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Tropical Storm Laura Discussion Number  14
NWS National Hurricane Center Miami FL       AL132020
500 AM EDT Sun Aug 23 2020
 
Laura has maintained an impressive convective pattern despite the 
center being located over extreme south-central Dominican Republic. 
Numerous cloud tops of -85C to -90C have been noted over the  
Barahona peninsula, an indication that extremely heavy rainfall has 
been occurring there. The center of Laura passed over or very near 
Santo Domingo around 0430Z based on a noticeable wind shift that 
was measured at the international airport. Laura's outflow pattern 
has also continue to improve in all quadrants. The initial intensity 
of 40 kt is based on earlier scatterometer and aircraft data, along 
with surface observations along the north coast of the Dominican 
Republic.
 
Laura has continued to move west-northwestward and the initial 
motion estimate is now 285/16 kt. There has been a significant 
westward shift in the latest NHC model guidance, which appears to be 
due to most of the global models taking the center of Laura farther 
south over central or southern Hispaniola rather than emerging it 
off the north coast of Haiti like the GFS is and has been 
forecasting. Given that the most intense convection has persisted 
along the southern coast of Hispaniola, that is where the most 
likely area that a low-level and/or mid-level circulation is most 
probable to develop or persist. As a result, the new NHC track 
forecast favors a more southerly and westerly track solution 
similar to the preponderance of the track guidance. However, the 
new forecast track has not been shifted as far to the left as the 
consensus models in the event that the models shift back to the 
north. However, the latter scenario is appearing less likely based 
observed satellite trends since the previous advisory.
 
Little if any significant change in strength is expected due to 
Laura moving pretty much down the spine of Hispaniola and Cuba 
during the the next 36 hours, with the strongest wind likely 
remaining over water in the northeast quadrant where the pressure 
gradient will be the tightest between the cyclone and the Bermuda 
High. By 48 hours and continuing until landfall, Laura is forecast 
to remain in a low shear and very favorable upper-level outflow 
environment while passing of extremely warm SSTs near 31C. This 
should allow for significant strengthening to occur once the cyclone 
regains a decent inner core after exiting Cuba. The new NHC 
intensity forecast is a blend of the intensity forecasts by the GFS 
and ECMWF global models and the corrected consensus models HCCA and 
FSSE.
 
Key Messages:
 
1. Tropical storm conditions are expected across portions of the 
Dominican Republic and Haiti, the Turks and Caicos, the 
southeastern Bahamas, and Cuba through Monday. Heavy rainfall is 
likely across these areas and could cause mudslides and flash and 
urban flooding.
 
2. Tropical storm conditions are possible the central Bahamas and 
Andros Island tonight and Monday, and in the Florida Keys on 
Monday.
 
3. The details of the long-range track and intensity forecasts
remain uncertain since Laura is forecast to move near or over
portions of the Greater Antilles through Monday. However, Laura is
forecast to strengthen over the Gulf of Mexico and could bring storm
surge, rainfall, and wind impacts to portions of the U.S. Gulf Coast
by the middle of next week. This could result in a prolonged period
of hazardous weather for areas that are likely to be affected by
Tropical Storm Marco earlier in the week. Interests there should
monitor the progress of Laura and Marco and updates to the forecast
during the next few days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0900Z 18.8N  70.9W   40 KT  45 MPH
 12H  23/1800Z 19.8N  73.7W   40 KT  45 MPH...OVER WATER
 24H  24/0600Z 20.9N  77.5W   40 KT  45 MPH...INLAND
 36H  24/1800Z 22.2N  81.1W   40 KT  45 MPH...INLAND
 48H  25/0600Z 23.5N  84.2W   45 KT  50 MPH...OVER WATER
 60H  25/1800Z 24.9N  87.0W   60 KT  70 MPH
 72H  26/0600Z 26.4N  89.4W   75 KT  85 MPH
 96H  27/0600Z 29.9N  92.5W   85 KT 100 MPH
120H  28/0600Z 35.0N  91.4W   30 KT  35 MPH...INLAND
 
$$
Forecaster Stewart
 
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