#vawx A 7/11 chase

Oppressive heat and humidity coupled with an approaching “cold” front plus a lee trough were enough to cause the SPC to issue a Marginal Risk for my typical chase area today (and a Slight Risk further north):VA_swody1 Thursday

So just after early convection had already fired I picked up my chase partner at 1:30ish and headed south on U.S. Route 220 and turned east on VA Route 40 at Rocky Mount. We paused at Glade Hill to watch radar and await some definition. We kept an eye on billowing convection to our south and noticed a small pileus cap on this updraft near Martinsville:Pileus cap on storm near Martinsville

This was part of a line of towers that appeared to be going up along a lee trough lined up from southwest to northeast. We finally decided to get ahead of this activity and pushed east on Rte 40 to Gretna.

Pausing there we noticed the chaotic nature of the storm bases while the radar signatures weakened considerably. At the same time a cluster back west near Rocky Mount began to look very energetic, spitting out numerous lightning strikes on radar. However with its generally eastward trajectory both Smith Mountain Lake and Smith Mountain itself were between us and this storm. Thus we made the command decision to bail north on U.S. Route 29 and get into position in northern Pittsylvania county ahead of the cell.

Before we reached our vantage point we came across this raccoon lying on the side of a rural road:Raccoon on side of road

When these critters are out and about during daylight hours it’s not a good idea to mess with them and this guy acted like he wasn’t feeling good. We didn’t stop to help!

Reaching a vantage point just south of the metropolis of Hurt we pointed the chasemobile west to watch this convection approach and switched on the livestream. This, too, was now dissipating but we did see a small lowering under a new cell that built on the northern flank of the action:

After watching this for a while a stronger complex crossing I-81 just north of Roanoke caught our attention when it received a severe warning:

Plotting its movement we realized we had to scoot quickly northward to intercept. Thus we made our way back to Rte 29 and zoomed up to Yellow Branch where we turned east on VA Route 24. Passing through Rustburg we motored across U.S. Route 460 and made our way into northwestern Appomattox county.

We identified what turned out to be an awesome vantage point and parked for quite a while as we watched this complex stream by just to our north. This was our first view of a large precipitation shaft under the base:major rain shaft storm #2

As the action continued northeast we witnessed a large lowering gather under the base:large lowering under storm #2

It didn’t appear to be rotating – and a review of a time lapse video verifies that – so I didn’t call it in as a wall cloud. A bit later another lowering really snapped our attention to it:pseudofunnel storm #2

This also turned out to be a SLC (“Scary Looking Cloud”) that wasn’t rotating but it certainly looked like a wall cloud with a funnel dangling under it. This was the radar reflectivity and velocity view at the time:

The convection continued to build into a formidable line with strong outflow winds. We enjoyed the cool air rushing outward from the storms and watched as the moisture fed into the leading edge of a building shelf cloud:moisture feed storm #2

When the precipitation approached we departed and wove our way between rain shafts down to the town of Appomattox.

Overall it was a very satisfactory 7/11 chase, even without the Slurpees!

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#vawx Rotation via storm merger

Yet another local chase this afternoon afforded me the chance to check out my “livestream light” setup using my old iPhone and a mobile hotspot. Instability was abundant thanks to a very juicy air mass and an upper level impulse provided a bit of lift. However shear was almost non-existent given very light winds aloft.

An acoustic storm finally tempted me enough to saunter over to a local vantage point to check out the situation. This was the initial radar view as I set up the simple livestream equipment and switched it on:IMG_0992

A few minutes later the northern and southern convection began to merge just west of Salem:

As the merger took hold I could make out an initial hint at a rain-free base with a lowering under it at 5:10 pm (EDT):first hint at lowering about 1710 EDT

A short while later at 5;18 pm here was the radar view coupled with what I could see visually, As indicated by the yellow polygon the storm had received a severe warning by this time.

The merger produced some interesting rotation features which led to a definite wall cloud popping up over Fort Lewis Mountain shown here at 5:29 pm:wall cloud building over Ft Lewis Mtn 1729 EDT

The wind was at my back at this point meaning the storm had definite inflow characteristics. In addition I ran a time-lapse which proved the entire base – and this wall cloud – was rotating so I sent in a Spotter Network report via the RadarScope app. This feature dissipated after a couple of minutes but shortly thereafter another evolution of a wall cloud danced over the ridge line to my northwest at about the time of the accompanying radar velocity frame:

Shortly thereafter the rain approached my location just as the storm began weakening on radar so I motored home for dinner.

