Wednesday's Nor'easter to have lower impact than originally feared

An early-season Nor'easter is taking shape along the coast of South Carolina today, but is now forecast to be weaker and move farther offshore than originally forecast, resulting in lower impacts to the New Jersey and New York coasts than originally feared. The storm will head north-northeast along the coast on Wednesday, intensifying into a 990 mb Nor'easter, a few hundred miles south of Long Island, NY, by Wednesday evening. The storm will likely bring wind gusts up to 50 mph and a storm surge of 2 - 3 feet along the coasts of Virginia, Maryland, New Jersey, and New York, including New York City. High waves of 10 - 20 feet will ride on top of this surge, and cause moderate beach erosion along much of the coastline damaged by Hurricane Sandy. The greatest flooding will occur during the Wednesday early afternoon high tide cycle, near 1 pm EST. Fortunately, the high tides this week will be some of the lowest of the month, since we are midway between the new moon and full moon. The Nor'easter's strongest winds will likely affect eastern Long Island and coastal Massachusetts, where wind gusts up to 60 mph will be possible Wednesday evening and Thursday. The storm's heaviest rains will stay offshore, and only Eastern Massachusetts can expect to see more than 1" of rain. The storm isn't going to tap into a large reservoir of cold, Arctic air, which will limit snowfall amounts to perhaps 1 - 2" along a swath from Northern New Jersey northeastwards, across Western Massachusetts and into Maine. While the storm will slow down recovery efforts from Hurricane Sandy, this is a pretty ordinary Nor'easter of the type the Northeast sees several times per year, and will not cause major damage.


Figure 1. Predicted wind speed for 1 pm EST Wednesday, November 7, 2012, from the 12Z (7 am EST) run of the GFS model made on Tuesday, November 6, 2012. Winds tropical storm-force (39+ mph) are predicted to affect Southern New Jersey, eastern Long Island, Rhode Island, and Massachusetts, but miss the areas hardest hit by Sandy--northern New Jersey and the New York City area.


Figure 2. Predicted storm surge at Sandy Hook, NJ for Wednesday's Nor'easter, from the experimental Extratropical Storm Surge model, run by NOAA"s Meteorological Development Laboratory. This model used winds from this morning's 6Z (1 am EDT) run of the GFS model. The peak storm surge (yellowish-brown line) is predicted to be 3.7', occurring Wednesday afternoon. High tide (green line) occurs near 1 pm Wednesday afternoon, resulting in a peak storm tide of approximately 7.8' around 1 pm Wednesday (black line). For comparison, Sandy delivered a 8.6' storm surge to Sandy Hook before their tide gauge failed, with the storm tide reaching 13.2' above MLLW (Mean Lower Low Water.)

More Sandy links
I gave a TED talk in Bermuda in October 2011, and presented a list of nine potential $100 billion weather disasters that could happen in the next 30 years. Number six on my list was a hurricane hitting New York City. “We really don’t know what climate change is going to do to hurricanes,” I said, “but it makes sense that it’ll probably make the strongest ones stronger.” If you want to see what I had to say about a hurricane hitting New York City, plus the other eight disasters I think have at least a 10% chance of happening in the next 30 years, the 18-minute video is up on the main TED site. (I've since updated my list to twelve potential $100 billion disasters, and plan on running a blog series on the topic in 2013.)

Was Sandy a hurricane at landfall? Lee Grenci, a senior lecturer and forecaster at the Department of Meteorology at Penn State, weighs in on the matter in this guest blog post. He presents evidence that Sandy was not a hurricane at landfall, and was instead a rapidly evolving hybrid storm. Lee , who is a frequent contributor to Weatherwise magazine, will be joining wunderground as a featured blogger in December, and we're looking forward to having his excellent writings!

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Jeff Masters