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Tropical Storm Paulette Discussion Number  12
NWS National Hurricane Center Miami FL       AL172020
500 PM AST Wed Sep 09 2020
 
Paulette's satellite presentation has not changed since this 
morning, with the center exposed just to the south of the deepest 
convection.  Between this morning's ASCAT pass and the most recent 
satellite classifications from TAFB and SAB, which are unchanged at 
T3.0 and T3.5, respectively, the maximum wind estimate remains 50 
kt.  Paulette continues to move into an area of stronger 
southwesterly shear, which is now estimated to be 25-30 kt, and 
this shear is likely to increase further to 30-35 kt within the 
next 24 hours.  As a result, Paulette is expected to begin 
weakening by Thursday, and the NHC forecast is embedded among the 
tightly clustered intensity guidance during the first 2-3 days.  
The shear is expected to relax gradually from 48 hours and beyond 
and turn out of the southeast, which should allow for some 
restrengthening on days 3 through 5 when shear magnitudes could go 
as low as 10 kt.  The HWRF and COAMPS-TC models in particular take 
full advantage of this environment and bring Paulette to hurricane 
intensity by day 4.  The updated NHC intensity forecast is not 
nearly this aggressive, but it does indicate a little more 
strengthening at the end of the forecast period than has been shown 
in previous forecasts, lying closest to the statistical-dynamical 
guidance.  Model environmental trends will be monitored, and 
additional intensity adjustments at the end of the forecast period 
will be made accordingly in subsequent forecasts.

Paulette remains on a west-northwestward course (295/9 kt), located 
to the south of low- to mid-level ridging which extends across the 
central and western Atlantic.  The track models suggest that when 
the cyclone weakens in a day or two, lower-level winds could steer 
the cyclone westward for a short time.  However, a combination of 
the ridge weakening and Paulette's expected re-strengthening should 
cause the cyclone to turn northwestward in 2-3 days and maintain 
that trajectory through the end of the forecast period.  The only 
significant change from the previous forecast is that the 5-day 
forecast point has been shifted westward, with the GFS, ECMWF, 
HWRF, and HCCA models all lying on the left side of the guidance 
envelope by that time.

 
FORECAST POSITIONS AND MAX WINDS
 
INIT  09/2100Z 20.5N  47.4W   50 KT  60 MPH
 12H  10/0600Z 20.9N  48.9W   50 KT  60 MPH
 24H  10/1800Z 21.4N  50.9W   45 KT  50 MPH
 36H  11/0600Z 21.6N  52.7W   40 KT  45 MPH
 48H  11/1800Z 22.3N  54.1W   40 KT  45 MPH
 60H  12/0600Z 23.3N  55.4W   40 KT  45 MPH
 72H  12/1800Z 24.8N  56.6W   45 KT  50 MPH
 96H  13/1800Z 28.0N  60.5W   50 KT  60 MPH
120H  14/1800Z 30.5N  64.5W   55 KT  65 MPH
 
$$
Forecaster Berg
 
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