421
WTPZ41 KNHC 082035
TCDEP1

Tropical Storm Priscilla Discussion Number  17
NWS National Hurricane Center Miami FL       EP162025
200 PM MST Wed Oct 08 2025

The satellite presentation of Priscilla has fallen apart quickly
over the past 18 hours.  Over the past 6 hours, deep convection has
gradually diminished.  The latest CI numbers from TAFB and SAB are
65 kt, while objective intensity estimates from UW-CIMSS have
decreased to the 47-53 kt range.  An ASCAT-C pass from 1750 UTC
showed peak vectors of 55 kt.  Given the low bias due to the
resolution of this instrument, the initial intensity is maintained
at 60 kt.

The initial motion estimate is northwestward, or 315 degrees at 7
kt.  Priscilla is moving along the southwestern side of a mid-level
high pressure ridge near the Texas/Mexico border.  In 24-36 hours or
so, a large trough or cutoff low near the California coast should
induce a turn toward the north.  By 48 hours, Priscilla will likely
have weakened into a shallow cyclone moving in the low-level
environmental flow.  The latest NHC track forecast has been adjusted
very slightly to the right of the previous official forecast, and
lies close to the HFIP Corrected Consensus (HCCA) approach.

Water temperatures along Priscilla`s path are quickly decreasing.
The cyclone is expected to cross the 26 degree C isotherm in about
12 hours.  Priscilla is also moving into an increasingly dry
environment.  The GFS and ECMWF simulated satellite imagery show
the storm losing its convection and degenerating to a remnant low
in about 48 hours, but given how the convection looks now, it
wouldn`t be surprising if this occurred sooner.  The global and
regional models then show the remnant low dissipating by hour 72.
There are no major changes to the NHC intensity forecast, which is
near the middle of the guidance envelope.


KEY MESSAGES:

1.  Tropical storm conditions are possible along the Baja California
Sur Pacific coastline within the Tropical Storm Watch area though
this evening.  Interests elsewhere in the Baja California peninsula
should monitor the progress of Priscilla.

2.  Moisture associated with Priscilla will lead to heavy rainfall
and a flash flood risk across portions of Arizona, southern Utah,
through the Four Corners into southwest Colorado and far northwest
New Mexico from Thursday into Saturday.

3.  Large swells generated by Priscilla are affecting the Pacific
coast of Baja California Sur as well as portions of the coast of
southwestern and west-central Mexico. These swells are likely
to cause life-threatening surf and rip current conditions, in
addition to some coastal flooding.


FORECAST POSITIONS AND MAX WINDS

INIT  08/2100Z 22.0N 113.0W   60 KT  70 MPH
 12H  09/0600Z 22.8N 114.0W   50 KT  60 MPH
 24H  09/1800Z 24.0N 114.8W   45 KT  50 MPH
 36H  10/0600Z 25.3N 115.2W   40 KT  45 MPH
 48H  10/1800Z 26.3N 115.3W   30 KT  35 MPH...POST-TROP/REMNT LOW
 60H  11/0600Z 27.0N 115.1W   25 KT  30 MPH...POST-TROP/REMNT LOW
 72H  11/1800Z...DISSIPATED

$$
Forecaster Hagen