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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Quoting GeorgiaStormz:
Since Sandy is hitting off tide now, will that mean no subway flood?




At this rate it will be ashore in 2 hours.


It's 110 miles SE of Atlantic City moving NW at 28. 110/28 = 3.92 hours until landfall. Maybe a little earlier than that depending on if it picks up anymore foreward speed.
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Snowshoe, WV: Link

Glad I don't live there! There are already scattered outages here in central Hampshire County, WV were I work. We lost power briefly, but it came right back on. Businesses are closing early and grocery stores are cleaned out. We have heavy rain and breezy conditions right now, but not too bad yet. I have a feeling that will change tonight.
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Dr. Masters is on CNN right now. He just said there'll probably be water in the subways.
Member Since: July 18, 2006 Posts: 0 Comments: 398
Here is NSTAR's outage map for New England:

http://outage.nstar.com/outage/

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Quoting largeeyes:
I hope Dr. Masters doesn't take this the wrong way....but from 4 days ago...



However, it is likely that the models are overdoing the strength of Sandy at landfall. The models have trouble handling the transition from tropical storm to extratropical storm in these type of situations, and I expect that the 940 mb central pressure of Sandy predicted at landfall Monday in Delaware by the ECMWF model is substantially overdone.

Jeff Masters


Nailed it....4 days ago! Hats off to ECMWF.


No one is perfect...but those 925 mb runs from the GFDL were overdone.

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Dr. Jeff is on CNN cool...
starting to get nervous about these trees around me
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Quoting presslord:
Link

Link got messed up.
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tallshipbounty.orgLink
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Doc on CNN
Member Since: September 23, 2005 Posts: 14 Comments: 11262


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Quoting hydrus:
Yes. But the good news if there is any, tide will not be at its highest for a lot of areas at the time of landfall.
That is good news, but unlike most hurricanes that pass by with a big windshift, onshore winds will continue north of where Sandy makes landfall for at least a couple more days. That will only add to the worst damage that has already been done.
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I hope Dr. Masters doesn't take this the wrong way....but from 4 days ago...



However, it is likely that the models are overdoing the strength of Sandy at landfall. The models have trouble handling the transition from tropical storm to extratropical storm in these type of situations, and I expect that the 940 mb central pressure of Sandy predicted at landfall Monday in Delaware by the ECMWF model is substantially overdone.

Jeff Masters


Nailed it....4 days ago! Hats off to ECMWF.
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620. Skyepony (Mod)
Wind..
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Quoting hydrus:
Yes. But the good news if there is any, tide will not be at its highest for a lot of areas at the time of landfall.

Dr. Ryan Maue seems to think that the greatest surge will lag behind the center a bit, which would be terrible. Whether that actually happens is yet to be seen.
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Sandy's forward speed has increased to a remakable 28 mph. Eta now just 4 hours away.


SUMMARY OF 200 PM EDT...1800 UTC...INFORMATION
----------------------------------------------
LOCATION...38.3N 73.1W
ABOUT 110 MI...180 KM SE OF ATLANTIC CITY NEW JERSEY
ABOUT 175 MI...285 KM SSE OF NEW YORK CITY
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...NW OR 305 DEGREES AT 28 MPH...44 KM/H
MINIMUM CENTRAL PRESSURE...940 MB...27.76 INCHES
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Quoting GTcooliebai:
Wow look at Snowshoe, WV that's a lot of snow!

No wonder they call it Snowshoe. xD
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Quoting dogsgomoo:
Texas Storm Chasers say that LGA is already flooded. http://twitpic.com/b8jh2b

New York LaGuardia (#LGA) already has flooding. #nysandy #njs... on Twitpic

Confirmation?


Lets not sensationalize, yes the runways are under water, same with JFK, but that is bound to happen when you build an airport, basically on an island. The airports and terminals themselves are fine.
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Quoting dogsgomoo:
Texas Storm Chasers say that LGA is already flooded. http://twitpic.com/b8jh2b

New York LaGuardia (#LGA) already has flooding. #nysandy #njs... on Twitpic

Confirmation?


Confirmed. NY1 News had it on a few minutes ago. No major damage, but several inches of water mad it over the tarmack
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The rats will be coming out all 50 million of them. The surge will pop them up.
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physics question: as the central pressure center drifts east of the gulf stream into colder and colder waters, won't the colder waters bulge a little less since cold water is heavier? Is that either taken into account, or too small to notice in an 98 mph wind?

I am liking that dry wedge that has moved from the south side to the east side. Hope it has time to wrap around to the north or even east.

It is tragic about the Bounty's crew. How odd that a tall sail powered ship would be lost due to power outage.
Member Since: December 28, 2006 Posts: 115 Comments: 1590
Near Seaside Park NJ, the main body of convection (according to water vapor loop) has just hit the coast, at 1:39pm:



The server is too busy, I am having a tough time getting any newer images now, but here is one at 1:59pm, showing the worst part of the storm entering North Jersey, about to hit Staten Island right now.


Member Since: December 28, 2010 Posts: 0 Comments: 134
Wow look at Snowshoe, WV that's a lot of snow!
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Quoting Grothar:


I believe New Yorkers have a word for people like that, but I don't think I can post it here.


Jets fans??

