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10/29/09 FCST: OK/TX/KS/MO/AR/LA

Even though I was hoping Friday's bombogenesis chase day would pan out, it looks like Thursday is going to have the best daytime tornado potential with this monster trough.

Models have agreed on a squall line developing after dark Wednesday and track it to around a DFW-OKC-ICT line at 12z Thursday. Here's where it gets interesting. The deepening surface low will suck up the remnant frontal boundary from the previous system and pull it north as a warm front with a very moist airmass to the south. This frontal boundary is still deep in the gulf (and actually still moving south attm) and I want to be just south of wherever this boundary sets up Thursday afternoon. With the models now showing the trough breaking apart into two separate shortwaves, it looks like there is another surface low that tries to develop in front of the southern wave. Recent runs have shown this cyclogenesis clearly in the moisture fields with the best dp's being sucked back west into the subtle secondary low in OK along the front instead of being drawn up into the bombing low over NE. This should keep the effective warm front pretty far south, especially given early morning showers slowing its northward progress.

According to model precip forecasts, the squall line will be maintained and strengthen through the afternoon as it moves into AR. I've been watching this on the models for a few days and ALL of the runs of the GFS and NAM fired convection in the warm sector in front of the squall line and south of the warm front. Should this happen, the environment will be very favorable for supercells and tornadoes given the excellent shear making up for the meager instability... given a semi-discrete nature. Although this is a high shear/ low cape event, the storm speeds will not be outrageous because the storms should be well west of the strongest mid-level flow, 30-40 mph to the northeast is doable.

Right now I'm liking somewhere in southeast OK as a starting point. Probably end up deep in the heart of Arkansas before all is said and done.

Synoptically, this system is an absolute beast. And regardless of the time of year, throw 70's dewpoints under a jet like this and you've got trouble. Now we just have to nail down those pesky mesoscale details.
10/29/09 FCST: TX/OK

Looking at the new 0Z WRF the area from DFW-FSM may have to be upgraded to Moderate risk. A surface wave forms during the afternoon near Dallas and moves NNE toward the Red River at 0Z then toward FSM at around 3Z. The winds back and surface temps upper 70’S & DP near 70. Tornado parameters are moderate in the 21Z-3Z time frame.
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