Superstorm Sandy intensifying, bringing record storm surges

By: Dr. Jeff Masters , 2:54 PM GMT on October 29, 2012

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The final countdown to Hurricane Sandy's arrival has begun, and this extraordinary and historic storm is already causing havoc all along the U.S. coast from North Carolina to Massachusetts. The scale of this massive storm truly earns Sandy the title of "superstorm". Sandy's tropical storm-force winds span an area of ocean 940 miles in diameter, and both North Carolina and the island of Bermuda, 700 miles to the east, are under tropical storm warnings. The region of ocean covered by 12-foot high seas spans an area of ocean an incredible 1560 miles in diameter. Winds near hurricane force are expected to affect waters from Virginia to Massachusetts today. Record storm surge flooding has already occurred in regions along the New Jersey coast this morning, and the highest water levels recorded in over a century of record keeping are expected over much of the New Jersey and New York coasts this evening during the 8 - 9 pm EDT high tide cycle. Sandy brought sustained winds of 60 mph and waves 30 feet high early this morning to the buoy east of Cape Hatteras, NC. A wind gust of 58 mph occurred at New York City's La Guardia Airport at 9:51 am EDT, and a buoy at Robins Reef, NJ recorded sustained winds of 42 mph, gusting to 55 mph. As of 8 am EDT, Sandy has dumped heavy rains of 7.87" at Cape Hatteras, NC; 4.01" at Ocean City, MD; 3.12" at Dover, DE; and 3.22" at Virginia Beach, VA. As of 9 am EDT, peak storm surge values of 5" were observed at Lewes, Delaware, 4.2' at Cape May, NJ, 4' at Atlantic City, NJ, 2.9' at Philadelphia, and 3.9' at New York City.

Latest data from the Hurricane Hunters shows that Sandy is intensifying as its core traverses the warm waters of the Gulf Stream. At 8 am EDT, an Air Force hurricane hunter aircraft found top winds of 98 mph in the heavy thunderstorms to the southwest of Sandy's center, at a point about 150 miles east-northeast of Cape Hatteras, NC. A dropsonde released in the eye measured a central pressure of 945 mb, but observed winds of 19 knots at the surface, so Sandy is probably a 943 mb hurricane that is very close to Category 2 strength. The Hurricane Hunters did not observe an eyewall, and saw very little temperature difference from inside to outside the eye, so Sandy is not going to be able to undergo rapid intensification. The storm could still see an increase of 5 mph in its winds before landfall tonight between 6 pm - 10 pm EDT, due, in part, to interaction with the low pressure system to its west that is pulling the hurricane towards the coast. The new, higher winds of Sandy don't have a lot of time to pile up additional storm surge water, so the NHC storm surge forecasts will probably not change today. But it is clear that Sandy is not going to pull its punch, and this superstorm is going to deliver a punishing multi-billion dollar blow to a huge area of the Eastern U.S.


Figure 1. Morning satellite image of Hurricane Sandy.

Sandy already producing a record storm surge
The National Weather Service in Atlantic City, NJ said that isolated record storm surge flooding already occurred along portions of the New Jersey coast with this morning's 7:30 am EDT high tide cycle. As the tide goes out late this morning and this afternoon, water levels will fall, since the difference in water levels between low tide and high tide is about 5'. However, this evening, as the core of Sandy moves ashore, the storm will carry with it a gigantic bulge of water that will raise waters levels to the highest storm tides ever seen in over a century of record keeping, along much of the coastline of New Jersey and New York. The peak danger will be between 7 pm - 10 pm, when storm surge rides in on top of the high tide. The full moon is today, which means astronomical high tide will be about 5% higher than the average high tide for the month, adding another 2 - 3" to water levels. This morning's 9:30 am EDT H*Wind analysis from NOAA's Hurricane Research Division put the destructive potential of Sandy's winds at a modest 2.9 on a scale of 0 to 6. However, the destructive potential of the storm surge was record high: 5.8 on a scale of 0 to 6. This is a higher destructive potential than any hurricane observed since 1969, including Category 5 storms like Katrina, Rita, Wilma, Camille, and Andrew. The previous highest destructive potential for storm surge was 5.6 on a scale of 0 to 6, set during Hurricane Isabel of 2003. Sandy's storm surge will be capable of overtopping the flood walls in Manhattan, which are only five feet above mean sea level. On August 28, 2011, Tropical Storm Irene brought a storm surge of 4.13' and a storm tide of 9.5' above MLLW to Battery Park on the south side of Manhattan. The waters poured over the flood walls into Lower Manhattan, but came 8 - 12" shy of being able to flood the New York City subway system. According to the latest storm surge forecast for NYC from NHC, Sandy's storm surge is expected to be 10 - 12' above MLLW. Since a storm tide of 10.5' is needed to flood the subway system, it appears likely that portions of the NYC subway system will flood. The record highest storm tide at The Battery was 10.5', set on September 15, 1960, during Hurricane Donna.


