Severe Weather Discussion for March 20 – 24, 2007.
– Isolated severe thunderstorms are possible on Tuesday for western Oklahoma into southern Kansas, primary threat is hail to nickel size.
– Severe thunderstorms are possible on Wednesday for west Texas into western Oklahoma. Primary threats are tornadoes, large hail, and strong winds.
– Severe thunderstorms are possible for Thursday – Saturday across portions of the region.
Models have backed off the heavy rain threat today and I'm doing the same. While we still have decent rain potential, the 4-6 inch stuff appears to be gone for now.
Isolated severe thunderstorms are possible on Tuesday across parts of western Oklahoma into Kansas. The likelihood of storm development is rather small given subtle mid-level pattern. However, atmosphere will be unstable with LIs to -6 and CAPE values around 1000 J/Kg. If any thing can break the cap, large hail will be possible.
Wednesday currently has my interest, especially the 12z NAM-WRF which has very impressive instability parameters. The models have trended slower with the large closed/cutoff low in the SW U.S. This is not a shocker with this type of system. It also makes some aspects of Wednesday's forecast difficult. For now, the models tend to agree that a dryline will form in the Texas panhandle on Tuesday and make a run at Oklahoma on Wednesday as wind fields aloft strengthen. If the NAM-WRF is correct on warming things up, this will help the dryline mix eastward. Current there is not a well-defined vortmax to set off storms on Wednesday. However, well timed jet streaks appear to move in at peak heating and this should be enough to break the cap. Anything that forms will have the potential to become a supercell with associated threats.
The remainder of the week is very tough and severe potential will continue all week. Not sure if any day has a bigger chance that any other, but will need to watch. With the upper system hanging back west, there may be several chances at convection. The upper system is progged to lift out on Saturday/Sunday as an upstream kicker moves in.
Discussions will continue this week and I'll try to pin down significant days before they happen.
Risk area for any part of OK/TX (valid: 03/20, Day 1, Day 2, Day 3):
Slight: 50%, 100%, 80%
Moderate: 0%, 40%, 0%
High: 0%, 0%, N/A
Level 2 – Watching Wednesday
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