Tuesday, October 14, 2014

A not-so-successful day

After checking radar this morning and taking a quick peek at the short term models I voted to go all in for chasing today...and bag tomorrow morning. It looked to me that the main line was going to come thru a couple hours earlier than I'd originally thought so a Wednesday morning chase was not going to be viable.

Meanwhile a convective line fired out ahead of everything else, setting up between the U.S. Rte 29 and 501 corridors early this morning. Thus I rolled out of the driveway at 9 a.m. and headed toward Chatham VA where I reevaluated the situation. Noting that a line segment was steaming quickly northward from the Milton NC area I scooted east from Chatham on Rte 57. I watched the southern end go by but didn't see anything of real interest.

I continued east to Halifax and then to South Boston to intercept two more line segments moving northward into an area of >500 (j/kg) CAPE and 25+ knot low level shear. Wandering around the countryside west of South Boston I watched both segments stream by while dodging the heaviest rain and hearing a couple of peals of thunder. Here's a photo looking south at the end of the last segment:
The only feature of real interest came at the southern end of this final segment which showed a ragged lowering - not impressive enough to label a wallcloud - that corresponded to a couple of adjacent red/green pixels on the radar velocity scan. (I didn't get a photo of the feature.) That phase of the chase concluded about 2 p.m.

With no other convection to the south I took a break and rolled westward to Danville where I chilled for a while to await what I expected would be more action during the late afternoon. Unfortunately by 5 p.m. the radar was still empty of activity well upstream of my location so I called it a chase as I realized that the rest of the convection would occur after dark.

Not a great chase but not a bust either. Hey, it's October!!

Monday, October 13, 2014

Might have to head out at oh-dark-thirty Wednesday

The oncoming deep diving trough and associated weather system is still slowing down thanks to an increasing negative tilt and a few other factors (blocking ridge off the coast, etc). I plan to monitor short term models and radar Tuesday afternoon for any cells popping up ahead of the system and might just preposition east of the mountains for the late afternoon.

Meanwhile Wednesday morning looks like a painfully early rise time in order to get ahead of the action. Here's today's 18Z 4km NAM radar representation for 12Z (8 am) Wednesday:
This squall line is actually 60-70 miles west of where this morning's model run had it located at 8 am Wednesday. Even so to get set up ahead of it will mean me leaving home by 0630 and heading for (probably) Danville. If it is delayed this much I may have a chance at seeing something over the Piedmont during the late morning or early afternoon. 

Keeping my fingers crossed for a chaseable setup!!

Sunday, October 12, 2014

Late Tuesday and early Wednesday?

The mighty Euro model has arm-wrestled the GFS into agreeing with slowing down the eastward progression of the long wave trough. That may mean convection won't happen until very late Tuesday, perhaps after dark. The flip side is that there may be chaseable storms Wednesday morning / early afternoon over the Piedmont.

Regardless here's a SPC SREF graphic showing the supercell composite parameter (probability >1.0) for 21Z Tuesday.
We'll see how the models look tomorrow.

Saturday, October 11, 2014

Tuesday looking incredible

Granted this is only one run of the NAM, and granted the GFS isn't quite this spectacular, but even if the parameters shown above are only half right Tuesday could be a very interesting day. And the GFS has been consistently showing this kind of setup for several days now.

Concerns about chasing Tuesday: Lack of storm visibility due to overcast, blazingly fast storm speeds, and the probability of a squall line. If any cells go up east of the probable squall line I need to be on them quickly.

Keeping a very close eye on it.

Wednesday, October 08, 2014

Another October tease?

Yesterday and last evening Kentucky and West Virginia were belted by discrete severe storms with potential tornadoes. Here in Virginia the best activity happened after dark so chasing wasn't on the menu (altho' I did mosey to the local park in late afternoon to spy anything interesting...there wasn't.)

The past few runs of the GFS have been teasing another potential Virginia chase day this coming Tuesday (10/14). This morning's 12Z run provided this MUCAPE and bulk shear outlook:
CAPE values are generally <500 but shear values are off the charts as yet another long wave trough digs through the region. IF anything discrete can go up Tuesday this could be a decent chase opportunity but I'm guessing a low-topped squall line is most likely in this HSLC (high shear / low CAPE) setup.

I'm not holding my breath but I'm not ignoring the setup either. One more chase this fall?