29 October 2012

Sandy's historic landfall expected tonight

Hurricane Sandy continues to loom ominously off the U.S. east coast, bringing very heavy rain and tropical storm to hurricane force winds to many millions of people well before the worst arrives. The coastal flooding is already terrible, as expected (even as far south as Miami and Fort Lauderdale!). Locations from North Carolina to Maine will continue to see incredible coastal flooding/erosion, with the worst near and north of where the center crosses land (approximately southern NJ into NYC, Long Island, CT, RI, and MA). Inland flooding will also be a large problem in the coastal states as well as the inland states throughout the northeast. Finally, the 50-90mph winds that many places will experience can easily damage roofs, break tree limbs, and uproot trees, bringing power lines down with them.

At 8am EDT today, Sandy was a Category 1 hurricane with 85mph sustained winds, and a 946mb central pressure (it's that very low pressure that creates the strong winds at the surface).  The wind field is so large that tropical storm force winds (45mph+) extend 485 miles out from the center.  The center is located approximately 300 miles south of NYC and 300 miles east of Norfolk... heading for a landfall late tonight near Atlantic City.  I have multiple long radar loops available at http://andrew.rsmas.miami.edu/bmcnoldy/tropics/radar/index.html#sandy12

Perhaps the trickiest part of this system from a warning perspective is that Sandy may not technically be a hurricane by the time it reaches the coastline later tonight. It is interacting with a cold front that is draped on the coastline and is losing some of its tropical characteristics. It actually has a warm front forming off to its east and a cold front to its south... a sign that it's transitioning to an extratropical cyclone.

This absolutely does not make it any less dangerous! It has been intensifying (by both tropical AND extratropical mechanisms), and this interaction with the mid-latitude front is exactly what has been forecast to occur for days now. With or without a hurricane or a hurricane warning, this storm is extraordinary, unprecedented, and must be taken very seriously.  The storms it has been compared to are the 1938 Great New England Hurricane, Hurricane Gloria in 1985, and the "Perfect Storm" of 1991.  Sandy will join this crowd, and likely surpass some (if not all) of them in total impacts and damage.

This is truly a worst-case scenario that will cost tens of billions of dollars and claim hundreds of lives.  Huge unthinkable storm surges along the entire northeast U.S. coast (particularly in the New York City and northern NJ region), mostly reaching their worst at night and during a full moon (already higher-than-normal tides), large rainfall amounts over several states, 2-3 FEET of wet snow in the mountains of WV, and widespread power outages for perhaps 10 million people.

If you're in the affected areas, be aware of nearby streams/creeks/rivers that could quickly turn into white water rivers... large trees near your house... and be prepared to lose power for several days.  Also, remember to check up on family and friends who might be at a higher risk than you.

A good source of constant updates through the coming couple of days is the Capital Weather Gang's live blog... and for the latest local bulletins and warnings, check your local National Weather Service office.

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