Wednesday, October 3, 2007

Severe Episode Possible this Weekend

Friday, Saturday, and Sunday (5th-7th) all have potential to be good chase days across the plains as a large western trough will slowly move east. Large model discrepancies past Saturday night keep Sunday's potential a question mark at this time. Friday, I will not be able to chase due to previous arrangements but the bulk of the action may be elevated north of a retreating front in Nebraska/S. Dakota because of a stout cap. If storms can fire along the boundary or in the warm sector, there's a chance they could produce tornadoes due to sufficient instability coupled with great shear.

Saturday, looks to be potentially a big day depending on timing of the associated lift in the mid levels as well as any jet streaks rounding the base of the trough. Again, the cap will be strong but it appears there will be enough forcing to overcome it. Below is the NAM/WRF 12z run from today at 500mb and 850mb:

Still pretty far out but Saturday sure holds potential in central Nebraska.

On Sunday, the picture is a bit less clear due to differences in the medium range models. Most WFO's around the plains seem to favor the faster ejection of the trough to the northeast, much like the latest ECMWF runs. The GFS on the other hand shows a slower solution that cuts the low off further from the northern branch of the jet and slowly drifts it towards the southern plains. Here is the GFS 12z from today for 500mb:

I will post details hopefully Thursday night or Friday as to what days I'll be chasing and where.

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