118
WTPZ42 KNHC 240838
TCDEP2
HURRICANE VANCE DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL EP222026
300 AM CST SAT OCT 24 2026
SATELLITE IMAGERY INDICATES THAT VANCE'S CONVECTIVE STRUCTURE HAS
CHANGED LITTLE DURING THE PAST SEVERAL HOURS. THE EYE REMAINS RAGGED
AND INTERMITTENTLY OBSCURED BY CLOUDS, SURROUNDED BY DEEP CONVECTION
WITHIN THE EYEWALL WHERE CLOUD-TOP TEMPERATURES ARE AROUND -75 C.
RECENT MICROWAVE IMAGERY REVEALED A SLIGHT NORTHWARD TILT OF THE
VORTEX, REFLECTING THE PERSISTENT MODERATE SOUTHERLY VERTICAL WIND
SHEAR. A 0353 UTC METOP-C SCATTEROMETER PASS HELPED REFINE THE
ANALYZED WIND RADII. SUBJECTIVE DVORAK AND OBJECTIVE INTENSITY
ESTIMATES REMAIN IN THE 90 TO 100 KT RANGE. GIVEN THESE ESTIMATES
AND THE RELATIVELY STEADY SATELLITE PRESENTATION, THE INITIAL
INTENSITY IS HELD AT 95 KT.
THE INITIAL MOTION IS NORTH-NORTHWESTWARD, OR 335/6 KT. THIS GENERAL
MOTION SHOULD CONTINUE THROUGH TONIGHT AS THE SUBTROPICAL RIDGE
WEAKENS IN RESPONSE TO A BROAD MID- TO UPPER-LEVEL TROUGH NEAR THE
WEST COAST OF THE UNITED STATES. THE TRACK GUIDANCE REMAINS IN GOOD
AGREEMENT THROUGH TONIGHT, BUT VANCE'S FORWARD SPEED IS EXPECTED TO
DECREASE AS IT ENTERS A REGION OF WEAK STEERING CURRENTS.
CONSIDERABLE CROSS-TRACK SPREAD DEVELOPS AMONG THE GUIDANCE
SOLUTIONS BEGINNING AROUND 36 H, PARTLY DUE TO DIFFERENCES IN HOW
WELL VANCE MAINTAINS ITS VERTICAL STRUCTURE AS INCREASING SHEAR AND
COOLER WATERS AFFECT THE CYCLONE. A WEAKER SYSTEM COULD BE STEERED
MORE WEST-NORTHWESTWARD, WHILE A STRONGER HURRICANE WOULD BE MORE
LIKELY TO CONTINUE NORTHWARD. GIVEN THE SUBSTANTIAL SPREAD, EVEN
BETWEEN THE HCCA AND GDMI AIDS AFTER DAY 3, TRACK FORECAST
CONFIDENCE REMAINS QUITE LOW AS VANCE APPROACHES THE VICINITY OF THE
SOUTHWESTERN AND WEST-CENTRAL COAST OF MEXICO NEXT WEEK. THE NHC
TRACK FORECAST REMAINS LARGELY UNCHANGED FROM THE PREVIOUS
PREDICTION, LYING NEAR THE HCCA AND GDMI AIDS THROUGH DAY 3 AND
REPRESENTING AN AVERAGE OF THESE TWO SOLUTIONS THEREAFTER.
VANCE'S INTENSITY APPEARS TO HAVE LEVELED OFF DURING THE PAST
SEVERAL HOURS AFTER THE HURRICANE UNDERWENT A PERIOD OF RAPID
INTENSIFICATION ON FRIDAY. ALTHOUGH SOME FLUCTUATIONS IN STRENGTH
REMAIN POSSIBLE TODAY, COOLER SEA SURFACE TEMPERATURES ASSOCIATED
WITH THE WAKES OF RECENT TROPICAL CYCLONES HAVE REDUCED THE OCEAN
HEAT CONTENT ALONG PORTIONS OF VANCE'S FORECAST TRACK. THESE COOLER
WATERS, COMBINED WITH INCREASING VERTICAL WIND SHEAR, SHOULD INDUCE
A WEAKENING TREND BEGINNING TONIGHT AND CONTINUING THROUGH SUNDAY.
THE AFOREMENTIONED DIFFERENCES IN THE TRACK GUIDANCE HAVE ALSO
CONTRIBUTED TO CONSIDERABLE SPREAD AMONG THE INTENSITY SOLUTIONS,
WITH THE POSSIBILITY OF MORE SUBSTANTIAL WEAKENING THAN CURRENTLY
FORECAST. VANCE COULD MOVE BEYOND THE COOLER WATERS BY 48 H,
ALLOWING FOR A BRIEF PERIOD OF RESTRENGTHENING BY 60 H. THEREAFTER,
INCREASING VERTICAL WIND SHEAR, DECREASING MID-LEVEL MOISTURE, AND
POSSIBLE LAND INTERACTION SHOULD LEAD TO ANOTHER WEAKENING TREND
LATE IN THE FORECAST PERIOD. THE NHC INTENSITY FORECAST REMAINS
SIMILAR TO THE PREVIOUS PREDICTION AND LIES NEAR THE UPPER END OF
THE GUIDANCE ENVELOPE THROUGH MUCH OF THE FORECAST PERIOD.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0900Z 12.4N 102.8W 95 KT 110 MPH
12H 24/1800Z 13.1N 103.1W 95 KT 110 MPH
24H 25/0600Z 14.3N 103.4W 90 KT 105 MPH
36H 25/1800Z 15.2N 103.7W 85 KT 100 MPH
48H 26/0600Z 15.9N 104.1W 85 KT 100 MPH
60H 26/1800Z 16.2N 104.2W 90 KT 105 MPH
72H 27/0600Z 16.6N 104.3W 85 KT 100 MPH
96H 28/0600Z 17.5N 104.4W 70 KT 80 MPH
120H 29/0600Z 18.5N 104.5W 60 KT 70 MPH
FORECASTER GIBBS
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