418
WTPZ41 KNHC 090233
TCDEP1
TROPICAL STORM PRISCILLA DISCUSSION NUMBER 18
NWS NATIONAL HURRICANE CENTER MIAMI FL EP162025
800 PM MST WED OCT 08 2025
SOME CONVECTION HAS RE-DEVELOPED IN ASSOCIATION WITH PRISCILLA,
MAINLY IN DISORGANIZED BANDS WELL REMOVED FROM THE CENTER. THIS
CONVECTION IS NOT WELL-ENOUGH ORGANIZED TO KEEP THE SATELLITE
INTENSITY ESTIMATES FROM DECREASING. BASED ON THESE DECREASES SINCE
THE PREVIOUS ADVISORY, THE INITIAL INTENSITY IS REDUCED TO 50 KT.
THE INITIAL MOTION ESTIMATE REMAINS NORTHWESTWARD, OR 320/8 KT. AS
MENTIONED PREVIOUSLY, PRISCILLA IS MOVING ALONG THE SOUTHWESTERN
SIDE OF A MID-LEVEL HIGH PRESSURE RIDGE NEAR THE TEXAS/MEXICO
BORDER. IN 24 H OR SO, A LARGE MID-LATITUDE TROUGH OR CUTOFF LOW
NEAR THE CALIFORNIA COAST SHOULD CAUSE A NORTHWARD TURN. BY 48 H,
PRISCILLA WILL LIKELY HAVE WEAKENED INTO A SHALLOW CYCLONE STEERED
BY THE LOW-LEVEL FLOW, WHICH IS RATHER WEAK. THE TRACK GUIDANCE HAS
NOT CHANGED SIGNIFICANTLY SINCE THE LAST ADVISORY, AND THE NEW
FORECAST TRACK IS VERY SIMILAR TO THE PREVIOUS TRACK.
THE FORECAST TRACK TAKES PRISCILLA OVER COLDER SEA SURFACE
TEMPERATURES AND INTO A DRIER ENVIRONMENT, AND THESE FACTORS SHOULD
CAUSE CONTINUED WEAKENING. THE LATEST SIMULATED SATELLITE IMAGERY
FROM THE GFS AND ECMWF MODELS FORECAST THE CYCLONE TO STOP PRODUCING
CONVECTION IN ABOUT 36 H, AND THE NEW INTENSITY FORECAST CALLS FOR
THE SYSTEM TO DECAY TO A REMNANT LOW AT THAT TIME. THE REMNANT LOW
IS STILL SHOWN AS DISSIPATING BY 72 H IN AGREEMENT WITH THE GLOBAL
MODELS. THE NEW INTENSITY FORECAST IS AN UPDATE OF THE PREVIOUS
FORECAST.
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 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 09/0300Z 22.6N 113.6W 50 KT 60 MPH
12H 09/1200Z 23.4N 114.4W 45 KT 50 MPH
24H 10/0000Z 24.6N 115.1W 35 KT 40 MPH
36H 10/1200Z 25.7N 115.2W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 11/0000Z 26.5N 115.1W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 11/1200Z 27.2N 114.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 12/0000Z...DISSIPATED
FORECASTER BEVEN
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