Official Discussion issued by the National Hurricane Center

Laura (AL132020) DATA RELEASED: 8/21/2020 3:00:00 PM UTC

Copy of official data

Tropical Storm Laura Discussion Number   7
NWS National Hurricane Center Miami FL       AL132020
1100 AM AST Fri Aug 21 2020

A NOAA Hurricane Hunter aircraft has been investigating the system 
this morning and found that the maximum winds have increased to near 
40 kt, and therefore the cyclone is being named.  The Hurricane 
Hunters also found that the center of the storm is located somewhat 
to the south of previous estimates.  The system is better organized 
than it was yesterday, but still lacks well-defined banding 
features.  However, some upper-level outflow is now noted over the 
southern portion of the circulation.  The official forecast calls 
for some slow strengthening during the next couple of days, but the 
intensity forecast is quite uncertain and depends on how much 
interaction with land will occur.  For now, we will assume that the 
northern part of the circulation will remain over water so that the 
system will not be too disrupted by Hispaniola and Cuba.  The 
official intensity forecast remains close to the model consensus 
except at days 4 and 5 where it is a little lower due to these 
uncertainties.

With the repositioning of the center, the motion is very uncertain
but is estimated to be 270/16 kt.  Laura is expected to move mainly
west-northwestward on the south side of a subtropical high pressure
system over the next couple of days.  Later in the forecast period,
the tropical cyclone should turn toward the northwest as it moves
around the western periphery of the high.  The official track
forecast has been adjusted to the south of the previous one and is
on the northern side of the guidance suite.

Tropical storm warnings have been issued for the northern Leeward
Islands, Puerto Rico, and the Virgin Islands.

Key Messages:

1. Tropical storm conditions are expected across portions of the 
northern Leeward Islands, the Virgin Islands, and Puerto Rico today 
through Saturday, and Tropical Storm Warnings are in effect.  Heavy 
rainfall is likely across this area beginning today and could cause 
mudslides and flash and urban flooding through Sunday.

2. Tropical storm conditions are possible along the northern coasts 
of the Dominican Republic and Haiti, the southeastern Bahamas, 
and the Turks and Caicos islands Saturday and Sunday, and Tropical 
Storm Watches are in effect.

3. The details of the long-range track and intensity forecasts 
remain more uncertain than usual since Laura is forecast to move 
near or over portions of the Greater Antilles through Monday. 
However, Laura could bring storm surge, rainfall, and wind impacts 
to portions of Cuba, the Bahamas, and Florida early next week and 
the northeast U.S. Gulf Coast by the middle of next week. Interests 
there should monitor the progress of Laura and updates to the 
forecast over the next few days.

FORECAST POSITIONS AND MAX WINDS

INIT  21/1500Z 17.0N  60.2W   40 KT  45 MPH
12H  22/0000Z 17.4N  62.7W   40 KT  45 MPH
24H  22/1200Z 18.3N  66.0W   45 KT  50 MPH
36H  23/0000Z 19.2N  69.5W   45 KT  50 MPH
48H  23/1200Z 20.2N  73.4W   45 KT  50 MPH
60H  24/0000Z 21.6N  77.1W   50 KT  60 MPH
72H  24/1200Z 23.2N  80.7W   55 KT  65 MPH
96H  25/1200Z 26.5N  85.5W   65 KT  75 MPH
120H  26/1200Z 29.5N  87.5W   65 KT  75 MPH

$$
Forecaster Pasch