Monday 11 June 2012

2012 Chase Day 5 - Stephens Co (TX), Young Co (TX), Clay Co (TX) supercell

Mon 11 Jun 

After spending the night in Ponca City (OK), and consequently allowing the cold front to move over us during the overnight period, we headed south on the I35 via Oklahoma City towards the Texas border, passing through the cold front to the other side once again. Initially the plan was to chase around the Red River, but as we moved farther ahead from the cold front, it became apparent that the cap was too strong to be broken, despite surface temperatures reaching 103F (39C) on the in-car thermometer.
Car thermometer showing 103F close to the border with Oklahoma and Texas

Instead, we decided to head towards a newly developing cluster of storms close to the I20 corridor west of Dallas (TX). The bulk of them were moving southeastwards, but one supercell began to split, with the left mover heading in a more northeastwards direction, very slowly towards us.

We chased towards the storm, and took a road south from Graham towards its core, but stopped to take the opportunity to snap some photos. At this stage the anvil had covered 180degrees of the sky, and rain and small hail started falling. Moreover, there were numerous CGs being produced from the anvil, with almost instantaneous loud thunder. The storm, while heading straight for us, developed new updrafts on it's western flank, and we decided to try and head north to avoid the damaging hail that had been reported in the core.
Approaching the gust front
Some nice shear funnel clouds in the mid-layers

Heading northwestwards, we were hit by 50mph winds as the outflow briefly caught up with us. We passed through Newcastle (TX) and stopped at Olney (TX) to observe a new tower shooting rapidly up on the eastern flank of the storm - this really was a monster of a storm.
Looking back at the approaching gust front
New tower (updraft) shooting up on the eastern flank

We were desperately trying to get to the southern side of the storm (currently on the north side) so that we could observe it much better, but this monster just kept growing linearly to the east and west, really inhibiting our chances. We tried several routes westwards, but it kept backbuilding to the west on the flanking line. By now it was starting to get darker as the sun started to set, with a brilliant orange sunset through the anvil haze.

Just west of Archer City (TX) we parked up to watch the gust front come in, with lightning (although mainly IC) becoming very frequent as darkness fell, and the wind picking up considerably as the gust front approached. It also felt noticeably cooler as well.
Gust front approaching from the South West
Gust front approaching near Archer City (TX), with lightning becoming more frequent
The rain was fast approaching so we jumped back in the car and raced eastwards to Windsthorst (TX) to get ahead of the gust front again and to shoot some lightning. Then heading north, we decided to punch the core of the storm by parking in Henrietta (TX) and letting the entirety of the storm move across us.

We were treated to strong winds, very heavy rain, and some hail, but not a huge amount. This was all accompanied by frequent lightning, the majority being CC, but several close CGs were spotted at times, but the sound was often muffled by the strong winds and heavy rain in the downdraft.
CC lightning at Henrietta (TX)

CG lightning at Henrietta (TX) - shame the shot was out of focus!

Eventually the storm passed to our east, and looking back at the radar loops it seems that the main hail core went to our south east. Nevertheless it was a cracking storm, definitely better than anything I have ever witnessed in the UK!

Radar screen grab

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