Tuesday chasing for the Piedmont?

Quick look at one forecast model this morning piqued my interest in Tuesday afternoon / evening for chasing.  Directional wind shear in Northern VA is evident - altho' not much speed shear - so some rotation could manifest in storms that go up courtesy of a lee trough (in the "lee" or east of the Blue Ridge) over the Piedmont.  That, combined with localized effects like outflow boundaries and the proximity of the Potomac River / Chesapeake Bay, could mean some good chasing conditions Tuesday.  Any storms that do form will be slow-movers, so heavy rain can be expected wherever these cells meander.  But slow-movers mean more time to make real time chasing decisions too!

A May chase!

I had to "force" a chase today, but I was rewarded with some great views.  Starting out in Culpeper at 2:15 pm I saw that the moisture and instability parameters resulting from the backdoor front hanging over the Blue Ridge mountains formed a corridor just south of town, so I motored down to a rural spot in Madison county to await several cells that were slowly traversing eastward across the Shenandoah Valley.  While I was waiting a very noisy cell built literally half a mile north of my position, dumping copious quantities of rain and CGs but leaving me dry.  As this cell met up with the ones drifting eastward over the mountains I was rewarded with a clear view of this slowly moving wall cloud:

When the rain filled in around me I moved a bit northward to a position just off Rte 29 near the Culpeper / Madison county line as a hail marker went up on the cell approaching me from the northwest.  It had a bit of a lowering on it as well as some indicated rotation on radar:

 Following the path of this storm with my trusty laptop / aircard combination I wound through the back roads of Madison county down to Route 15, keeping just ahead of the rain shaft and stopping to photograph features like this one showing gathering scud:

Finally stopping in the town of Orange to take stock of the storm's motion I decided to core punch the main updraft that had hail indicated on radar.

Thus, I sped south on Route 15 to Gordonsville, then westward on Route 33 to find the midsection of the storm.  At Barboursville I turned south on Route 20 and finally found the heavy rain and frequent CG's of the main updraft, complete with what may have been another wall cloud but was too hard to see clearly.  I gave up on the storm just north of Charlottesville to avoid the potential traffic there.  Pretty good Virginia chase!  Now I have video to review...

In the hunt again

Last night's convection was impressive but waaaaay after I wanted / needed to go to bed.  Thus I am taking the opportunity this afternoon to watch for storms building near the Blue Ridge.  As of this point there are a few decent cells in the Shenandoah Valley, but I am determined to be patient enough to wait for things to fire east of the mountains.

Waiting....

Sitting here at home watching radar and darting outside occasionally to keep an eye on the local convective towers that are struggling to break through the cap.  According to the radar loop the backdoor cold front (or a strong Chesapeake Bay breeze) is crossing I-95 as I write this, so I'm hopeful that will let loose the hounds...errrr, stir up the convection.  Otherwise the nearest storms are over near Charlottesville and up around DC, neither of those in my desirable chasing locales.   Waiting...

UPDATE 9:30 pm:

This is the only action I've witnessed for the past 3 hours.  These cells formed over the higher terrain in West Virginia and have been slowly oozing eastward, barely making it across the Blue Ridge at this hour.  So much for the convective potential for today, which included us being in a (now-cancelled) Severe TS watch area.  How much more disappointing can this May become?  This is beginning to remind me of 2007, which was the worst Northern Virginia chase season I've experienced to date.

End of the May chase drought?

This is the SPC's forecast graphic for severe weather tomorrow, providing hope for a late day chase.  A mesoscale convective system (MCS) - an organized complex of storms - is forecast to roll from northwest to southeast across the Chesapeake Bay area late tomorrow afternoon and evening.  If that holds true some really good storms could pop on the southern edge of the complex which would put me in chasing mode!!  The forecast for Friday also holds promise for storms as a backdoor cold front sinks southward through our area.  Haven't had the opportunity to do a detailed analysis of the model data yet but I'm holding the SPC and the local NWS Sterling forecasters to their discussions!

Chaser circus

The Hokie Stormchase team learned first hand yesterday how crazy Oklahoma storm chasing can be these days.  They were part of a veritable circus of chasers out for the SPC High Risk and PDS (potentially dangerous situation) tornado watch issued for yesterday.  Hopefully the circus will spread out a bit more and the Hokies can get clearer views of the action.  (That's one of the benefits of chasing here in Northern Virginia:  not much competition.)
As for here it looks like we'll see a few scattered storms Saturday and more on Sunday, followed by several days of decent weather.  Toward Memorial Day weekend the models are leaning toward more storms, which would be good for me for chasing purposes...but nothing like yesterday's circus in OK.

Weekend storms?

