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Tropical Storm Elsa Discussion Number  19
NWS National Hurricane Center Miami FL       AL052021
1100 PM EDT Sun Jul 04 2021
 
Similar to this time last night, Elsa has undergone another 
convective bursting pattern, except that tonight this has translated 
into at least some slight strengthening. An Air Force Reserve 
reconnaissance aircraft investigating the cyclone this evening has 
found maximum 850-mb flight-level winds of 55 kt and reliable SFMR 
surface winds of about 55 kt. Although there have been SFMR winds of 
60 kt or more reported northeast and north of the center, those 
values appear to be contaminated by shoaling and/or breaking waves 
owing to the shallow water flowing in and around the offshore Cayo 
Anclitas and Cayo Pingues archipelagos. The estimated center 
pressure of 1004 mb based on dropsonde data also does a higher 
intensity of 60 kt. Therefore, based on the most reliable data, the 
intensity has been increased to 55 kt.

The initial motion estimate is 310/13 kt.  There remains no 
significant change to the previous few track forecasts and synoptic 
reasonings. Elsa is expected to move northwestward and then 
northward around the western periphery of a mid-level subtropical 
ridge during the next 3 days, followed by acceleration toward the 
northeast on days 4 and 5 as the cyclone moves near the southeast 
U.S. coast and then over the northwestern Atlantic. The new NHC 
track forecast is basically just an update and extension of the 
previous advisory track, and lies close to a blend of the tightly 
packed corrected consensus model HCCA and the simple consensus 
models TVCA and GFEX.

Cuban radar data from Pilan and Camaguey have occasionally revealed 
an eye-like feature in the low -and mid-levels of the cyclone where 
cloud top temperatures have been colder than -80C and also where 
significant lightning activity has been occurring. Given that the 
circulation centers have become better aligned and the upper-level 
outflow pattern is well-established and steadily improving, some 
additional strengthening during the next 12 h is forecast, which 
calls for Elsa to be near hurricane strength before landfall occurs 
along the south-central coast of Cuba tomorrow. Over the eastern 
Gulf of Mexico late Monday and Tuesday, some restrengthening is 
forecast after Elsa clears Cuba, but southwesterly vertical wind 
shear is expected to hinder the intensification process.  The 
official intensity forecast remains on the high side of the 
numerical model guidance, and follows a blend of the HCCA intensity 
consensus model, and the LGEM and and Decay-SHIPS 
statistical-dynamical models.
 
Key Messages:
 
1. Widespread heavy rain will continue to affect portions of Jamaica 
tonight where isolated to scattered flash flooding and mudslides 
will be possible. Heavy rain will then impact the Cayman Islands and 
Cuba tonight into Monday 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 may result in isolated flash flooding.
 
2. Tropical storm conditions and a dangerous storm surge are
expected with hurricane conditions possible in portions of eastern
Cuba tonight.  Tropical storm conditions are expected in portions
of central and western Cuba tonight and Monday, and will spread
into portions of the Florida Keys by late Monday.
 
3. Tropical Storm and Surge Surge Watches are in effect for
portions of the west coast of the Florida peninsula where tropical
storm conditions and a dangerous storm surge are possible beginning
as early as Monday night and continuing into Tuesday.
 
4. There is a risk of tropical storm conditions, storm surge,
and rainfall impacts along the remainder of the Florida Peninsula
Tuesday night through Wednesday and the coasts of Georgia and the
Carolinas Wednesday and Thursday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  05/0300Z 20.6N  79.2W   55 KT  65 MPH
 12H  05/1200Z 21.9N  80.7W   60 KT  70 MPH
 24H  06/0000Z 23.5N  82.1W   50 KT  60 MPH
 36H  06/1200Z 25.1N  82.9W   50 KT  60 MPH
 48H  07/0000Z 27.1N  83.2W   50 KT  60 MPH
 60H  07/1200Z 29.2N  82.8W   45 KT  50 MPH...INLAND
 72H  08/0000Z 31.5N  81.6W   35 KT  40 MPH...INLAND
 96H  09/0000Z 36.0N  76.0W   35 KT  40 MPH...INLAND
120H  10/0000Z 41.0N  66.8W   40 KT  45 MPH...OVER WATER
 
$$
Forecaster Stewart
 
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