Tuesday, May 28, 2013

Southern Plains Threatened Again on Wednesday

For at least the third time in at least a week, the Southern Plains will be threatened by an unusually high risk of severe weather. The Storm Prediction Center has issued a Moderate Risk of severe weather in accordance with this heightened risk.

A storm system will begin to reach a negative tilt going into Wednesday, indicating that the highest mid-level vorticity values associated with this storm will be pointed towards the southeast. As a result, the storm system will strengthen and amplify the pattern that this severe weather risk will be in. Strong jet stream divergence to the immediate east of the moderate risk area, as well as a strengthening lower level jet stream will lead to an atmospheric wind field that favors severe weather.

Projected radar reflectivities for Wednesday evening

Projected updraft helicity for Wednesday evening
A special convective WRF model that was run earlier today is indicating that a tornadic environment will share the stage with a damaging wind-style convective cluster. You can see the intense thunderstorm formation over the Plains for Wednesday evening on the top image, and these storms are split into two categories. The first involves the linear thunderstorms spread from central Nebraska down to the border of the Texas and Oklahoma panhandles. The second type of storms is the individual cells in Oklahoma. While one would expect the individual cells to have more potential than the linear system, it looks like the strongest helicity values will be placed inside the linear storm cells.

Regardless of where the highest helicity values end up, anyone inside the moderate risk area should be watchful for the potential of tornadoes, damaging winds and large hail.


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