May 22, 1996 Benkelman, NE Chase By Bill Reid And Friends

Subject: Chase Account, 5/22/96:  Benkelman NE Supercell
X-Status: 

May 22 ---- deja vu day.  It was on that date in 1995 that I witnessed a
spectacular, rotating, low precipitation supercell thunderstorm----the
"Shamrock, Texas" hailstorm.  This baseball and softball-sized hail producer
hammered much of the VORTEX armada between Shamrock and Reed, Oklahoma, that
evening.  The cell was the first of two supercells which took similar paths to
the east-southeast.  I managed to stay out of the hail that day, as I stayed
just west and south of the updraft.  I'll forever envy Al Moller and his slides,
however, as his vantage point east of that first storm gave him a perfect,
jaw-dropping view of the cell.  Exactly one year later, I was about 300 miles
farther north, and a somewhat similar storm scenario unfolded.

Early on Wednesday, May 22, 1996, it was pretty clear where I wanted to be when
those first storm towers went up:  northwest Kansas.  I was in Perryton, Texas,
so all it took was a three-to-four-hour drive up U.S. 83.  (With me in a
four-car caravan were several friends from the Los Angeles area:  Charles
Bustamante, Keith Brown, and Curt Kaplan.  In addition, Kinney Adams, from
Milwaukee, was tagging along, as were Steve Hodanish and Udo Maurer.  Udo is
producing a documentary on storms and storm chasers for German and French
audiences.)  An east-west oriented warm front was moving north through Kansas as
a strong low-level southerly jet became established above the Southern Plains.
An upper trough of low pressure was over the Great Basin, and disturbances were
moving through the High Plains on the southwest winds aloft.  With moist, warm
air in Kansas and dry surface air moving east through eastern Colorado, the
outlook called for a moderate risk of severe weather for much of Nebraska and
northern Kansas, near and along the warm front.

We arrived in Oakley, Kansas, around 3 p.m. CDT, and we were starved for data.
Scattered fracto-cumulus clouds were streaming northward, the temperature was
about 81F, the dew point 63F and moderate SSE winds were blowing, but where was
the best convergence?  By combining Keith's laptop computer, cell phone, and my
thumb, we managed to download all pertinent surface data and discussions outside
of a Conoco gas station near Oakley.  My thumb was required to hold the DC
adaptor for the cell phone inside of the cigarette-lighter outlet of my
Pathfinder----actually, I was required to jam the stupid thing in as hard as I
could for several consecutive minutes.  One false move by me and we'd have to
start all over again.  Why can't getting data in the middle of nowhere be
simple?  The data obtained revealed nothing surprising.  It appeared that the
best surface moisture convergence was still a little farther north and
northwest.

Around 4:30 p.m. CDT a tornado watch box was issued for much of western Nebraska
and northeast Colorado.  However, cumulus towers were beginning to make some
headway against the "cap" south of Brewster, Kansas, in Thomas County.  At the
same time we learned of a storm in "northeast Colorado" on NOAA weather radio
out of Goodland.  (Come on, Goodland, you can be more specific than that!)  We
couldn't see the storm referred to yet, but even though it was in the watch box
and perhaps only an hour or two away, we decided to make sure the Thomas County
stuff didn't explode.  Fortunately(?), this activity got sheared apart and
weakened quite quickly, so we hopped back onto Interstate 70 and headed west.
Soon the "northeastern Colorado" storm was within our sights to the northwest.
It was moving east.

We blazed north from Goodland to Haigler, Nebraska, on Route 27.  The isolated
cell had excellent structure----a solid, tilted updraft, backsheared anvil, an
overshooting top----and inflow winds from the southeast at about 25 mph..  It
did not appear to be rotating (yet!) when we arrived just south of the updraft
base at Haigler.  It was 6 o'clock magic time (MDT), and this dark and ragged
updraft base was just beginning to churn.  Upward cloud motion in the base was
very impressive, and soon we were chased eastward several miles as rain and
small hail began to fall.  The storm had a southward component, and its ominous
base was now right along U.S. 34.  At 6:20 p.m. MDT, near Parks, Nebraska, we
observed a "debris cloud" tornado only a mile or two northwest of us.  It was
nicely backlit by the sunny skies just behind the storm, but there never was any
condensation funnel.  The dusty tornadic "whirl" appeared to be moving towards
us and light rain curtains encroached, so we scooted east a few more miles.

The tornado was brief, but the best part was just beginning.  As we neared
Benkelman we found ourselves under the leading (eastern) edge of the updraft
base, and the view directly above was absolutely incredible----a soaring
vertical wall of cloud----a giant, rotating, laminar-sided supercell!  We were
all astonished; the storm looked nothing like this 30 minutes earlier!  

To our northwest downdraft winds were marked by dust plumes, and these were
recycled right back up into the storm.  A well-defined rear-flank downdraft
(RFD) notch cut into the base, but I did not see any obvious lowering or wall
cloud.  The storm was still relatively high-based.  At the north-south highway
just south of Benkelman were a few other chasers, including Bobby Prentice, Matt
Crowther, and Betsy Abrams.  The storm was too close, though! It was difficult
to capture the immensity of it all on film and videotape with the thing
practically on top of me.  Since the storm was moving east-southeast, and since
U.S. 34 continued east-northeast, there was only one viable road
option----south.  This storm reminded me of the one exactly one year prior, and
I wanted photos like those Al Moller took!  I needed to be farther east!

Though the updraft base was still right above Benkelman, my yearning for better
storm-structure position pulled me south into Kansas on Road 161.  During this
time a small and narrow tornado WITH a condensation funnel struck near
Benkelman, but I did not see it.  (I saw it the next day on The Weather Channel,
thanks to Matt and Betsy!)  I stopped a couple of times on the road south to
Bird City to admire the storm---it was just as beautiful as any dumb-old tornado
anyway!  We reached U.S. 36 and Bird City, Kansas, at 8:10 p.m. (back into
Central Daylight Time now), and the supercell now had a smaller companion
updraft immediately behind it.  Unfortunately, the setting sun was only
illuminating the upper portions of the supercell.  I never did make it east of
the storm.

At Atwood near sunset (around 8:53 CDT) the storm base was nearing U.S. 36.  A
very pronounced dry punch/RFD notch cut into the base, and I decided to get
closer before dark by taking the paved road northeast to Ludell.  Tornado sirens
were sounding as we reached the little town.  The clear slot was just to our
north, and a raggedy bunch of lowerings were northeast of it.  Clouds above us
cascaded downward and dissipated, and massive cumuliform cloud towers were
visible through the dry slot.  Our wall cloud area remained a bit messy and
unorganized.  Though there appeared to be some rotation, we observed no tornado.


We followed the storm into Oberlin, and it was tornadic once again.  Spotters
reported a tornado about nine miles west of town, but darkness prevailed and we
had to be content with sporadic lightning.  We found a motel with vacancy in
Oberlin---and the folks were in the basement!  I assured the clerk that the
threat was over, as the storm was east of town.

Around 11 p.m. CDT the Oberlin sirens were wailing again:  another tornadic
supercell was approaching!  This brunt of this second cell hit just west and
south of Oberlin.  Sporadic golfball-sized hail fell in town, but a patrol car
coming in from the west was minus a windshield thanks to baseball-sized hail.  

What a dynamic duo!  Twin supercells!  Deja vu on May two-two.

Bill Reid