Figure 2. Observed storm tide (red line) and predicted storm surge for Hurricane Sandy at The Battery on the south shore of Manhattan, New York City, from the experimental Extratropical Storm Surge model, run by NOAA"s Meteorological Development Laboratory (green line) and the NYHOPS model from the Stevens Institute of Technology (pink curve), which uses a highly detailed 3D ocean model and even includes rainfall and tributary inflows. These models have a storm surge of 5 - 6', which brings the maximum storm tide--the water level reached as a result of the combined action of the tide and the storm surge--to 11' above MLLW (Mean Lower Low Water.) Irene brought a storm tide of 9.5' above MLLW to The Battery in 2011. At a storm tide of 10.5', water will likely pour into the Lower Manhattan subway system, unless efforts to sandbag the entrances are successful. The NWS in NYC is predicting a 10 - 12' storm tide at The Battery during tonight's 9 pm high tide cycle.


Figure 3. Observed storm tide (red line) and predicted storm surge for Hurricane Sandy at Atlantic City, New Jersey, from the experimental Extratropical Storm Surge model, run by NOAA"s Meteorological Development Laboratory (green line) and the NYHOPS model from the Stevens Institute of Technology (pink curve), which uses a highly detailed 3D ocean model and even includes rainfall and tributary inflows. These models predict a maximum storm tide--the water level reached as a result of the combined action of the tide and the storm surge--of ' above MLLW (Mean Lower Low Water.) Irene brought a storm tide of 9.5' above MLLW to The Battery in 2011. At a storm tide of 10.5', water will likely pour into the Lower Manhattan subway system, unless efforts to sandbag the entrances are successful. The NWS in Atlantic City is predicting a 9.5' storm tide for the city during tonight's 8 pm high tide cycle, which would be the highest water levels ever observed in Atlantic City.

Links for Sandy
To find out if you need to evacuate, please contact your local emergency management office. They will have the latest information. People living in New York City can find their evacuation zone here or use this map. FEMA has information on preparing for hurricanes.

People with disabilities and caregivers seeking information on accessible shelter and transportation can contact portlight.org

Atlantic City beach cam

Ocean City, MD webcam

Statue of Liberty cam

An impressive 1-minute resolution satellite loop of Sandy today is at the CSU RAMMB website.

Our Weather Historian, Christopher C. Burt, has an excellent post on Late Season Tropical Storms that have affected the U.S. north of Hatteras. He also has a post, Historic Hurricanes from New Jersey to New England.

Hurricane Sandy info from NASA.

Joe Romm at climateprogress.org has a thoughtful piece called, How Does Global Warming Make Hurricanes Like Irene More Destructive?

For those of you wanting to know your odds of receiving hurricane force or tropical storm force winds, I recommend the NHC wind probability product.

Wunderground has detailed storm surge maps for the U.S. coast.

The National Hurricane Center's Interactive Storm Surge RIsk Map, which allows one to pick a particular Category hurricane and zoom in, is a good source of storm surge risk information.

Storm Surge prediction model from the Stevens Institute of Technology, which use a highly detailed 3D ocean model and even includes rainfall and tributary inflows.

Research storm surge model run by SUNY Stonybrook for New York City.

Climate Central has a nice satellite image showing which parts of New York Harbor are below five feet in elevation.

I'll have an update this afternoon.

Jeff Masters

Hurricane Sandy 1 (gwegret)
Post-Hurricane Sandy waves pound the Deerfield Beach, FL fishing pier!
Hurricane Sandy 1
Hurricane Sandy Long Neck Delaware (mal247)
On Rehoboth Bay
Hurricane Sandy Long Neck Delaware

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The water levels at Battery Park would be 6.68 feet above only the predicted tidal levels. As far as the comparison with predicted water levels that include the winds and pressure, it would appear to be running fairly close or slightly below the predictions, currently.
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1231. ncstorm
Quoting aislinnpaps:
It was people in Atlantic City who stayed and they are asking for help now.(NJ)


I feel so bad for them..the coast guard cant assist? Gov Christie just seemed a little cold in that briefing..
Member Since: August 19, 2006 Posts: 13 Comments: 15137
1230. Dakster
Quoting DataNerd:
Battery level now 8.9 ft


Yep... Hopefully it will help out, but right now it still looks like it could break 10'.
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Quoting DataNerd:



Here's to hoping. It's still rising right now.


