May 5 2007 chase




Writing this account several months after the fact.  This chase began early in the day and not far from the previous night's historic, deadly tornadic supercell. 

The 12Z RAOBs already showed very strong, only weakly-capped instability in place due to very rich/deep BL moisture entrenched over the high plains. 

Cells went up around noon in the Dodge City to Hill City corridor but had trouble organizing and appeared high-based and outflow dominant. 






I moved east and south with the idea of staying ahead of the tail end of the line.  Near Macksville I encountered a swath of extensive tree damage from a large, violent tornado the night before.


It was a very hazy day with poor visibililty.  I moved south of Pratt and found the southernmost storm near Coates.  I watched three convective plumes successively rise and glaciate on the storm's hind flank... this is the final one which quickly became supercellular (410pm)
417pm - updraft became very beefy w/ knuckles on anvil underside
435pm - I moved northeastward to just south of Pratt as the storm earned a tornado warning.  The updraft was quite elongated, with the apparent action area/dynamic wall cloud on its very hind end
449pm - moved north of Pratt to near Iuka, where another wall cloud took shape
455pm - a small collar cloud developed in front of a fattening funnel.  The structure reminded me of the 02/28/07 supercell at sunset near Yates Center.  I moved north, and in a dramatic scene the funnel constricted and elongated while curving northeastward and northward behind me.  It never became tornadic before being blown apart.
Not feeling like stair-stepping on side roads that might turn to mud, I stayed on pavement though I knew I'd lose sight of the meso for a few minutes.  I carefully re-entered the trailing portion of the FF core west of Stafford.  As the heavy rain began to let up I regained a clear view of the RFB to my south-southeast.  Violent cloud-base rotation ensued, and a dusty tornado touched down at 522pm about 3 miles southwest of Stafford.  It lasted about 30 seconds.  (Note the windshield wipers pointing to and/or obliterating the tornado; actually, if I recall correctly, the tornado had just dissipated).  Regardless, this was the high-point of my day (especially with chase vehicles in front of me seemingly not realizing we were on a collision course with a tornadic circulation)... and am disappointed I didn't get better documentation with either digital stills or video.
528pm - moved through a hoarde of chase vehicles and parked east of Stafford with a view back to the west.  The wall cloud looming over town was enormous and displayed moderate rotation.  As I was on the phone with NWSICT, the meso whipped up two high-based funnels... quite dramatic.  The town of Stafford was very fortunate the storm did not tornado at this time.
531pm - one more still of the storm as it continued to the north-northeast.  Not long after, another meso occlusion produced a laminar funnel about halfway between Stafford and Raymond which, like the Iuka event, did not touch down.  The storm went downhill thereafter and was clearly outflow-dominant by the time it crossed the highway 56 corridor near Chase.

Having stuck with the storm for too long, I intercepted the next supercell down the line east of Great Bend (631pm, in photo), too late for its tornado.  It appeared strongly HP, but I followed it for a bit and it apparently produced a couple weak tornadoes up closer to I-70.  Tornadic potential began to increase across the board (in spite of numerous storms overturning the atmosphere) due to acceleration of the 500-1000m agl flow... and I missed a few more tornadoes from another storm down the line that passed through the Macksville/Radium areas.  Had given up the day due to needing to work in the morning... but turned back when hearing of that final storm.  Finally intercepted it near Ellinwood (where the Greensburg storm had also inflicted damage the night before)... it was heavily rain-wrapped and I abandoned the chase for good due to low visibility/darkness.



Maps, weather data


representative hodograph for Stafford KS (2230Z) via Haviland profiler

storm motion: 210 deg @ 31 kts

0-1 km SRH: 148 m2/s2

0-3 km SRH: 177 m2/s2

0-1 km bulk shear: 22 kts

0-6 km bulk shear: 62 kts

7-10 km SR flow: 36 kts