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Hurricane Henri Forecast Discussion Number 26
2021-08-22 11:06:19| National Hurricane Center (Atlantic)
Issued at 500 AM EDT Sun Aug 22 2021 000 WTNT43 KNHC 220905 CCA TCDAT3 Hurricane Henri Discussion Number 26...Corrected NWS National Hurricane Center Miami FL AL082021 500 AM EDT Sun Aug 22 2021 Henri's satellite presentation has remained largely unchanged overnight and early this morning. Deep convection remains over the center and NWS Doppler radar imagery has revealed a convection band that wraps around the circulation forming a loose banding-eye feature. An Air Force Reserve Hurricane Hunter aircraft that has been in the storm for much of the night has reported that the pressure is slightly lower than earlier, around 986 mb, but the flight-level and SFMR winds are not quite as high as before. The initial intensity is maintained at 65 kt for this advisory. The current reconnaissance mission will be in Henri for a few more hours and should provide additional information on the storm's intensity. Henri has been moving just west of due north or 350/15 kt. The storm is expected to move north-northwestward today around the northeastern portion of a cut-off low over the central Appalachians. Some deceleration is indicated by the model guidance, but this motion should bring the center near the eastern portion of Long Island and into southern New England later this morning or early this afternoon. There is still a little spread in the track guidance regarding the landfall point, but the updated NHC forecast lies very close to the previous advisory for the first 12 hours, and is between the multi-model consensus aids and the ECMWF and GFS which are slightly to the left. Regardless of the exact landfall location, storm surge, rainfall, and wind hazards will extend far from the center. After landfall, Henri should slow down and turn east-northeastward on Monday as it becomes embedded in the southern extent of the mid-latitude westerlies. The guidance envelope has shifted a little westward from 24 to 48 hours, and the NHC forecast has been adjusted accordingly. Henri has moved north of the north wall of the Gulf Stream and will encounter cooler waters on its approach to New England. Although some slight weakening is possible, Henri is expected to at or near hurricane strength when it reaches the coast of southern New England. Even if slight weakening does occur it will have little difference on the expected storm surge, wind, and rainfall impacts. Rapid weakening should occur after landfall. Henri is expected to weaken to a tropical depression by early Monday, and become post-tropical shortly thereafter. With the center within radar range and fairly well trackable, hourly Tropical Cyclone Updates will be issued beginning at 600 AM EDT (1000 UTC) to provide updates on Henri's center location. These updates will continue as long as the center remains trackable in radar imagery. Key Messages: 1. Dangerous storm surge inundation is expected to begin this morning in portions of Long Island, Connecticut, Rhode Island, and southeastern Massachusetts, where a Storm Surge Warning has been issued. Residents in these areas should follow any advice given by local officials. 2. Hurricane conditions are expected to begin this morning in portions of Long Island, Connecticut, and Rhode Island, where a Hurricane Warning is in effect. Tropical storm conditions will begin in these areas within the next couple of hours. 3. Heavy rainfall may lead to considerable flash, urban, and small stream flooding, along with the potential for widespread minor to isolated moderate river flooding over portions of Long Island, New England, eastern New York and New Jersey. 4. Swells from Henri will continue to affect much of the east coast of the U.S. during the next day or so. These swells could cause life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 22/0900Z 40.1N 71.2W 65 KT 75 MPH 12H 22/1800Z 41.5N 71.7W 60 KT 70 MPH...INLAND 24H 23/0600Z 42.7N 72.4W 30 KT 35 MPH...INLAND 36H 23/1800Z 43.5N 72.3W 25 KT 30 MPH...POST-TROP/INLAND 48H 24/0600Z 43.8N 70.5W 25 KT 30 MPH...POST-TROP/INLAND 60H 24/1800Z 44.2N 67.3W 25 KT 30 MPH...POST-TROPICAL 72H 25/0600Z...DISSIPATED $$ Forecaster Brown
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