641
WTNT43 KNHC 242035
TCDAT3
TROPICAL STORM HUMBERTO DISCUSSION NUMBER 1
NWS NATIONAL HURRICANE CENTER MIAMI FL AL082025
500 PM AST WED SEP 24 2025
SATELLITE DATA INDICATES THAT INVEST 93L OVER THE CENTRAL TROPICAL
ATLANTIC HAS NOW DEVELOPED INTO TROPICAL STORM HUMBERTO. VISIBLE
SATELLITE IMAGERY SHOWS THAT THROUGHOUT THE DAY, THE LOW-LEVEL
CENTER HAS BECOME WELL-DEFINED, WITH PERSISTENT AND ORGANIZED DEEP
CONVECTION MAINLY LOCATED OVER THE EASTERN SIDE OF THE SYSTEM.
SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB WERE BOTH
DATA-T/2.5 35 KT. DPRINT AND DMINT OBJECTIVE INTENSITY ESTIMATES
FROM UW-CIMSS RANGE FROM 31 TO 35 KT. USING THESE DATA, THE
INITIAL INTENSITY IS SET TO 35 KT.
THE SYSTEM IS ESTIMATED TO BE MOVING WEST-NORTHWESTWARD AT 300/13
KT, BUT THIS IS OF LOW CONFIDENCE SINCE THE CENTER HAS ONLY RECENTLY
FORMED. A WEST-NORTHWESTWARD TO NORTHWESTWARD MOTION IS
ANTICIPATED THROUGH THE NEXT SEVERAL DAYS ALONG THE SOUTHWESTERN
PERIPHERY OF A MID-LATITUDE RIDGE. TOWARDS THE END OF THE FORECAST
PERIOD, AN APPROACHING TROUGH MOVING OFFSHORE THE EAST COAST OF THE
UNITED STATES WILL ERODE THE RIDGE AND ALLOW THE SYSTEM TO TURN MORE
NORTHWARD. HOWEVER, THERE IS QUITE A BIT OF UNCERTAINTY WITH THE
FORWARD SPEED AND CROSS-TRACK SPREAD OF THE SYSTEM. THIS IS
INCREASINGLY APPARENT BEYOND DAY 3 AS THERE ARE COMPLEX STEERING
COMPONENTS WITH TIMING DIFFERENCES IN THE GLOBAL MODELS, INCLUDING
THE APPROACHING TROUGH AND POTENTIAL BINARY INTERACTION WITH INVEST
94L. THE NHC TRACK FORECAST LIES NEAR THE CONSENSUS AIDS GIVEN SOME
OF THESE UNCERTAINTIES, AND THERE IS LOWER THAN NORMAL CONFIDENCE IN
THE TRACK FORECAST.
THE STORM IS WITHIN A FAVORABLE ENVIRONMENT FOR STRENGTHENING WITH
WARM SEA SURFACE TEMPERATURES NEAR 29C AND MOIST MID-LEVEL RH
VALUES. THE SYSTEM WILL BE DEALING WITH SOME MODERATE WESTERLY WIND
SHEAR FOR THE NEXT DAY OR SO THAT WILL LIKELY CAUSE AN ASYMMETRIC
STORM STRUCTURE. EC AND GFS SHIPS GUIDANCE DEPICT THE SHEAR SLIGHTLY
WEAKENING IN THE DAY 2 TO 4 TIME FRAME, AND WITH INCREASING
DIVERGENCE ALOFT, A SLIGHTLY GREATER RATE OF STRENGTHENING IS SHOWN
AT THAT TIME. THE LATEST NHC FORECAST FOLLOWS THESE TRENDS AND LIES
NEAR THE CONSENSUS INTENSITY AIDS.
FORECAST POSITIONS AND MAX WINDS
INIT 24/2100Z 20.1N 54.9W 35 KT 40 MPH
12H 25/0600Z 20.9N 56.0W 40 KT 45 MPH
24H 25/1800Z 21.6N 57.0W 45 KT 50 MPH
36H 26/0600Z 22.0N 57.5W 50 KT 60 MPH
48H 26/1800Z 22.5N 58.2W 55 KT 65 MPH
60H 27/0600Z 22.9N 59.0W 60 KT 70 MPH
72H 27/1800Z 23.6N 60.6W 70 KT 80 MPH
96H 28/1800Z 26.0N 64.3W 90 KT 105 MPH
120H 29/1800Z 29.1N 67.1W 95 KT 110 MPH
FORECASTER KELLY
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