Sandy hook just hit 10.11'
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It was people in Atlantic City who stayed and they are asking for help now.(NJ)
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1227. Msdrown
Anybody have a live camera link to Newport RI waterfront area???
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Now 8.9' at the battery...
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Battery level now 8.9 ft
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Quoting ncstorm:
I really hope you guys are listening to Jim Cantore about landfall being sooner and helping with the surge for Battery Park..I think Battery Park wont be as extreme as predicted..



Here's to hoping. It's still rising right now.
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Quoting aislinnpaps:


If I understood it correctly, some officials and people stayed on Barrier Island and now want help. Christie said go to the highest place you can and they won't be there to help until at least tomorrow.
Quoting aislinnpaps:


If I understood it correctly, some officials and people stayed on Barrier Island and now want help. Christie said go to the highest place you can and they won't be there to help until at least tomorrow.



Wonder what "some" is.


Hopefully they ride it out ok.
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1222. ncstorm
I really hope you guys are listening to Jim Cantore about landfall being sooner and farther south and helping with the surge for Battery Park..I think Battery Park wont be as extreme as predicted..
Member Since: August 19, 2006 Posts: 13 Comments: 15137
1221. Dakster
Quoting yonzabam:


6.68' above predicted levels at this time seems surreal. Is that really the case?


Yes... to both questions.
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Quoting DataNerd:


I am wondering what the heck he means by "many"


A couple hundred or a couple thousand? How many people stayed???!?

Really a bad deal with this surge still going up, and your going to get pounding wave action as well.....


Smacks of another crystal beach.


They didn't give a #, but apparently the mayor there told citizens he wanted them to stay.
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Quoting yonzabam:


6.68' above predicted levels at this time seems surreal. Is that really the case?

Not the predicted storm tide, above the predicted astronomical tide.
Member Since: August 2, 2006 Posts: 46 Comments: 11666
Quoting DataNerd:
Governor Christie has stated that for those who did not evacuate "we will not be able to help you until tomorrow due to the conditions".



He also made some pretty pointed statements about people not leaving, so apparently they think they have a fair number of people trapped/ or in high risk areas that did not leave.


Not good.


If I understood it correctly, some officials and people stayed on Barrier Island and now want help. Christie said go to the highest place you can and they won't be there to help until at least tomorrow.
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Sandy Hook NJ station just reached record level.

New London, CT just reached highest level during the storm so far, so did Islap. Battery Park in NYC will do this within the hour.

Link to all the New Jersey stations
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Quoting yonzabam:


6.68' above predicted levels at this time seems surreal. Is that really the case?


The predicted levels only consider the astronomical tides, not the storm. So 6.68' above what you'd expect with a full moon.
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Quoting 1900hurricane:
Atlantic City, NJ is now below 950 mb!




Record breaking!
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Quoting charlottefl:
Press Conference by the Governor of NJ,
The mayor of Atlantic City, NJ urged residents to stay.
There are many residents still on the beach. One shelter is a block away from the bay, now under water.


I am wondering what the heck he means by "many"


A couple hundred or a couple thousand? How many people stayed???!?

Really a bad deal with this surge still going up, and your going to get pounding wave action as well.....


Smacks of another crystal beach.
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Quoting TropicalAnalystwx13:
Current damage total estimates for Sandy are ~$20 billion. I think it will end up higher...much higher if NYC's subway system floods, which there is a high chance it does.


That's a prediction. It hasn't even arrived yet.
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Weather Underground ‏@wunderground
Many rivers and streams around Philadelphia approaching flood stage. http://wxug.us/tm70 #Sandy
Retweeted by Jim Cantore
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Atlantic City, NJ is now below 950 mb!

Member Since: August 2, 2006 Posts: 46 Comments: 11666
Governor Christie has stated that for those who did not evacuate "we will not be able to help you until tomorrow due to the conditions".



He also made some pretty pointed statements about people not leaving, so apparently they think they have a fair number of people trapped/ or in high risk areas that did not leave.


Not good.
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Huge gusts of wind. Gutters in yards.
Lots of rain.
Kinda scary.
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AccuWeather.com ‏@breakingweather
83 mph wind gust in Eatons Neck, N.Y.
Expand Reply Retweet Favorite
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Quoting Dakster:


Storm Surge increasing. Now 6.68' above predicted levels.

