Chasing Day in Review

If one word was used to describe today’s events, it would be “bust.” Chasers use that term frequently, on days that plans don’t come together, or the atmosphere just doesn’t cooperate. But it’s a reminder as to why TWISTEX and other researchers are out studying storms… to determine why some storms produce tornadoes, and others don’t. All the parameters looked to be in place (resulting in a marginal risk) but things didn’t formulate until late in the evening, and by that time the crew was out of position. Most chasers would agree that chasing at night is not advised. Although because we are so far north it was still light at 9:15pm, the consensus was to call it a night.

It was amazing to see the popularity of storm chasing in these small towns in rural locations. All chasers-meteorologists-weather enthusiasts are generally looking at the same models and radar data, so it’s common for them to converge on a certain exit off the Interstate. Dozens of cars arrived, full of thrill-seeking storm chasers. We also saw some of the tourist companies with vans loaded with tornado seeking passengers.. these signs seemed to confirm that the atmosphere would trigger severe weather in the vicinity of our location.

Members of TWISTEX said they were looking forward to a chase in South Dakota, typically because of the lesser crowds, the better visibility, and the prime location for storms to become tornadic. The one drawback is the network of roads. Because it is a less populous state, there may not be a road in a place you want to chase. That was one of the limitations in trying to access some of the late-developing storms… it would have been difficult to track them because it wouldn’t be easy to get there!

Our day began in Valentine, NE and we charted northwest to Kadoka, SD by noon before re-grouping in Murdo, SD along I-90 shortly after lunchtime. It was in Murdo we spent most of the day, as forecasters analyzed the conditions before executing a plan. I learned that at this point in the day (when afternoon heating peaks, between 2 and 5 pm on average) the best tools for storm chasing become the visible satellite, and the surface observations. Combined with what you see with your own eyes, those items usually are the best guidance.  In order to track convection, you want for cumulonimbus clouds to be tall, growing, and have definite puffy edges. These sort of clouds result when the “cap” is broken, or the upper levels of the atmosphere become favorable for towering clouds to develop.  Looking at surface observations reveal wind direction, dewpoint, and temperature… basic weather trails that are crucial when identifying where severe weather will break out.

While waiting for the cap to bust, temperatures started to cool and the overcast skies were not conducive to development in our area. Given the targeted chase areas for tomorrow and Wednesday, TWISTEX decided to halt operations for the night and reconviene in the morning! Severe weather parameters for tomorrow look similar, but there is some potential for development. Wednesday still holds the most potential.

Throughout our travels today, we logged roughly another 300 miles. 

There were some highlights today though: we crossed the Central-Mountain time zone line about four times. We chose a vintage South Dakota landmark “1880 Town” as a parking spot for a few hours to wait for initiation. We encountered the highest elevation on I-90 in Oacoma, SD.  We also caught sight of the famed “Dominator” chase vehicle, seen on the Discovery Channel show Storm Chasers.


About Maureen McCann

7News Meteorologist, KMGH Denver
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