Day 7, Tuesday May 21th 2002

Route: From Cheyenne, Wyoming to Buffalo and from there east into South Dakota
Highlights: Formation of a line of thunderstorms over the Big Horn mountains just west of Buffalo, WY.
Text: Rob Groenland

Another quite long drive, from the southern to northern part of Wyoming. A cold front is forecasted to move into Wyoming through the course of the day. A few severe thunderstorms are expected to move through the eastern and northern parts of the state. We captured a beautiful line of storms and kept up with this line as it moved east.

The alarm clock goes off at 06.45 AM after a night of little sleep. The whole night freight trains moved through the backyard of our hotel (this is really not possible in the Netherlands). It's Rob's and Jules turn to prepare the weather briefing. An evaluation of the weather maps learns that there is a high chance of thunder storms or even supercells today in central and northern sections of Wyoming. The shear looks especially good! This is a point in time where the heart of a meteorologist will tick a little bit faster.

After the briefing we calculate the time needed to reach the risk area. As there is some time left we can have quite a relaxed breakfast. Around 10 AM we start our chase by driving through the typical wild west-landscape of southern and central Wyoming. Around lunch time we stop near Casper to do an internet update in a so called trucker restaurant. To the west of us we can see the development of a line of impressive cumulus clouds. In the restaurant we check radar, satellite and the latest ground observations. It seems we have to go a little bit further north.

As we drive further over I-25 in the direction of Buffalo, the cumulus to the west of us quickly grow into a line of thunder storms (positioned over the Big Horn mountains, just west of Buffalo). We film and make a lot of pictures of the approaching gust front, whirling dust on the ground and spectacular vertical lightening. We decide to follow this line as it moves to the east. Via the town of Gilette we drive into Newcastle. We see a complete sand storm as we drive right under the so called outflow of the thunderstorms. When it gets dark, we stopped chasing this storms.

We are quite excited about tomorrow. The line with storms will be forecasted over Kansas and eastern Nebraska. Therefore we will drive into South Dakota this evening to spare ourselves a hundred miles tomorrow.

Regards,
WeatherBug StormChase Team 2002