May 25, 2012

Preliminary May 25 Target: Quinter KS

What We Saw

Initiation was explosive around 4:30 pm, southwest of Hays KS.   The first storm moved northeast and crossed I70 near Russell KS.  Two other storms developed, one west of Rush Center and the other west of LaCrosse, later in the afternoon and evening.  All three became supercells and all three produced tornadoes.  

The picture at right shows the first storm....shortly after it developed.  We estimate it took only a few minutes between the time it was a small tower and this blossoming cumulonimbus with explosively expanding anvil.

The formation of the base/wall cloud was very interesting.   It formed as a detached scud cloud that drifted under the updraft, attached and developed the classic "bell shape" underhang, as shown in the photo.

This storm became a supercell quickly.  And we followed it as it approached I70, at which time it put down a very brief weak tornado just south of I70.   It had a very impressive radar presentation at the time.  Our position is shown as a white circle on the radar reflectivity plot below.

This is about the time we encountered literally hordes of chasers.   Large tour groups in vans, car caravans, and many groups of people with cameras on tripods, in some cases in the middle of the dirt roads we travelled.   

As we came to one intersection, a person driving an SUV coming from our left, stopped abruptly in the middle of the intersection, and was rear ended by the person driving behind her.  There was large damage to both cars, though neither driver was injured.

We eventually found roads along which few chasers were clustered....and, eventually, when the meteorology got 

somewhat complicated (the obvious storm was weakening and we expected development not the storms further south), it was interesting to see the hordes of chasers stay with the first storm, and we ended up alone with the second tornadic storm we intercepted.  That experience was reminiscent of the experiences Thom and I had years ago, when we had storms "to ourselves."

Even on the first storm, when it showed signs of deviate movement to the right (instead of the radar indicated northeastward motion), we got out on our own.  The picture at the top of this blog entry shows us looking at the mesocyclone area, with the ROTATE armada (an NSF funded project).  You'll note no other chasers in that location.  Also, if you look closely on the right, you'll see the RFD notch corresponding to the center of the mesocyclone to the right of the road.  You'll also see no other chasers in the picture we had found a dirt road (thank goodness for AWD) that only some chaser colleagues of mine had found...but none of the hordes.

As we dropped south towards the second storm, we noted it had formed a wall cloud, dimly lit by the setting sun.  Just at sunset it produced a beautiful tapered elephant trunk tornado.   Our pictures are blurry because of the low light, but you can see the funnel, and then the "rope out" stage, in which the tornado shrinks in diameter, and is pushed around by the storm's forward flank outflow.  In fact, in the last stage before sunset, the rope was so elongated, 

perhaps for miles, to form a right angle, where the tornado was still in contact with the ground.  I tried a panorama shot with my iPhone....and it too is blurry, but if you look at the center of the picture you'll see the forming tornado.

Forming Russell KS tornado, May 25, 2012.  Sunset...literally. half the disk of the sun was right behind the tornado. This was about 5 minutes after the picture below.   At first I thought the tornado was forming on a separate wall cloud, but now I realize that it was forming where it should...on the northwest part of the bent back horseshoe wall cloud (with the RFD reaming out the middle).  You can see the RFD cut on the image below.

I've also posted a short movie shot with my iPhone video cam showing the anvil lightning associated with the LaCrosse KS tornadic supercell.  That was the storm due south of the one we were on and it turns out that was the storm of the day (producing an EF2 tornado).  We dawdled around too much with Storms 1 and 2 to make it down there by sunset.

I'll post more when I get more time.   But this was another wonderful chase day for us, during a week filled with some frustrations, but lots of 

Meteorological Blather

[Update, 215 PM CDT:  We are currently in Great Bend, KS.  The models are suggesting storm initiation around Dodge City, with storms moving initially northeast towards the boundary.  The hodographs in this area are becoming strongly tornadic...meaning, the wind shear suggests that any storms that move towards the boundary draped just north of us along I70 will become tornadic, with perhaps a strong and violent tornado in there.]

We'll be targeting the region north of a warm front/dryline/cold front join  somewhere near, dare I say it, Quinter, KS (inside joke). This judgment is based before I see the 12 UTC run of the the 06 UTC run and the latest run of the RAP.

There are differences between those, chiefly with the issue of CIN. The RAP forecast soundings in the area of a curious shallow ground-based stable layer or inversion for many places in that area, except just along I70 or so. Don't know why an inversion would be showing up, unless it's outflow's not a frontal inversion, and it is very shallow. The WRF-NAM doesn't have that....

But both models have more than sufficient CAPE, for a change. What is striking is the ENIORMOUS 0-1 and 0-3 SREH projected by both models in the area bounded about 50 miles in diameter from a point somewhere between Wakeeney and Goodland. Geesh. Anyway, that is our target right now.