May 16, 1999   NE Kansas Chase

For the first time this spring, I was caught off guard with what happened later in
W.Iowa. During the morning hours, the whole atmosphere transformed over that
area, and it was now very apparent that tornadoes were a distinct possibility by
the afternoon. Just a few hours of indecision can lead to a bust and today was a
prime example of this. Much of W.Iowa was in the favored left front quad of a very
strong mid-level jet max , and the low level jet was piling deep moisture into that
area in the vicinity of the warm front. A surface low was expected to deepen over
E. Nebraska by afternoon, resulting in a large area of backed surface winds in
W/C Iowa. My first target zone was over W.Iowa, but there was little chance/hope
of making it to W.Iowa before all hell broke loose!! I had to figure out a second
chase area that was close enough to reach by late afternoon, and still have the
possibility of severe storms/tornadoes. The second target zone was further to the
southwest along the dry line over NE Kansas. Pressure falls would be substantial
here and this would cause good convergence and probably locally backed sfc
winds. Kathryn Ray was planning to chase with me, but my chase partner Brian
Stertz had to work- even though he was chomping at the bit to chase. He also
really liked the W.Iowa for the best chance of significant tornadic supercells.

Kathryn and I got a late start, hopefully not too late!! We planned to head straight north from Tulsa towards the Topeka KS area. The target zone was anticipated
north of Topeka along the KS/NE border. The low level jet was expected to ride
up over the dry line in that area by evening. We reached Topeka around 5pm,
and we found out that W.Iowa had a cluster type outbreak of tornadoes earlier in
the afternoon. We were starting to see evidence that the cap was weakening, as
storms were now back building sw along the dry line. Satellite also indicated
that C.Kansas and parts of W.Texas were also exploding with supercells. The
shortwave was now entering the Plains!! We decided to hold along the KS/NE
border and wait for the storms to back build down the dry line. Several severe
storms attempted to get established in and around our area, but we were right
under the jet core. So as could be expected, the speed shear was too strong!!
Speed shear is created by differing wind speeds aloft which cause the column
or storm to spin. This is one of the many critical factors for tornado development.

We watched storm after storm fire along the dry line and briefly produce large
hail (up to golfball sized). Further to our southwest, the C.Kansas supercells
became tornadic and well established. I strongly believe this area was where instability was strong enough to overcome the incredible speed shear. Early
evening passed by without any sustained supercell development in NE Kansas.
Meanwhile, several tornadoes( a few reported to be 1/2 mile wide) were now
spotted between Salina and Emporia KS. A bust chase was looking more and
more apparent at this time. Today, I was stuck betwixt and between for the first
time this year. The severe storm we were tracking over Marshall Co. weakened
just before sunset, and this signaled the end of our uneventful chase. I just wish
I had committed earlier in the day!! We drove through the heavy cores that were
the remnants of the earlier supercells in C.Kansas in route to Tulsa. Hindsight
remains 20-20!!