| I always forget about how Sandy became post-tropical an hour before landfall, so it doesn't count as a hurricane landfall even though it had hurricane force winds. (That storm kind of had a hurricane inside a nor'easter) That is why the news has been talking about 30 years. Tropical Storm Henri Discussion Number 20 NWS National Hurricane Center Miami FL AL082021 500 PM EDT Fri Aug 20 2021 Henri appears to be slowly gaining strength. Deep convection has been increasing during the past few hours and the upper-level outflow continues to become better established on the east side of the circulation. However, the low-level center is still located near the northwestern edge of the deep convection due to ongoing northerly wind shear. An ASCAT-B pass from a few hours ago showed peak winds of around 55 kt, with the strongest winds on the southeast side of the circulation. Based on this data, the initial intensity is set at 60 kt. An Air Force Reserve Hurricane Hunter aircraft is scheduled to investigate Henri again this evening and the data the plane collects will be very helpful in estimating the storm's strength and structure. The tropical storm appears to be making the advertised turn to the right, with the latest initial motion estimated to be 335/6 kt. A trough over the central Appalachians is expected to cut off tonight, and the combination of that feature and a building ridge to the east/northeast of Henri should cause the storm to accelerate to the north on Saturday. The latest model runs have generally trended to the left again and are a bit faster, with most showing landfall in about 48 hours. Most of the models now show a slight left turn before landfall as Henri gets caught in the circulation of the aforementioned trough. The latest GFS and ECMWF ensemble members continue to span a region from near New York City to Cape Cod for the landfall point. Based on the latest consensus aids, the official track forecast has again been nudged to the west of the previous one and shows landfall occurring on Sunday. After day 3, Henri is forecast to eject northeastward. The ongoing northerly shear is expected to decrease tonight, and the global models show a favorable upper-level wind pattern developing over the storm through the weekend. These more conducive atmospheric conditions combined with the warm Gulf Stream waters should allow Henri to strengthen to a hurricane tonight or early Saturday, with additional intensification expected into Saturday night. By early Sunday, however, Henri is forecast to cross the north wall of the Gulf Stream, and that should end its opportunity for strengthening. Although steady to rapid weakening is forecast while Henri moves over cooler waters south of Long Island and New England, it will likely still be at or very near hurricane intensity when it reaches the coast. Post-tropical transition is forecast to occur by day 3 and the system should dissipate in 4 or 5 days. Users are reminded to not focus on the exact forecast of the center of Henri since impacts will extend far from the center. Key Messages: 1. Dangerous storm surge inundation is expected to begin Sunday in portions of Long Island, Connecticut, Rhode Island, and southeastern Massachusetts, where a Storm Surge Warning has been issued. Dangerous storm surge is possible beginning Sunday in western portions of Long Island and Connecticut in the Storm Surge Watch area. Residents in these areas should follow any advice given by local officials. 2. Hurricane conditions are expected to begin Sunday in portions of Long Island and Connecticut, where a Hurricane Warning has been issued. Hurricane conditions are possible Sunday across portions of Rhode Island and southeastern Massachusetts. 3. Heavy rainfall may lead to considerable flash, urban, and small stream flooding, along with the potential for widespread minor and isolated moderate river flooding, over portions of Long Island and New England Sunday into Monday. 4. Swells from Henri will continue to affect much of the east coast of the U.S. through the weekend. These swells could cause life-threatening surf and rip currents. FORECAST POSITIONS AND MAX WINDS INIT 20/2100Z 31.2N 73.9W 60 KT 70 MPH 12H 21/0600Z 32.8N 73.3W 65 KT 75 MPH 24H 21/1800Z 35.8N 72.3W 75 KT 85 MPH 36H 22/0600Z 38.9N 71.9W 75 KT 85 MPH 48H 22/1800Z 40.8N 72.4W 65 KT 75 MPH 60H 23/0600Z 42.0N 72.8W 45 KT 50 MPH...INLAND 72H 23/1800Z 42.9N 72.6W 30 KT 35 MPH...POST-TROPICAL 96H 24/1800Z 43.8N 68.9W 25 KT 30 MPH...POST-TROPICAL 120H 25/1800Z...DISSIPATED $$ Forecaster Cangialosi WTNT33 KNHC 202041 TCPAT3 BULLETIN Tropical Storm Henri Advisory Number 20 NWS National Hurricane Center Miami FL AL082021 500 PM EDT Fri Aug 20 2021 ...HENRI ALMOST A HURRICANE... ...HURRICANE AND STORM SURGE WARNINGS ISSUED FOR PORTIONS OF LONG ISLAND AND SOUTHERN NEW ENGLAND... SUMMARY OF 500 PM EDT...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...31.2N 73.9W ABOUT 290 MI...470 KM SSE OF CAPE HATTERAS NORTH CAROLINA ABOUT 695 MI...1115 KM S OF MONTAUK POINT NEW YORK MAXIMUM SUSTAINED WINDS...70 MPH...110 KM/H PRESENT MOVEMENT...NNW OR 340 DEGREES AT 7 MPH...11 KM/H MINIMUM CENTRAL PRESSURE...994 MB...29.36 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY: A Storm Surge Warning is in effect for the south shore of Long Island from Mastic Beach to Montauk Point, the north shore of Long Island from Oyster Bay to Montauk Point, from Greenwich, Connecticut to Chatham, Massachusetts, including Nantucket, Martha's Vineyard, and Block Island. A Hurricane Warning is in effect for the south shore of Long Island from Fire Island Inlet to Montauk Point, for the north shore of Long Island from Port Jefferson Harbor to Montauk Point, and from New Haven, Connecticut, to west of Watch Hill, Rhode Island. A Tropical Storm Warning is in effect from west of Port Jefferson Harbor to west of New Haven, Connecticut, and for the south shore of Long Island from west of Fire Island Inlet to East Rockaway Inlet. A Tropical Storm Watch in effect from Manasquan Inlet, New Jersey, to west of East Rockaway Inlet, New York, including New York City. SUMMARY OF WATCHES AND WARNINGS IN EFFECT: A Storm Surge Warning is