elsa 
approaches the Florida Keys, Florida Peninsula, and coastal Georgia 
Monday through Wednesday, heavy rainfall may result in isolated 
flash, urban, and minor river flooding.  Mid to late week, heavy 
rains across coastal South Carolina and North Carolina may result in 
isolated flash and urban flooding.
 
2. Tropical storm conditions and a dangerous storm surge are
expected to continue across portions of central and western Cuba
today.  Hurricane conditions are also possible along the south coast
this morning.
 
3. Tropical storm conditions are expected in portions of the
Florida Keys and southwestern Florida tonight and Tuesday, where a
Tropical Storm Warning is in effect.  A Tropical Storm Watch and
a Storm Surge Watch are in effect for much of the west coast of
Florida.
 
4. There is a risk of tropical storm conditions and storm surge
impacts along the coasts of Georgia and the Carolinas Wednesday and
Thursday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/0900Z 21.0N  79.9W   55 KT  65 MPH
 12H  05/1800Z 22.2N  81.3W   55 KT  65 MPH...INLAND
 24H  06/0600Z 23.9N  82.5W   50 KT  60 MPH...OVER WATER
 36H  06/1800Z 25.9N  83.2W   55 KT  65 MPH
 48H  07/0600Z 28.0N  83.4W   55 KT  65 MPH
 60H  07/1800Z 30.1N  83.0W   45 KT  50 MPH...INLAND
 72H  08/0600Z 32.5N  80.9W   35 KT  40 MPH...INLAND
 96H  09/0600Z 36.8N  74.3W   40 KT  45 MPH...OVER WATER
120H  10/0600Z 42.0N  64.3W   40 KT  45 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Cangialosi/Reinhart
 
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