493
WTPZ41 KNHC 071449
TCDEP1
HURRICANE PRISCILLA DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP162025
800 AM MST TUE OCT 07 2025
CLOUD TOP TEMPERATURES ASSOCIATED WITH PRISCILLA'S EYEWALL
CONVECTION CONTINUE TO COOL, AND THE STRUCTURE OF THE EYE HAS
GRADUALLY BEEN IMPROVING OVER THE PAST 6 H. SUBJECTIVE DVORAK
CLASSIFICATIONS FROM TAFB AND SAB RANGE FROM 90-102 KT, AND
OBJECTIVE NUMBERS HAVE RISEN TO THE 88-102 KT RANGE. THE INITIAL
INTENSITY HAS BEEN RAISED TO 95 KT, WHICH IS AN AVERAGE OF THE
LATEST SATELLITE ESTIMATES.
INTENSITY GUIDANCE IS IN GOOD AGREEMENT THAT PRISCILLA SHOULD PEAK
IN STRENGTH IN ABOUT 12 HOURS OR SO WHILE THE HURRICANE REMAINS OVER
WARM WATERS AND IN A MOIST, MODERATE SHEAR ENVIRONMENT. PRISCILLA IS
NOW EXPLICITLY FORECAST TO BECOME A CATEGORY 3 HURRICANE OVER THE
NEXT 12 HOURS. AFTER THAT, THE HURRICANE IS FORECAST TO MOVE OVER
PROGRESSIVELY COOLER WATERS, REACHING THE 26 DEGREE C SEA-SURFACE
TEMPERATURE ISOTHERM AROUND HOUR 36. PRISCILLA WILL ALSO BE MOVING
INTO A DRIER ENVIRONMENT AS IT GAINS LATITUDE. THEREFORE, THE NHC
FORECAST CALLS FOR WEAKENING BEGINNING WEDNESDAY. SOUTHWESTERLY
VERTICAL WIND SHEAR IS FORECAST TO INCREASE OVER THE CYCLONE IN 3 TO
4 DAYS, AND SIMULATED SATELLITE IMAGES FROM THE GFS AND ECMWF MODELS
INDICATES THAT PRISCILLA SHOULD LOSE ITS CONVECTION AND BECOME A
REMNANT LOW SHORTLY BEFORE THE SYSTEM REACHES THE BAJA CALIFORNIA
PENINSULA. ENHANCED MOISTURE IS LIKELY TO BE TRANSPORTED NORTHWARD
OVER PORTIONS OF THE SOUTHWESTERN U.S. LATE THIS WEEK, RESULTING IN
THE POTENTIAL FOR HEAVY RAINFALL.
THE HURRICANE IS MOVING NORTHWESTWARD (305/9 KT) AROUND THE
SOUTHWESTERN PORTION OF A MID-LEVEL RIDGE OVER NORTHERN MEXICO. THIS
MOTION SHOULD CONTINUE FOR THE NEXT COUPLE OF DAYS WHILE THE CENTER
OF PRISCILLA MOVES PARALLEL TO, BUT REMAINS OFFSHORE OF, THE
SOUTHERN BAJA CALIFORNIA PENINSULA. BY THURSDAY, AN AMPLIFYING
TROUGH OFF THE U.S. WEST COAST IS FORECAST TO ERODE THE STEERING
RIDGE TO THE NORTH OF PRISCILLA. THE WEAKNESS IN THE RIDGE SHOULD
INDUCE A NORTHWARD TURN LATER THIS WEEK AND INTO THE WEEKEND. THE
TRACK MODELS ARE IN FAIRLY GOOD AGREEMENT THROUGH ABOUT 60 H.
THEREAFTER, SPREAD INCREASES, MAINLY IN THE ALONG-TRACK DIRECTION.
THE NEW NHC TRACK FORECAST IS NEARLY ON TOP OF THE PREVIOUS
PREDICTION, PERHAPS A TAD FASTER, AND LIES IN BETWEEN THE FASTER
HFIP CORRECTED CONSENSUS (HCCA) AND THE SLOWER GOOGLE DEEP MIND
ENSEMBLE MEAN.
KEY MESSAGES:
1. TROPICAL STORM CONDITIONS ARE POSSIBLE ALONG THE BAJA CALIFORNIA
SUR PACIFIC COASTLINE WITHIN THE TROPICAL STORM WATCH AREA LATER
TODAY INTO WEDNESDAY. INTERESTS ELSEWHERE IN THE BAJA CALIFORNIA
PENINSULA SHOULD MONITOR THE PROGRESS OF PRISCILLA.
2. HEAVY RAINFALL ASSOCIATED WITH PRISCILLA WILL IMPACT PORTIONS OF
BAJA CALIFORNIA SUR TODAY INTO WEDNESDAY. ITS MOISTURE WILL LEAD TO
HEAVY RAINFALL ACROSS WEST-CENTRAL MEXICO FROM TODAY INTO THURSDAY
MORNING AND ACROSS THE U.S. DESERT SOUTHWEST FROM LATE THIS WEEK
INTO THIS WEEKEND, WHICH COULD RESULT IN FLASH FLOODING,
PARTICULARLY IN AREAS OF HIGHER TERRAIN.
3. SWELLS GENERATED BY PRISCILLA ARE AFFECTING PORTIONS OF THE
COAST OF SOUTHWESTERN AND WEST-CENTRAL MEXICO AS WELL AS THE COAST
OF THE SOUTHERN BAJA CALIFORNIA PENINSULA. THESE SWELLS ARE LIKELY
TO CAUSE LIFE-THREATENING SURF AND RIP CURRENT CONDITIONS.
FORECAST POSITIONS AND MAX WINDS
INIT 07/1500Z 19.8N 110.1W 95 KT 110 MPH
12H 08/0000Z 20.5N 111.2W 100 KT 115 MPH
24H 08/1200Z 21.5N 112.5W 90 KT 105 MPH
36H 09/0000Z 22.6N 113.8W 75 KT 85 MPH
48H 09/1200Z 23.7N 114.9W 60 KT 70 MPH
60H 10/0000Z 25.1N 115.4W 50 KT 60 MPH
72H 10/1200Z 26.3N 115.5W 40 KT 45 MPH
96H 11/1200Z 28.7N 114.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 12/1200Z 31.5N 113.3W 15 KT 15 MPH...POST-TROP/REMNT LOW
FORECASTER HAGEN
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