Target Area 8/4/2009

Target: Bridgeport, NE

Timing and Storm Mode:

Late afternoon, 4PM CDT. Scattered convection, possible super cells.

Synopsis:

NW flow aloft over the target area with a cold front running to the SE. A trough of low pressure will move out of eastern WY into western NE.

18Z RUC 200mb:

Discussion:

18Z Surface Analysis:
The SPC is calling for a 5% chance for tornadoes across eastern WY and western NE and SD this afternoon. I am dubious as to whether this will verify but thought it was worth doing a bit of analysis. There is a pronounced trough of low pressure in eastern WY as depicted in the 18Z surface observations in the graphic above. This trough should translate east across western NE later this afternoon. Dew points in and to the east of the target are still in the mid to upper 50's which while not good storm material by OK standards, is plenty to get something going on the high planes. An area of ~1000kg-1 CAPE is forecast over far western NE according to the 18Z RUC run. While the hodographs are not very impressive, there is a decent amount of shear for any storms that fire to work with.

I like Bridgeport as a target area for a couple of reasons. The first is there is a decent road network there and I believe storm motions will be to the SE. That should put the target downstream of most of the action and allow for easy repositioning as the afternoon unfolds. Second, I like the higher Td's in the area. The further north you go the lower the Td's. If anything does fire, I think the southern portion of the SPC area has the best chance of something tornadic. Finally, I like the position of the cold front just to the south of the target. The cold front isn't progged to move much in the next 12 hours, however as the area reaches maximum heating in the late afternoon, the cold front may serve as a lifting mechanism to help fire the convection.

Overall, I am not impressed with this setup, but keeping at forecasting is what I hope will improve my skills over time.

Finally, here is a shot of the current radar and surface front positions according to GRLevel3.