High Risk : 22 May 2008

This afternoon and evening there is a HIGH RISK of severe convective thunderstorms over parts of central Kansas. The SPC upgraded its earlier-issued MODERATE risk at 2000 UTC to highlight an enhanced risk for tornadoes in Kansas along the warm front. As of 2030 UTC, two distinct lines of discrete and potentially-supercellular storms had formed in wrn KS, and the westernmost line was developing soutward into the eastern TX panhandle. Tornado watches extended from the front range of northern Colorado/southern Wyoming (where a large tornado passed just a few miles east of Fort Collins around midday), through southwestern Nebraska and into western Kansas, Western Oklahoma, and the eastern Texas panhandle.




All of this was in response to a large upper-level trough (500 hPa plot below) that this morning resided over the SWrn US. Strong southerly/south-southwesterly flow ahead of the trough axis (50-70 kt at 500 hPa) was forecasted to overspread the high plains this afternoon overtop strong southeasterly/south-southeasterly flow at 700 hPa, 850 hPa, and the surface. In west-central KS, along the warm front, surface winds were expected to back to near easterly (resulting in very strong lowest-level shear and hodographs very favorable for tornadoes).