Thursday, May 26, 2011

5/26 - 11:45am MDT - Upslope Storms in Northeast Colorado

Good morning from I-70 westbound near Burlington, Colorado! We're on the hunt for upslope thunderstorms in Northeast Colorado (maybe Eastern Wyoming?) today since this appears to be the best chance for severe weather across the Plains. The reason we call these storms "upslope" is because they form when easterly or southeasterly winds blow into the higher elevations near the Rocky Mountains, causing air to lift as it does. This lift helps to create thunderstorms because the lifting air cools to its condensation point (a cloud is born) as it increases in elevation with the topography. Check out the graphic I made this morning to explain this concept to our tour guests during our briefing for a good visual:

It appears that shear will be quite good today, so rotating thunderstorms and supercells aren't out of the question. The tornado risk doesn't appear to be high today, but storms that have formed out this way over the past couple of weeks have had a history of overachieving by producing tornadoes and landspouts. Dew points will be in the upper 40's and 50's this afternoon across Eastern Colorado, which is good for storm development in this area. The elevation here compensates for the lack of moisture in the air, so you don't need the 60 degree + dew points that you need in the Central and Southern Plains. We already have dew points in the 40's this morning and the southeast upslope winds to carry in even more moisture, so we're well on our way:

The Storm Prediction Center has issued what's called a "See Text" for Northeast Colorado and Eastern Wyoming today. This means that the SPC doesn't feel this risk area merits a Slight Risk, but instead they want to direct your attention to the textual discussion below the graphic on the webpage for further information. This does not mean there won't be severe weather out here today. Since there will only be a couple isolated supercells affecting a small population, it's not worth it to issue a Slight Risk area. These supercells could put down tornadoes as I said before, but the risk to life and property is minimal due to the aforementioned low population out here. That's good news because we will have a great view of these storms today without the dangers and hinderance that populated areas pose to storm chasers. There is also a 2% tornado risk through extreme Northeast Colorado, Eastern Wyoming, and Western Nebraska, which is something new on the 1630z SPC outlook that wasn't included with the early morning one. Hopefully we'll find some good storms today!

Don't forget to follow me on Facebook and Twitter for the latest chase updates this afternoon!

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