There aren't any strong forecast signatures for organized convection for the next week or so.  Saturday and Sunday have some limited potential, but as of this morning's model runs the upper level support is weak to non-existent.  May is usually a good chase month here in Northern Virginia but this year has been spectacularly unproductive for me thus far, some of which can be attributed to bad luck during last week's storminess.  As a storm chaser I don't have to witness tornadoes to be satisfied, but a decent lightning display would help...
While waiting for convection to fire here I'll be chasing vicariously through the Hokie Storm Chase team which is motoring across Tennessee on I-40 at the moment to position themselves for what appears to be a fruitful chasing week in the Plains.  May they witness many rampaging supercells this spring, all in uninhabited regions of Tornado Alley.

Another frustrating lack of results

My 2010 chase season just can't seem to catch on all cylinders yet.  I was in DC for a meeting yesterday afternoon and so had to fight the Friday traffic back home while keeping a weather eye out for convective towers.  Upon arriving home just after 5:00 pm I had nothing, so I just about gave up on chasing given the time and my lack of overall energy after a long week.  Of course when I checked radar at 5:25 pm I spied a brand new cell near Culpeper which changed everything.  I grabbed my chase gear and headed up Route 17 toward Bealeton in hopes of intercepting that cell.  As I neared there however that particular storm essentially died before my eyes while the storm just to its north - over northern Fauquier county and moving ENE - was exhibiting supercell characteristics.  Even tho' I generally don't chase that far north I bent the rules and motored into rural Prince William county (against the continuous stream of traffic escaping the DC area for the weekend) in an intercept attempt.  Alas, even tho' that cell was indeed growing and looking ominous I couldn't catch it before it entered the Northern VA chaser-avoidance zone and then crossed the Potomac River.  (Please note that storm above as the cell marked "H3" with a tornado signature on it!!!)  In weary disgust I headed back into southern Fauquier county to watch the development of two more cells near Culpeper, winding up south of Morrisville along the Rappahannock River as I watched both these new storms die before my eyes.  Now REALLY disgusted I headed back home, not even seeing any lightning until after dark when a few cells passed near us.
Looking back on it I don't think I could have done anything different than I did, but that somehow doesn't ease the frustration of a missed supercell and dying storms.

UPDATE 16 May 3:11 pm:  Found the NWS tornado warning online for southern Maryland.  It was issued at 7:34 pm Friday 14 May for the storm that eluded me.  Other media reports indicate funnels were sighted near Waldorf MD.  Lots and lots of hail reports from that evening.

Slight risk for Friday

Looks like the front that pushed through here last night and cooled temperatures considerably will be grinding its way northward again in response to a eastward tracking surface low that looks to head well north of the Northern VA area.  This will result in temperatures in the 80's, more humidity, and possibly some decent boomers around here tomorrow, but the main threats would again be hail and wind since the shear is speed-related and not directional.  Not sure we'll get much widespread rain with the upper level support staying well to our north, but individual locales may get a drenching.  I won't know until mid-afternoon tomorrow whether I'll be able to chase, so I'll be making decisions on the fly...again. 
Meanwhile the Hokie Storm Chase team is delaying its scheduled Sunday (5/16) departure for Tornado Alley as things out west are quieting down for a few days.  That's probably good news for the residents of the Alley, but not so good for chasers.  Good luck to both!

Not fair!!

This just isn't fair!   Look at severe indications both north and south of the Northern VA area...and you can ignore the one marker NW of Fredericksburg as it must have been a mistake.  All I'm seeing at the moment is gray overcast and light rain....yuck!

UPDATE 6:00 pm
Looks like the MCS that coalesced earlier today has completed its push through Northern VA with no - repeat - no chaseable storms.  When I heard a hint of an MCS in last night's forecast discussion I cringed because today's lack of chasing results (gray overcast mushy stuff) is what can happen.  The southern edge of the system did fire some good looking cells that had both hail markers and rotation indicators on GRLevel3, but they were well south of I-64 and way out of my interception range today especially considering the 35+ knot forward speeds.  Oh well....the good news is that my new MiFi card worked very well, providing great signal strength even in rural Spotsylvania county.  I was able to access my usual chasing websites via both my laptop and my ITouch.  Friday???

Chasing tomorrow!

With a warm front hanging around just to the north of the Potomac River and the forecast instability (see above) it looks like I'll be "forced" to use some vacation hours to chase tomorrow afternoon.  With wind speed shear expected but little or no directional shear I'd normally expect to see some decent hail and little else, but the warm front in the vicinity provides a wild card.  I wouldn't rule out a minor spinup or two as cells approach the boundary.  My initial target will be dictated by what time I can break away from the workplace responsibilities vs. where convection is firing.  I'll likely make a last-minute real time decision on where to position the chasemobile.

Say that again???

