Thursday, April 14, 2011

Risk for Severe Storms Saturday

An intensifying low pressure storm system in the Four Corners region of the western U.S. this Thursday morning is going to track through the southern Plains today, then move northeast toward the Great Lakes at the end of this week. Along the way, it should produce rounds of severe weather. This storm system will impact the Commonwealth by Saturday with overcast skies in the morning with showers.

But as we get into our afternoon hours of peak heating, instability will be at its greatest as the surface cold front linked to that low pressure system in the Great Lakes begins its sweep through the state. Ahead of that front, there will be sufficient wind shear, lift, and instability for strong to severe (potentially rotating) thunderstorms to develop in the afternoon and continue through the evening until the cold front passes into the Bay by Midnight.
Here's a time-line of the storm system on Saturday:

We'll be overcast in the Commonwealth by Saturday morning, and showers should expand east into central Virginia from the west before Noon.

Saturday afternoon, as mentioned above, is when we'll have our enhanced threat for severe thunderstorms.

Isolated thunderstorms that develop in central Virginia (east ahead of the main line of storms along the cold front) will be the most likely to rotate and potentially produce a few tornadoes.

Once the cold front starts sweeping through central Virginia, storms should be in a long "squall" line with damaging straight-line winds being our primary threat into the evening.

The cold front will reach the Chesapeake Bay around Midnight, pushing storms to the east.

Although we'll have the downside of a severe weather threat, the good news out of this storm system is that it should bring heavy rain into the entire Commonwealth, which is something we still need in most of the area! Widespread accumulations of a half-inch to around an inch look likely. Here's the potential rainfall accumulation by late Saturday night:

Stay with CBS 6, we'll keep you ahead of the storm!
--Meteorologist Carrie Rose--