September 21 2006 northcentral KS tornadic mini-supercell chase



No introduction really for this chase.  However, I will say that in reviewing video, I confirmed that the Beloit event--aside from being a very surreal experience--also was

my first time having "heard" the sound of a tornado.  No waterfalls, no jet engines or locomotives.  Instead, it sounded like a strange, almost mechanical "whir"

of some sort... mixed with wind.  <g>  In all seriousness, it was an incredible sound... and an incredible event altogether.






Anticipating an early show, I left KC at 730am with an initial target of Lyons KS.  Checked 12Z obs/model data along I-70, and adjusted my target northwestward to Hoisington.  Made it there by noon.  The strength of the dry slot advertised by the NAM and GFS was certainly panning out.  Eventually I wandered up to the Russell county line, where pesky stratocu were more minimal.  A deepening cyclonic arc of convection was already underway in far NW KS, on the northern periphery of the ejecting mid-level low.

A NNW-moving storm developed on the tail of the convective arc, about 30 miles to my west.  I opted to check this one out and jogged up to I-70.  It looked fairly vigorous as I approached it near Hays, but was soon tackled by more messy cells from the south.  Its FF core pelted me with some half inch hailstones, though, which was a good sign.  Here is an image of the Hays storm taken at 108pm.
Equipment problems from hell (a pattern lately) ensued thereafter.  I was able to grab an ICT radar image courtesy of WIFI, and headed east to intercept additional development as it spiraled northward across I-70; one cell in particular looked to have its eyes set on Russell.  When I reached town, I parked just north of I-70 and noticed something impressive coming out of the rain (145pm).
Moved north a shade and started video for the day at that time...  my first recorded words being, "I'm a little bit shocked."
Another shot of this stout updraft.
The mini-supercell now sported a mini-wall cloud.  I figured I'd have enough time to get north of town where I would have a clear view of things, and thus started to head north on Highway 281 at 151pm.  The Russell tornado touched down literally seconds after I turned my back on the storm.
Through trees and buildings, I soon noticed some definite funny business beneath the updraft, and then verified the full-fledged tornado.  I snapped this over-the-shoulder still (154pm) while looking for a good place to pull over.
Finally, I found a relatively clear vantage point on the northwest side of town to watch the tornado.  (156pm)
A telephone pole and a raindrop both vie for camera time.
Tornado hit some sort of manufacturing building about this time, ripping pieces of the roof off into the air.
Dissipating tornado, and parent mesocyclone with RFD cleft!  Amazing. (159pm)
The storm passes right up Highway 281.
Fully HP, the supercell engulfed the town of Waldo ~230pm (as in photo).  I abandoned the storm at that time.  With no nowcasting available, I instinctively headed east on Highway 18 to look for new cells.  A tornado warning was issued for a nice-looking storm to my northeast near Sylvan Grove.  I tried to catch up with it north of Lincoln, but was sideswiped by a new storm(s) farther south.
The southern storm became visible as I neared the Mitchell county line on Highway 14 (325pm).  I was still very confused as to what I was looking at; I thought this was the northern storm, due to some confusing reports in the tornado warning text.
From radio reports, it was becoming clear the northern storm was producing a long-track tornado.  [As it turned out, the storm was just far enough ahead of me that haze and/or visibility restrictions caused by the southern storm's FF core made it impossible to see, even though it was tracking only 10 miles to my northwest.]  Still not understanding the situation, I became frustrated as I continued to pursue the southern storm along Highway 14 (shown in this photo, 335pm, looking southwest).  It was highly elongated, with no visible rotation or condensing inflow at cloud base.
From the latest warning, it seemed I could beat the northern storm's tornadic updraft to the Jewell county line.  When I got north of Beloit, a new tornado warning was issued for northeastern Mitchell county-- for the southern storm!  I finally let the confirmed-tornadic storm go and prepared to intercept/closely observe the southern storm, whose increasingly rounded updraft was just to my south (photo, 358pm).
I moved back to the intersection of Highway 14 and Highway 24 in northwest Beloit for a closer look (photo, 401pm).  An SWS on the tor warning came over the radio, indicating a tornado was spotted near Beloit.  However, the more I looked around, the less clear it was to me where the area of "interest" really was.  I climbed back into the vehicle and began moving back north. Then I noticed that rain was being driven ferociously against my car, and only on the right-hand side.  This was indicative of strong easterly inflow winds into the updraft base overhead.

The tornado revealed itself to me at 406pm as a broad, frenzied circulation racing erratically northward 20 yards to my right in a farm field.  (A scary moment until it moved onward).  The ground was soaked, thus dust/debris was minimal.  The tornado then became more focused/organized into a cylinder... then began to decelerate and became very tough to see.  Meanwhile, the mesocyclone finished passing overhead and became astonishingly clear.  Here is the first photo I took of the mesocyclone as I followed it up Highway 14.  The indistinct tornado is emanating from the particularly angry lowered portion of the meso, to the right of the highway.


The updraft base darkened and lowered dramatically, as the transition to a broad multiple vortex tornado occurred.  Due to the relatively small scale of the event (minisupercell with extremely low cloud base), photos suggest I was following a good distance behind the tornado.  In actuality, I was only following 100-200 yards behind it.
Video turned out quite well.  Photos, not so much.
Cropped photo showing ugly vortices dancing through trees.  Rotation at cloud base was violent... but didn't seem to translate well to the surface. 
On a few occasions, individual vortices came careening left to right around the near side of the tornadocyclone.  I caught one of them in this photo... just above the wiper blade and to the left of the highway.
The tornado's appearance was impressive in that it was about four times wider than it was tall.  But it wasn't a large tornado; it's just that the cloud base was literally right above the treetops... perhaps only 100 feet off the ground.
Between the LEO vehicle, trees, powerpoles, and haybales, as well as steady rain and the windshield wipers... this wasn't any easy event to document.
One of the most awesome things about this storm was its small size.  I moved northward in concert with the astonishingly vertical back wall of the updraft, which was no more than a couple miles off to my northwest.
The tornado dissipated about 413pm in conjunction with the entire low-level mesocyclone rapidly raising its base and shrinking!
One final shot of the mini-supercell as it continues northward over flooded farm fields.
The remainder of the chase, I successively attempted to intercept three additional tornado-warned storms.  Structure was messy and difficult to discern.  This storm was the third of the bunch, near Glasco KS.  By this point, it was very chilly out; about 57F in my location.  Whatever instability had been attained within the dryslot to fuel this remarkable three-hour event had surely come and gone.



Maps, weather data


observed supercells


Base reflectivity of mini-supercell during birth of Russell tornado (NWSICT)


18Z NAM 00-hr "first guess" at RSL

(note: BL not warm enough so instability, in particular 0-3km CAPE, is underdone)

MLCAPE: 395 J/kg

MLCINH: 9 J/kg

0-3 km MLCAPE: 95 J/kg

MLLCL: 602 m

MLLFC: 1620 m

0-1 km SRH: 101 m2/s2