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Tropical Storm Madeline Discussion Number 4
NWS National Hurricane Center Miami FL EP142022
900 AM MDT Sun Sep 18 2022
A large burst of deep convection has developed southwest of
Madeline's center during the past few hours, with another broken
line of convection oriented parallel to the southwestern coast of
Mexico. The current intensity remains 40 kt as a blend of the
latest Dvorak Current Intensity numbers from TAFB and SAB, and the
latest UW-CIMSS SATCON estimate.
Madeline is located along the southwestern periphery of a large
mid-tropospheric high, and to the southeast of a deep-layer trough
to the west of California. The initial motion is northward, or
350/9 kt, but this steering set up should cause Madeline to
gradually turn northwestward later today, and then
west-northwestward and westward away from the coast of Mexico from
36 hours and beyond. The track guidance is tightly clustered
through 48 hours, but there is more spread after that, with a few
models keeping Madeline too strong and maintaining a northwestward
motion. These models are discounted, and the official forecast
continues to show a westward bend, following the GFS, ECMWF, and
model consensus solutions.
Madeline's broad circulation, and continued moderate to strong
easterly shear, argue against much, if any, intensification during
the next day or so. The official forecast still allows for the
possibility for some minimal strengthening during the next 24 hours
while Madeline is over warm waters. After 24 hours, the storm is
forecast to begin moving across the cold wake left behind by former
Hurricane Kay, which is expected to induce weakening. The updated
NHC intensity forecast is a little lower than the previous
prediction, and it now shows Madeline degenerating into a
post-tropical remnant low by 60 hours, when model simulated
satellite imagery from the GFS and ECMWF indicate that all deep
convection should have dissipated.
KEY MESSAGES:
1. Heavy rains from Madeline are expected for portions of coastal
southwestern Mexico into Monday. This rainfall may produce flash
and urban flooding, along with possible mudslides in areas of higher
coastal terrain.
2. Tropical storm conditions are possible for the southwestern
coast of Mexico from Manzanillo to Cabo Corrientes today and
tonight.
FORECAST POSITIONS AND MAX WINDS
INIT 18/1500Z 18.5N 106.9W 40 KT 45 MPH
12H 19/0000Z 19.5N 107.6W 40 KT 45 MPH
24H 19/1200Z 20.4N 108.8W 45 KT 50 MPH
36H 20/0000Z 21.0N 110.1W 40 KT 45 MPH
48H 20/1200Z 21.3N 111.3W 35 KT 40 MPH
60H 21/0000Z 21.5N 112.4W 30 KT 35 MPH...POST-TROP/REMNT LOW
72H 21/1200Z 21.6N 113.8W 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 22/1200Z 21.4N 116.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 23/1200Z 21.1N 119.7W 20 KT 25 MPH...POST-TROP/REMNT LOW
$$
Forecaster Berg
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