136
WTNT43 KNHC 300256
TCDAT3
HURRICANE HUMBERTO DISCUSSION NUMBER 22
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082025
1100 PM AST MON SEP 29 2025
NORTHWESTERLY VERTICAL WIND SHEAR IS CAUSING HUMBERTO TO LOSE
STRENGTH TONIGHT. GEOSTATIONARY SATELLITE AND MICROWAVE IMAGES
INDICATE THAT THE CLOUD PATTERN HAS BECOME ASYMMETRIC WITH THE
INNER CORE NOW FRAGMENTED AND LOCATED NEAR THE WESTERN EDGE OF THE
CLOUD MASS. THE AIR FORCE HURRICANE HUNTERS HAVE BEEN INVESTIGATING
THE HURRICANE OVER THE PAST FEW HOURS AND HAVE FOUND THAT THE
MINIMUM PRESSURE HAS INCREASED TO AROUND 963 MB. THE AIRCRAFT DATA
ALSO INDICATE THAT THE MAXIMUM WINDS HAVE LOWERED TO AROUND 100 KT.
HUMBERTO IS MOVING NORTH-NORTHWESTWARD AT 12 KT ON THE SOUTHWEST
SIDE OF A SUBTROPICAL RIDGE. THE HURRICANE SHOULD TURN NORTHWARD ON
TUESDAY AS THE RIDGE SHIFTS EAST AND WEAKENS. ON WEDNESDAY, A MID-
TO UPPER-LEVEL TROUGH IS EXPECTED TO AMPLIFY OVER THE NORTH
ATLANTIC, CAUSING HUMBERTO TO TURN SHARPLY TO THE NORTHEAST OR
EAST-NORTHEAST AND ACCELERATE. THE MODELS ARE IN GOOD AGREEMENT,
AND NO SIGNIFICANT CHANGES WERE MADE TO THE PREVIOUS FORECAST.
THIS TRACK TAKES THE CORE OF HUMBERTO WELL WEST AND THEN NORTH OF
BERMUDA.
CONTINUED STEADY WEAKENING IS EXPECTED AS NORTHWESTERLY VERTICAL
WIND SHEAR AND INTRUSIONS OF DRY AIR PERSIST OVER THE NEXT DAY OR
TWO. BY LATE WEDNESDAY, HUMBERTO IS EXPECTED TO MERGE WITH A MID-
TO UPPER-LEVEL TROUGH, AND THAT SHOULD CAUSE THE SYSTEM TO DEVELOP
FRONTAL FEATURES AND COMPLETE EXTRATROPICAL TRANSITION. HUMBERTO IS
EXPECTED TO GROW SIGNIFICANTLY IN SIZE AS IT BECOMES EXTRATROPICAL.
THE LARGE EXTRATROPICAL LOW IN COMBINATION WITH IMELDA WILL CAUSE
ROUGH MARINE CONDITIONS OVER A LARGE PORTION OF THE WESTERN AND
CENTRAL ATLANTIC. SEE KEY MESSAGES BELOW FOR MORE INFORMATION.
KEY MESSAGES:
1. HUMBERTO'S OUTER RAINBANDS COULD PRODUCE GUSTY WINDS AND HEAVY
RAINFALL OVER BERMUDA ON TUESDAY AND WEDNESDAY. PLEASE FOLLOW
LOCAL UPDATES FROM THE BERMUDA WEATHER SERVICE FOR IMPACTS FROM
BOTH HUMBERTO AND IMELDA.
2. DANGEROUS MARINE CONDITIONS, INCLUDING HIGH SURF AND
LIFE-THREATENING RIP CURRENTS, WILL CONTINUE TO AFFECT BEACHES OF
THE NORTHERN CARIBBEAN, BAHAMAS, BERMUDA, AND MUCH OF THE EAST COAST
OF THE UNITED STATES THROUGH THE WEEK.
FORECAST POSITIONS AND MAX WINDS
INIT 30/0300Z 30.1N 68.5W 100 KT 115 MPH
12H 30/1200Z 32.0N 68.8W 85 KT 100 MPH
24H 01/0000Z 34.4N 67.7W 75 KT 85 MPH
36H 01/1200Z 36.1N 64.5W 70 KT 80 MPH
48H 02/0000Z 37.4N 58.6W 70 KT 80 MPH...POST-TROP/EXTRATROP
60H 02/1200Z 39.8N 50.4W 65 KT 75 MPH...POST-TROP/EXTRATROP
72H 03/0000Z 43.4N 40.1W 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 04/0000Z...DISSIPATED
FORECASTER CANGIALOSI
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