#vawx A tropical remnant chase to start September?

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With the Atlantic tropical basin coming alive there’s hope for a storm chase of tropical remnants here in the Old Dominion. At the moment Fiona and Gaston both look like they’ll steer clear of the U.S. mainland. However the third system – to be Hermine if it develops – may be a factor.

Here’s the current 7 day WPC forecast map.9nhwbg_conus

“Hermine” is the low pressure just off the west coast of Florida. The orange arrow I’ve added shows the 10 day Euro model forecast of its track. IF this path is correct (too far ahead to bet on) the southeastern states could be very wet and windy as September begins.

However this track doesn’t bode well for chasing convective activity here in Virginia. But if the storm’s path shifts and pushes northward along or just west of the Appalachians the beginning of meteorological autumn (Sept 1st) may provide an interesting chase opportunity.

We’ll see.

 

#vawx A welcome cold front with more shelf cloud action

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Although a strong cold front promised relief from the Mid-Atlantic heat and humidity it didn’t bring much shear with it. Thus today’s chase was yet another “shelfie-fest”with a squall line providing the outflow.

Heading out just after 1 pm today I rolled to Rocky Mount to refuel the chasemobile and choose whether to continue south on U.S. 220 or go east on VA Route 40. After reviewing radar I chose the latter as a squall line was taking on the typical southwest – northeast orientation associated with a cold front passage. This time tho’ I didn’t stop in Glade Hill but maneuvered south and west from there to a Franklin county hilltop.shelf from Franklin county vantage

When the shelf cloud began to fill the western horizon I continued east and south along more rural roads into Pittsylvania county. At this point the shelf was very close so I didn’t stick around long to watch:

As I pushed further east I stopped intermittently for short periods to observe the shelf at close hand with rain nipping at my heels:Right behind me

I wound up heading south on Virginia Route 41 toward Danville and then diverting east to U.S. 29 near Blairs. At this point the leading edge of the northern section of the line was east of Rte 29 while the southern section was dissipating. I did drop all the way south to U.S. 58 in Danville where I paused to grab a snack and evaluate the situation.

With little hope of anything more interesting to see (retreating in front of shelf clouds gets old after a couple hours) I called off the chase and headed home. It was an enjoyable and relaxing chase but I’m itching for something more. Unfortunately without tropical help this time of year doesn’t hold much more potential.

#vawx A shelf-y chase with a hint of mesocyclone

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Although conditions were similar to recent chases (lots of CAPE, little shear) today had some extra impetus in the form of a short wave crossing the mountains. With storms going up along the ridgelines to the south I motored down the driveway at 1:30 for Rocky Mount. Intending to stop there to evaluate things I instead turned east on VA Route 40.

At Glade Hill I rolled south and then east along rural routes to a hilltop vantage point for a peek at the convection. After switching on the live feed and watching for a while I realized the activity wasn’t pushing east as fast as I’d originally thought so I moved back west and then north to the Glade Hill vicinity. There one cell showed symptoms of a mesocyclone and accompanying wall cloud:

As this feature progressed northward I ventured in the same direction for a bit until it became obvious that (a) the rain was cutting off my forward path and (b) convection to the south was strengthening (it had become severe-warned). Thus I bailed on the northern complex and reversed direction, speeding south to Rte 40 and turning east.

I dithered some on how far east to travel before finally jumping onto the Museville Road and heading south. Just before reaching Callands I found a spot to pause and watch for several minutes as an impressive shelf cloud approached, grumbling with copious amounts of thunder:shelf cloud approaching Callands

When this leading edge neared the radar view suggested that I needed to vacate the premises or face possibly serious consequences:

Thus I finished the journey to Callands where I diverted east on VA Route 57. Finding a spot to – briefly – stop near Rondo I had this view of the shelf coming right at me over a tobacco patch:shelf cloud near Rondo

Instead of continuing to race in front of the line I chose to scoot south just in front of it all the way to VA Route 41. In doing so the leading edge of the shelf overtook me so I stopped to snap a couple of photos from inside the “whale’s mouth”:Whales mouth Pittsylvania county

I wound up going thru Dry Fork and stopping near U.S. Route 29 just north of White Oak Mountain. As the original storm faded and another one built on the outflow the resulting lightning output was fierce, close, and rapid enough that I kept my hands away from anything metal in the chasemobile. At one point the local TV station lost my live feed, due – I think – to a nearby cell tower being affected by the electrical discharges.

