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Hurricane Willa Forecast Discussion Number 12
2018-10-23 04:34:54| National Hurricane Center (East Pacific)
Issued at 900 PM MDT Mon Oct 22 2018 000 WTPZ44 KNHC 230234 TCDEP4 Hurricane Willa Discussion Number 12 NWS National Hurricane Center Miami FL EP242018 900 PM MDT Mon Oct 22 2018 Willa's eye is no longer apparent in geostationary imagery, but an SSMIS overpass from 0049 UTC showed a remnant inner eye along the northern edge of a larger outer eyewall that has taken shape over the past few hours. The initial intensity has been lowered to 125 kt based on a blend of the latest Dvorak Final-T and CI numbers from TAFB. Given that the eyewall replacement cycle is well underway and that moderate southwesterly shear now affecting the hurricane is expected to increase, continued gradual weakening is forecast through landfall, and the new NHC intensity forecast through 24 hours is near or a bit above the FSU Superensemble. Despite the forecast decrease in the peak winds, Willa is expected to remain a dangerous major hurricane through landfall, and will bring life- threatening storm surge, wind, and rainfall hazards to Las Islas Marias and portions of west-central and southwestern Mexico on Tuesday. After moving inland, Willa will rapidly weaken, with dissipation forecast by Wednesday over the high terrain of Mexico. Moisture from the remnants of Willa is forecast to spread northeastward over northern Mexico and portions of Texas where a swath of heavy rainfall is expected midweek. The initial motion estimate remains northward, or 360/08. The track forecast reasoning remains unchanged, as Willa is expected to gradually recurve as it is steered by a large mid-level ridge centered to the east and a shortwave trough approaching from the northwest. The new NHC track forecast has been adjusted slightly left of the previous one due to the initial position and motion and lies along the eastern edge of the guidance envelope near the HCCA consensus aid. There continue to be differences in the forward speed of the cyclone as it approaches the coast, and the NHC forecast remains close to the forward speed of the consensus aids. Key Messages: 1. A life-threatening storm surge is expected Tuesday along the coasts of the Isla Marias, and along the coast of southern Sinaloa and Nayarit states in west-central and southwestern Mexico near the path of Willa. Residents should rush preparations to completion to protect life and property and follow any advice given by local officials. 2. Everyone in the Isla Marias, and within the hurricane warning area along the coast of west-central Mexico should prepare for life- threatening major hurricane winds associated with the core of Willa. Hurricane force winds will also extend inland across the mountainous areas of west-central Mexico as Willa moves inland. 3. Heavy rainfall from Willa is likely to produce life-threatening flash flooding and landslides over much of southwestern and west-central Mexico. FORECAST POSITIONS AND MAX WINDS INIT 23/0300Z 20.5N 107.2W 125 KT 145 MPH 12H 23/1200Z 21.5N 106.9W 115 KT 130 MPH 24H 24/0000Z 23.0N 105.8W 85 KT 100 MPH...INLAND 36H 24/1200Z 25.3N 102.7W 30 KT 35 MPH...INLAND 48H 25/0000Z...DISSIPATED $$ Forecaster Brennan
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