Re: Wow....a possible 5 ft storm Surge in Long Island Sound?
Posted by Chris in Tampa on 8/21/2021, 1:04 am
Experimental peak storm surge forecast for Henri:
https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/?peakSurge#contents

For some information about Sandy, see page 9 (PDF page 11) in this PDF file:

https://tidesandcurrents.noaa.gov/publications/Hurricane_Sandy_2012_Water_Level_and_Meteorological_Data_Report.pdf

I also include a screenshot below along with a screenshot of locations.







Kings Point, NY had a storm surge of 8.54 feet and the storm tide was 14.31 feet for Sandy.

Tidal observations for later for Henri:
https://tidesandcurrents.noaa.gov/inundationdb/storm/Henri.html

Kings Point, NY station:
https://tidesandcurrents.noaa.gov/stationhome.html?id=8516945






If you look back at the forecast for the public advisory before Sandy:
https://www.nhc.noaa.gov/archive/2012/al18/al182012.public_a.030.shtml?
This is what the forecast was for Sandy:

STORM SURGE...THE COMBINATION OF AN EXTREMELY DANGEROUS STORM SURGE
AND THE TIDE WILL CAUSE NORMALLY DRY AREAS NEAR THE COAST TO BE
FLOODED BY RISING WATERS. THE WATER COULD REACH THE FOLLOWING
DEPTHS ABOVE GROUND IF THE PEAK SURGE OCCURS AT THE TIME OF HIGH
TIDE...

NC NORTH OF SURF CITY INCLUDING PAMLICO/ALBEMARLE SOUNDS...3 TO 5 FT
SE VA AND DELMARVA INCLUDING LOWER CHESAPEAKE BAY...2 TO 4 FT
UPPER AND MIDDLE CHESAPEAKE BAY...1 TO 3 FT
LONG ISLAND SOUND...RARITAN BAY...AND NEW YORK HARBOR...6 TO 11 FT
ELSEWHERE FROM OCEAN CITY MD TO THE CT/RI BORDER...4 TO 8 FT
CT/RI BORDER TO THE SOUTH SHORE OF CAPE COD INCLUDING BUZZARDS
BAY AND NARRAGANSETT BAY...3 TO 6 FT
CAPE COD TO THE MA/NH BORDER INCLUDING CAPE COD BAY...2 TO 4 FT
MA/NH BORDER TO THE U.S./CANADA BORDER...1 TO 3 FT

SURGE-RELATED FLOODING DEPENDS ON THE RELATIVE TIMING OF THE SURGE
AND THE TIDAL CYCLE...AND CAN VARY GREATLY OVER SHORT DISTANCES.
GIVEN THE LARGE WIND FIELD ASSOCIATED WITH SANDY...ELEVATED WATER
LEVELS COULD SPAN MULTIPLE TIDE CYCLES RESULTING IN REPEATED AND
EXTENDED PERIODS OF COASTAL AND BAYSIDE FLOODING. IN ADDITION...
ELEVATED WATERS COULD OCCUR FAR REMOVED FROM THE CENTER OF SANDY.
FURTHERMORE...THESE CONDITIONS WILL OCCUR REGARDLESS OF WHETHER
SANDY IS A TROPICAL OR POST-TROPICAL CYCLONE. FOR INFORMATION
SPECIFIC TO YOUR AREA...PLEASE SEE PRODUCTS ISSUED BY YOUR LOCAL
NATIONAL WEATHER SERVICE OFFICE.





This is the forecast as of 11pm EDT Friday for Henri:

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,
NY...3-5 ft
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,
NY...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.








I don't know the forecast for New York City. Flushing is 3-5 ft. From Cape May, NJ to East Rockaway Inlet, NY is 1-3 ft. I don't want to make any assumptions about New York City. I will say that the current forecast, as of right now, has the storm making landfall east of New York City in Long Island. For Sandy, landfall occurred south of New York City in New Jersey. With Sandy, not only was water going into Long Island Sound, it was also coming in from the south of New York City. As long as NYC is west of the storm they shouldn't see as much water rise coming from the south. I don't know about the water from the east, coming from Long Island Sound into New York City. Obviously some of those areas are 3 to 5 feet. Water level rise is hard to talk about because it relies on so many different factors, like exactly how high up you are, where you are in comparison to the storm and the tide. And if right at the coast, destructive waves on top.

But just in general, there shouldn't be the overall flooding that there was in Sandy based on the current forecast for New York and Connecticut. Sandy was a huge storm and the water level rose over a large area. I can't say that if Henri got stronger than expected and made landfall that there might not possibly be a higher surge near an eye where there were onshore winds. But for most everyone, and perhaps everyone, on the current forecast it shouldn't be as bad as Sandy in terms of the water rise for New York and Connecticut. Some parts of Rhode Island and especially Massachusetts though could see a greater water rise than was seen in Sandy. And of course wind wise, I would think most all of these areas will be worse than Sandy. Sandy didn't bring too much wind to these areas. So trees down and power outages are likely going to be a major problem in the region where it makes landfall.
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Wow....a possible 5 ft storm Surge in Long Island Sound? - AquaRN, 8/20/2021, 11:47 pm
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