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Sandy moving ashore, bringing record storm surge flooding

By: Dr. Jeff Masters, 10:40 PM GMT on October 29, 2012

Hurricane Sandy is making its final approach, and will be ashore near the Delaware/new Jersey border early this evening. The scale of this massive storm truly earns Sandy the title of "superstorm", and no storm since at least 1988 has struck the U.S. with a wider area of tropical storm-force winds. High wind warnings are posted from Northern Michigan to Lake Okeechobee, Florida, and from Chicago to Maine. All-time low pressure records have been set at Atlantic City, NJ, Philadelphia, PA, and Wilmington Delaware. The rain is coming down in sheets along the east coast, where heavy rain stretches from Virginia to Pennsylvania and New York. Virginia Beach, VA has seen 9.26", Dover, DE has seen 6.36" and Ocean City, MD has seen 6.31". Some of the heaviest rain, apart from close to the center, is actually on the far western side, where a strong band of precipitation has set up running north to south from Erie, PA south to Pittsburgh, PA. This strong band of rain is moving west into Ohio. Wind gusts have been peaking above 80 mph in New York, Rhode Island, and Massachusetts this afternoon. The strongest gusts we've seen today include 86 mph at Westerly, RI, 84 mph on Plum Island, NY, and 83 mph on Cuttyhunk Island, MA. Sustained winds speeds of 40+ mph stretch from Delaware to Rhode island, with the strongest sustained wind closest to the center of circulation in Lewes, DE. All of this strong, onshore wind has been pushing huge amounts of water toward the shore, where it has nothing to do but pile up over land. As of 5pm EDT, here are the highest storm surges seen:

Kings Point, NY: 7.85 ft
Sandy Hook, NJ: 7.55 ft
Bridgeport, CT: 7.3 ft
New Haven, CT: 6.82 ft
The Battery, NY: 6.7 ft
New London, CT: 5.76 ft
Atlantic City, NJ: 5.69 ft
Lewes, DE: 4.46 ft

We just added live tide gauge heights on our wundermap, so you can follow the changes in surge as Sandy roars ashore.

Figure 1. MODIS satellite image of Hurricane Sandy taken at 2:20 pm EDT Monday, October 29, 2012. At the time, Sandy was a Category 1 storm with 90 mph winds. Image credit: NASA.

Sandy bringing high winds all the way to Chicago
The scope of this storm is truly astonishing. As Sandy combines with the fall low pressure system over the Northeast U.S., its circulation will intensify, and winds over the Great Lakes will increase. Storm warnings are posted for Tuesday on Lake Michigan near Chicago, where sustained 55 - 60 mph winds and waves of 20 - 25 feet are expected. Storm warnings are posted on Lake Erie and Lake Ontario, and high winds from Sandy blowing off of Lake Erie caused damage to signs in Port Clinton, Ohio this afternoon. Check out this webcam view of a very angry Lake Erie. High wind warnings extend from northern Michigan to Central Florida.

Sandy's storm tide peaking early this evening
Storm surge should peak between 7 - 8 pm, and high tide will peak a little later, 8 - 9 pm, depending upon location. The storm tide--how high the water gets above some reference point, commonly chosen to be the average of the daily lowest low tide of the month (Mean Lower Low Water, MLLW) is what we use to discuss how bad storm surge flooding is. The storm tide is the combination of the storm surge and the tide. At Sandy Hook, NJ, the storm tide has reached 10.11', and is still rising. This breaks the old record set by Hurricane Donna in 1960, and the Nor'easter of Dec 11th, 1992. As of 6 pm EDT, the storm tide at The Battery in New York City was 10.1'. The record is 10.5', set during Hurricane Donna of 1960. That also happens to be the level the Lower Manhattan subway system will flood, unless the defenses have been improved since last year's Hurricane Irene. High tide is at 8:53 pm. The rise in surge has slowed down, but the surge may not be slowing down fast enough to avoid record flooding in New York City.

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

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?

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.

I have to cut this post a bit short due to the many media interviews I'm involved with, but will be back in the morning with much more.

Jeff Masters and Angela Fritz


The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.