Anyone have a web cam link to Battery or a recent picture they can post?


6.68' above predicted levels at this time seems surreal. Is that really the case?
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1206. KEEPEROFTHEGATE (Mod)
18L XXXX
Member Since: July 15, 2006 Posts: 170 Comments: 53548
Press Conference by the Governor of NJ,
The mayor of Atlantic City, NJ urged residents to stay.
There are many residents still on the beach. One shelter is a block away from the bay, now under water.
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Quoting victoriahurricane:


Link not found



Its 8.79 FYI. Find it manually here (annoying noaa server error: Link


Governor is on livestream right now.
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Current damage total estimates for Sandy are ~$20 billion. I think it will end up higher...much higher if NYC's subway system floods, which there is a high chance it does.
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Quoting sunlinepr:
NY constructin crane collapse / hanging in 75mph wind.... Apartments already sold up to 90million each....

Yes, it's an expensive building, but more important it's at a key point in NYC. 57th and 6th. That's Carnegie Hall, Carnegie Deli! area. Plus the most expensive real estate in the city on that block of 57th between 5th and 6th. I have no idea how they're going to go about securing that crane, but it's not gonna' be secure tonight and if it falls it can only be bad.
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1201. Dakster
Quoting charlottefl:
8.77' at the battery now


Storm Surge increasing. Now 6.68' above predicted levels.

Anyone have a web cam link to Battery or a recent picture they can post?
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"Hurricane Central@twc_hurricaneMT @twcMariaLaRosa: Part of Atlantic City's boardwalk (built to hold up a firetruck) obliterated! #Sandy #ACY #NJwx pic.twitter.com/6ZzrMEeQ
"
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Wunderground is being slammed!! Glad folks are paying attention......Looks like quite a few pages in the history books are fixin to change!! GOD bless our many friends in the NE!!
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Quoting DataNerd:
Current stage at the battery:
Link


Link not found
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8.77' at the battery now
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1196. KEEPEROFTHEGATE (Mod)
Member Since: July 15, 2006 Posts: 170 Comments: 53548
1195. Dakster
Datanerd - The site is overloaded... All I get is a red x on your post.

8.63 feet and 964.8mb pressure.
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1194. zawxdsk
Interesting - latest observation at Cape May was winds from the direct south???
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Water is pouring into Long Beach, Long Island...
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1192. Dakster
Quoting wolftribe2009:
Sandy brought a wind gust of 117 mph to Mount Washington, NH at 5pm ET.


That is a calm day for that Mountain... Or at least it seems like it should be.
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Current stage at the battery:
Link
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1190. acl8610
If you look SE of the "center" of circulation, some pop-up showers have been forming, this may be due to colder air aloft flooding into the remnant warm core, creating instability. This cold air will steepen the low level lapse rates and allow the stronger winds at 925 and 850mb to mix down in gusts over the next few hrs. If anyone knows what a kata-front is, this is one to the extreme. It should continue to wrap around the low over time.
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Sandy brought a wind gust of 117 mph to Mount Washington, NH at 5pm ET.
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Quoting zawxdsk:
What was that record low pressure north of Hatteras?

950.3 hPa at Atlantic City


Ever? I believe it was 946 at Bellport Coast Guard Station here on Long Island during the 1938 Long Island Express.
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NYC News "NYC Mayor's Office@NYCMayorsOfficeBREAKING: At 7 PM, all four East River bridges will shut down: Brooklyn, Manhattan, Williamsburg and Ed Koch Queensboro Bridges. #Sandy"
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1186. Dakster
Battery running 6.66' above predicted... That puts it close to 11' if it continues.

(Had to be 6.66 above didn't it...)
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For those who want to watch the Governor's briefing the link is this: Link
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1184. centex
Quoting CaneWolf:
Battery at 8.4 - hope to see that green line (residual) level off soon. That might cut down the peak.

Battery floods at 8.5 I believe, subways in danger at I believe I heard 10ft. Prediction was 11ft... so we'll see.
I worry about that area in a few hours and DC/BA area tonight when the stronger winds and rains come.
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951 DataNerd: The big questions now are:
1. Exact landfall intensity, and storm surge.
2. How much inland surge are we going to see in vulnerable areas like Manhattan and NJ shore.
3. With reports of rescues occuring in Delaware, how many other people can we reasonable expect did not heed evacuation orders?
4. How long will the cyclone maintain winds in excess of 75 mph post landfall?


5 Is Sandy going to become a Cat.3 before crossing the Mississippi or after the crossing?
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jet ski! i love new york
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.