It finally happened! Another May chase! That’s says a lot given the unfavorable pattern for decent weather here in Virginia this spring.

I knew two things about Sunday’s setup: (1) A back door cold front would be slipping south and west across the state and (2) an upper level disturbance would top a weak ridge and cross the Appalachians to meet the wedge front near the U.S. Route 220 corridor in southern VA. The dynamics weren’t ballistic enough for the SPC to take note of (but I was ready!):VA_swody1

The main question – as usual – was when and where to target initially. Short range convective allowing models (CAMs) all generally agreed that storms would fire and head eastward over the mountains of West Virginia early Sunday afternoon. Then near Roanoke said convection would top the atmospheric ridge and pivot toward the south and southeast. My first inclination was to motor to the Martinsville area along the U.S. Route 58 corridor to await the action as it slid southward. I wanted a clear view of the storms as they interacted with the shear along the front.

However the CAMs differed on just how widespread the convection would be. Given the forecast late timing (near 7:00 pm) of the storms’ arrival near Martinsville I didn’t want to miss any earlier activity. Thus my solution was to watch satellite (for the front’s progress) and radar (for the storms’ progress) to decide where to go when. This mesoscale discussion also helped make up my mind:mcd0703

With storms advancing eastward toward the I-81 corridor my initial target became Wirtz to intercept cells after they crossed the Blue Ridge. I left home just after 3:00 pm and rolled down Rte 220 with a storm crossing the southern end of the Roanoke valley toward that very spot. When I stopped at a favored vantage point this was the radar depiction along with my view to the northwest:

After a few minutes went by and this southern cell basically sat still without intensifying (later I realized this was forming along the front itself) I became a bit impatient and decided to head further northeast to catch more robust action which would cross the Blue Ridge into Bedford county. So I pulled up stakes and drove northeast up VA Route 122 past Smith Mountain Lake.

At another favorite vantage point a few miles south of the town of Bedford I had this view of a lowering under the cloud base to my west:lowering under cloud base

However several things disturbed me at this point. First, the surface winds were out of the east. Second, the cloud bases overhead my position didn’t look very crisp. And third, this was the radar view after I’d been there a few minutes:IMG_2629

I realized that I had ventured into the wedge itself and the convection crossing the Blue Ridge and heading in my direction was weakening. Meanwhile the southwestern edge of the line over Roanoke was maintaining its intensity as it crept south. So I jumped back in the chasemobile and dutifully retraced my route southwestward down Rte 122 toward the area I’d abandoned earlier.

After a circuitous route on some rural roads in a vain attempt to out-maneuver the heaviest precipitation I would up on a hilltop in a residential area in Rocky Mount. In addition to a deluge of rain I was treated to a spectacular lightning barrage all around. I was apparently parked right underneath the front with cells merging and intensifying overhead. Here’s the reflectivity and velocity radar view that convinced me I was very near the front itself:

After the rain intensity slacked a bit I decided to call it a chase and head back toward the barn. Flash flood warnings had been posted for the area I was in with more warnings soon posted further south toward Martinsville. (In fact a Flash Flood Emergency was issued for that area.) If I’d decided to target further south per my initial thoughts I would have had to deal with heavy rain  and possibly flooded roads all the way home.

It wasn’t a great chase by May standards but I’ll take it this spring!