According to the National Weather Service’s Storm Prediction Center (SPC), there’s an elevated threat of tornadic thunderstorms across portions of the lower Great Lakes and Mid Atlantic.  Near the Great Lakes, northern Illinois, Indiana, Ohio, and western Pennsylvania is at risk of tornadic thunderstorms. In the Mid Atlantic, there’s an elevated risk over portions of central and southern New Jersey, eastern Pennsylvania , northern Delaware, and northeastern Maryland. The Philadelphia, Baltimore, Chicago,  and Washington DC metro areas are included in these elevated risk zones.

Thunderstorms with severe wind gusts will be possible this afternoon and evening from northern Illinois eastward into Pennsylvania. Severe gusts and hail will also be possible from parts of the central and northern Plains into the Midwest. While not everyone will see a thunderstorm in these areas, those that do may encounter severe thunderstorms capable of destructive wind gusts, large damaging hail, and isolated tornadoes.

Water-vapor imagery from the GOES-East weather satellite implies a belt of west-northwest mid to high-level flow extending across the northern High Plains east through much of the Midwest, and to the north of a flattened mid-level ridge extending from the Four Corners to Florida. According to the SPC, embedded within the flow, a convectively augmented disturbance over the southern Great Lakes will move east into Pennsylvania by early this afternoon.  This will help set the stage for severe weather later today.

Right now, the radar mosaic shows an organized line segment moving east along the Ohio-Lake Erie shoreline and a couple of other thunderstorm clusters over western Ohio and south-central Pennsylvania.  Gradual intensification of storms is expected this morning as the boundary layer heats downstream across Ohio into Pennsylvania and the Mid-Atlantic states.

Mid-air observations show a  moderate to very unstable airmass  in place over the upper Ohio Valley. The SPC says that severe gusts capable of scattered wind damage will be possible through the afternoon with any stronger

“Shear/buoyancy profiles will support organized storms, including supercells and linear clusters,” says the SPC in their latest convective outlook. Damaging wind and hail will be the primary hazards, though a tornado or two also could occur.