Boca Raton, Delray Beach, Boynton Beach Remain In Cone, But System Appears Headed For Gulf
UPDATED: 8AM August 21, 2020
BOCA RATON, FL (BocaNewsNow.com) — A dramatic shift to the south means Tropical Depression 13, likely to become Tropical Storm “Laura” later today, is unlikely to hit South Florida head-on as a hurricane. The system was targeting South Florida as late as Thursday night, but the early Friday morning forecast calls the storm disorganized and shifts it southward.
Development of hurricane-strength winds has also slowed.
Here is the 8 a.m. Bulletin from the National Hurricane Center, followed by the 5 a.m. “discussion.”
BULLETIN Tropical Depression Thirteen Intermediate Advisory Number 6A...corrected NWS National Hurricane Center Miami FL AL132020 800 AM AST Fri Aug 21 2020 Corrected latitude in summary block ...DEPRESSION NEARING THE NORTHERN LEEWARD ISLANDS... SUMMARY OF 800 AM AST...1200 UTC...INFORMATION ---------------------------------------------- LOCATION...17.9N 59.2W ABOUT 255 MI...415 KM E OF THE NORTHERN LEEWARD ISLANDS MAXIMUM SUSTAINED WINDS...35 MPH...55 KM/H PRESENT MOVEMENT...WNW OR 285 DEGREES AT 21 MPH...33 KM/H MINIMUM CENTRAL PRESSURE...1008 MB...29.77 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: None. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Tropical Storm Watch is in effect for... * The southeastern Bahamas and the Turks and Caicos Islands * Puerto Rico, Vieques and Culebra * U.S. Virgin Islands * British Virgin Islands * Saba and St. Eustatius * St. Maarten * St. Martin and St. Barthelemy * Antigua, Barbuda, St. Kitts, Nevis, and Anguilla A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests elsewhere in the northern Leeward Islands, the Virgin Islands, Puerto Rico, and the Dominican Republic should monitor the progress of this system, as additional tropical storm watches or warnings will likely be required for portions of those areas later today. Interests in Cuba and the remainder of the Bahamas should also monitor the progress of this system. 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 800 AM AST (1200 UTC), the center of Tropical Depression Thirteen was located near latitude 17.9 North, longitude 59.2 West. The depression is moving toward the west-northwest near 21 mph (33 km/h), and this motion is expected to continue for the next few days. On the forecast track, the depression is expected to move near or north of the northern Leeward Islands later today, near or north of the Virgin Islands and Puerto Rico on Saturday, and near or north of Hispaniola Saturday night. Maximum sustained winds remain near 35 mph (55 km/h) with higher gusts. Gradual strengthening is forecast, and the depression is likely to become a tropical storm by the weekend. The estimated minimum central pressure is 1008 mb (29.77 inches). HAZARDS AFFECTING LAND ---------------------- RAINFALL: The depression is expected to produce 3 to 6 inches of rain over Puerto Rico and the Virgin Islands through Sunday. Locally heavy rainfall could lead to flash and urban flooding, as well as an increased potential for mudslides. Some rivers may overflow their banks. 1 to 3 inches of rain with isolated maximum totals of 5 inches is expected over the northern Leeward Islands, the Dominican Republic, Haiti, the Turks and Caicos and southeast Bahamas. WIND: Tropical storm conditions are possible within the watch area later today through Saturday night. NEXT ADVISORY ------------- Next complete advisory at 1100 AM AST. $$ Forecaster Pasch 814 WTNT43 KNHC 210849 TCDAT3 Tropical Depression Thirteen Discussion Number 6 NWS National Hurricane Center Miami FL AL132020 500 AM AST Fri Aug 21 2020 Tropical Depression Thirteen remains very disorganized this morning. The associated convection is elongated from northwest to southeast, and the low-level center is located near the northwestern end of the convective area. Additionally, satellite imagery and model analyses indicate that the mid-level center is located several hundred miles to the southeast of the low-level center. Earlier aircraft and scatterometer data suggested the possibility that the system was an open wave. However, the currently available data is ambiguous on whether the system still has a closed circulation, so it will be maintained as a tropical depression. The initial intensity remains 30 kt. The initial motion is west-northwestward or 285/18 kt. There is little change to the track forecast philosophy through about 96 h. A strong subtropical ridge over the western Atlantic should remain north of the depression during the next few days, steering the cyclone at a fast pace to the west-northwest. After that, the ridge weakens some over the eastern Gulf of Mexico, and Tropical Depression Thirteen may interact with Tropical Depression Fourteen, which is also forecast to be in the Gulf by that time, with the result of these things being a turn toward the northwest or north-northwest. The track guidance has shifted southward since the last advisory, with the UKMET shifting far enough to the south that it takes the system over the Caribbean south of Cuba. The new forecast track is also shifted a bit southward from the previous track. However, it lies to the north of the GFS, the UKMET, and the various consensus models. It also lies north of the ECMWF model from 24-72 h. The intensity forecast remains low confidence. The separation between the low- and mid-level centers, as well as some westerly shear and dry air entrainment, suggests that significant strengthening is unlikely during the next 24 h or so. The dynamical models suggests the centers will become more vertically aligned around 36-48 h and that the shear should diminish. However, the system could be close to Hispaniola during this time, and be near Cuba thereafter, especially if it moves south of the forecast track. The upper-level winds over the Gulf of Mexico should be generally favorable for development if the cyclone doesn't get too close to Tropical Depression Fourteen. The possibilities range from the system degenerating to an open wave as seen in the GFS and ECMWF to a major hurricane as seen in the HWRF. Given the uncertainty, the intensity forecast is unchanged from the previous advisory, and it lies a little below the intensity consensus. Key Messages: 1. Tropical storm conditions are possible across portions of the northern Leeward Islands, the Virgin Islands, Puerto Rico, the southeastern Bahamas, and the Turks and Caicos islands later today through Saturday night, and Tropical Storm Watches have been issued for some of these islands. Heavy rainfall is likely across this area beginning today and could cause mudslides and flash and urban flooding through Sunday. 2. The details of the long-range track and intensity forecasts are more uncertain than usual since the system could move over portions of the Greater Antilles this weekend. However, this system could bring some storm surge, rainfall and wind impacts to portions of Hispaniola, Cuba, the Bahamas, and Florida this weekend and early next week. Interests there should monitor this system's progress and updates to the forecast over the next few days. FORECAST POSITIONS AND MAX WINDS INIT 21/0900Z 17.8N 58.5W 30 KT 35 MPH 12H 21/1800Z 18.1N 60.7W 30 KT 35 MPH 24H 22/0600Z 18.8N 64.0W 35 KT 40 MPH 36H 22/1800Z 19.7N 67.5W 40 KT 45 MPH 48H 23/0600Z 20.6N 71.1W 45 KT 50 MPH 60H 23/1800Z 21.8N 74.9W 50 KT 60 MPH 72H 24/0600Z 23.2N 78.5W 55 KT 65 MPH 96H 25/0600Z 26.5N 84.0W 65 KT 75 MPH 120H 26/0600Z 30.0N 87.0W 65 KT 75 MPH
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