ZCZC MIATCDAT3 ALL
TTAA00 KNHC DDHHMM
 
Tropical Storm Laura Discussion Number  16
NWS National Hurricane Center Miami FL       AL132020
500 PM EDT Sun Aug 23 2020
 
Satellite imagery and radar data from eastern Cuba show that the 
center of Laura has been moving over water between Haiti and eastern 
Cuba this afternoon.  There has been a recent uptick in convection 
near the center and the radar imagery has shown an increase in 
banding. An Air Force reconnaissance aircraft investigating Laura 
this afternoon has reported a minimum pressure that has fallen to 
around 1000 mb, and winds to support an intensity of 50 kt.  The 
plane very recently found a small area of stronger flight-level 
winds, but these winds may be associated with mesocyclone, and not 
representative of the large scale circulation. 
 
Laura continues to move briskly west-northwestward or 285/18 kt. The 
track forecast reasoning remains the same as the previous advisory.  
Laura should continue to move west-northwestward to the south of a 
deep-layer ridge that is forecast to build westward across Florida 
and the eastern Gulf of Mexico during the next day or two. The track 
guidance has continued to edge southward for the portion of the 
forecast near Cuba, and the NHC forecast has again been moved in 
that direction.  Laura should continue moving west-northwestward 
over the southeastern Gulf on Tuesday, but a turn toward the 
northwest is expected Tuesday night as the cyclone nears the western 
portion of the ridge.  A northwestward to north-northwestward motion 
should then continue around the western portion of the ridge until 
the cyclone reaches the northwestern Gulf coast.  The latest run of 
the ECMWF has shifted significantly eastward, however its ensemble 
mean and many of the stronger ensemble members remain farther west 
as a stronger cyclone is likely to be steered more westward by the 
deep-layer ridge. The GFS, UKMET, and HWRF remain close to the 
previous NHC track, so little change was made to the official 
forecast was made after 48 hours.
 
The intensity forecast during the next 24 hours is highly dependent 
on the track and the amount of interaction Laura has with Cuba.  If 
the storm stays along the southern coast or just offshore, the 
environment of warm water and low vertical wind shear could allow 
for some slight strengthening, but little overall change in 
intensity is indicated during the next 24 hours. After the center 
clears western Cuba, the upper-level wind pattern is predicted to 
quite favorable while the storm traverses the warm waters of the 
Gulf of Mexico.  The GFS, UKMET, and regional hurricane models all 
indicate significant deepening, and the NHC intensity forecast has 
been adjusted slightly upward. Although not explicitly shown, Laura 
could threaten the northwestern Gulf coast near major hurricane 
strength. 
 
Users are again reminded to not to focus on the exact details of
the track or intensity forecast at the longer range as winds, storm
surge, and rainfall hazards will extend far from the center.
 
Key Messages:
 
1. Tropical storm conditions are expected across portions of the
Haiti, the southeastern Bahamas, and Cuba through Monday. Heavy
rainfall is likely across Haiti, Cuba, and Jamaica through Monday
and these rains could cause mudslides and life-threatening flash and
urban flooding.
 
2. Tropical storm conditions are possible over the Middle and Lower
Florida Keys and the Dry Tortugas on Monday.
 
3. While the details of the long-range track and intensity forecasts 
remain uncertain, Laura is forecast to strengthen over the Gulf of 
Mexico and there is an increasing risk of dangerous storm surge, 
wind, and rainfall impacts along portions of the U.S. Gulf Coast by 
the middle of the week. This could result in a prolonged period of 
hazardous weather for areas that are likely to be affected by Marco. 
Interests along the Gulf Coast should monitor the progress of Laura 
and Marco and updates to the forecast during the next few days.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/2100Z 19.5N  75.2W   50 KT  60 MPH
 12H  24/0600Z 20.6N  78.3W   50 KT  60 MPH...NEAR CUBA
 24H  24/1800Z 21.8N  81.7W   50 KT  60 MPH...NEAR CUBA
 36H  25/0600Z 23.3N  84.9W   55 KT  65 MPH...OVER WATER
 48H  25/1800Z 24.7N  87.7W   60 KT  70 MPH
 60H  26/0600Z 26.1N  90.2W   75 KT  85 MPH
 72H  26/1800Z 28.0N  92.5W   90 KT 105 MPH
 96H  27/1800Z 32.7N  93.5W   45 KT  50 MPH...INLAND
120H  28/1800Z 37.0N  88.0W   25 KT  30 MPH...POST-TROPICAL
 
$$
Forecaster Brown
 
NNNN