Monday, October 07, 2013

Early frontal passage negated chasing today

Over the weekend I was dismayed to watch as each successive model run pointed toward an earlier time for today's cold front passage through Virginia.  The low CAPE / high shear regime looked enticing but the timing progressively got worse.  Sure enough when I awoke this morning the heavens had opened up with storms reaching our location before dawn.  That wasn't the worst part, though, as before 9:00 a.m. the Blacksburg NWS office fired off a severe thunderstorm warning for what would have been my initial target area:

To further rub salt into the wound the next cell south of this one generated enough low level rotation that a tornado warning was issued as the storm aimed directly at the city of Danville.  I would have had to roll down the driveway before daylight to even get close to intercepting these cells. That in itself would have meant driving through heavy downpours in a tail chase in an attempt to punch through and get ahead of the line.  A further complication was that highways all over the region were littered with traffic accidents as a result of the wet roads.

Thus, no chase for me today.  Instead I watched a live stream of the WDBJ Ch. 7 coverage of the Pittsylvania county warnings while I monitored the front's progress across northern Virginia.  Fortuitously that put me in position to nowcast via online platforms (FB and Twitter) warnings for Fredericksburg and vicinity.  That came about when I noticed a discrete cell merge with the line southwest of the city:
My internal antenna began twitching at this point so I posted my concerns about this section of the line.  Sure enough less than 20 minutes later this section of the line was both severe TS and tornado-warned.

I followed the circulation as it crossed over downtown Fredericksburg, furiously posting zoomed-in radar velocity graphics online accompanied by more nowcast information:
As the cell moved into eastern Stafford county the circulation weakened and the tornado warning was allowed to expire while new severe TS warnings were issued for localities further east and north.

Thus I guess I could claim to have chased virtually today, but I'd much rather be out with eyes, ears, and cameras observing and recording the action while someone else watches things online.  Oh well...there's still a month until my typical Veterans' Day chase season expiration so I'm not giving up on this year quite yet.

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