Tropical Storm Henri Forecast Discussion Number 27
ActuCyclone
22 août 2021
000 WTNT43 KNHC 221501 TCDAT3 Tropical Storm Henri Discussion Number 27 NWS National Hurricane Center Miami FL AL082021 1100 AM EDT Sun Aug 22 2021 Henri's presentation in both satellite and radar imagery has degraded significantly since the previous advisory due to the cyclone having moved over much cooler water. An eyewall feature is no longer evident and clouds tops have warmed markedly in the inner-core region around the center. Data from an Air Force Reserve reconnaissance aircraft, NOAA Doppler weather radars, and surface observations indicate that Henri's peak winds have decreased to 50 kt despite the central pressure remaining constant at about 987 mb. Henri is moving north-northwestward or 335/10 kt. The cyclone is forecast to gradually turn northwestward later this afternoon and possibly even move westward before stalling near the New York-Connecticut border later tonight owing to interaction with a mid- to upper-level low located over he DelMarVa region. The latter system is expected to be absorbed by Henri by early Monday morning before ejecting out slowly eastward to east-northeastward across southern New England by Monday afternoon and evening. Henri is then forecast to cross the southern Gulf of Maine and Nova Scotia as a remnant low on Tuesday. The new NHC track forecast is a little to the west and south of the previous advisory track, and lies close to the tightly packed simple- and corrected-consensus track models. Little change in strength is expected until Henri makes landfall in the Rhode Island-eastern Connecticut area this afternoon. After landfall, rapid weakening is forecast due to land interaction and entrainment of cooler air coming in off of the Atlantic Ocean. Henri should weaken to a tropical depression by early Monday, and become post-tropical by Monday afternoon or evening. Due to the degraded radar presentation of Henri, hourly Tropical Cyclone Updates (TCU) will be discontinued after the 1100 AM EDT advisory. Key Messages: 1. Dangerous storm surge inundation is expected to continue today 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. Tropical storm conditions will continue in portions of the tropical storm warning area into tonight. 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, New Jersey and northeast Pennsylvania. 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 22/1500Z 41.1N 71.6W 50 KT 60 MPH 12H 23/0000Z 42.4N 73.2W 35 KT 40 MPH...INLAND 24H 23/1200Z 43.0N 72.7W 30 KT 35 MPH...INLAND 36H 24/0000Z 43.3N 71.3W 25 KT 30 MPH...POST-TROP/INLAND 48H 24/1200Z 43.7N 68.7W 25 KT 30 MPH...POST-TROP/INLAND 60H 25/0000Z 44.3N 64.5W 25 KT 30 MPH...POST-TROPICAL 72H 25/1200Z...DISSIPATED $$ Forecaster Stewart