From here I ducked south on 29 over the mountain to scout out what features might be of interest for the 5 0’clock TV weather block. Once that block was over I called it a chase as the leading edge (and accompanying shelf cloud) was east of me and moving away.

A decent August chase if I do say so myself!

#vawx Not a bust, but a chase without a decent photo to show for it

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More “whack-a-mole” storms today. High CAPE (instability), no cap, and little shear allowed storms to go up early and rapidly and fall apart just as fast. The huge amount of water vapor in the air provides potential for flash flooding and that’s exactly what downtown Roanoke experienced today.

For several reasons I wasn’t prepared to chase early this afternoon but when thunder rattled the house I scrambled around gathering up gear. I headed down the driveway around 1:30 or so, barely ahead of the rain. Rolling north and then east I emerged onto U.S. Route 460 as heavy drops began to smack the windshield.

I desperately sought an open vantage point east of the highway in the Webster area but never found a clear sightline. Thus I repointed the chasemobile east on 460 and sped ahead of the action. After a couple of unsuccessful detours onto side roads to find an adequate view of the advancing complex I continued to Bedford and turned south on VA Route 122.

By this time a discrete cell on the eastern edge of the original action had gone severe-warned and looked like this on radar:IMG_5348Of course at this time I was also stuck in road construction, the bane of stormchasers everywhere. Finally extricating myself from the entangled mess I maneuvered via rural Bedford county roads to find a spot to watch the storm.

And by the time I did the radar view had degenerated into this diffuse blob:IMG_5349Note the second view is only 15 minutes after the first one, reemphasizing the need for wind shear to allow a storm to maintain its updraft. “What goes up must come down…quickly” in a low shear environment.

The leftover anvil from the original convection overspread the entire area and suppressed all potential activity for several hours. I called it quits and rolled home early. I did snap a few photos and even had the live feed up for a bit but none of the photos is even worth posting.

Maybe later this week we’ll have some shear from a weak front that is supposed to sag into Virginia and dissipate. Until then it’ll be “whack-a-mole” chasing at its finest.

 

#vawx 0 for August is not a good batting average

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So now it’s the second weekend of August and I have yet to chase any storms this month. To be fair I did pass up a couple of chances last week due to other considerations but being 0-for-August so far is a bit depressing.

Atlantic basin tropical activity has been relegated to the tremendous unnamed rain maker over the Gulf States (especially poor Louisiana) so there’s no convective hope from that quarter anytime soon. And the Bermuda High has rooted itself firmly in place this weekend sending dewpoints, temperatures, and heat indices soaring along the Atlantic seaboard. Altho’ CAPE – instability – is abundant updrafts are having a tough time climbing very high east of the mountains. The cap is pretty stout this afternoon with 700 mb temps over 12º (C) across the Piedmont:

rapNE_700_temp_006

The Bermuda High is forecast to drift further east early next week, allowing a trough to approach the Old Dominion. The forecast 700 mb temps for Monday afternoon look a bit cooler and thus more conducive to taller updrafts (and thus stronger storms).

NAMMA_700_temp_057

So perhaps there will be an opportunity for a chase or two next week. Bulk shear still doesn’t look robust but in these summer doldrums I’ll take what I can get!

#vawx A literal bolt from the blue example

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Lightning has always been a serious threat, thus the National Weather Service came up with the slogan “When Thunder Roars Go Indoors”. Their website on lightning safety has a tremendous amount of valuable information to absorb. This is one statement from that site :

“‘Bolts from the blue’ can strike 10-15 miles from the thunderstorm.”

