The energy that moved through the Midwest over the weekend is on its way east - and we're going to be dealing with the threat of severe weather for much of the week.
Dewpoints are already in the 60's through Virginia this morning, and temperatures quickly rising into the 80's for the afternoon. With two of the three storm ingredients accounted for, we wait for our trigger. Our uplift will come from some upper level energy moving through the Ohio Valley, in addition to orographic lift. That's what will make storms more widespread today - the two triggers we have.
Damaging wind gusts in excess of 60 mph and hail great than 1" in diameter are possible with Monday's storms. In addition there is the slight possibility that a tornado will form. Based on sounding (Skew-T) data, we're looking at the possibility of multi-cell and supercell storm formation this afternoon. This data was extrapolated for SHD.
Multi-cell formation can be in a cluster or a line - though based on today's guidance I'm leaning more towards a line of multi-cell storms (also known simply as a squall line). It's a great number of closely spaced updrafts and downdrafts that are in a north/south orientation and sometimes have a bow shape to them. Downbursts and large hail are most common with squall lines, as well as the threat for flash flooding.
Supercell formation is possible Monday as well. The key difference between a supercell and any other thunderstorm cell is that rotation is present among supercells. Not all supercells produce tornadoes, but almost all strong tornadoes come out of supercells.
They're not very common in Virginia, though they seem to be less uncommon this year. The last time supercell percentages were this high (or actually a little greater) was during the April 27/28 outbreak of tornadoes - also known as the most tornadic day in history.
Please have your severe weather plans in place at work, school, and home. Remember there are no sirens throughout the Shenandoah Valley. We will keep you up to date on air, online, and on your mobile phone (should you receive text alerts). If you are not signed up for text alerts, sign up now - the link is on the WHSV TV3 Daybreak facebook page! If you have a NOAA weather radio, make sure it's ready for this week.