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Posted at 11:09 PM ET, 10/27/2012

Hurricane Sandy: Raging winds and high water to leave mark on Mid-Atlantic


Extent of tropical storm and hurricane force winds at 11 p.m. Saturday night. (National Hurricane Center)
Sandy’s approach to the Mid-Atlantic region this evening is palpable. Its sprawling cloud shield has overspread the region and winds are already gusting over 30 mph at the Maryland and Delaware beaches.

At 11 p.m., Sandy was 360 miles east southeast of Charleston, South Carolina with sustained winds of 75 mph according to the National Hurricane Center. The central pressure was down to 960 mb. Tropical storm force winds extend up to an unreal 520 miles from the center.

Reading through blogs and recent statements from the National Weather Service, I’m presently most impressed by two things:

1) Sandy’s incredible size and its associated wind field

2) The amount of water it’s going to push ashore at the beaches

Sandy’s size and associated wind

Meteorologist Angela Fritz of wunderground notes Sandy is now tied for the second largest tropical cyclone since 1988.

“Sandy’s tropical storm-force winds now extend 450 nautical miles [520 miles] from the center on the northeast side of the hurricane,” Fritz writes. “This is a very, very large storm, and I suspect the #1 spot (Olga of 2001) is in jeopardy, as well.”

Evidence of the storm’s unusual size? It’s more than 300 miles east of South Carolina, and in eastern North Carolina, the National Weather Service has logged its first reports of downed trees.

I’m not the only one impressed by how big this storm is and how far from its center it’s generating hazardous winds. Writes our local National Weather Service office:

...CANNOT RECALL EVER SEEING MODEL FORECASTS OF SUCH AN EXPANSIVE AREAL WIND FIELD WITH VALUES SO HIGH FOR SO LONG A TIME. WE ARE BREAKING NEW GROUND HERE.

Reminder: a high wind watch covers the region Sunday night through Tuesday, for sustained winds of 35-45 mph and gusts to 60 mph.

Water at the Maryland and Delaware Beaches, the Chesapeake Bay and Tidal Potomac


Storm surge projection for Mid-Atlantic coast (Dan Satterfield)
The water is rising in Ocean City, Maryland, where levels are already 1.5 feet above average. Water levels are forecast to reach as much as 4 feet above normal by Monday with wave heights of 8 to 14 feet. Says the National Weather Service:

SEVERE FLOODING IS EXPECTED WITHIN A FEW HOURS EITHER SIDE OF HIGH TIDE MONDAY MORNING. . . . WATER LEVELS FROM CHINCOTEAGUE TO OCEAN CITY COULD RIVAL THOSE REACHED IN GLORIA IN 1985.

A similar situation is forecast for the Delaware beaches where coastal flood warnings and high surf warnings are also in effect. Assuming the storm moves north of the Maryland and Delaware beaches, winds will become offshore, ending the coastal flood risk Monday night into Tuesday.


Surface height of combined wave and swell Monday morning (WeatherBell.com)

The situation is not as serious for the western shores of the Chesapeake Bay and the Tidal Potomac. Some minor flooding is possible into Monday, with levels around 1 foot above normal. By Tuesday, some moderate flooding could occur, with levels up to 1.5 to 3 feet above normal and a coastal flood watch is in effect. By comparison, levels were up to 9 feet above normal during Isabel.

By  |  11:09 PM ET, 10/27/2012

Categories:  Latest, Tropical Weather

 
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