Storm Chasing with Weather Dan – Day 4

Continuing the “building” theme of this trip, with another day more promising than the last. However, our disappointments, too, continue to build.

May 20, 2011; 6:00 AM • by Weather Dan

This is part of Weather Dan’s ongoing 2011 storm chasing series. For a couple of weeks he’ll be running around the middle part of America looking for the meanest storms in the name of SCIENCE. Follow the action here.

Above: A friendly leprechaun welcomes you to the east Texas panhandle town of Shamrock, located about 20 miles west of the Oklahoma border on Interstate 40.

ENID, Okla. – Yesterday, it was the “Palmer Divide magic” that created the unchaseable (for us) tornaoes in northeastern Colorado. Today, as trip leader Chris White put it, we needed some “six o’clock magic.”

Today’s chase, which should have been sponsored by sadtrombone.com, was one we were more optimistic about than yesterday. We had the moisture we were lacking yesterday, and we also had some pretty strong winds, and the influence of both a dry line and warm front draped across Oklahoma.

Our chase plan today took us from our hotel in Shamrock, Texas east along Interstate 40 to Hinton, Oklahoma – about 30 minutes west of Oklahoma City. We watched the skies as we drove down the road, and used our stop in Hinton both to have lunch and to watch for further development. After retreating to the north and west, we found a nice little park in Calumet, Oklahoma. From there, we watched the sky and talked to some locals who stopped by.

We were watching for what are called “towering cumulus” clouds. While the name “cumulus” typically conjures images of white, puffy, fair-weather clouds, towering cumulus clouds are the first signs of the updrafts necessary to develop thunderstorms. If there are no towers, we have no storms.

Today, it was not meant to be.

Our day was foiled by the cap. Short for “capping inversion,” it’s a layer of warm air positioned above a layer of cooler air in the atmosphere. Because thunderstorms develop via ascent of an airmass warmer than the surrounding air, encountering a warm air layer aloft can slow the vertical trajectory of such an airmass. A strong capping inversion can inhibit or completely shut down thunderstorm development across an area.

When the towering cumulus clouds interact with the cap, the towers are prevented from going any higher. No towers, no thunderstorms. And that’s exactly what we got.

The theme of our trip so far has been “building.” We had a two-day drive, building up to a very marginal chase day, building up to a seemingly good chase day that ended in a bust, despite doing some very good forecasting. We were in location before the Storm Prediction Center issued either a mesoscale discussion (a discussion of the severe weather threat in a particular location) or the tornado watch that was ultimately canceled early. We put ourselves in the best position possible, but the weather did not cooperate.

Tomorrow, the “building” theme continues, as the dynamics continue to become more and more favorable for both severe thunderstorms and tornadoes. We’ve got a long day ahead of us, with an early meeting and departure for central Kansas. Hopefully we’ll find what we came here for – a strong, easily visible tornado touching down over the uninhabited parts of the Kansas prairie.

May 20, 2011 6:00 AM 0