Updated Virginia chasing summary for 2002-2011

I just finished updating the statistics for Virginia stormchasing for the period 2002-2011 and have come up with the following totals for these 10 years:

# Chases: 233

# Hail events: 15

# Wall clouds observed: 73

# Funnels observed: 27

# Tornadoes observed: 4

Now, for a couple of caveats:
(a) The total numbers for the ten different Mays are artificially lowered by the fact that May is the month I chase in Tornado Alley when possible, thus missing Virginia storms.
(b) The number of tornadoes may also be artificially lowered due to not being able to observe the near-ground environment under the funnels to determine whether the circulation actually reached the ground. I suspect that was the case for several funnels, but...

2011 Virginia chase season: DONE

And so I've declared it. After a few near misses during November's warmth I have declared this chase season to be over. It's time to tally up what I've seen this year and to possibly pen another book to cover the 2010 and 2011 seasons.

Here are two pictures that bookend this season:

28 February shelf cloud in eastern Culpeper county

13 October wall cloud in western Spotsylvania county

I'm now looking forward to some 2012 early spring chasing and possibly another expedition to Tornado Alley under the auspices of the Virginia Tech Stormchase team. I may post here occasionally before next spring but most of my weather posting until then will be over at Fredericksburg Weather. Stay tuned!!

Been tracking the potential for severe weather across the country this week. Here's the NWS Sterling Office's latest forecast discussion for Wednesday:

"PREFRONTAL TROF AND CDFNT WILL ENTER FCST AREA ON WED. ALTHOUGH BNDRY LYR XPCD TO RMN STABLE DESPITE PRESENCE IN WARM SECTOR... STEEPENING LAPSE RATES IN ASSOCIATION WITH ARRIVING POSITIVELY- TILTED UPR TROF AND CONTD FETCH OF WARM AND MOIST GULF AIR WILL PROVIDE MODEST ELEVATED INSTBY THAT MAY BE SUFFICIENT FOR TSTMS. TSTMS WERE INTRODUCED TO THE GRIDS WED AFTN AS SFC BNDRYS CROSS THE FCST AREA."

There will also be enough windshear to create the potential for rotating updrafts as well...

Visible cold front evidence

The cold front associated with the severe weather the past couple of days is shown here on the 1601Z visible satellite image. I added the blue line for emphasis, but it's pretty easy to tell where the front is by the line of convection. Myrtle Beach and Charleston SC are warm now, but their temperatures will be falling soon.

More indications of instability Wednesday

The 12Z NAM run is now showing 500-750 J/kg of CAPE for tomorrow (Wednesday) afternoon in eastern Virginia. That's not impressive until one realizes how good the shear and helicity values look, which means that we'll be looking at a classic low CAPE / high shear setup for the Mid-Atlantic tomorrow. That's obviously why the Storm Prediction Center has upgraded southeastern VA to a slight risk (15%) for severe storms, with Fredericksburg and much of the rest of the eastern portions of the state under a 5% risk.

My main concerns regarding chasing tomorrow are the potential for heavy rain (poor driving conditions) and low ceilings (poor visibility), but I can mitigate that by perusing satellite views and surface observations. If chasing conditions are marginal I won't be wandering too far afield, but if the sun pops through somewhere chaseable in eastern Virginia I will extend my range a bit beyond the normal sites. After all, I may not get another opportunity to chase for several months!

Convection this week?

Both the NWS Sterling forecast discussion and the models are hinting at possible instability Tuesday and/or Wednesday afternoon this week. The really interesting thing is that the wind shear, moisture, and helicity will be in place to almost certainly create rotating updrafts...if the instability is manifested. You can bet I'll be watching the models and forecasts over the next couple of days!

End of the 2011 Virginia storm chase season?

Maybe....and then again maybe not. The GFS model is now indicating some CAPE in central and northern Virginia for next Wednesday afternoon (11/16) as a front approaches, accompanied by negative LI's and some decent wind shear. Admittedly this is a long way out to trust any model solutions but it's worth keeping an eye on. I have stated many times that Veterans' Day usually signals the end of the chase season here, and this would be close enough to that self-proclaimed finale to qualify. More to follow as the days - and model solutions - pass.