| Track: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/024545.shtml?cone#contents Tropical Storm Dorian Discussion Number 11 NWS National Hurricane Center Miami FL AL052019 1100 PM AST Mon Aug 26 2019 An Air Force Reserve Unit Hurricane Hunter aircraft has been investigating Dorian this evening. Data from the plane indicate that the storm is not quite as strong as previously estimated, and based on flight-level winds and SFMR-observed surface winds the intensity is set at 45 kt. Fixes from the aircraft show that the center of the cyclone moved just south of the southern coast of Barbados within the last couple of hours, and tropical-storm-force winds were reported over that island. There is fairly well-defined upper-level outflow over the eastern semicircle of the circulation. Although some dry mid-level air is likely to continue to affect Dorian while it moves over the northeastern Caribbean, the dynamical guidance indicates that the shear will not become very strong. Therefore it is still expected that the cyclone will become a hurricane in a couple of days. Some disruption of the system will likely occur when the center moves near eastern Hispaniola. The official intensity forecast is on the high end of the model guidance and is subject to considerable uncertainty, particularly from days 3 to 5. Dorian continues to move west-northwestward, or 290/11 kt, while being steered by the flow on the south side of the subtropical ridge. In a day or two, the tropical cyclone is expected to turn northwestward due to a weakness in the ridge. The ridge is expected to build somewhat later in the forecast period, which should cause Dorian to turn slightly to the left. The ECMWF model is near the northern side of the guidance suite and the UKMET is near the southern side. The GFS model continues to practically dissipate the system so it was unable to generate a forecast track. The official track forecast was shifted a bit to the north, but lies south of the latest dynamical model consensus. It is advisable that one not focus on small changes in the forecast track due to uncertainties. Key Messages: 1. Dorian is expected to bring tropical storm conditions to portions of the Lesser Antilles through Tuesday morning, where tropical storm watches and warnings are in effect. Rainfall of 3 to 8 inches is expected from Martinique to St. Vincent, including Barbados, with isolated totals as high as 10 inches possible. 2. Tropical storm conditions are possible in Puerto Rico on Wednesday, where a tropical storm watch has been issued. Rainfall of 2 to 4 inches with maximum totals of 6 inches are possible across Puerto Rico and St. Croix. 3. Watches will likely be issued for portions of Hispaniola early Tuesday, as the threat of wind and rain impacts continues to increase. 4. While uncertainty is high, wind and rain impacts are possible in the Bahamas and Florida later this week and this weekend. Residents in these areas should monitor the progress of Dorian and ensure that they have their hurricane plan in place. FORECAST POSITIONS AND MAX WINDS INIT 27/0300Z 13.2N 59.7W 45 KT 50 MPH 12H 27/1200Z 14.0N 61.3W 50 KT 60 MPH 24H 28/0000Z 15.2N 63.5W 55 KT 65 MPH 36H 28/1200Z 16.5N 65.5W 60 KT 70 MPH 48H 29/0000Z 17.9N 67.6W 65 KT 75 MPH 72H 30/0000Z 21.0N 71.0W 50 KT 60 MPH 96H 31/0000Z 24.0N 74.8W 55 KT 65 MPH 120H 01/0000Z 26.5N 79.0W 60 KT 70 MPH $$ Forecaster Pasch Tropical Storm Dorian Advisory Number 11 NWS National Hurricane Center Miami FL AL052019 1100 PM AST Mon Aug 26 2019 ...DORIAN JUST PASSED VERY NEAR TO BARBADOS... ...TROPICAL STORM CONDITIONS WILL AFFECT PORTIONS OF THE WINDWARD ISLANDS THROUGH TUESDAY MORNING... SUMMARY OF 1100 PM AST...0300 UTC...INFORMATION ----------------------------------------------- LOCATION...13.2N 59.7W ABOUT 95 MI...155 KM ESE OF ST. LUCIA MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 13 MPH...20 KM/H MINIMUM CENTRAL PRESSURE...1003 MB...29.62 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The government of St. Lucia has discontinued the Hurricane Watch for St. Lucia. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Warning is in effect for... Barbados Martinique St. Lucia St. Vincent and the Grenadines A Tropical Storm Watch is in effect for... Dominica Grenada and its dependencies Saba and St. Eustatius Puerto Rico A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests in the Virgin Islands and Hispaniola should monitor the progress of Dorian as watches for these areas could be required early Tuesday. For storm information specific to your area in the United States, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. For storm information specific to your area outside of the United States, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 1100 PM AST (0300 UTC), the center of Tropical Storm Dorian was located by an Air Force Reserve Unit Hurricane Hunter aircraft near latitude 13.2 North, longitude 59.7 West. Dorian is moving toward the west-northwest near 13 mph (20 km/h) and this motion is expected to continue through Tuesday night, followed by a turn toward the northwest on Wednesday. On the forecast track, the center of Dorian is expected to move near or over the Windward Islands tonight and move into the eastern Caribbean Sea on Tuesday. Dorian is forecast to pass near or south of Puerto Rico on Wednesday, move near or over eastern Hispaniola, and move north of Hispaniola on Thursday. Maximum sustained winds are near 50 mph (85 km/h) with higher gusts. Some strengthening is forecast during the next 48 hours, and Dorian is expected to be a hurricane when it moves near Puerto Rico and eastern Hispaniola. Tropical-storm-force winds extend outward up to 45 miles (75 km) from the center. A wind gust to 55 mph (89 km/h) was recently reported in Barbados. The estimated minimum central pressure is 1003 mb (29.62 inches). HAZARDS AFFECTING LAND ---------------------- Rainfall: Dorian is expected to produce total rain accumulations of 3 to 8 inches in the Windward Islands from Martinique south to St. Vincent, including Barbados. Isolated maximum totals of 10 inches are possible across the northern Windward Islands. Rainfall totals of 1 to 3 inches are expected from the Grenadines, south to Grenada and across Dominica. Rainfall totals of 2 to 4 inches with maximum totals of 6 inches are possible across Puerto Rico and St. Croix. WIND: Tropical storm conditions are likely in the tropical storm warning area through Tuesday morning. Tropical storm conditions are possible within the tropical storm watch area in the Lesser Antilles through Tuesday morning, and in Puerto Rico on Wednesday. SURF: Swells generated by Dorian will begin affecting portions of the Lesser Antilles tonight and continue into Tuesday. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 200 AM AST. Next complete advisory at 500 AM AST. $$ Forecaster Pasch |