05/20/06 NOW: OK / KS / MO / AR

As cell in Harper Co, OK is topping at 50,000 ft and clearly broken above the LFC and returning 55 dbz, will go ahead and start a NOW thread. Over the past hour, baroclinic disturbance and extreme heating at the surface along a E/W-oriented stationary front/ wind shift line has exhibited a build in instability parameters which holds some potential for severe over N OK, S KS, and points downstream. Given seasonal norms, hopefull some interest in this developing weather.
I'm a little surprised reflectivity is as high as it is on the lowest tilt for tha storm. The nearest mesonet site (Woodward) is currently showing a temp of 100 with a dewpoint of 41! Yes, that's a 59F dewpoint depression! From a quick looksee on a SkewT, the LCL for that parcel looks to be about 600mb! I would bet that much of the precip from that storm is evaporating, which likely explains the severe thunderstorm warning that was just issued for that cell. The nearby Vici profiler is indicating only ~20kts from 300-600mb, so I can't imagine we'd see anything other than multicell mode. Directional shear is horribly bad in the 850-600mb depth, but not enough to compensate for the relatively weak flow aloft (i.e. RUC mesonalysis indicating ~30kts 0-6km shear). I would think that there may be a first-starter threat from those, given the very low sub-cloud RH. At least they've had some rain up there the past couple of weeks... It's still very dry, but the rains should have helped mitigate the fire situation a bit (and the fact that vegetation is not dormant helps too!). I'd think the damaging wind threat from microbursts (possibly dry) would be the main threat. It is right along the "front" (if you can call it that -- not much of a temp gradient, with Tds increasing a bit to the north of it), so I guess you never really know LOL
Since already up in this area me and my chase partner Sergio, are heading to it right now from the family reunion. Dosen't look all that great on radar but I am going through serious withdraw right now so I will take a peek at an hope I at least get a hail stone to satisfy me for the time being.
An isolated storm just fired in northeast AR in quite a favorable environment for it to strengthen further. RUC mesoanalysis shows 2500-3500 j/kg sbCAPE across the area and its pretty much right on the frontal boundary at the moment. The storm is completely isolated from anything else, and RUC mesoanalysis shows more than 300m2/s2 0-3km SRH invof the storm -- with the storm initiating in a "patch" of 0-3km low-level CAPE (indicating a slight decrease in CINH strength in that region), so assuming it's feeding off boundary layer inflow (quite likely), the storm could indeed quickly intensify and perhaps gain strong low-level rotation given the sufficient low-level SRH. The storm is also in a region of lower LCLs (given smaller td depressions).

I'm guessing storms could begin to develop to the west soon (i.e. southwest MO and northwest/northcentral AR) -- especially in any localized regions of enhanced moisture convergence (locally reducing CINH and allowing low-level parcels to reach their LFCs).
Jeff wrote:

"The nearest mesonet site (Woodward) is currently showing a temp of 100 with a dewpoint of 41!"

Noticed that too, but at the same time Alva (one county to the east) is showing a td of 64, and Ark City, KS, just to the north, a td of 63, and that Woodward cell has been returning 65 to 70 dbz at the lowest tilt for quite awhile now, so it is hard to imagine no precip falling to the ground at this point. CIN looks to be eroding over around Kay Co, OK, and I wouldn't be surprised to see some convection develop in that vicinity over the next couple of hours.

Just as writing this, noticed a new mesoscale discussion, with the main threat seeming to be "dry downbursts" over the area. However, as LLJ kicks in later, look for severe over this general area to persist, and then into Sunday.
Played around in Mooreland. Watched a lot of litghtning and a lot of rain. The rain did make it to the ground but unfortunately the convective blob of poop was going in all directions and had no organization. It was all elevated. Did get 1 or 2 good shots so will post them later. On an intersting note, the landfill SW of Mooreland is on fire big time.

James <_<