25 May 2012 – Russell, KS Chase

25 May 2012 – Russell, KS Chase

Started the day in Lawrence, Kansas, after visiting with John’s 88-year-old father (who is a Professor Emeritus at KU, and was a field-leading radar researcher and engineer). Initially, Friday look like a down day, with no chasing anticipated even the day before.

The meteorology looked very different on Friday morning, and it was clear that it would be a chase day! Quick perusal of data pointed to roughly a central Kansas target and we hit the road. Chased with John and, later in the day, Kathy Valequez / Linda Kitchen (the ORIGINAL Twister Sisters).

A quick look at the 12z setup:

60+ knot cyclonic flow at 300 mb over central Kansas:

With a similar 50+k not slow at 500 mb:

1623z surface obs analysis reveals a mesolow over the Oklahoma Panhandle, warm front extending across the southern third of Kansas, and a dryline (brown) extending south through the Texas Panhandle.

Ample moisture was in place south of the warm front (red), with a segment of the 68° F isodrosthem (green) running Southwest-Northeast south of the warm front (decent dewpoints also existed N of the warm front, especially further east). The moisture (including the rich 68 & 70 dewpoints) were advecting to the NW, suggesting the potential for significant instability later that afternoon.

12z Dodge City hodograph showed a promising broad loop, and was likely indicative of the shear pattern along much of the warm front east of the triple-point:

We drove to Great Bend, KS and further assessed how things were evolving.

21z SPC surface obs suggest mesolow/triple point had moved into West Central Kansas, with the warm front extending east – but a little further north, and the rich, deep moisture was along. and south of. the warm front (again, warm front red, dryline brown, and a segment of the 68 F isodrosotherm green, in this quickie analysis):

SPC Surface-based CAPA mesoanalysis suggests a highly unstable environment south of the warm front/east of the dryline…

…and more than sufficient 0-6 km shear, suggested potential for isolated supercells with possibility of tornadoes (highly backed sfc flow, with enhanced vorticity along the thermal boundary):

Visible satellite imagery showed a region of building cumulus along/just south of the warm front. We moved west from Great Bend, KS, to Rush Center, KS as the western end of the line of cu was exhibiting the greatest growth (particularly in later images).

We then chased from Rush Center, KS to Russell, KS.

Met up with a slew of great chase people at Rush Center, just before and during convective initiation: David Hoadley, Dr. Jason Persoff, Bill Hark, Chris Kridler, and the just engaged Danya Vettese and Brad Rousseau from the Canadian Weather Network – a classic chase convergence!!

Convective initiation of the first supercell (again click all for larger images) went up just NW of our group and the chase was on (to me, one of the great satisfactions in chasing is where you get to your target before the storms go up!):

Development of the updraft/inflow on the first supercell. This soon became obscured by a wall of dust kicked up from the Rear Flank Downdraft.

Linda has some video of the top of a funnel we saw that was obscured by dust below 4/5th up from the ground – nothing clear cut to determine what this actually was, but may have been concurrent with the TOR report…

Development of the wall cloud on the second supecell (I measured a 68 F dewpoint on my Kestral around the time this image was taken):

We moved south to consider intercepting another supercell to the SW, but kept our eye on the middle cell’s updraft.

We started back N again, as the middle supercell’s updraft continued to improve. Suddenly I saw about a half a minute of a perfectly vertical ‘Elephant Trunk’ tornado on the second supercell (we had moved S and were to the SSE of tornado) as we traversed a couple of hills and valleys. By the time we found a pull over with a clear view, all that was left was this tilted Cone:

Soon after we could see the condensation funnel back in contact with the ground – in a highly sheared configuration!

This ‘rope’ stage continued for a good four to five minutes, and seemed to maintain a near-steady form during that period!

This image was taken at the same minute as Russell KS’ sunset time (0149z):

Sinuous rope stage continued:

…while still maintaining contact with cloud base.

Lighting conditions were rapidly becoming even more difficult (the images below were all shot after sunset) – and I had no time to set up a tripod or window clamp. Most of these were shot handheld at 200 mm and 1/80th of a second.

Image stabilization helps, but I still would rather have the opportunity to tripod up, or to be able to shoot higher shutter speeds to further minimize blur.

Eventually the connection with cloud base was broken, while rotation continued in the condensation funnel – conservation of angular momentum!

Finally, the condensation funnel dissipated:

Here is 0.5° reflectivity tilt from the Dodge city radar. Notice the classic hook echo south of Gorham (again, we were to the south southeast):

Decent velocity couplet associated with this tornado:

As we later approached Russell from the south we slowed as we approached the hook echo. We slowly advanced, passing the various ROTATE project mobile radars and probes until we could see a white tornado cross the road right in front of us – (illuminated by lightning). We crossed the damage path not long after starting N again.

Here is a velocity couplet associated with the tornado that struck just south of Russell:

Click here for a link to an image of that tornado taken from about a quarter mile north of the Interstate.