Thunderstorms and high winds expected from the Ohio Valley to the Mid-Atlantic

A stormy Tuesday is in store for parts of the Mid-Atlantic and Ohio Valley. Damaging gusts and a couple of tornadoes are expected, especially near and east of the Appalachians, prompting the Storm Prediction Center to draw a broad zone of enhanced (Level 3 out of 5) risk for severe weather.

The zone at risk stretches from northeast Kentucky to New Jersey, and includes most of Pennsylvania, southern Ohio, West Virginia, Maryland, Virginia, the Delmarva Peninsula and D.C. That’s where scattered to numerous storms are expected, a few of which could produce significant severe weather.

Windy squall lines and rotating supercells will be possible. Any supercells would pose the risk of hail up to golf-ball size or an isolated tornado, while squalls would be more primed to produce damaging straight-line wind gusts.

The setup is similar to conditions that led to severe weather on Saturday and produced a few tornadoes in Pennsylvania. This time, the tornado risk may be greatest in southern Pennsylvania or even northern Maryland into New Jersey.

It’s all thanks to a sprawling storm system anchored by low pressure in western Quebec. That low pressure area is lifting a warm front north, pulling a warm, humid and juiced-up air mass across the Eastern Seaboard. That will set the stage for storms.

The same system is also swinging a cold front east, which will kick up locally severe thunderstorms in the storm’s warm sector. Additional storms may form along a lee trough, or a broad, diffuse strip of low pressure east of the Appalachians.

Any storms ahead of the front would have a better chance of existing as rotating supercells without immediately growing upscale into a squall line. That’s why the tornado risk may be locally greater in southern/southeast Pennsylvania toward Philadelphia or Dover and south toward D.C.

Otherwise, the primary concern will be sporadic destructive downburst gusts, since tall thunderstorms will be able to tap into fierce jet stream winds aloft. Those storms will effectively mix momentum to the surface, leading to a few isolated wet microbursts with 75 mph-or-higher gusts. It’s impossible to predict where any microbursts may occur.

The storm risk will be shunted farther south on Wednesday, with isolated severe weather along the Mid-Atlantic coastline. The main risk will be in southern Virginia near the Northern Neck or Tidewater, eventually pushing south into northeastern North Carolina.