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Hurricane Henri Intermediate Advisory Number 24A
NWS National Hurricane Center Miami FL AL082021
800 PM EDT Sat Aug 21 2021
...HENRI MOVING QUICKLY TO THE NORTH-NORTHEAST...
...A DANGEROUS STORM SURGE, HURRICANE CONDITIONS, AND FLOODING
RAINFALL EXPECTED IN PORTIONS OF THE NORTHEAST UNITED STATES
BEGINNING LATE TONIGHT OR EARLY SUNDAY...
SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
ABOUT 255 MI...410 KM S OF MONTAUK POINT NEW YORK
ABOUT 290 MI...470 KM ENE OF CAPE HATTERAS NORTH CAROLINA
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 18 MPH...30 KM/H
MINIMUM CENTRAL PRESSURE...988 MB...29.18 INCHES
WATCHES AND WARNINGS
CHANGES WITH THIS ADVISORY:
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 New
* North shore of Long Island from Montauk Point to Flushing New York
* Flushing New York to Chatham Massachusetts
* Nantucket, Martha's Vineyard, and Block Island
A Storm Surge Watch is in effect for...
* East Rockaway Inlet to Mastic New York
* 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
* New Haven Connecticut to west of Westport Massachusetts
* 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
* Westport Massachusetts to Chatham Massachusetts, including
Martha's Vineyard and Nantucket
* Coastal New York and New Jersey west of East Rockaway Inlet to
Manasquan Inlet, 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
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
Interests elsewhere in the northeastern U.S. should monitor the
progress of Henri.
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 800 PM EDT (0000 UTC), the center of Hurricane Henri was located
near latitude 37.4 North, longitude 71.0 West. Henri is moving
toward the north-northeast near 18 mph (30 km/h) and this motion is
expected to continue through tonight. A decrease in forward speed
and a turn toward the north-northwest is expected on Sunday. On the
forecast track, Henri is expected to make landfall on Long Island or
in southern New England on Sunday.
Maximum sustained winds are near 75 mph (120 km/h) with higher
gusts. Strengthening is forecast through tonight. Although some
weakening is expected prior to landfall on Sunday, Henri is forecast
to be at or near hurricane strength when it reaches the coasts of
Long Island and southern New England.
Hurricane-force winds extend outward up to 45 miles (75 km) from
the center and tropical-storm-force winds extend outward up to 150
miles (240 km).
The minimum central pressure reported by a NOAA Hurricane Hunter
aircraft data is 988 mb (29.18 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
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...
Flushing, NY to Chatham, MA including Narragansett Bay, Buzzards
Bay, Vineyard Sound, and Nantucket Sound...3-5 ft
North shore of Long Island from Flushing to Montauk Point, NY
including Long Island Sound...3-5 ft
South shore of Long Island from Mastic Beach to Montauk Point,
Chatham, MA to Sagamore Beach, MA including Cape Cod Bay...2-4 ft
South shore of Long Island from East Rockaway Inlet to Mastic Beach,
Cape May, NJ to East Rockaway Inlet, NY...1-3 ft
Sagamore Beach, MA to Merrimack River including Massachusetts
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
WIND: Hurricane conditions are expected in the hurricane warning
area late tonight or on Sunday, with tropical storm conditions
expected by tonight. Tropical storm conditions are expected in the
tropical storm warning area late tonight and Sunday.
RAINFALL: Henri is expected to produce rainfall amounts of 3 to 6
inches over portions of Long Island, New England, southeast New
York, and northern New Jersey Sunday into Monday, with isolated
maximum totals near 10 inches. Heavy rainfall from Henri may result
in considerable flash, urban, and small stream flooding, along with
the potential for minor and moderate river flooding.
TORNADOES: A tornado or two may occur Sunday over southern New
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 today
and Sunday. These swells could cause life-threatening surf and rip
current conditions. Please consult products from your local
Next complete advisory at 1100 PM EDT.