May 10 2010 chase
Summary: My first chase of 2010. The obvious concerns for this system for days on end were the "last-minute" northward return of the warm sector toward latitudes near the
upper system's strong large scale ascent (KS and northern OK), along with the limited horizontal width of the warm sector relative to the near-extreme vertical shear environment.
Having chased a good number of very-strong-shear tornado outbreaks (e.g. 4/15/03, 5/4/03, 5/8/03, 5/10/03, 9/16/06, 6/5/07, 5/10/08), I knew the "how-far-downstream-to-set-up" issue
would be a critical one for potential success on this chase... muddied by the question of whether storms would cross the warm front before this even happened.
I ultimately decided to chase no farther south than ~Guthrie OK given that I had to work at 7 A.M. the following day. While tempted to chase the wider warm sector near OKC's latitude
(despite somewhat lower confidence in initiation), I knew that would put me a few hours farther from home and would likely have me chasing till much later in the evening.
As it was, I managed to be home by 10 P.M. and well rested for my shift the next day.
I departed Kansas City a little later than I wanted (1145 A.M.) and reached Blackwell OK by 3:20 P.M. Though initially planning to wander southeast a bit and wait for the
younger southern updrafts to mature, I wasn't able to resist dashing westward to see what the Grant co. supercell looked like given its amazing radar appearance. I arrived to the storm
about 4 P.M., just as a large tornado had apparently wrapped up in rain ~10 miles to my NW. Meanwhile, the trailing RFD gust front just N of Highway 11 (which I initially
mis-identified as the primary rainfree base given the low-visibility murk of the wrapped up meso well N) produced some moderate rising motions and a couple of small lowerings.
My car thermometer never exceeded 70°F, and its likely the storm had crossed the surface warm front sometime in the past 30 minutes--though this did not
preclude it from producing a significant tornado 15 minutes later, near the KS border.
I abandoned the storm soon after, zigzagging east, south, and east again in a "recovery" attempt to intercept the current tail-end-charlie storm which was finally becoming better organized
to my south. While flanking the northern edge of the core I received pea- to quarter-sized hail for about 15 minutes. By 520 P.M. I acquired an excellent view of the supercell updraft near
Burbank OK (intersections of Highway 60 and Highway 18), about 10 miles to my WSW at that time. A rather low-based, sloped, large wall cloud was present, with a very large
RFD cut on its south side. Interestingly, WFO Tulsa surveyed a 2.6-mile-wide damage path associated with these features from 512-525 P.M.--comprised of a 1.4-mile-wide EF-1 tornado and
additional RFD damage--ending 1.5 miles west of my location. However, it was impossible to discern anything tornadic (e.g. condensation beneath cloud base, individual vortices, etc.)
from my position at the time... perhaps due to the rainbands behind the cloud base and the haze/poor visibility to the cool side of the warm front. Though I didn't observe anything classically
tornadic, it's interesting that the appearance of the wall cloud itself was quite similar to the wall cloud which spawned the multi-vortex-to-wedge tornado on the first storm near Medford.
With time, the RFD slot filled with dense precipitation and the adjacent wall cloud became blotted out from south to north. Meanwhile, the storm appeared to be cycling a new updraft/
large scale meso immediately to my southeast, which was verified by radar. In response to this, I departed the intersection at 5:28 P.M. and headed east. Soon after, at 5:33 P.M.,
a beautiful fully-condensed cone tornado appeared suddenly to my right--just south of Highway 60. In the span of the next 10 seconds the tornado completely evaporated,
though I did manage to video its very latter/truncated stage. Thereafter, two low-level mesos/wall clouds--stemming from the new updraft--crossed the highway in front of me.
The leading (east-southeastern) wall cloud filled the sky with spectacular cascading/rotating motions; this was the wall cloud which had produced the tornado just prior. The trailing
(west-northwestern) wall cloud was larger/beefier, with condensing inflow on its forward edge. After the stubby leading meso continued across the highway, it produced another
tornado at about 541 P.M. This one took on a rope appearance and lasted nearly a minute. My car thermometer registered a temp of 66°F from the time I intercepted this storm
through the two visible tornadoes (obviously suggestive of considerable CIN to surface parcels), though a review of surface data suggests the ambient inflow airmass
(a tad SE away from storm-scale effects) may have been a bit warmer.
