27 February 2011

February 27th - Severe Weather Outbreak

A pretty impressive set up in a less than impressive area. Storms were expected to develop in three areas today.... near the triple point, along the warm front, and a long an upper level impulse, with a conditional threat of storms blowing up down the dry line toward the Red River. By 4:30 P.M. the impulse kicked off scattered elevated hailers in KS (some of them severe warned) and now is kicking off storms in W AR. The triple point is lighting up with thunderstorms (possible supercells) near Woodward, OK. The dryline is still capped attm, but a dryline bulge was evident SW of OKC near the Red River Valley. As the dry line moves east to the OKC area near 00z, sufficient cooling will occur and I expect thunderstorms to explode into one giant QLCS (see 2/24). Further east a long the warm front, if thunderstorms can sustain themselves a few may be capable of producing significant tornadoes (especially in NE AR, NW TN). At the moment an isolated tornado warned supercell has formed along the warm front in WC TN about an hour west of Nashville.  Chasers are all out in OK/KS betting on the cap breaking with a couple supercells going before dark. Will their perseverance pay off? I will attempt to do a running play by play for those not fortunate enough to have access to radar or data.

*Valid WW as of 2251z

*Isolated thunderstorm near Medford, OK. Chasers showing what looks to be an LP type storm capable of producing very large hail at the moment. Surface based cape near 2000 j/kg are in place ahead of the cell. The current storm motion is on the hodograph... so storm-relative winds are weak... it will take a significant turn to the right to improve its storm-relative wind profile.

Dry line bulge showing up on KFDR. Cap index values are decreasing in far south-central Oklahoma ahead of the dry line surge in the red river valley ... Viewing satellite data, towering Cu continue to slowly develop in this area. Surface based storms could develop in the next few hours, especially as the EML/700 temps cool.
*First tornado warning of the day. Isolated supercell about 50 miles WNW of Nashville. First of a many more likely to come as the day progresses.
*A small storm is trying to fire in far S. MO near the warm front as the upper level impulse (currently located near the AR/OK stateline) swings on through at around 50kts. Little Rock will be launching a special balloon at 03z per the request of the SPC. Certainly something to monitor.
*Special sounding from OUN
UPDATE: 5:30 P.M.
*A split looks to be occurring with the supercell. Chasers are reporting a wall cloud with decent rotation. If this storm can deviate to the right, it would greatly improve its' storm relative wind profile and be a major threat for the next several hours. Nothing is imminent yet, but the cell keeps moving into a favorable environment and continues to look better on radar.
6:00 P.M ---

*Supercell has now gone tornado warned... apparently there was a weak tornado reported, but that remains to be verified by multiple sources. Visually the storm on streams and through uploaded pictures look pretty cold and outflowy. I am not there though so I really can't and won't criticize. Good luck to all those out there!

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