May 18-23, 1998

May 18

We departed about lunch time heading for southern Minnesota.  When we arrived in the mid evening the atmosphere was strongly capped.  Only a cold front well off to our west would be capable of producing thunderstorms.  We witnessed two weak elevated thunderstorms that managed to tap the surface moisture for only a brief moment, but faded quickly.  We checked into a hotel in Rochester, MN for the night.  A strong line of storms moved in from the west and began to drop Quarter size hail on our hotel.  We had a great view of the hail under a covered outdoor walkway at the hotel.  Piles of hail formed under water spouts and rivers of hail flowed in the parking lot.   A very unexpected finish to day 1.

May 19

We headed southwest towards the Nebraska Panhandle when we were stopped by a flat tire (Group 1 called this a "slow leak") that group 1 had started by getting a nail into the tire.  We managed to find someone who could fix the tire relatively quickly in Iowa and were on our way.  We lost about 2 hours due to the slowdown.  We made it out to Ogalala in the Nebraska panhandle shortly before sunset as a squall line moved in from the west.  We experienced a strong gust front as the line passed over.  We also watched lightning outside our hotel later and had a nearby cloud to ground strike that sent us quickly to our room.

May 20

We drove up to Alliance waiting for storms to intensify as they moved towards us.  We encountered a storm to our north that produced a wall cloud and a ground based spinup but we were too far away to determine if it was a tornado.  Later we headed southeast to a cell with a tornado warning.  We witnessed an anticyclonic funnel cloud and found ourselves stuck on the northwest side of the tornadic cell until sunset.  We spent the night in Sidney.

May 21

At 11am a tornado warning was issued near Scottsbluff so we headed up to the northwest  but the storms were weak by the time we got to them.  A nice smaller supercell formed just to our south around lunch time so we watched it from a highway marker stop.  A tornado watch was issued at 4pm for most of western Nebraska.  We headed south out of Gering and encountered a storm that produced a spectacular wall cloud, but no tornado.  A tornado was reported near Sterling, Colorado so we headed southeast to try to get into a good position.  We drove south out of Hayes Center (which was a great move as 10 minutes later Spotters reported softball size hail in the town) since there was no shelter from the hail in sight.  We were overtaken by rain and wind driven small hail but were lucky enough not to encounter large hail.  After emerging from the rain we saw a rotating wall cloud to our southeast with a funnel cloud.  A short time later a column of dust could be faintly seen rising up from the ground under the wall cloud.  Quite an incredible day.

May 22

Moderate risk over eastern Nebraska busted on this day.  We spent the evening driving east to Lincoln to spend the night.

May 23

We went to the east side of Kansas City.  Storms formed northeast of a surface low and moved through northern Missouri.  We bumped in to storm chaser Jeff Piotrowski, who quickly lost us as he speeded down the highway.   We made it to the storm and set up behind the flanking line to witness a few wall clouds before darkness set in and we took to the long drive back home.  All told it was a very successful chase for us.

A rotating wall cloud on May 20th with debris cloud underneath	Very strong thunderstorm on May 21st with lowering of the cloud base
Appears to be a wall cloud on further inspection	Indeed a wall cloud
The wall cloud refuses to drop a funnel cloud	The storm begins to weaken
A storm over the Nebraska Panhandle that is starting to rotate	Sure enough the storm eventually shows very strong rotation
A close-up of the base with a possible wall cloud forming	The storm exhibits stronger rotation...but no funnels or tornadoes
An overshooting top somewhere in Colorado	Kelvin-Helmholtz instability waves