in effect for... * South shore of Long Island from Mastic Beach to Montauk Point * North shore of Long Island from Oyster Bay to Montauk Point * Greenwich Connecticut to Chatham Massachusetts * Nantucket, Martha's Vineyard, and Block Island A Storm Surge Watch is in effect for... * South shore of Long Island from west of Mastic Beach to East Rockaway Inlet * North shore of Long Island from west of Oyster Bay to Flushing * Flushing New York to west of Greenwich Connecticut * North of Chatham Massachusetts to Sagamore Beach Massachusetts * Cape Cod Bay A Hurricane Warning is in effect for... * South shore of Long Island from Fire Island Inlet to Montauk Point * North shore of Long Island from Port Jefferson Harbor to Montauk Point * New Haven Connecticut to west of Watch Hill Rhode Island A Hurricane Watch is in effect for... * Watch Hill Rhode Island to Sagamore Beach Massachusetts * Nantucket, Martha's Vineyard, and Block Island A Tropical Storm Warning is in effect for... * Port Jefferson Harbor to west of New Haven Connecticut * South shore of Long Island from west of Fire Island Inlet to East Rockaway Inlet A Tropical Storm Watch is in effect for... * Manasquan Inlet New Jersey to west of East Rockaway Inlet New York, including New York City A Storm Surge Warning means there is a danger of life-threatening inundation, from rising water moving inland from the coastline, during the next 36 hours in the indicated locations. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. This is a life-threatening situation. Persons located within these areas should take all necessary actions to protect life and property from rising water and the potential for other dangerous conditions. Promptly follow evacuation and other instructions from local officials. A Hurricane Warning means that hurricane conditions are expected somewhere within the warning area. A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm- force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion. A Tropical Storm Warning means that tropical storm conditions are expected somewhere within the warning area within 36 hours. A Storm Surge Watch means there is a possibility of life- threatening inundation, from rising water moving inland from the coastline, in the indicated locations during the next 48 hours. For a depiction of areas at risk, please see the National Weather Service Storm Surge Watch/Warning Graphic, available at hurricanes.gov. A Hurricane Watch means that hurricane conditions are possible within the watch area. A watch is typically issued 48 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. A Tropical Storm Watch means that tropical storm conditions are possible within the watch area, generally within 48 hours. Interests elsewhere in the northeastern U.S. and Atlantic Canada should monitor the progress of Henri. Additional watches or warnings will likely be required later tonight or Saturday. For storm information specific to your area, including possible inland watches and warnings, please monitor products issued by your local National Weather Service forecast office. DISCUSSION AND OUTLOOK ---------------------- At 500 PM EDT (2100 UTC), the center of Tropical Storm Henri was located near latitude 31.2 North, longitude 73.9 West. Henri is moving toward the north-northwest near 7 mph (11 km/h). A turn toward the north is expected by tonight, and Henri is forecast to accelerate in that direction through early Sunday. On the forecast track, Henri is expected to make landfall in Long Island or southern New England on Sunday. Maximum sustained winds are near 70 mph (110 km/h) with higher gusts. Strengthening is forecast during the next day or so, and Henri is expected to become a hurricane tonight or Saturday and be at or near hurricane strength when it makes landfall in Long Island or southern New England. Tropical-storm-force winds extend outward up to 115 miles (185 km) from the center. The estimated minimum central pressure is 994 mb (29.36 inches). HAZARDS AFFECTING LAND ---------------------- Key messages for Henri can be found in the Tropical Cyclone Discussion under AWIPS header MIATCDAT3, WMO header WTNT43 KNHC and on the web at hurricanes.gov/graphics_at3.shtml?key_messages. STORM SURGE: The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide... Watch Hill, RI to Chatham, MA including Narragansett Bay, Buzzards Bay, Vineyard Sound, and Nantucket Sound...3-5 ft Chatham, MA to Sagamore Beach, MA including Cape Cod Bay...2-4 ft East Rockaway Inlet, NY to Montauk Point, NY...2-4 ft North shore of Long Island...2-4 ft Flushing, NY to Watch Hill, RI...2-4 ft Cape May, NJ to East Rockaway Inlet, NY...1-3 ft The deepest water will occur along the immediate coast in areas of onshore winds, where the surge will be accompanied by large and dangerous waves. Surge-related flooding depends on the relative timing of the surge and the tidal cycle, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office. WIND: Hurricane conditions are expected in the hurricane warning area on Sunday, with tropical storm conditions expected by early Sunday. Hurricane conditions are possible in the hurricane watch area on Sunday, with tropical conditions possible by early Sunday. Tropical storm conditions are expected in the tropical storm warning area and possible in the tropical storm watch area on Sunday. RAINFALL: Henri may produce rainfall amounts of 3 to 6 inches over Long Island and New England Sunday into Monday, with isolated maximum totals near 10 inches. Heavy rainfall from Henri could result in considerable flash, urban, and small stream flooding, along with the potential for widespread minor and isolated moderate river flooding. SURF: Swells generated by Henri should continue to affect Bermuda during the next day or so. Swells are expected to increase across much of the east coast of the U.S. and Atlantic Canada tonight and into the weekend. These swells could cause life-threatening surf and rip current conditions. Please consult products from your local weather office. NEXT ADVISORY ------------- Next intermediate advisory at 800 PM EDT. Next complete advisory at 1100 PM EDT. $$ Forecaster Cangialosi |