National Weather Service

5-Day Uncertainty Track last updated Thu, 18 Sep 2025 14:49:09 GMT Wind Speed Probabilities last updated Thu, 18 Sep 2025 14:49:09 GMT

Issued at 1100 AM AST Thu Sep 18 2025 010 WTNT42 KNHC 181443 TCDAT2 Tropical Storm Gabrielle Discussion Number 6 NWS National Hurricane Center Miami FL AL072025 Issued by the NWS Weather Prediction Center College Park MD 1100 AM AST Thu Sep 18 2025 Gabrielle continues to struggle this morning as a pronounced swirl of low-level clouds is unable to muster up much in the way of deep convection near its center. Gabrielle's poor structure is due to ongoing westerly vertical wind shear and a significant amount of dry air entrainment that is infiltrating its circulation. The initial intensity is held at 45 kt based on recent scatterometer data of at least 40 kt, but this value remains above the latest satellite intensity estimates. Atmospheric conditions are expected to remain hostile for a couple more days, meaning Gabrielle is likely maintain its current intensity or weaken during that time. It is even possible it could decay into a non-convective post-tropical low for a time. Assuming it survives, most guidance suggests that the storm will move into more conducive conditions that persist into early next week, allowing Gabrielle to organize and strengthen as it tracks north to northeastward. The NHC intensity forecast is near the low end of the guidance envelope for the first 3 days, but lies closer to the middle of the guidance at days 4 and 5. Gabrielle's more erratic track over the past 24-48 hours has now smoothed out over the past 12-24 hours with a west-northwestward motion at 13 kt. This west-northwest to northwest motion should persist over the next few days as the storm is steered primarily by a subtropical ridge over the central Atlantic. A turn toward the north or northeast is forecast to occur late this weekend and early next week when Gabrielle rounds the western periphery of the ridge and a frontal system approaches from the west. The NHC track forecast was adjusted just west of track given the guidance's more westerly consensus of a weaker system inside the next 48 hours. Gabrielle's forward motion is a little faster as well, especially between hours 48-120 when it should accelerate thanks to increased steering flow on the western side of the Atlantic ridge. Confidence in the long range forecast remains low, and interests in Bermuda should continue to monitor Gabrielle over the next several days. FORECAST POSITIONS AND MAX WINDS INIT 18/1500Z 20.3N 51.7W 45 KT 50 MPH 12H 19/0000Z 21.1N 53.2W 40 KT 45 MPH 24H 19/1200Z 22.1N 55.3W 40 KT 45 MPH 36H 20/0000Z 23.2N 57.4W 40 KT 45 MPH 48H 20/1200Z 24.4N 59.2W 40 KT 45 MPH 60H 21/0000Z 25.9N 60.6W 45 KT 50 MPH 72H 21/1200Z 27.7N 61.5W 50 KT 60 MPH 96H 22/1200Z 31.4N 61.9W 70 KT 80 MPH 120H 23/1200Z 36.5N 56.2W 80 KT 90 MPH $$ Forecaster Mullinax/Blake