To verify my conclusion that I had definitely seen rotation here are the low and mid-level rotation tracks from roughly 5-6 pm (EDT):

 

Gotta watch those cell mergers!!

#vawx An operational field test of a new capability

Today – Independence Day – provided an unexpected opportunity to livestream sans my usual setup when a storm approached the southwestern side of the Roanoke valley and I  headed to a local vantage point to observe.

Other than my trusty iPhone all I brought with me was my old iPhone (SE) and my portable hot spot. Using the old phone as an iTouch I had collected time-lapses of storms but today I “test drove” it as a live streaming platform with an app I hadn’t tried yet. The short version: it worked like a champ!

After a couple of glitches I got things figured out about the time the first storm petered out. Fortunately another more energetic cell had built to the east of that one:

This new storm provided some interesting structure along with plenty of CG’s so I swung the livestream view around to watch it while I snapped photos with the iPhone:

The right frame even shows a bit of an inflow tail into the updraft.

I kept the livestream setup (old iPhone on a cheap tripod) on the hood of the chasemobile and realized that I hadn’t turned off the app’s access to the microphone. Thus the livestream actually had audio which I don’t normally provide (I do prefer SOME privacy). Overall this simple setup seems to work just fine, which means I have a backup capability in case my regular setup – laptop, cables, and webcams – decides to take a vacation in place.

Or maybe the future holds a simpler livestreaming setup…

#vawx A short but eventful early July chase

As it turned out Tuesday July 2nd provided some chasing interest and a bit of excitement for a bunch of Bedford county residents…but I’m getting ahead of myself.

True to my instincts I did not preposition myself to await convection but instead watched radar as cells moved southeast from the I-64 corridor in western Virginia. Somewhat before 3:00 pm I decided to motor east to the town of Bedford to intercept this line of storms:IMG_0908

Pausing at a local park to see what would transpire this was my view of the most vigorous cell as it loomed behind the Peaks of Otter with an annoying smaller – but sheared – updraft in the foreground:Storm approaching Peaks of Otter

To gain a better view of this end of the line I dropped south a few miles without seeing anything more clearly. Given the trajectory of the action I reversed directions, heading back north to U.S. Route 460 where I turned eastward. Reaching a rural road leading north I motored closer to the line, becoming more and more frustrated with the lack of clear views of the oncoming convection. (It’s amazing how one stupid tree can block one’s line of sight!)

Finally I stopped at one fairly open spot to observe a shelf cloud developing east of the Peaks of Otter:Shelf advancing east of the Peaks

Turning around to the north I had this view of a storm base as it approached Forest VA:storm base nearing Forest

There was plenty of lightning associated with this activity and, after I’d retreated south and east to a point along Rte 460 two separate positive CG’s crashed down near my previous location:IMG_0927

With the convection still building along the western edge of the line I chose to go south from here to check it out. I wound up on VA Route 43 south of Bedford and then turned west on VA Route 24 to get closer to the storm. This was my view from the Staunton River High School parking lot looking west:Looking west from Staunton River HS

Knowing that this was the best view I was going to get without heading further south toward Smith Mountain Lake (which I didn’t want to do) I made a command decision to core punch this storm. This was the VIL at the time of that decision:IMG_0943

I puttered westward on Rte 24, reaching Chamblissburg about the same time as the precipitation. I never reached what I’d label as heavy rain but the wind picked up considerably. Rounding a curve on the two lane highway I suddenly caught sight of emergency vehicles ahead and realized the road was blocked. I couldn’t see what the blockage was from but I assumed it was from trees across the highway.

Doing a U-turn I moved east a couple of miles and pulled off as the rain finally got heavier punctuated by some pea-sized hail. This was the VIL at the time:IMG_0949

Taking a look at the map I rerouted around the blockage via rural roads, seeing plenty of tree limbs down and tree debris on the pavement along the way. I finally reached Rte 24 just on the other side of the blockage and eventually made my way back to the barn.

