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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
 
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