On July 12th I witnessed just such a bolt. At the end of the day’s chase I wound up on a storm in Pittsylvania county, approaching from the north.early view of svr storm updraft

Just as I rolled to a stop at this vantage point a CG (cloud-to-ground) struck a couple of miles from me. The base of the storm was still 9-10 miles away at the time! The bolt came out of the anvil and snaked all the way to the ground.

So lightning is something to be wary of in any thunderstorm, even if it’s not raining where you are.

#vawx A chasing drought doesn’t equate to an overall drought

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I haven’t chased in a week and it’s not because there haven’t been any storms. Instead when there have been storms worth chasing I’ve had other commitments, and when I’ve had time to chase the storms have been heavy rainers that I didn’t feel like going after. In fact this summer has been rather wet compared to normal.

The chasing drought can be laid at the feet of the jet stream’s northward retreat. Upper level winds over Virginia are very weak in early August meaning little or no available shear. Convection thus becomes a case of “what goes up must come down” as the vertical rain shaft cancels out the updraft. While that can create some pretty unique outflow boundaries and cool shelf clouds it also makes chasing a “dodge ’em” activity. Chasing (or being chased by) squall lines and multicell complexes becomes tiresome and a bit humdrum after a while, especially when every severe thunderstorm warning contains the phrase “60 mph wind gusts” and nothing else.

From now through early fall what little hope arises for longer lasting discrete storms typically comes from tropical remnants. The lower atmosphere helicity (spin) these systems bring with them have contributed to some exciting chases in past years. Thus I have my eye on the tropics and am paying as much attention to National Hurricane Center forecasts as I am Storm Prediction Center outlooks. So far there’s little on the horizon to generate hope but one never knows.

Of course as the jet stream begins to sag southward again I’ll also be watching troughs as they approach the Mid-Atlantic. A strong cold front with some decent wind shear thrown in can still work chasing wonders this time of year. I’ve been known to chase all the way up to Veterans Day given the right setup.

#vawx Another garden variety storm chase

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Even tho’ the last day of a very hot July only held promise of garden variety (i.e. “build and collapse”) storms I headed out anyway. I picked up my chase partner at 2:30, having moved up that rendezvous an hour given that convection started earlier than anticipated. With updrafts already going up east of the Blue Ridge we rolled south on U.S. Route 220 to Rocky Mount.

Pausing there we decided to move east on VA Route 40 to get ahead of a nascent line that was mostly visible via the Mark 1 eyeball vs. radar echoes. During a stop near Glade Hill to sort things out I gave in to the temptation to dive south in order to intercept a decent-looking complex near Martinsville. Thus we drove over to U.S. Route 29 and rolled south to Danville.

The original cell was slowly but surely sagging south of the state line so we dropped down to the North Carolina welcome center to check it out. All the while we kept an eye on a developing line out ahead of “our” storm that was just north of Danville. After the first storm weakened we pushed back into Virginia and then east on U.S. Route 58. The developing convective line was just north of the highway and gusted out into a shelf cloud as we watched.Storm N of Rte 58

When this line also sagged south we dropped into North Carolina once again, pausing for a good while along a rural lane less than a mile south of the state line to observe.

At this point we decided to break away from this activity and let it continue south and east. Meanwhile more convection was crossing the Blue Ridge near Roanoke so we retraced our path back to Route 29 and scurried north to Altavista. There we diverted northwest on VA Route 43 to check out the action as it crossed Bedford county.Storm over Bedford county
Updrafts in this new convection persisted in developing lowerings under rain-free bases and we kept up with it as best we could. Driving east on VA Route 24 back to the Rte 29 corridor we eventually rolled thru Rustburg and continued east via rural roads. We were thus able to keep an eye on the activity that was now encroaching on U.S. Route 460 a few miles north of us.