Issued at 1500 UTC THU SEP 18 2025 000 FONT12 KNHC 181443 PWSAT2 TROPICAL STORM GABRIELLE WIND SPEED PROBABILITIES NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072025 ISSUED BY THE NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1500 UTC THU SEP 18 2025 AT 1500Z THE CENTER OF TROPICAL STORM GABRIELLE WAS LOCATED NEAR LATITUDE 20.3 NORTH...LONGITUDE 51.7 WEST WITH MAXIMUM SUSTAINED WINDS NEAR 45 KTS...50 MPH...85 KM/H. Z INDICATES COORDINATED UNIVERSAL TIME (GREENWICH) ATLANTIC STANDARD TIME (AST)...SUBTRACT 4 HOURS FROM Z TIME EASTERN DAYLIGHT TIME (EDT)...SUBTRACT 4 HOURS FROM Z TIME CENTRAL DAYLIGHT TIME (CDT)...SUBTRACT 5 HOURS FROM Z TIME WIND SPEED PROBABILITY TABLE FOR SPECIFIC LOCATIONS CHANCES OF SUSTAINED (1-MINUTE AVERAGE) WIND SPEEDS OF AT LEAST ...34 KT (39 MPH... 63 KM/H)... ...50 KT (58 MPH... 93 KM/H)... ...64 KT (74 MPH...119 KM/H)... FOR LOCATIONS AND TIME PERIODS DURING THE NEXT 5 DAYS PROBABILITIES FOR LOCATIONS ARE GIVEN AS OP(CP) WHERE OP IS THE PROBABILITY OF THE EVENT BEGINNING DURING AN INDIVIDUAL TIME PERIOD (ONSET PROBABILITY) (CP) IS THE PROBABILITY OF THE EVENT OCCURRING BETWEEN 12Z THU AND THE FORECAST HOUR (CUMULATIVE PROBABILITY) PROBABILITIES ARE GIVEN IN PERCENT X INDICATES PROBABILITIES LESS THAN 1 PERCENT PROBABILITIES FOR 34 KT AND 50 KT ARE SHOWN AT A GIVEN LOCATION WHEN THE 5-DAY CUMULATIVE PROBABILITY IS AT LEAST 3 PERCENT. PROBABILITIES FOR 34...50...64 KT SHOWN WHEN THE 5-DAY 64-KT CUMULATIVE PROBABILITY IS AT LEAST 1 PERCENT. - - - - WIND SPEED PROBABILITIES FOR SELECTED LOCATIONS - - - - FROM FROM FROM FROM FROM FROM FROM TIME 12Z THU 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON PERIODS TO TO TO TO TO TO TO 00Z FRI 12Z FRI 00Z SAT 12Z SAT 12Z SUN 12Z MON 12Z TUE FORECAST HOUR (12) (24) (36) (48) (72) (96) (120) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - LOCATION KT BERMUDA 34 X X( X) X( X) X( X) X( X) 23(23) 7(30) BERMUDA 50 X X( X) X( X) X( X) X( X) 6( 6) 3( 9) BERMUDA 64 X X( X) X( X) X( X) X( X) 1( 1) 1( 2) $$ FORECASTER MULLINAX/BLAKE

Issued at 1100 AM AST Thu Sep 18 2025 000 WTNT32 KNHC 181442 TCPAT2 BULLETIN Tropical Storm Gabrielle Advisory Number 6 NWS National Hurricane Center Miami FL AL072025 Issued by the NWS Weather Prediction Center College Park MD 1100 AM AST Thu Sep 18 2025 ...GABRIELLE STILL STRUGGLING OVER THE CENTRAL ATLANTIC... SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION ----------------------------------------------- LOCATION...20.3N 51.7W ABOUT 755 MI...1220 KM ENE OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...WNW OR 300 DEGREES AT 15 MPH...24 KM/H MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES WATCHES AND WARNINGS -------------------- There are no coastal watches or warnings in effect. DISCUSSION AND OUTLOOK ---------------------- At 1100 AM AST (1500 UTC), the center of Tropical Storm Gabrielle was located near latitude 20.3 North, longitude 51.7 West. Gabrielle is moving toward the west-northwest near 15 mph (24 km/h), and this motion is expected to continue over the next couple days, followed by a northwestward turn this weekend. Maximum sustained winds remain near 50 mph (85 km/h) with higher gusts. Little change in strength is forecast during the next 48 hours, but some gradual intensification is forecast over the weekend. Tropical-storm-force winds extend outward up to 290 miles (465 km) from the center. The estimated minimum central pressure is 1004 mb (29.65 inches). HAZARDS AFFECTING LAND ---------------------- None NEXT ADVISORY ------------- Next complete advisory at 500 PM AST. $$ Forecaster Mullinax/Blake

...GABRIELLE STILL STRUGGLING OVER THE CENTRAL ATLANTIC... As of 11:00 AM AST Thu Sep 18 the center of Gabrielle was located near 20.3, -51.7 with movement WNW at 15 mph. The minimum central pressure was 1004 mb with maximum sustained winds of about 50 mph.