082
WTNT42 KNHC 252037
TCDAT2
TROPICAL STORM GONZALO DISCUSSION NUMBER 4
NWS NATIONAL HURRICANE CENTER MIAMI FL AL072026
800 PM CVT FRI SEP 25 2026
THE OVERALL STRUCTURE OF GONZALO HAS CHANGED LITTLE TODAY. THE
CIRCULATION IS ELONGATED FROM THE NORTH-NORTHEAST TO SOUTH-SOUTHWEST
WITH THE ADVISORY POSITION SET AS A MEAN BETWEEN A COUPLE OF
LOW-LEVEL VORTICITY CENTERS ON EITHER END OF THE ELONGATED CENTER.
DEEP CONVECTION REMAINS DISPLACED WELL TO THE NORTHEAST OF THE
ESTIMATED CENTER DUE TO MODERATE TO STRONG SOUTHWESTERLY SHEAR.
OBJECTIVE AND SUBJECTIVE SATELLITE INTENSITY ESTIMATES HAVE NOT
CHANGED MUCH, THEREFORE THE INITIAL INTENSITY REMAINS 45 KT, IN LINE
WITH THE EARLIER SCATTEROMETER DATA.
GONZALO HAS BEEN MOVING MORE NORTHWARD TODAY WITH AN INITIAL MOTION
ESTIMATE OF 350/10 KT. THE STORM IS EXPECTED TO BE STEERED
NORTHWARD TO NORTH-NORTHWESTWARD DURING THE NEXT COUPLE OF DAYS
BETWEEN A MID-LEVEL TROUGH TO ITS NORTH AND A RIDGE OVER WESTERN
AFRICA. GONZALO'S FORWARD SPEED IS EXPECTED TO DECREASE AS THE
SYSTEM BECOMES INCREASINGLY SHALLOW AND IS STEERED BY THE WEAKER
LOW-LEVEL FLOW. THE NEW OFFICIAL TRACK FORECAST IS SIMILAR TO THE
PREVIOUS ADVISORY AND LIES CLOSEST TO THE LATEST GOOGLE DEEP MIND
ENSEMBLE PREDICTION.
THE VERTICAL SHEAR OVER GONZALO IS FORECAST TO INCREASE
SIGNIFICANTLY ON SATURDAY AND WITH GRADUALLY DECREASING SEA SURFACE
TEMPERATURES ALONG THE FORECAST TRACK, WEAKENING SHOULD BEGIN BY
SATURDAY MORNING. SIMULATED SATELLITE IMAGERY FROM THE GLOBAL
MODELS INDICATE THAT GONZALO WILL LOSE ORGANIZED DEEP CONVECTION IN
24 TO 36 HOURS, AND THE NEW NHC FORECAST SHOWS THE SYSTEM BECOMING A
POST-TROPICAL REMNANT LOW BY SUNDAY MORNING. THE INTENSITY FORECAST
IS IN BEST AGREEMENT WITH THE TYPICALLY RELIABLE CONSENSUS AIDS.
KEY MESSAGES:
1. TROPICAL STORM CONDITIONS WILL CONTINUE ACROSS PORTIONS OF THE
CABO VERDE ISLANDS TONIGHT.
2. HEAVY RAINS FROM GONZALO COULD AFFECT THE EASTERN PORTIONS OF
THE CABO VERDE ISLANDS AND THE WESTERN COAST OF AFRICA BETWEEN
GUINEA-BISSAU TO SENEGAL THROUGH SATURDAY. AREAS OF FLASH FLOODING
WILL BE POSSIBLE ALONG THE AFRICA COAST WITH SOME ISOLATED FLASH
FLOOD CONCERNS FOR THE EASTERN ISLANDS OF CABO VERDE.
FORECAST POSITIONS AND MAX WINDS
INIT 25/2100Z 16.2N 22.7W 45 KT 50 MPH
12H 26/0600Z 17.6N 22.9W 45 KT 50 MPH
24H 26/1800Z 19.0N 23.3W 35 KT 40 MPH
36H 27/0600Z 20.0N 23.5W 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 27/1800Z 20.6N 23.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
60H 28/0600Z 21.2N 24.3W 20 KT 25 MPH...POST-TROP/REMNT LOW
72H 28/1800Z 21.7N 24.6W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 29/1800Z 22.0N 25.0W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 30/1800Z...DISSIPATED
FORECASTER BROWN
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