651
WTPZ41 KNHC 090845
TCDEP1

Tropical Storm Priscilla Discussion Number  19
NWS National Hurricane Center Miami FL       EP162025
200 AM MST Thu Oct 09 2025

Priscilla has been gradually losing its organized deep convection
overnight.  As a result, objective and subjective satellite
intensity estimates have fallen, and the initial intensity is
lowered to 45 kt for this advisory.  While scatterometer data did
not measure the core of the storm, it did show tropical-storm-force
winds about 40 miles offshore of Baja California Sur.  The wind
radii have been adjusted accordingly.

The estimated motion is northwestward at 7 kt.  As Priscilla becomes
a shallow vortex, it is expected to turn north-northwestward later
this morning in the low-level flow. By Friday, the system should
slow and drift northward, stalling off the coast of the Baja
California Peninsula until the circulation opens into a trough.

The storm has moved over the 26 degree C isotherm toward
progressively cooler waters.  Mid-level humidities are also falling,
and vertical wind shear is forecast to increase substantially.
These atmospheric and oceanic conditions should accelerate
Priscilla`s transition into a post-tropical cyclone.  The latest NHC
intensity forecast now calls for Priscilla to become a post-tropical
cyclone in 24 hours and dissipate off the coast of Baja California
in a couple of days or so.


KEY MESSAGES:

1.  Tropical storm conditions are possible along the Baja California
Sur Pacific coastline within the Tropical Storm Watch area for the
next several hours.  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 through 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  09/0900Z 23.3N 114.1W   45 KT  50 MPH
 12H  09/1800Z 24.3N 114.8W   40 KT  45 MPH
 24H  10/0600Z 25.5N 115.1W   35 KT  40 MPH...POST-TROPICAL
 36H  10/1800Z 26.4N 115.2W   30 KT  35 MPH...POST-TROP/REMNT LOW
 48H  11/0600Z 27.0N 114.9W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  11/1800Z...DISSIPATED

$$
Forecaster Bucci