This thing will be ashore by 5 pm by the looks of things, this will be ahead of the high tide so that is better... the fetch will be S-N once the eye is ashore and that is not helping the tide, but crossing it.
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Quoting NewYork4Life:
Sandy pretty lame so far here 50 mi. north of NYC..
That will change soon .
Member Since: September 27, 2007 Posts: 1 Comments: 21734
Quoting Articuno:

And the storm surge may come in faster?? ???
Yes. But the good news if there is any, tide will not be at its highest for a lot of areas at the time of landfall.
Member Since: September 27, 2007 Posts: 1 Comments: 21734
Sandy pretty lame so far here 50 mi. north of NYC..
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Quoting presslord:


Hey, you!!! 'bout time for you to cut the fan down a couple notches...


Hey be thankful we're not dealing with Sandy, cept for some rough surf. I was live at Folly on Saturday, erosion wasn't a big issue and the surfers were out in full force. That north wind for us was a saving grace, mainly offshore since Friday as Sandy made her closest approach.
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Quoting DrewE:


Yes sir! Are you on the south side?

I hate to be the a negative nancy, but the chances of us losing power are getting higher and higher as this is progressing.

Check this out. It's an outage map from Dominion Power. Link


I'm near Midlothian. And yep... those numbers are sure to go up.
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I wouldn't be surprised if Sandy makes landfall as a hurricane.
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Quoting ncstorm:


he was forced into calling an evacuation because of the media and some weatherman..will they be apologizing to him?
From a jail cell, after a thorough "stop and frisk".
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Texas Storm Chasers say that LGA is already flooded. http://twitpic.com/b8jh2b

New York LaGuardia (#LGA) already has flooding. #nysandy #njs... on Twitpic

Confirmation?
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Quoting CybrTeddy:
Already worse than Irene.


A friend of mine got married right there last summer, wakes from passing boats splashed up onto the pavement even without a storm...that place is going to be innundated.
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Quoting ncstorm:
I may get bashed but I think NYC wont be as bad as was stated....


Bash.
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599. Skyepony (Mod)
Recon extrapolated 939.6 mb (~ 27.75 inHg) from the center of Sandy. Will be interesting to see what the dropsonde says.
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Ok... so one tree down soo far and there are people near me starting to lose power
Governor Corbett of Pennsylvania said that Chester, Lancaster, Adams and York counties in Pennsylvania will probably get hit the worst... woo hoo that means me
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Southern NJ then into Philly?
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Quoting RitaEvac:
According to radar New England isn't gonna get any rain.


Maybe not the heavy stuff. We've had light rain most of the day. Hoping it doesn't soften up the ground too much as the winds pass.

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Quoting RitaEvac:
May not ever really get much rain in NYC, northern Jersey



TWC has already back off their initial rainfall totals for that area, now showing 2-5 inches, and looking at the current radar trends, that may even be generous.
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594. dader
Quoting ncstorm:


they are not even getting wind like that either..i think we are going to see pictures of NJ where it looks like a bomb was dropped there..


That's why it's a crapshoot. At JFK Airport, they are and will be getting some serious winds. But at the Battery, not so much.
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Quoting sfranz:
The winds are creating an "instant autumn" in south-central MA. Tree branches should be next.

Last night my yard was totally cleaned up.




My power went out at Noon in Se. Mass. The leaves are flying off the trees.
My ears started popping Fruday but now it seems like a pressure on my head.
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Quoting hydrus:
With the faster forward speed, the damage from wind will increase substantially. and be stronger for areas well inland from where she makes landfall.

And the storm surge may come in faster?? ???
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As many of these hurricanes and tropical storms seem to come in after dark, one positive aspect of Sandy seems to be that she will hit while there is still daylight.
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Quoting Chucktown:


Agreed, Bloomberg may come out smelling like a rose.


Hey, you!!! 'bout time for you to cut the fan down a couple notches...
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Quoting Chucktown:


Agreed, Bloomberg may come out smelling like a rose.


he was forced into calling an evacuation because of the media and some weatherman..will they be apologizing to him?
Member Since: August 19, 2006 Posts: 13 Comments: 16014
can someone help me understand the 940mb and 90mph winds... how does this get categorized? looks listed still as Cat 1??
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Quoting dader:


The rain won't be as bad. The wind is really a crapshoot. But the flooding could be something people haven't seen in a long time.


they are not even getting wind like that either..i think we are going to see pictures of NJ where it looks like a bomb was dropped there..
Member Since: August 19, 2006 Posts: 13 Comments: 16014
Quoting ncstorm:
I may get bashed but I think NYC wont be as bad as was stated....


Agreed, Bloomberg may come out smelling like a rose.
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With the faster forward speed, the damage from wind will increase substantially. and be stronger for areas well inland from where she makes landfall.
Member Since: September 27, 2007 Posts: 1 Comments: 21734
According to radar New England isn't gonna get any rain.
Member Since: July 14, 2008 Posts: 1 Comments: 9645
Quoting ncstorm:
I may get bashed but I think NYC wont be as bad as was stated....

I feel the rain will be pretty much nothing. But that the wind will still be pretty powerful, but not for as long as originally forecast. I imagine the flooding is still going to get bad, but maybe not as bad if she makes landfall hours before high tide?
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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.

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