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Tropical Storm Vicky Discussion Number  10
NWS National Hurricane Center Miami FL       AL212020
1100 AM AST Wed Sep 16 2020
 
Hostile vertical shear of 50 to 60 kt has finally taken a toll on 
Vicky. A 1227 UTC ASCAT-B overpass showed peak winds of 35 kt north 
of the center, and that is the basis for the advisory intensity. The 
strong shear is expected to continue while Vicky moves over marginal 
26-27C SSTs, so additional weakening is forecast. Vicky should 
become a tropical depression in around 24 hours before weakening to 
a remnant low in about 2 days, with dissipation expected by day 3. 
However, the timing of when organized deep convection will finally 
cease is difficult to determine, so its is possible Vicky could 
weaken faster than indicated here or hang on a bit longer.
 
The initial motion estimate is more westward, or 270/08. Vicky 
should continue moving westward for the next day or two before 
turning west-southwestward in the low-level flow. The new NHC track 
forecast is south of the previous one and is close to the new 
multi-model consensus aids.

The ASCAT data were also used to modify the initial 34-kt wind 
radii. 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  16/1500Z 21.5N  34.7W   35 KT  40 MPH
 12H  17/0000Z 21.6N  36.0W   35 KT  40 MPH
 24H  17/1200Z 21.7N  37.7W   30 KT  35 MPH
 36H  18/0000Z 21.5N  39.5W   30 KT  35 MPH
 48H  18/1200Z 21.0N  41.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  19/0000Z 20.5N  42.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 72H  19/1200Z...DISSIPATED
 
$$
Forecaster Brennan
 
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