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Tropical Storm Larry Discussion Number   5
NWS National Hurricane Center Miami FL       AL122021
800 PM CVT Wed Sep 01 2021

Afternoon satellite imagery indicates that Larry continues to 
become better organized, with visible imagery hinting at eye 
formation and a partial SSM/IS overpass suggesting that a 37 GHz 
convective ring is present around the center.  Satellite intensity 
estimates are now 65 kt from SAB and 55 kt from TAFB, and the 
initial intensity is increased to 60 kt, which is a 30 kt increase 
since this time yesterday satisfying the 24-h definition of rapid 
intensification.

The initial motion is now 275/19 kt.  Larry is expected to move 
around the south and southwest sides of a subtropical ridge during 
the next five days, with a general westward motion for 24-36 h, 
followed by a turn toward the west-northwest and, by 96-120 h, a 
turn toward the northwest.  The spread in the track guidance after 
36 h has decreased a little in the latest model runs.  However, the 
guidance envelope has again shifted a little to the west.  The new 
forecast track will also be shifted a little westward, and it lies 
on the southern edge of the various consensus models.

Conditions appear favorable for additional rapid intensification 
during at the next 36-48 h, and the intensity forecast now calls for 
Larry to become a hurricane in less than 12 h and become a major 
hurricane in about 48 h.  Given current trends, this part of the 
intensity forecast could be conservative.  There is lower confidence 
in the intensity forecast after 48 h.  Larry is expected to 
encounter somewhat increased shear, and around the 72 h point it is 
expected to encounter some dry air.  After 96 h, moderate shear is 
forecast to continue, but the cyclone is expected to move into a 
more moist air mass and over increasing sea surface temperatures.  
On top of these factors, there is the good chance that Larry will 
have fluctuations in intensity after it becomes a major hurricane 
due to eyewall replacement cycles.  The intensity guidance basically 
keeps a steady intensity from 60-120 h, and the official forecast 
follows that trend.  However, this part of the intensity forecast is 
in the middle of the guidance, and it is possible Larry could be 
stronger than forecast during this time.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  01/2100Z 12.5N  29.4W   60 KT  70 MPH
 12H  02/0600Z 12.6N  31.8W   70 KT  80 MPH
 24H  02/1800Z 13.0N  34.9W   85 KT 100 MPH
 36H  03/0600Z 13.7N  38.0W   95 KT 110 MPH
 48H  03/1800Z 14.6N  40.9W  100 KT 115 MPH
 60H  04/0600Z 15.6N  43.5W  105 KT 120 MPH
 72H  04/1800Z 16.9N  46.2W  105 KT 120 MPH
 96H  05/1800Z 19.5N  50.5W  105 KT 120 MPH
120H  06/1800Z 22.5N  54.0W  105 KT 120 MPH
 
$$
Forecaster Beven
 
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