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Tropical Storm Elsa Forecast Discussion Number 29
2021-07-07 11:06:49| National Hurricane Center (Atlantic)
Issued at 500 AM EDT Wed Jul 07 2021 000 WTNT45 KNHC 070906 TCDAT5 Tropical Storm Elsa Discussion Number 29 NWS National Hurricane Center Miami FL AL052021 500 AM EDT Wed Jul 07 2021 The central convection associated with Elsa dissipated for a time earlier this morning, although the latest radar and satellite imagery shows a new band forming in the northern semicircle. This decrease was likely caused by a combination of shear and dry air entrainment, and it has caused the cyclone to weaken. Aircraft and surface observations indicate the central pressure has risen to near 1004 mb, and the initial intensity is decreased to a possibly generous 55 kt based on aircraft and Doppler radar data. After a slight jog to the left, the storm has resumed a motion of 360/12. This motion should continue for the next 12 h or so until landfall occurs across the northwestern Florida peninsula. Thereafter, a gradual turn toward the north-northeast is expected by, followed by acceleration toward the northeast as Elsa moves into the mid-latitude westerlies. The forecast guidance has shifted a little to the left since the last advisory, and the new forecast track is also nudged in that direction. The new track lies a little to the right of the various consensus models. While little change in strength is forecast before landfall, there is a chance that the new convection could cause a short-lived re-intensification. So, based on this possibility a hurricane warning remains in effect for portions of the west coast of Florida. After landfall, Elsa should weaken as it crosses the southeastern United States, followed by some re-intensification as it accelerates back over the Atlantic. The system is expected to become extratropical by the time it reaches the Canadian Maritimes in 72 h. The new intensity forecast is at the upper edge of the guidance envelope and has only minor adjustments from the previous forecast. 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 coastal 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 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. Hurricane conditions are possible during the next several hours along a portion of the west coast of Florida, where a Hurricane Warning is in effect. Tropical storm conditions are occurring across portions of the western Florida peninsula and will continue to spread northward along the west coast of the state within the warning area through today. 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 state by Thursday night or Friday. FORECAST POSITIONS AND MAX WINDS INIT 07/0900Z 28.5N 83.5W 55 KT 65 MPH 12H 07/1800Z 30.2N 83.3W 50 KT 60 MPH 24H 08/0600Z 32.6N 82.0W 40 KT 45 MPH...INLAND 36H 08/1800Z 35.3N 79.4W 35 KT 40 MPH...INLAND 48H 09/0600Z 38.1N 75.6W 40 KT 45 MPH...INLAND 60H 09/1800Z 41.5N 70.9W 45 KT 50 MPH...OVER WATER 72H 10/0600Z 45.6N 64.6W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 11/0600Z 54.0N 50.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 12/0600Z...DISSIPATED $$ Forecaster Beven
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