| Track: https://www.nhc.noaa.gov/refresh/graphics_at5+shtml/?cone#contents Floater: https://www.star.nesdis.noaa.gov/GOES/floater.php?stormid=AL052021#homePageLink NHC highlights the uncertainty with the track. "However the discrepancy in the models makes confidence in this track lower than usual." And of course intensity remains uncertain too. "Therefore the official intensity forecast, like the previous one, is quite conservative and on the lower end of the guidance suite." And in the record department: "Elsa is the earliest-known fifth named storm on record for the Atlantic basin in the satellite era (1966-present), breaking the record formerly held by Edouard on July 6, 2020." Tropical Storm Elsa Discussion Number 3 NWS National Hurricane Center Miami FL AL052021 500 AM AST Thu Jul 01 2021 The tropical cyclone's cloud pattern became a little better organized overnight, with convective banding features becoming more evident over the western and southwestern portions of the circulation. Upper-level outflow is well-defined to the west of the system, and restricted over the eastern semicircle. The current intensity is set at 35 kt in agreement with Dvorak estimates from SAB and TAFB, and just slightly above the maximum winds from an earlier scatterometer pass, making the cyclone a tropical storm. Elsa is the earliest-known fifth named storm on record for the Atlantic basin in the satellite era (1966-present), breaking the record formerly held by Edouard on July 6, 2020. The storm has been accelerating westward overnight, and the initial motion is around 275/22 kt. A strong subtropical ridge is situated to the north of the storm, and this feature should steer the system quickly to the west-northwest for the next 3 days or so. There is significant uncertainty in the track forecast from days 3-5. The ECMWF model turns the cyclone northward after interacting with Hispaniola while the other models such as the GFS, HWRF, and U.K. Met take Elsa across western Cuba and into the southeastern Gulf of Mexico. The official forecast is similar to the previous one, and within the latter suite of guidance. However the discrepancy in the models makes confidence in this track lower than usual. Some intensification is likely for the next day or two, since Elsa is expected to be in an environment of warm sea-surface temperatures, fairly low vertical wind shear, and high mid-level relative humidity. However, the fast forward motion could result in some decoupling of the low- and higher-level circulation which would limit strengthening. Also, the potential interaction of the storm with the mountainous land masses of the Greater Antilles later in the forecast period could disrupt the circulation somewhat. Therefore the official intensity forecast, like the previous one, is quite conservative and on the lower end of the guidance suite. Key Messages: 1. Tropical storm conditions are expected beginning early Friday in portions of the Windward and southern Leeward Islands. 2. Heavy rainfall from the system will move quickly across the Windward and southern Leeward Islands, including Barbados, on Friday. Isolated flash flooding and mudslides are possible. 3. There is a risk of wind and rainfall impacts in portions of the Virgin Islands, Puerto Rico, Hispaniola, Cuba, the Turks and Caicos and the southeastern Bahamas through early next week. Interests in these areas should monitor the system's progress and updates to the forecast. 4. Interests in Florida should monitor updates to the forecast for this system, but it is too soon to determine what if any impacts could occur there next week given the uncertainty in the long-range forecast. FORECAST POSITIONS AND MAX WINDS INIT 01/0900Z 9.4N 48.8W 35 KT 40 MPH 12H 01/1800Z 10.3N 52.0W 40 KT 45 MPH 24H 02/0600Z 11.7N 56.7W 50 KT 60 MPH 36H 02/1800Z 13.2N 61.8W 50 KT 60 MPH 48H 03/0600Z 14.9N 66.9W 55 KT 65 MPH 60H 03/1800Z 16.7N 71.2W 55 KT 65 MPH 72H 04/0600Z 18.0N 74.5W 50 KT 60 MPH 96H 05/0600Z 21.0N 79.5W 50 KT 60 MPH 120H 06/0600Z 24.5N 82.0W 55 KT 65 MPH $$ Forecaster Pasch Tropical Storm Elsa Advisory Number 3 NWS National Hurricane Center Miami FL AL052021 500 AM AST Thu Jul 01 2021 ...DEPRESSION BECOMES TROPICAL STORM ELSA... SUMMARY OF 500 AM AST...0900 UTC...INFORMATION ---------------------------------------------- LOCATION...9.4N 48.8W ABOUT 865 MI...1390 KM ESE OF THE WINDWARD ISLANDS MAXIMUM SUSTAINED WINDS...40 MPH...65 KM/H PRESENT MOVEMENT...W OR 275 DEGREES AT 25 MPH...41 KM/H MINIMUM CENTRAL PRESSURE...1006 MB...29.71 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: The Meteorological Service of Barbados has issued a Tropical Storm Warning for St. Vincent and the Grenadines. 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... * Guadeloupe 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, in this case within 36 hours. Interests elsewhere in the Windward Islands, Leeward Islands, the Virgin Islands, Puerto Rico, the Dominican Republic, and Haiti should monitor the progress of this system. Additional watches and warnings will likely be required later today. For storm information specific to your area, please monitor products issued by your national meteorological service. DISCUSSION AND OUTLOOK ---------------------- At 500 AM AST (0900 UTC), the center of Tropical Storm Elsa was located near latitude 9.4 North, longitude 48.8 West. Elsa is moving toward the west near 25 mph (41 km/h). An even faster motion to the west-northwest is expected over the next 24 to 36 hours. On the forecast track, the system will pass near or over portions of the Windward Islands or the southern Leeward Islands on Friday, move into the eastern Caribbean Sea late Friday and Friday night, and move near the southern coast of Hispaniola on Saturday. Maximum sustained winds have increased to near 40 mph (65 km/h) with higher gusts. Some additional strengthening is forecast during the next couple of days. Tropical-storm-force winds extend outward up to 105 miles (165 km) from the center. The estimated minimum central pressure is 1006 mb (29.71 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Tropical Storm Elsa can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT5, WMO header WTNT45 KNHC and on the web at www.hurricanes.gov/graphics_at5.shtml?key_messages. WIND: Tropical storm conditions are expected in portions of the Windward and southern Leeward Islands within the warning areas on Friday. Tropical storm conditions are possible in the watch areas on Friday. RAINFALL: Elsa is expected to produce rainfall totals of 3 to 6 inches with maximum totals of 8 inches on Friday across the Windward and southern Leeward Islands, including Barbados. This rain may lead to isolated flash flooding and mudslides. NEXT ADVISORY ------------- Next intermediate advisory at 800 AM AST. Next complete advisory at 1100 AM AST. $$ Forecaster Pasch |