Monday, October 27, 2014

Four year anniversary of a fruitful late October chase

Four years ago today a strong cold front triggered severe storms across the Mid-Atlantic that resulted in the SPC issuing this probabilistic outlook graphic:
This, in turn, led to the following storm reports from that day:

Having followed the progress of this system across the country with its accompanying eastward march of severe weather I was primed to chase. With my chase gear in the vehicle I attended a meeting in southern Maryland that day, departing (fortunately) just as severe weather warnings were first posted for the region. Following a quick stop at a WiFi spot to check radar - not having mobile WiFi at that time - I rolled westward along VA Route 3 toward Fredericksburg.

Spying this approaching storm I stopped to observe and photograph the obviously rotating cell:
Zooming in to the area circled in red I saw this funnel:

I stayed east of this storm for a while as it cycled down and then back up but never witnessed another funnel. It was a very productive chase as the season was reaching its conclusion that year!

Wednesday, October 22, 2014

"See Text" goes away today

Today the Storm Prediction Center shifted to its new five tiered convective outlook system. In doing so the fabled "See Text" category has disappeared. Thus I felt it my civic duty to share photos of a couple of Virginia storms that I've intercepted underneath this now-departed regime.

First there was this storm on June 24 2006:
I was heading west through rural Stafford county after looking at an earlier cell in King George county. I spied this feature through the treeline to my left and quickly whipped onto a southward route where I found a spot to pull off and snap this photo.

Then came this little gem on May 28 2009:
This was looking west across the Rappahannock River valley from a favorite viewing spot next to a quarry. I had been watching and filming a cell east of me before turning around to look at the next storm to the west. This wallcloud and funnel surprised both me and the met. at NWS Sterling when I called in a report. The circulation was apparently below their radar horizon (~60 miles straight line) but rotation was obvious in the video I took.

Farewell "See Text"!!

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.