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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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