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Tropical Storm Wilfred Forecast Discussion Number 3
2020-09-19 04:46:22| National Hurricane Center (Atlantic)
Issued at 1100 PM AST Fri Sep 18 2020 241 WTNT43 KNHC 190246 TCDAT3 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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