797
WTPZ42 KNHC 010848
TCDEP2
TROPICAL STORM GIL DISCUSSION NUMBER 5
NWS NATIONAL HURRICANE CENTER MIAMI FL EP072025
1100 PM HST THU JUL 31 2025
GEOSTATIONARY SATELLITE IMAGES INDICATE THAT GIL CONTINUES TO BECOME
BETTER ORGANIZED UNDERNEATH THE SOUTHERN PORTION OF A CENTRAL DENSE
OVERCAST THAT CONTAINS A FAIRLY LARGE AREA OF -70 TO -80 DEGREE C
CLOUD TOPS. GIL IS ALSO DISPLAYING BANDING FEATURES THAT WRAP MOST
OF THE WAY AROUND THE CYCLONE. THE LATEST SUBJECTIVE DVORAK
ESTIMATES ARE A CONSENSUS 3.5/55 KT FROM TAFB AND SAB. OBJECTIVE
NUMBERS FROM UW-CIMSS ARE A BIT LOWER. GIVEN CONTINUED IMPROVEMENT
IN ORGANIZATION OVER THE PAST FEW HOURS, THE INITIAL INTENSITY HAS
BEEN SET TO 55 KT, AND THIS MIGHT BE A TAD CONSERVATIVE. ASCAT
PASSES FROM 0437 AND 0527 UTC WERE HELPFUL IN ANALYZING THE WIND
FIELD, AND THE DATA INDICATE THAT GIL'S RADIUS OF MAXIMUM WINDS
(RMW) IS STILL ABOUT 50 N MI.
THE INITIAL MOTION IS WEST-NORTHWESTWARD, OR 300/14 KT. A FAIRLY
STRONG MID-TROPOSPHERIC RIDGE WILL CONTINUE TO PREVAIL TO THE NORTH
OF GIL FOR THE NEXT FEW DAYS, WHICH SHOULD MAINTAIN THE
WEST-NORTHWESTWARD TRACK, WITH ADDITIONAL ACCELERATION EXPECTED OVER
THE NEXT 36 H. THE OFFICIAL FORECAST IS VERY NEAR THE PREVIOUS ONE
AND LIES BETWEEN THE FASTER HCCA AND THE SLOWER TVCE CONSENSUS
AIDS. BY LATE IN THE FORECAST PERIOD, THE SYSTEM WILL LIKELY TURN
TO A MORE WESTWARD TRACK FOLLOWING THE LOW-LEVEL FLOW.
GIL SHOULD STRENGTHEN STEADILY OVER THE NEXT 12 TO 24 H AS THE
VERTICAL WIND SHEAR DECREASES TO THE 0-5 KT RANGE. THE CHANCE OF
RAPID INTENSIFICATION IS NOT VERY HIGH SINCE THE RMW IS CURRENTLY 50
N MI, AND THE SEA-SURFACE TEMPERATURES THAT GIL IS FORECAST TO
TRAVERSE ARE FORECAST TO DECREASE QUICKLY, CROSSING THE 26C ISOTHERM
IN ABOUT 24 H. BEYOND 24 H, WEAKENING IS EXPECTED DUE TO DECREASING
SSTS. IN ABOUT 60 H, THE WEST-SOUTHWESTERLY VERTICAL WIND SHEAR IS
FORECAST TO INCREASE ALONG GIL'S PATH, AND THIS SHOULD CAUSE GIL TO
LOSE ITS CONVECTION AND BECOME POST-TROPICAL IN ABOUT 3 DAYS, AS
SHOWN BY THE GFS AND ECMWF SIMULATED SATELLITE SOLUTIONS. THE NHC
INTENSITY FORECAST IS TOWARD THE HIGH END OF THE INTENSITY GUIDANCE
DURING THE FIRST 36 H AND DOWN THE MIDDLE OF THE GUIDANCE ENVELOPE
THEREAFTER.
FORECAST POSITIONS AND MAX WINDS
INIT 01/0900Z 14.8N 120.1W 55 KT 65 MPH
12H 01/1800Z 15.8N 122.3W 65 KT 75 MPH
24H 02/0600Z 17.3N 125.6W 70 KT 80 MPH
36H 02/1800Z 18.7N 129.0W 65 KT 75 MPH
48H 03/0600Z 20.1N 132.2W 55 KT 65 MPH
60H 03/1800Z 21.2N 135.3W 45 KT 50 MPH
72H 04/0600Z 22.1N 138.1W 35 KT 40 MPH...POST-TROPICAL
96H 05/0600Z 23.0N 143.3W 30 KT 35 MPH...POST-TROP/REMNT LOW
120H 06/0600Z 23.9N 148.3W 25 KT 30 MPH...POST-TROP/REMNT LOW
FORECASTER HAGEN
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