2011-05-11 FCST: KS/OK/TX

[Andrew Stoller]

http://www.rap.ucar.edu/weather/sat...=large&endDate=20110511&endTime=-1&duration=3

http://www.rap.ucar.edu/weather/rad...=black&endDate=20110511&endTime=-1&duration=4

She's clearing out big time. Game on. I think the SPC prematurely downgraded to a slight risk as the presence of clearing and the morning MCS lay down outflow boundaries could enhance the severe risk.

 

[Adam Atkins]

The further south the better. I prefer the warm side of the jet and stronger cap in these highly dynamic setups. Clearing has quickly caused temps to rise into the upper 70s and low 80s in NW TX. The dryline is already trying to mix east with a nice westerly punch...if initiation holds of and some decent instability develop, there will be a narrow time window when the best deep-layer shear arrives late this afternoon and early evening for a tornado or two. I would play NW TX into SW Oklahoma where I expect CAPE to climb higher than the northern targets due to a combination of boundary layer mixing/heating and insane lapse rates.

EDIT: Very nice outflow boundary from Altus and ENE up I-44. The cirrus outflow from the C TX convection needs to move out of the area quickly or initiation could be hosed.

 

[Lance Maxwell]

As far as I can see, the blowoff from the convection down in N TX is going to pretty much eliminate any type of destabilization that might have occurred otherwise in WC and C OK.

 

[Andy Wade]

More crapvection initiating along the Red River S of Altus, OK. That area of SW OK may be out of play now (Altus-Hobart-Clinton) unless that dissipates very quickly.

 

[Atreyu Neyhart]

Clouds are suddenly tearing apart in Central KS. The sun will come out and lead to more destabilization. That increased tornado risk is looking more likely.

 

[Kelly Sugden]

Air mass is already modifying in SW Kansas with temps in the 70s, tds a few degrees higher, 25 mph SE wind, and some accas over Dodge. Feel WC Kansas could see redevelopment which latest HRRR runs have been trending to.

 

[Paul Redmond]

While the dryline is mixing eastward, yet another round of disappointment appears evident for central and south texas, though there could still be some action west of San Antonio. It appears that the drought is destined to continue at least for today. I am also less than impressed with the squal line through much of north central texas, though the rain is most welcome. The rapid moving tail end charlie near Kerrville appears interesting.

 

[Chris Hayes]

I'm not chasing, but if I were I would be worried about moisture advection being cut off due to the MCS in OK/TX. Thing just keeps filling in and getting longer.

 

[Jeff Snyder]

Color me unimpressed. A couple hours ago, I was seeing some potential for southwestern Oklahoma. I had been hoping that moisture would be able to sneak back northwestward as strong pressure falls occurred in the panhandles and adjacent areas of KS. However, shortly after noon, convection redeveloped along the OFB in far southwestern OK and northwestern TX. In addition, an organizing MCS / marginal bow echo is moving into north-central Texas, which is likely going to ensure that good moisture return does not occur in western Oklahoma. Given the thermodynamic situation, I'm not sure how kinematic field is being affected (e.g. it may be difficult to develop a strong LLJ given the current arrangement of convection in OK and N TX).

Current profiler data from Haviland (SW KS) shows S (actually, a few degrees E of due S) at 300 mb currently. Yes, meridional flow aloft can still "work" in the high Plains, but the hodographs still need to look decent (which they would if we had strong southeasterlies at 850 mb, for example). Visible satellite supports the observation of southerly upper tropospheric flow, with the anvils from convection in S OK and N TX moving almost due northward. Almost as important, however, are the lower Tds (57-61 F generally) that characterize the outflow / cold pool in much of western Oklahoma. This, in turn, will advect northwestward into Kansas, which means that the marginal Tds already in S KS (e.g. 51 F @ DDC, 52 F @ PTT, etc.) won't really improve that much. With the seasonably-unimpressive dewpoints, we'll need to see higher temps to develop moderate CAPE, which in turn may yield some LCL issues later.

Again, I'm primarily looking only at the OK threat area -- I'm unable to target KS today, and I haven't really looked at locales nearer the sfc low much. I think the usual warm sector play today is hosed, so, if I were chasing farther N, I'd have to look at alternative targets that currently have quite atypical shear profiles (e.g. the area in far eastern CO and western KS) where storm motions may be surprising to some chasers. There is a decent sfc boundary up there, and you never know what can happen when strong convection interacts with sfc boundaries. Current analyses indicate that the upper-tropospheric flow has cut off... In my experiences, in these cases, the best prob for tornadoes is tucked up near the sfc low (perhaps along an occluded front) as close to the mid-level low as one can get with >300-400 j/kg SBCAPE. Time to start looking at 0-3km CAPE analyses...

 

[Steven Howell]

Paul, that cell does look interesting, as does the little guy out near Del Rio and Eagle Pass, starting to look like a flying eagle. The HRRR 16Z run 1km AGL reflectivity has a flying eagle in SW Williamson county at 21Z....

 

[Paul Redmond]

Yes, the one near kerrville it seemed to be weakening for a while yet has just been posted severe. I would not even try that one from San Antonio with it racing to the northeast.

Those little guys around del rio occur quite regularly and usually become right moves, sometimes literally going in circles. Today could be interesting though. If it crosses the Rio grand, then I might consider calling it a day at work and venturing west to Hondo.

 

[Steven Howell]

that cell out near Llano and Mason will likely continue to intensify and evolve, the cap is weakening out in that area and is breaking to the east as well. We are still pretty capped here in Austin, but looks to be on a weakening trend as well. This could be an interesting evening....