Eastern Pacific Basin Tropical Cyclones

Tropical Storm Pamela Forecast Discussion


000
WTPZ41 KNHC 110832
TCDEP1

Tropical Storm Pamela Discussion Number   5
NWS National Hurricane Center Miami FL       EP162021
300 AM MDT Mon Oct 11 2021

The tropical storm has been relatively steady in strength during the
past several hours.  A large area of deep convection continues, but
the center is located near the northern edge of the thunderstorms
due to northerly shear.  An ASCAT-A pass from several hours ago
showed maximum winds in the 40-45 kt range in the northeastern
quadrant, and all of the latest Dvorak estimates are 3.0/45 kt.
Based on this satellite data, the initial intensity is held at 45
kt.

Pamela is moving west-northwestward at 10 kt, and a west-northwest
to northwest motion should continue for about another 12 hours as
the storm moves in the flow on the southwest side of a mid-level
ridge.  By tonight and early Tuesday, Pamela should reach the
western periphery of the ridge, which should cause a turn toward the
north.  A faster motion to the northeast is expected beginning
Tuesday night when the storm becomes embedded in the flow on the
southeast side of a broad mid- to upper-level trough, and that
should bring the cyclone inland over west-central Mexico on
Wednesday.  The new NHC track forecast is a little to the right of
the previous one, to be in better agreement with the latest
consensus aids.

Pamela has been gradually strengthening despite moderate northerly
shear.  The upper-level pattern is expected to become more favorable
for the storm later today.  These favorable winds aloft combined
with warm SSTs and a moist environment should promote steady to
rapid strengthening until Pamela reaches the coast of Mexico.  The
NHC intensity forecast lies at the high end of the model guidance
and continues to show Pamela becoming a dangerous major hurricane
prior to landfall.  After Pamela moves inland, rapid weakening is
expected as the storm moves over the rugged terrain of west-central
Mexico.


Key Messages:

1. Pamela is forecast to be a major hurricane when it reaches the
coast of west-central mainland Mexico on Wednesday, and it could
bring life-threatening storm surge and dangerous winds to a portion
of that area.  Residents in this area should monitor the progress of
this system and ensure they have their hurricane plan in place.
Hurricane watches will likely be required later this morning.

2. Pamela is expected to pass near or south of the southern tip of
the Baja California peninsula as a hurricane Tuesday night or early
Wednesday, and could bring strong winds to the extreme southern
portion of the peninsula. Watches could be required for portions of
this area later today.

3. Heavy rains associated with Pamela are expected to move over the
Mexican States of Sinaloa and western Durgano along with southern
portions of Baja California Sur Tuesday and Wednesday. This will
pose a threat of significant and life-threatening flash flooding and
mudslides.


FORECAST POSITIONS AND MAX WINDS

INIT  11/0900Z 16.2N 107.6W   45 KT  50 MPH
 12H  11/1800Z 16.9N 108.5W   55 KT  65 MPH
 24H  12/0600Z 18.2N 109.4W   70 KT  80 MPH
 36H  12/1800Z 19.9N 109.3W   85 KT 100 MPH
 48H  13/0600Z 21.8N 108.3W  100 KT 115 MPH
 60H  13/1800Z 24.2N 106.4W   75 KT  85 MPH
 72H  14/0600Z 26.9N 103.3W   35 KT  40 MPH...INLAND
 96H  15/0600Z...DISSIPATED

$$
Forecaster Cangialosi



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