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Tropical Storm Wilfred Discussion Number   3
NWS National Hurricane Center Miami FL       AL232020
1100 PM AST Fri Sep 18 2020
 
Conventional satellite imagery shows that Wilfred's surface 
circulation has lost quite a bit of definition during the last 
several hours, and it has been difficult to pinpoint the center.  
Additionally, deep convection has become less organized and the 
cloud tops just to the east of the estimated center position have 
warmed considerably.  The initial intensity is generously held at 
35 kt for this advisory and is in best agreement with blend of the 
subjective and objective satellite intensity estimates. 
 
The GFS and ECMWF global model soundings indicate 30-35 kt of 
northeasterly shear at about 300 mb, and it's apparently 
undercutting the much lighter, diffluent southeasterly flow above.  
Statistical-dynamical guidance, however, still show an outside 
chance of some strengthening Saturday, and the NHC forecast follows 
suit.  Afterward, a combination of Teddy's massive outflow and 
increasing northwesterly shear produced by an mid- to upper-level 
trough to the north of the cyclone, should induce slow weakening on 
Sunday and this trend should continue through the forecast period.

The initial motion is estimated to be west-northwestward, or 
285/16 kt, and the cyclone is being steered by a low to 
mid-tropospheric subtropical ridge to the north.  A few of the 
global models are hinting at a slow turn toward the north-northwest 
prior to dissipation as the steering pattern becomes very meridional 
with developing high amplitude high pressure over the eastern 
Atlantic, and Hurricane Teddy well to the northwest creating a large 
weakness over the western Atlantic.  For now, the NHC forecast shows 
some reduction in forward speed at day 3, before dissipation, and 
lies close to the consensus aids, HCCA and TVCA.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/0300Z 12.8N  36.0W   35 KT  40 MPH
 12H  19/1200Z 13.5N  38.3W   40 KT  45 MPH
 24H  20/0000Z 14.5N  40.9W   40 KT  45 MPH
 36H  20/1200Z 15.8N  43.8W   35 KT  40 MPH
 48H  21/0000Z 16.7N  46.3W   35 KT  40 MPH
 60H  21/1200Z 17.3N  48.3W   30 KT  35 MPH
 72H  22/0000Z 17.9N  50.0W   25 KT  30 MPH...POST-TROP/REMNT LOW
 96H  23/0000Z...DISSIPATED
 
$$
Forecaster Roberts
 
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