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Tropical Storm Elsa Forecast Discussion Number 30
2021-07-07 17:04:28| National Hurricane Center (Atlantic)
Issued at 1100 AM EDT Wed Jul 07 2021 000 WTNT45 KNHC 071503 CCA TCDAT5 Tropical Storm Elsa Discussion Number 30...Corrected NWS National Hurricane Center Miami FL AL052021 1100 AM EDT Wed Jul 07 2021 Corrected Taylor County to Dixie County in the first paragraph. An Air Force Hurricane Hunter aircraft has made several fixes in Elsa this morning, and recent observations from the plane indicated that the center is now on the coast making landfall. The aircraft found that the central pressure remained about steady with maximum winds of 55 kts up to landfall. Sustained tropical-storm-force winds are being reported from observing sites within the warning area, with an unofficial report of a sustained wind of 54 kt gusting to 62 kt at Horseshoe Beach in Dixie County, Florida during the past half hour. Center fixes indicate that Elsa has continued northward, with a motion estimate of 360/12 kt. Elsa should turn toward the north-northeast today as it moves along the northwestern periphery of an Atlantic subtropical ridge. On Thursday, the cyclone should begin to accelerate northeastward on the southeast side of a broad mid-tropospheric trough over the eastern United States and Canada. The official track forecast is on top of the latest multi-model consensus, TVCA, solution. This is only slightly to left of the previous NHC track, and shows the center moving near the northeastern U.S. coast within the next 48 hours. Weakening will occur while the cyclone moves over land during the next 36 hours or so, and the official intensity forecast closely resembles the decay-SHIPS guidance. Since winds of 35 kt are possible near the coast well to the southeast of the center within the next day or two, a tropical storm warning is in effect for a portion of the southeast U.S. coast. Some slight reintensification is shown when the center moves near the coast in 48-60 hours. However, since the water temperatures are rather cool near the northeast coast, strengthening will probably be influenced by baroclinic forcing associated with a 500 mb shortwave trough. The system will likely become extratropical by 72 hours if not sooner while it moves through Atlantic Canada. Key Messages: 1. As Elsa moves across the western and northern Florida Peninsula today, heavy rainfall may result in considerable flash, urban, and isolated moderate river flooding. Heavy rainfall across southeast Georgia, South Carolina, North Carolina, and southeastern Virginia may result in isolated flash and urban flooding, with considerable flash and urban flooding possible across southeast Georgia and the Lowcountry of South Carolina. Heavy rainfall across the Northeast and New England Thursday and Friday could lead to isolated flash and urban flooding. 2. There is still a danger of life-threatening storm surge along portions of the west coast of Florida today, and a Storm Surge Warning is in effect for that area. 3. Tropical storm conditions wile continue today across portions of the northeast Gulf coast today within the warning area. 4. Although the center of Elsa is expected to remain inland of the coastline from Georgia through the Carolinas during the next day or two, tropical storm conditions are expected along much of the coasts of Georgia and South Carolina. Tropical storm conditions are also possible along the coast of the mid-Atlantic states by Thursday night or Friday. FORECAST POSITIONS AND MAX WINDS INIT 07/1500Z 29.9N 83.6W 55 KT 65 MPH 12H 08/0000Z 31.7N 82.9W 35 KT 40 MPH...INLAND 24H 08/1200Z 34.3N 80.9W 30 KT 35 MPH...INLAND 36H 09/0000Z 37.3N 77.6W 30 KT 35 MPH...INLAND 48H 09/1200Z 40.6N 73.3W 35 KT 40 MPH...NEAR COAST 60H 10/0000Z 44.5N 68.0W 40 KT 45 MPH...NEAR COAST 72H 10/1200Z 49.0N 60.9W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 11/1200Z 58.0N 47.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 12/1200Z...DISSIPATED $$ Forecaster Pasch
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