26 August 2011

All eyes on Irene as it heads toward US coast

As of the latest advisory, Irene is heading N at 12kts with 90kt sustained winds.  It's about 330 miles S of Cape Hatteras NC.  The latest forecast track, watches, and warnings can be found at http://www.nhc.noaa.gov/storm_graphics/AT09/refresh/AL0911W+gif/092739W_sm.gif  The track is very ominous, and one of the worst-case scenarios for the entire northeast coast.  It's been 6 years since the US has experienced a major hurricane landfall, and that was Wilma when it hit just south of Naples FL with 105kt winds.  The last non-major (Cat 1-2) US hurricane landfalls occurred in 2008: Dolly, Gustav, and Ike (TX, LA, TX).

The first and strongest US landfall is expected in the early morning hours on Saturday, near Morehead City, NC, as a Category 2 (90kt) storm.  In addition to the powerful winds gusting up to 125mph, the storm surge will be quite high... up to 9' in surge-prone areas like Pamlico Sound.  Keep in mind that large violent waves are on top of that storm surge, and both are on top of the normal tides.

A long-range radar loop from Morehead City can be found here:
and a short-range radar loop can be found here:
Also, the exact time and location of landfall is almost irrelevant for a storm this large... the effects of the hurricane will be felt far from the center and for at least 12 hours before the eye crosses the coastline.

Further north and a day later, Irene will be just off of the NJ coast, and creating a large storm surge in the Chesapeake and Delaware Bays as well as along the ocean.  Norfolk VA is in a very sensitive area, and can expect a 6-7' surge.  It could still be a powerful Category 1 storm at that time, so wind gusts up to 120mph could affect coastal VA, MD, DE, and NJ.  There is still a lot of concern for New York City, where low-lying parts of the city exposed to water are home to large numbers of people.  Again, the evacuation map for NYC can be found here: http://www.nyc.gov/html/oem/downloads/pdf/hurricane_map_english.pdf

The image below shows what the latest forecast storm surge will be in the DE/MD/NJ/NY area:

Then on top of all of this is the rainfall.  The image here shows the 5-day forecast accumulated rainfall totals (in inches). Many areas in the northeast have just gotten a lot of rain unrelated to the hurricane, so the ground is saturated prior to getting up to a foot of additional rain.

Please visit my tropical Atlantic headquarters.

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