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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