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Tropical Storm Pamela Discussion Number 12
NWS National Hurricane Center Miami FL EP162021
900 PM MDT Tue Oct 12 2021
Westerly shear has continued to prevent Pamela from restrengthening
this evening. Although there was a significant burst of deep
convection since the previous advisory, the center remains on the
northwestern edge of the convective cloud mass and more recently the
cloud tops associated with that burst has begun to warm. A blend of
subjective Dvorak T- and CI-numbers from SAB and TAFB, and the
latest UW-CIMSS SATCON estimate stills support an initial intensity
of 60 kt. Another Air Force Reserve reconnaissance aircraft is
scheduled to investigate Pamela overnight, which should provide a
better assessment of the cyclone's intensity.
Recent center fixes show that Pamela has made its much anticipated
north-northeastward turn, and it is now moving 020/10 kt. The
tropical storm should accelerate northeastward during the next 12 to
24 hours as it gets caught in deep-layer southwesterly flow between
a mid-level ridge over the western Gulf of Mexico, and an
approaching mid-latitude trough to the northwest. This motion
should bring the center of Pamela to the coast of west-central
mainland Mexico around 1200 UTC Wednesday morning. After that time,
Pamela or its remnants should continue moving quickly northeastward
across central and northern Mexico through Wednesday night.
Although a 36-h post-tropical cyclone point is shown over southern
Texas, the low-level center is likely to dissipate over the
mountainous terrain of Mexico late Wednesday or Wednesday night.
Pamela will be moving over very warm SSTs of around 31C overnight,
and that combined with a slightly more conducive upper-level wind
pattern should allow Pamela to restrengthen into a hurricane before
it reaches the coast of Mexico Wednesday morning. After landfall,
rapid weakening will occur as Pamela moves over the rugged terrain
of west-central Mexico. The latest NHC intensity forecast is again
near the higher side of the guidance envelope, but it shows a
slightly lower peak intensity before landfall than the previous
official forecast.
Although Pamela is likely to dissipate over the rugged terrain of
Mexico, deep moisture associated with the system's remnants are
likely to spread over north-central and northeastern Mexico on
Wednesday, and then move into portions of the south-central United
States late Wednesday or Thursday.
Key Messages:
1. Pamela is forecast to restrengthen into a hurricane before it
reaches the west-central coast of Mexico on Wednesday morning, and
life-threatening storm surge and dangerous hurricane-force winds
are expected within the Hurricane Warning area. Residents in this
area should follow any advice given by local officials.
2. Heavy rains associated with Pamela are expected to move into the
Mexican States of Sinaloa and western Durango along with southern
portions of Baja California Sur tonight and Wednesday. This will
pose a threat of significant and life-threatening flash flooding and
mudslides.
3. Heavy rains associated with the remnants of Pamela are expected
across portions of central Texas and southeastern Oklahoma late
Wednesday and Thursday. This may result in considerable flash and
urban flooding impacts.
FORECAST POSITIONS AND MAX WINDS
INIT 13/0300Z 21.9N 108.7W 60 KT 70 MPH
12H 13/1200Z 23.8N 106.9W 70 KT 80 MPH...NEAR THE COAST
24H 14/0000Z 26.6N 103.3W 30 KT 35 MPH...INLAND
36H 14/1200Z 29.7N 99.7W 20 KT 25 MPH...POST-TROP/INLAND
48H 15/0000Z...DISSIPATED
$$
Forecaster Brown
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