ZCZC MIATCDAT5 ALL TTAA00 KNHC DDHHMM Tropical Storm Elsa Discussion Number 24 NWS National Hurricane Center Miami FL AL052021 500 AM EDT Tue Jul 06 2021 Elsa is now located over the Florida Straits, with tropical-storm-force wind gusts occurring across the Lower and Middle Keys. Doppler radar data and satellite images indicate that the core of Elsa is fairly small and has maximum winds of around 50 kt. The outer rainbands associated with Elsa are spreading northward across southern Florida, and a cluster of deep convection has been lingering over portions of central and western Cuba. The Air Force Hurricane Hunters will be investigating Elsa later this morning, and the data the plane collects will be valuable in assessing the storm's intensity and structure. Elsa is moving to the north-northwest at about 10 kt on the western periphery of a subtropical ridge that is located over the central Atlantic. The storm should turn northward later today as it moves in the flow between the ridge and a mid- to upper-level low over the south-central U.S. This motion should take the core of Elsa parallel to and likely just offshore of the west coast of Florida through tonight. After that time, a slight turn to the north-northeast is forecast as another trough moves across the north-central U.S. This slight change in heading should bring Elsa inland across the Big Bend region of Florida by early Wednesday and then across coastal Georgia and the Carolinas Wednesday night through early Friday. Thereafter, the storm is expected to accelerate and move northeastward off the mid-Atlantic and New England coasts. The NHC track forecast is basically unchanged from the previous one and lies close to the model consensus aid TVCA. Now that Elsa is gradually pulling away from Cuba, it will have an opportunity to strengthen. However, the environmental conditions are only marginal for the storm to do so. Dry air on the western side of the cyclone and some westerly shear should prevent rapid intensification, but the small cyclone will likely strengthen slowly before it moves inland over the Big Bend of Florida. The GFS model shows Elsa deepening by 5-10 mb before landfall, and the ECMWF shows even greater pressure falls. Based on these models, the intensity forecast is nudged upward and now shows Elsa just below hurricane force before landfall in Florida. After Elsa moves inland, steady weakening is forecast, but the system is expected to restrengthen over the western Atlantic as it transitions into an extratropical cyclone. Based on this new forecast, a Hurricane Watch has been issued for a portion of the west-central and Big Bend Florida coast. In addition, it should be noted that much of the west coast of the Florida Peninsula is expected to see wind, rain, and surge impacts since that region will be on Elsa's east side. A Tropical Storm Watch has also been issued for the Georgia coast and portions of the South Carolina coast. Key Messages: 1. Heavy rain will impact Cuba today resulting in significant flooding and mudslides. As Elsa moves across the western Florida Peninsula through Wednesday, heavy rainfall may result in isolated flash, urban, and minor river flooding, with considerable flash and urban flooding possible in southwest and western portions of Florida. Mid to late week, heavy rainfall across coastal 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. 2. There is a danger of life-threatening storm surge along portions of the west coast of Florida tonight and Wednesday, and a Storm Surge Warning is in effect for that area. 3. A Hurricane Watch has been issued for a portion of the west-central and Big Bend coast of Florida, where hurricane conditions are possible tonight and early Wednesday. Tropical storm conditions are expected across portions of the Florida Keys and much of the west coast of the state, where a Tropical Storm Warning is in effect. 4. A Tropical Storm Watch has been issued for the Georgia coast and portions of the South Carolina coast, where tropical storm conditions are possible late Wednesday and early Thursday. FORECAST POSITIONS AND MAX WINDS INIT 06/0900Z 24.1N 82.4W 50 KT 60 MPH 12H 06/1800Z 25.7N 82.9W 55 KT 65 MPH 24H 07/0600Z 28.0N 83.1W 60 KT 70 MPH 36H 07/1800Z 30.4N 82.5W 40 KT 45 MPH...INLAND 48H 08/0600Z 32.9N 81.0W 30 KT 35 MPH...INLAND 60H 08/1800Z 35.5N 78.2W 30 KT 35 MPH...INLAND 72H 09/0600Z 38.5N 74.3W 35 KT 40 MPH...OVER WATER 96H 10/0600Z 45.9N 62.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 11/0600Z 54.7N 48.4W 35 KT 40 MPH...POST-TROP/EXTRATROP $$ Forecaster Cangialosi/Reinhart NNNN