Monday, April 4, 2011

Warm & Windy Monday Ahead of Strong Storm System Tuesday

Monday will be blustery as a strong low pressure system tracks eastward closer to us. This tightening of the pressure gradient between high pressure east of the Southeast U.S. Atlantic coast and the approaching low pressure from the west will create gusty southwest winds up to 40 mph in central Virginia, with gusts around 50 mph in the counties highlighted in tan on this map (Wind Advised counties).

This storm system has a strong cold front at the surface causing temperatures to drop about 20 degrees in its wake. It also has a history of producing severe weather, primarily in the form of damaging winds and hail. All of central Virginia will have a slight risk for severe thunderstorms early Tuesday morning as that cold front approaches:

Our primary threat will be damaging straight-line winds in excess of 65 mph, as these thunderstorms will likely occur in the form of a squall line with frequent lightning and heavy downpours. It looks like a mature squall line will track into western Virginia around Midnight tonight:

This squall line should sweep swiftly into central Virginia while most of you are asleep, so don't be surprised if you are awakened between 3-5 a.m. Tuesday in the Metro as these strong to severe thunderstorms track through.

The squall line should weaken as it tracks toward the Chesapeake Bay, reaching the Eastern Shore by 7 a.m. Rain will continue behind the squall line as the cold front begins moving through central Virginia after sunrise:

I expect the rain to taper off from west to east behind the cold front during the rest of Tuesday morning, with Tuesday afternoon likely being dry with rapidly decreasing clouds. Rainfall accumulations look like they'll range half an inch to an inch from Tuesday morning's storm system:

A seasonable air-mass will settle back into the Mid-Atlantic behind Tuesday morning's cold front with highs Tuesday and Wednesday in the mid-60s.