BULLETIN - EAS ACTIVATION REQUESTED   

TORNADO WARNING  
NATIONAL WEATHER SERVICE NORMAN OK  526 PM CDT MON MAY 10 2010  
  
THE NATIONAL WEATHER SERVICE IN NORMAN HAS ISSUED A  
  
* TORNADO WARNING FOR...  
  NORTHERN CLEVELAND COUNTY IN CENTRAL OKLAHOMA...  
  SOUTHWESTERN LINCOLN COUNTY IN CENTRAL OKLAHOMA...  
  SOUTHEASTERN OKLAHOMA COUNTY IN CENTRAL OKLAHOMA...  
  NORTHERN POTTAWATOMIE COUNTY IN CENTRAL OKLAHOMA...  
  
* UNTIL 615 PM CDT  
  
* AT 527 PM CDT...NATIONAL WEATHER SERVICE RADAR 

INDICATED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING

A TORNADO OVER WESTERN NORMAN...4 MILES WEST OF DOWNTOWN

NORMAN...MOVING NORTHEAST AT 70 MPH

"Moving northeast at 70 MPH"!!!????? 

(Jaw drops to the floor...) 

Tornado outbreak in the Plains

Looks like the SPC's High Risk for today is verifying.  Check out all the radar-indicated tornadic signatures (purple triangles) shown in the above view from the Wichita KS airport high-def radar.  It's a chaser's dream day, but there are a lot of people who live in these areas as well.  Keep them in your prayers!

One that got away

Given that the cold front passed through the Northern Virginia area around 10:00 a.m. I was not expecting a chase today.  I was headed to the metropolis of Orange this morning so I couldn't have chased anything that happened east of I-95 anyway.  On my way back out of Orange around 1:20 p.m. I noticed a solitary convective tower to the east, with a well-developed anvil that made my mouth water as a potential chase target.  I knew from the low angle on the horizon that I was way out of position and would never catch up to it, but I decided to check the actual location via my new handy-dandy mobile WiFi device and my ITouch.  I was amazed to find out that this solitary storm was already over the Eastern Shore - see above graphic at roughly the correct time - and steaming toward Chincoteague!  By my rough calculation (via Google maps) I was drooling over a storm that was 140 miles from me!!!!  Wow!  That kind of visibility may be common in the flat rural areas of Tornado Alley but I'm not accustomed to such vistas here in the Mid-Atlantic!!

Not Friday, but maybe Saturday afternoon

Doesn't look like Friday will be productive as of my latest perusal of the forecast models, but early Saturday afternoon may hold some promise.  The solutions seem to be slowing down the frontal passage just a bit, sliding it through the I-95 corridor about lunchtime or a bit after.  If I can manage to be east of the interstate by 2 pm or so I may squeeze in a chase Saturday.  We'll see what transpires convection-wise and how well I can match up my schedule with any good-looking cells (fingers crossed).

GFS model leaning toward Friday chasing

The NWS Sterling forecast for our area has a slight chance of storms Friday afternoon with better chances Friday night and Saturday.  The GFS seems to want to speed up the oncoming system and associated cold front, pushing the front through here early Saturday morning but creating some decent chase parameters for late Friday afternoon and evening (see graphic above for instability).   These parameters include both speed and directional shear plus dewpoints in the upper 60's.  If we can just convince the well-known "lee trough" to form east of the mountains on Friday afternoon that would provide a convective trigger to fire off storms ahead of the cold front itself.  The countdown is underway.

CG from Apr 26 chase

Just for the heck of it I'm posting this enhanced video frame capture of a CG strike (right side) and lowered base (left side) on the storm I was watching from a perch just north of the Rappahannock River in King George county.  The storm itself was over Caroline county. 
I suppose this is in reaction to frustration at not having any storms to chase today while knowing that I very likely won't be able to chase tomorrow or Monday.  (sigh....)

AccuWeather.com - WeatherMatrix | East Coast Storm Chasing, My Best Photos

Amen, Jesse. East Coast chasing is challenging but rewarding as long as the chaser doesn't expect to see a lot of tornadoes. I do get a kick out of being on a storm when it goes severe on a day that neither the SPC nor the local weather forecast office expects severe weather. Oh, and I've never experienced "chaser convergence" on a storm here in Virginia...!!

AccuWeather.com - WeatherMatrix | East Coast Storm Chasing, My Best Photos

Cold front is slowing down...

The models are showing the approaching cold front slowing down, moving the severe weather threat to later Sunday into Monday afternoon.  The local models from Sterling WFO show a zero chance of thunderstorms this afternoon anywhere in Northern VA, so - altho' I'll be checking radar - it looks like today is a no-go for chasing and I'm not available for chasing tomorrow or (probably) Monday.  The good news for chasers is that the pattern seems to be heating up overall, with today's SPC convective outlook showing a Moderate Risk area for the second day in a row (see above).  The Hokie Stormchase team is gearing up for its annual trip to Tornado Alley, so their chances of seeing some good storms are improving.

EDIT:  11:40 a.m. SPC has posted a High Risk for portions of Arkansas, Mississippi, and Tennessee.  Watch out for more long track severe tornadoes in these areas!