Wednesday, May 16, 2012

5/16 - 10:45am CDT - To Colorado We Go!

After spending quite a bit of time in Texas over the past few days we are on our way north to Colorado this morning. We're going to try to chase some storms that may form in the upslope flow of the Front Range of the Rockies. Here's how these form: Moist air flows from east to west up the gentle slope of the mountains during the afternoon. This moist air when lifted by the terrain condenses because it's moving into cooler air aloft. As more air rises up this gentle east-west slope, it continues to condense to form clouds and eventually thunderstorms. Since the mountains act as a constant source of lift, these storms can be pretty reliable as long as other ingredients are in place.

Here's the issue for today though... Moisture is going to be hard to come by today because the last major system to roll through the Plains last week pushed all the moisture down toward the Gulf of Mexico. A little bit of it will be returning to the region today though and we can already see that happening on the current surface map. Dew points right now are in the 30's with a couple 40 degree plus readings across the eastern part of Colorado where these storms will form. In a perfect world you'd want easterly winds to be blowing in better moisture and to create better low-level shear, but this morning we're dealing with southeasterly winds. The good part is that it doesn't take as much moisture to generate these storms as it does in lower elevations. Generally you want dew points to be above 40 degrees in this region, and that's something we may struggle to get today if the computer models are correct.

Putting all of this together with some weak southwest winds at 500 mb (18,000 ft) there is a chance for some storms in Eastern Colorado today. With potentially weak moisture return the setup for anything severe looks very "iffy" at this point and the Storm Prediction Center has placed parts of Eastern Colorado under only a general thunderstorm risk because of this. We'll keep an eye on the surface observations this morning and afternoon to determine whether moisture will return as needed.

Last night I had a good internet connection at our hotel and was able to upload some video. Check out my footage of our encounter with golf ball size hail and flash flooding east of Lajitas, Texas on Monday:

Follow me on Twitter and Facebook for updates on our chase today!

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