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Tropical Storm Willa Forecast Discussion Number 3
2018-10-20 22:32:07| National Hurricane Center (East Pacific)
Issued at 400 PM CDT Sat Oct 20 2018 000 WTPZ44 KNHC 202032 TCDEP4 Tropical Storm Willa Discussion Number 3 NWS National Hurricane Center Miami FL EP242018 400 PM CDT Sat Oct 20 2018 Willa appears to be wrapping up quickly, and the low-level center is now embedded beneath a ragged central dense overcast. ASCAT data from several hours ago indicated winds were as high as 40 kt, but more recent satellite estimates support an intensity between 45-55 kt, and the maximum winds are set at 50 kt for this advisory. Willa has turned west-northwestward and slowed down, and the initial motion is estimated to be 295/5 kt. The cyclone is forecast to recurve around the western edge of a mid-level ridge that lies over Mexico during the next few days, and then accelerate northeastward into mainland Mexico by days 4 and 5 ahead of a broad mid-latitude trough. Compared to previous model runs, the new track guidance has sped up significantly and also now shows a sharper recurvature, both of which suggest that Willa's hazards could reach the coast of Mexico sooner than originally thought. The GFS and ECMWF remain the fastest of the models, and although the updated NHC track forecast trends in their direction, it hangs back a bit to give some weight to the HWRF, HCCA, and Florida State Superensemble. Even with that consideration, the new forecast does bring Willa to the coast sooner than before. The satellite signature suggests that the storm is organizing quickly and is probably in the beginning stages of rapid intensification (RI). The RI indices are even higher this afternoon than they were this morning, and incredibly, the HWRF, SHIPS, HCCA, and Florida State Superensemble all bring Willa near or at major hurricane intensity in 36 hours. The NHC forecast follows those models' lead and indicates significant strengthening over the next couple of days. A peak in intensity is likely to occur between 48-72 hours, followed by some weakening due to lower oceanic heat content and increasing vertical shear. Despite the expected weakening, Willa is expected to reach the coast of west-central mainland Mexico as a hurricane in about 4 days. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 15.2N 105.8W 50 KT 60 MPH 12H 21/0600Z 15.5N 106.3W 65 KT 75 MPH 24H 21/1800Z 16.1N 106.9W 85 KT 100 MPH 36H 22/0600Z 16.8N 107.4W 105 KT 120 MPH 48H 22/1800Z 17.6N 107.8W 110 KT 125 MPH 72H 23/1800Z 19.1N 108.1W 100 KT 115 MPH 96H 24/1800Z 22.0N 106.5W 80 KT 90 MPH 120H 25/1800Z 24.5N 103.5W 40 KT 45 MPH...INLAND $$ Forecaster Berg
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