Monday, May 10, 2010

The morning update

Much to my surprise, the moisture is returning with dew points up to 60 in OKC at 15 UTC with a 65 just south into TX in the narrow plume of moisture to the west of FWD. It looks like the moisture is deep at FWD on the sounding from this morning. The shear is already large and there is no reason to suspect it will diminish. The hodographs are large and semi-circular from 0-3km.

Currently though there is a deep low cloud deck with indications of wave clouds. This corresponds nicely with OUN's sounding and low level stable layer. The water vapor imagery continues to indicate a dry intrusion aloft is setting up from MAF to OUN to Tulsa. The dryline itself is already in place at AMA, and should be moving rather quickly with the arrival of the shortwave in the next few hours. Convective initiation should occur according to the data prior to 21 UTC and possibly as early as 19 UTC if I have done my wave phase speed analysis correctly.

Presumed 700 hPa cold advection is already occurring into the TX panhandle. BIG question is when will the cloud cover break up over Oklahoma, and where it will recede long enough for temperatures to climb. If the clouds hold strong, which is in doubt, then where they do break up will determine the locations, at least partly, for CI. Sounds like May 3rd all over again.

East moving storms with right movers to the south-southeast. Gonna be a long day for some folks in Oklahoma. And SPC and I are of the same opinion ... maximum threat over a limited window of time. As per my discussion last night, the rightfully acknowledge the limited span of the best thermodynamics and rightfully acknowledge that the shear may be too strong such that storms may need time to fully organize. Thus the CI forecast location is somewhat removed from the maximum tornado risk area. I still wonder though if the environment is really conducive to long track tornados.

I think the answer is yes, but I wouldnt be surprised if a few storms go up, put down a tornado, then proceed to do nothing more that put down very large hail.

Also the nature of the straightline hodograph over the CI area might be conducive to splitting supercells initially. At least a portion of the northern end of the CI area may rapidly transition to an MCS.

ARW run from NCAR indicates that CI will occur by 20 UTC, and I would guess is probably an hour or two late given the use of the MYJ PBL scheme. But it does indicate that the threat area for more isolated storms along the dryline will be further south into Oklahoma. But once storms like these get going in the model there is no telling how correct it is given the bad mass fluxes at this scale (3 km). Suffice it to say the model is trending towards my line of thinking.

Clouds starting to thin over SW OK ... game on. First batch of CI I forecast for east of Liberal KS. If I were chaing today I would be in Oklahoma City east side waiting for data until 1pm.

Potentially dangerous situation tornado watchboxes should be the norm today.