076
WTPZ42 KNHC 220848
TCDEP2
TROPICAL STORM VANCE DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL EP222026
300 AM CST THU OCT 22 2026
VANCE'S SHIELD OF DEEP CONVECTION HAS EXPANDED SINCE THE LAST
ADVISORY, WITH CLOUD-TOP TEMPERATURES ABOUT ITS CENTER READING
COLDER THAN -85 DEGREES C. WHILE AN ASCAT-C PASS AROUND 0430 UTC
REVEALED MAX WINDS ONLY AROUND 30-35 KT, SATELLITE IMAGERY SUGGESTS
THAT VANCE HAS BECOME INCREASINGLY ORGANIZED OVER THE LAST COUPLE OF
HOURS. THE LATEST SUBJECTIVE DVORAK INTENSITY ANALYSIS FROM TAFB
WAS AT 2.5/35 KT, WHILE OBJECTIVE ANALYSES FROM UW-CIMSS
RANGED FROM ABOUT 34-49 KT. GIVEN THE SYSTEM'S IMPROVED PRESENTATION
ACROSS SATELLITE IMAGERY, ALONG WITH THE UPWARD TREND IN OBJECTIVE
ESTIMATES, VANCE'S INITIAL INTENSITY WAS RAISED TO 45 KT.
THE INITIAL MOTION WAS ESTIMATED TO BE 275/6 KT. VANCE CONTINUES TO
RIDE THE SOUTHERN FLANK OF A MID-LEVEL RIDGE ANCHORED OVER MEXICO
AND THE SOUTH-CENTRAL US. AS THE RIDGE SHIFTS EASTWARD, VANCE IS
EXPECTED TO TURN TO THE NORTHWEST OVER THE NEXT COUPLE OF DAYS. BY
DAY 3, HOWEVER, FORECAST CONFIDENCE DECREASES SIGNIFICANTLY, AS THE
CYCLONE IS EXPECTED TO ENTER AN ENVIRONMENT CHARACTERIZED BY WEAK
STEERING FLOW, RESULTING IN A WIDE SPREAD OF SOLUTIONS ACROSS TRACK
GUIDANCE. THE LATEST NHC TRACK FORECAST REFLECTS ONLY A SLIGHT SHIFT
LEFTWARD FROM THE PREVIOUS ADVISORY, WHICH CLOSELY FOLLOWS GDMI AND
HCCA GUIDANCE.
SHIPS GUIDANCE CONTINUES TO DEPICT AN ENVIRONMENT FAVORABLE FOR
STRENGTHENING AHEAD OF VANCE, CHARACTERIZED BY WARM SSTS, LOW
VERTICAL WIND SHEAR, AND AMPLE MID-LEVEL MOISTURE. PROBABILITIES FOR
RAPID INTENSIFICATION HAVE BACKED OFF SLIGHTLY BASED ON THE LATEST
SHIPS RUN, HOWEVER, VANCE IS STILL ANTICIPATED TO BECOME A MAJOR
HURRICANE BY THE END OF THE WEEKEND. THEREAFTER, A GRADUAL WEAKENING
TREND IS FORECAST AS THE CYCLONE ENCOUNTERS INCREASING VERTICAL WIND
SHEAR AND LESS FAVORABLE OUTFLOW. THE LATEST NHC INTENSITY FORECAST
IS LITTLE CHANGED FROM THE PREVIOUS ADVISORY, AND GENERALLY FALLS
WITHIN THE UPPER-END OF THE GUIDANCE ENVELOPE.
FORECAST POSITIONS AND MAX WINDS
INIT 22/0900Z 9.7N 101.5W 45 KT 50 MPH
12H 22/1800Z 10.0N 102.1W 50 KT 60 MPH
24H 23/0600Z 10.5N 102.8W 70 KT 80 MPH
36H 23/1800Z 11.1N 103.4W 85 KT 100 MPH
48H 24/0600Z 11.8N 103.9W 95 KT 110 MPH
60H 24/1800Z 12.7N 104.3W 105 KT 120 MPH
72H 25/0600Z 13.8N 104.7W 100 KT 115 MPH
96H 26/0600Z 15.5N 105.2W 95 KT 110 MPH
120H 27/0600Z 16.8N 105.5W 90 KT 105 MPH
FORECASTER EVANS/GIBBS
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