I followed the weakening supercell northeast through the Pawhuska and Bartlesville communities and let it go at that time. On my way home, I took a small jog NW to view a
trailing tornado-warned supercell approaching the town of Sedan KS. This storm's updraft was very elongated and linear-looking.
All in all this was a relatively enjoyable first chase of the year when considering some of my tactical decisions were poor. I ultimately ended up playing the immediate cool side of
the surface warm front (where I obviously didn't expect a substantial tornado threat, given an only modestly deep boundary layer and the warm-ish EML preceding the upper system)...
whereas I fully intended to play the narrow warm sector for days on end. This was a result of leaving KC too late given slightly earlier storm initiation, as well as the fact that
the storms I chased were on the northern envelope of my rough target area where the warm sector was successively narrower. However, had I left earlier I probably would have not observed
the Grant co. storm at all, probably driving straight to Perry/Guthrie OK and chasing the early (primarily nontornadic) duration of the Red Rock-Burbank-Pawhuska storm.
I haven't looked at the radar evolution closely, but it appeared the initial updraft(s) stage of the Red-Rock-storm-to-be took substantially longer to consolidate/organize
than the Medford storm did, and thus--despite a broader warm sector at its latitude--it had a comparatively shorter duration with which to become solidly well-organized
amidst the intense shear before crossing the warm front. This may have been a negative re: potential tornado production near the I-35 corridor (where the storm should have been
strongly surface-based amidst an obviously very potent thermodynamic/shear environment).
5:21 P.M. - Initial view of supercell updraft from near Burbank OK, looking WSW. Large wall cloud/possible tornadocyclone
and huge arcing RFD slot labeled in photo. WFO Tulsa surveyed damage from a very large EF-1 tornado in this location.
5:21 P.M. - Same, photo zoomed in on the wall cloud/tornadocyclone.
5:22 P.M. - same, video capture.
5:22 P.M. - Forward/leading edge of supercell updraft, which was cycling a new mesocyclone
5:33 P.M. - gorgeous, fully-condensed cone tornado just south of Highway 60... which was rapidly dissipating by the time I started recording it (vid capture).
The new mesocyclone ultimately spawned two wall clouds, and the leading/east-southeasternmost produced this tornado.
5:34 P.M. west-northwesternmost of the two wall clouds--looking N
5:41 P.M. - leading wall cloud produces another tornado (this one with a rope appearance), behind the hill as indicated in photo--looking NE (vid capture)
5:44 P.M. - occluded large scale meso--looking N (vid capture)
Maps, weather data
20Z unanalyzed METARs/OK mesonets
18Z Lamont RAOB; 21Z Lamont RAOB (partially contaminated); 21Z Norman RAOB
18z Lamont RAOB hodograph w/ Medford stm mot estimate
storm motion: 253 deg @ 44 kts
0-1 km SRH: 509 m2/s2
0-3 km SRH: 588 m2/s2
0-1 km bulk shear: 34 kts
0-6 km bulk shear: 63 kts
7-10 km SR flow: 37 kts
19z Lamont profiler hodograph w/ Medford stm mot estimate
storm motion: 253 deg @ 44 kts
0-1 km SRH: 410 m2/s2
0-3 km SRH: 466 m2/s2
0-1 km bulk shear: 31 kts
0-6 km bulk shear: 68 kts
7-10 km SR flow: 45 kts
21z Norman RAOB hodograph w/ Norman stm mot estimate
storm motion: 260 deg @ 51 kts
0-1 km SRH: 443 m2/s2
0-3 km SRH: 679 m2/s2
0-1 km bulk shear: 29 kts
0-6 km bulk shear: 75 kts
7-10 km SR flow: 28 kts
21z Purcell profiler hodograph w/ Norman stm mot estimate
storm motion: 260 deg @ 51 kts
0-1 km SRH: 328 m2/s2
0-3 km SRH: 537 m2/s2
0-1 km bulk shear: 21 kts
0-6 km bulk shear: 76 kts
7-10 km SR flow: 33 kts
2221-2238z mean INX VWP hodograph w/ Burbank storm motion estimate
storm motion: 243 deg @ 44 kts
0-1 km SRH: 776 m2/s2
0-3 km SRH: 972 m2/s2
0-6 km bulk shear: 67 kts