Wednesday, May 23, 2012

5/23 - 11:50am CDT - Nebraska or Colorado?

Today we're in the Cornhusker state of Nebraska in search of severe storms. Yesterday's chase in what ended up being extreme southern South Dakota was short-lived as storms that formed up that way south of Murdo, SD quickly dissipated due to a low amount of moisture and contamination of their inflow via a layer of clouds that formed to the south of them. The storm we chased had a nice structure for a few minutes and even put down a bit of a wall cloud before it fell apart.

A cold front situated across the center of Nebraska will be the focus for storms this afternoon. The band of clouds on the satellite image is roughly where the front is located right now and it will slowly sag south and east today. A low forming over Eastern Colorado/Western Kansas should help back the winds out of the east this afternoon here in portions of Nebraska and that will increase low-level wind shear needed for rotating storms as that happens. This low will also create easterly winds in Northeast Colorado, so that may be a secondary target area for today.

We're already seeing some easterly winds beginning to set up in Nebraska this morning and we'll be watching where those develop this afternoon as well. Dew points are still quite low this morning in the upper 50's, but more moisture should move in this afternoon and bump up dew points to around 60 or higher. This is still a bit low for good storms, but we'll probably be better off than we were yesterday in this regard. Dew points in Northeast Colorado won't have to be as high for good storms thanks to the elevation there.

The environment today is rather "capped" as we say, meaning there's a warm layer of air above the surface layer that's prohibiting storm development. As surface heating gets going later this afternoon and into this evening there should be enough energy for updrafts to break through this cap and form storms. This means that storms should be fairly isolated at least starting out, which is a good thing since isolated storms are more organized, more likely to produce a tornado, and easier to chase. Some of these isolated storms may become supercells, and that's exactly the thing we're after since they may produce a few tornadoes today. Storms may condense into one or more lines of storms later this evening as the cap quickly erodes after dark. The Storm Prediction Center has a Slight Risk for severe weather today from Colorado to Minnesota and that includes a couple areas of 5% tornado risk. There's a chance we may bug out on our plans for Nebraska and move to the secondary area you see there in Northeast Colorado, so stay tuned.

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