We saw a few more lowerings including one that may have been a brief wall cloud before calling off the chase due to approaching twilight. After a late dinner in Lynchburg we motored home after dark, pleased with making a decent chase out of not much to work with.

#vawx A screen grab of the 7/27 Danville wall cloud

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In my post about Wednesday’s (7/27) chase I mentioned a wall cloud on a cell over Danville that I didn’t get a still photo of. Here’s a screen grab from the live stream camera:27Jul16 wallcloud over DANThis is heading east on U.S. Route 58 just before taking the expressway exit south (overhead highway signs ahead).

For reference here’s the radar velocity view at about the same time (I stopped on the conveniently wide shoulder of the exit ramp to check it out):IMG_5278

Now all I need to do is figure out why the live stream data rate was so low that day. A review of the video clips show them to be very jumpy and erratic as the outgoing data rate was less than half of what it should have been…even on Rte 58 with an abundance of cell signal.

#vawx Another plethora of storms

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Given plenty of CAPE but little shear I figured today would entail slow moving heavy rainers/hailers and I wasn’t disappointed. I was, however, pleased to see several cells develop initial wall clouds before gusting out.

I left home just after 1 pm to get east of the mountains before convection got too serious. Of course a severe warned storm caused wind damage in Salem shortly after I’d left the Roanoke valley. Parking briefly at Glade Hill to evaluate I decided to intercept that same complex at Burnt Chimney after it crossed the Blue Ridge mountains.

As I traveled north and then turned east toward Burnt Chimney I caught a glimpse of the cloud base dipping down. When I finally had a clear view there was a genuine wall cloud wrapping up west of the town.wall cloud over Burnt Chimney

I live streamed from this location until the wall cloud approached within a mile and then I dove back south and east to stay ahead of it. I caught glimpses of the feature by stopping a few times but within several minutes this cell began gusting out into a shelf cloud.

Reaching VA Route 40 at Glade Hill (again) I motored east to Penhook, staying just south of the precipitation as the storm edged eastward. I turned south on rural roads,  drove through Museville, and pushed east into Pittsylvania county where I found an open vantage point next to a corn field. From here I watched the leading edge slowly push by, shedding CG’s (cloud-to-ground lightning bolts) and heavy rain not far north of me.IMG_5258

Complex along Rte 40

Turning to the west I watched from the same vantage point as another lowering / wall cloud briefly wrapped up.Lowering W of Museville

When the rain approached and more storms fired southwest of this action I pulled up stakes and rolled to Callands. Upon perusing radar and maps I turned south on VA Route 57, driving through some heavy rain under rapidly developing cells. Taking another rural route south toward Axton I wound up at a favorite viewing spot to see this shelf with leading edge lowerings approaching from the west.leading edge lowerings from Axton areaI was able to stick here for 10 minutes or so before I concluded that I was in the wrong place at the wrong time. This activity approaching from the west was about to meet up with a strong storm moving north and I was in the “merge zone”.IMG_5265

After first verifying with the local TV channel that they weren’t using the live feed on the air I hopped back in the chasemobile and turned south again. After I cleared the merge area I stopped to watch and photograph this southern cell as it moved toward me with a lowering under both the southern and northern edges. The updraft appeared to be splitting but it never got that far (not enough shear to support it).Cell S of Martinsville

After sitting there a few minutes the imminent cell merger between this storm and the western convection became visually apparent just west of me.Imminent cell merger E of Martinsville

Pushing south to U.S. Route 58 I pointed the chasemobile east and motored toward Danville to miss the growing hail core under this southern updraft. However as I rolled along more storms went up east of me and one developed a nice wall cloud in front of me.IMG_5278(I didn’t get a still photo since I was driving but I may be able to pull a frame from the dashcam video.)

I wandered around the Danville vicinity for a while, even briefly dropping into North Carolina to try for a view of some rapidly growing storms approaching Yanceyville. I did see a lot of CG’s but finally gave up and called off the chase to avoid getting sucked further south into what I consider no-mans-land for chasing.

It was a good chase!

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