The blogpost title says it all. I was unsure about today’s setup given differing model solutions and I discovered that I wasn’t alone. The local NWS office hedged their bets in the forecast discussion text and the Storm Prediction Center continually downgraded the severe threat from a Slight Risk in yesterday’s Day 2 outlook to a Marginal Risk in this morning’s Day 1 to just general thunderstorms in the afternoon Day 1 update.
Outflow from a short wave crossing the Appalachians did kick up a line of storms across West VA which continued into Virginia. After deciding to leave home around 1 pm after I saw the “whites of their eyes” (radar returns) I headed for Burnt Chimney in Franklin County. Strong cells were coming across the Blue Ridge both toward the U.S. Rte 460 corridor and toward the VA Rte 40 corridor so I figured an initial target of Burnt Chimney would hedge my bets.
My main concern when I stopped to review conditions was that the SPC mesoanalysis page showed a persistent 10 degrees C isotherm over the area at 700 mb. That represents a pretty stout cap for these parts and it didn’t seem to be either cooling or advecting away. Nevertheless I chose to target the southern portion of the area when a discrete cell went up ahead of the line near the Wirtz/Boones Mill area. (Did I mention that visibility was rather poor due to the haze from the high dew point values?)
When the rain approached I drove south on U.S. Route 220 and then turned east on Rte 40, stopping near Glade Hill to watch for a while. I could hear thunder grumbling to my north as this cell merged with the line. When the rain again approached I moved south from Glade Hill and then east again, leapfrogging from one vantage point to another to keep dry.
At the intersection of Sago and Museville Roads in western Pittsylvania county I had this view to the west of the approaching shelf cloud: This feature stretched almost 180 degrees along the horizon and after a brief stop here I relocated once again to a spot just west of Callands where I snapped a photo of this section of the line with some incipient greenage showing:
Reaching VA Route 57 at Callands I dropped southwest to a vantage point where I finally decided to conduct a “static core punch” instead of continuing to leapfrog ahead of the line. The cap’s influence was being felt as none of the cells looked to be intensifying either visually or on radar. Radar VIL values didn’t indicate any hail and the velocity data didn’t show any particularly strong winds so I pointed the chasemobile’s nose at the oncoming shelf cloud and waited.
Having made that decision I continued photographing the line’s approach:
Just before the rain began in earnest I had a good view of the “whale’s mouth” under the shelf cloud itself:
I let the rain do its thing for a few minutes before pulling up stakes and motoring back north to Callands. I wound up taking the Museville Road back and then rolling along via another county route to Snowville Road which led northward to Penhook. Along the way I came across this vista of a foggy post-rainfall Smith Mountain:
All in all it was a pretty benign chase, one in which I really didn’t have high expectations due to the uncertainties. Now the question is what will happen tomorrow as a strong short wave / vorticity lobe drops into the Mid-Atlantic? Will we really see enough severe threat to warrant the current Day 2 Slight Risk?
I’m not going to lose any sleep dithering about it.