Account by Andrew
Revering (Convective Development):
Leaving Plymouth, MN at 6 a.m. Monday
morning (6/9/03) we headed southwest targeting O'Neill, NE. Along the way we
stopped at KOOL 98, an Oldies station in Mitchell, SD where our friend
and on-air personality Kory
Hartman allowed us to use the station's high
speed Internet access for some last minute data. After viewing the
latest surface observations and satellite imagery, we decided that
O'Neill was still a good target, so we headed south out of Mitchell.
While on the way down, the Storm Prediction center issued a tornado
watch box for our area. We continued south to O'Neill where we were
forced to stop at a library for data since our Internet connectivity
through cell phone was unsuccessful. Bill Doms got there first and got
all of the data up. By the time Peggy, Mel, myself, Erik, and Mike got there Bill had all the data ready to show us. We all agreed
that things looked good just a bit to our north. Cumulus were beginning to pop just northwest of O'Neill. Dave Floyd, the Warning Coordination
Meteorologist from Goodland, KS was also chasing in the area. He talked
to him on the phone and he along with some other tour groups in the area
were all in agreement to head north to the cumulus field.
On our way north, just west of Spencer, NE along the NE/SD line we
noticed an interesting 'feature' with intense vertical motion and
condensing scud. This was a very small updraft which was amazing to
watch with the amount of updraft strength it had at it's updraft base,
but the cell itself was pathetic, with no rain core or structure other
than for the updraft base. Mel was particularly interested in this and I
wanted to ignore it. But we stuck with it since I was overruled. I'm so
glad I was!
After watching this feature and following it slowly for quite a
while, the updraft got behind two separate cells just to the east which
developed. These cells processed going through backbuilding and merging
stages. The two cells to the east became one and this updraft we watched
also merged with these two cells. Together it became one powerful
supercell. The updraft we watched for such a long time eventually turned
into a wall cloud and updraft base for the main updraft, eventually
producing the tornado! It was amazing to watch this evolution.
Just as we could visually watch the two cells to our east merge into
one, Rob Koch from KSTP in Minneapolis called us and confirmed the cells
merged. He also stated that the inflow/outflow couplet was
"amazing". As the storms merged our rotation under the updraft
intensified, a funnel dropped and eventually became the tornado... about
5 miles north of Stuart, NE. Touchdown was approximately 7:15 p.m.
Click Here for a Photo Account
of the Chase