#vawx It’s “whack-a-mole” chase season

We’re in the summer doldrums season now with very light upper level winds and plenty of heat and humidity. Storms will fire pretty much every afternoon somewhere along the slopes of the Blue Ridge and ooze out over the Piedmont before dissipating as nightfall approaches. This is “whack-a-mole” chase weather in which outflow-dominant storms can potentially produce strong winds and hail as updrafts collapse and send out outflow boundaries to create new updrafts.

I will be keeping an eye on radar to see what transpires but prepositioning somewhere in anticipation of convection isn’t in the cards. It’s too hot and sticky to go sit in the chasemobile and wait on popup storms! Bedford and Franklin counties will probably be the eastern limit of any chasing this week with perhaps a venture into Henry county (Martinsville vicinity) if the action warrants.

#vawx It was a serendipitous 7th anniversary of THE Derecho

On this 7th anniversary of THE Derecho of 2012 I actually sneaked in a chase. Needing to be in Pittsylvania county before lunch for family reasons I threw my chase gear into the vehicle just in case the short range models were correct. Very little shear was available due to light upper level winds but with temperatures in the 90s and dew points in the mid-60s there was plenty of instability present.

By noon updrafts were growing to the southwest so I knew my chances of seeing a storm or two were reasonable. Finished with the family responsibilities I headed south on U.S. Route 29 to check out the southern activity but was very distracted by a line of anvils to the northwest. Turning west on VA Route 40 at Gretna I rolled to Union Hall where I stopped at a rural vantage point to take stock of the situation. There was a growing updraft to the south that I was mightily tempted to follow as it took shape:

However the siren song of an impressive line of storms crossing the Appalachians was strong and the thought of intercepting them had two advantages over chasing the southern cell:

(a) The short range models – especially the HRRR – had indicated that convection pushing east over the Piedmont would rapidly weaken (which happened) and  (b) the storms moving from West Virginia into Virginia had the added benefit of allowing me to intercept them closer to home.

Thus I bade farewell to the southern stuff and motored first to Burnt Chimney for a targeting decision. Which part of the line should I intercept? A particular cell taking aim at the town of Bedford looked likely to maintain its intensity so that’s what I decided to target. I drove northeast up VA Route 122, crossing Smith Mountain Lake to continue on to a vantage point a few miles southwest of Bedford. This, indeed, proved to be a good decision as the “Tail-End Charlie” cell along that part of the line looked promising:

As the base began to cross the Blue Ridge another updraft went up ahead of it and took over as the dominant cell:

This new storm had broad rotation and even showed signs of ingesting some scud into the updraft:storm crossing Blue Ridge

Per a time lapse video that section of the base was indeed slowly rotating at the time of this photo.

However the overall complex quickly became outflow dominant with the strong winds (~30 mph at my location) and heavy rain providing a rapid cool-down. As the outflow swept across my location I snapped this photo of the radar view in the foreground with the storm in the background:radar and live view of storm

When the precipitation approached I dropped south a couple of miles to avoid possible hail and to await my opportunity to pick my way homeward.

I finally decided to head back north on Rte 122 to Bedford and then turned west on U.S. Route 460. After pushing through moderate rainfall I emerged onto mostly dry pavement just about the time I came across emergency vehicles and storm damage about 6 miles west of Bedford in the Thaxton vicinity. Several large tree limbs had snapped off and a tree had blown down across a house on the north side of the highway. I did a U-turn in order to stop and take a brief video and a couple of photos which I uploaded onto social media as a storm report, tagging both the local TV station and NWS Blacksburg.

Obviously the outflow winds had been very much stronger here than I’d experienced!

#vawx No current chasing = time to look back at past events on this date

No chasing today so I thought I’d share a previous June 27th outing. Turns out that I’ve had a number of chases on this date. Here’s a photo of a wall cloud over Danville VA from four years ago (6/27/15) looking west from a favored vantage point:wall cloud over DAN 27 Jun 15

Limited chasing chances will dominate the next few days due to personal commitments and the summertime “death ridge” settling in. Saturday and/or Sunday may be provide something but we’ll have to see.