If you live in or around any of the counties shaded in blue on this map, odds are that your commute’s gonna suck as you head home this evening. Severe thunderstorms are firing up all over the place, and these counties are all under a severe thunderstorm watch through nightfall. Damaging winds, large hail, and some tornadoes are possible in these storms.
A severe thunderstorm watch means that conditions are favorable for the development of severe thunderstorms, and you should watch for storms developing nearby. A severe thunderstorm warning is issued when damaging winds in excess of 60 MPH and/or quarter-size hail or larger are imminent within the next couple of minutes. The same goes for tornado watches and warnings.
Heat and humidity at the surface are leading to an unstable atmosphere this afternoon, and when you combine this instability with adequate wind shear and some small upper-level disturbances swinging through the region, we have a setup for a widespread severe weather day everywhere from Florida to New York.
We’ve already seen one supercell with a hook echo threaten the northwestern suburbs of Philadelphia, and severe thunderstorms are creeping through New Jersey and probably toward the New York City metro area between 5:00 PM and 6:00 PM. Storms are a little more isolated down near Washington D.C. and Baltimore, but they’re just getting going across this region. It takes a little bit of bright sunshine to cause pile-up wrecks on the Beltway, so you know how it goes. The story is the same down near Raleigh, Greensboro, and Charlotte.
Keep delays, traffic jams, and the threat of the weather itself in mind as you get ready to leave the office and head home over the next couple of hours. Please do not park under an overpass, even if it’s hailing or if you’re under a tornado warning.