2013-05-08 FCST: TX / OK / KS

[Derek Weston]

Could be a fun little day across the southern plains. A relatively narrow corridor of workable CAPE (mostly on the order of 1000 - 1500 j/kg, but with pockets higher) should be realized across W TX/OK/KS... coupled with 40-50kt(ish) bulk shear should prove to be just enough to pop off some supercells. Turning with height is pretty solid, with an easterly component to the surface winds that I always like to see. Cells should pop off the dry line well as mid levels should be oriented perpendicularly. Dewpoint depression should be relatively large (80s/50s) until towards evening when perhaps remaining discrete storms might have a window for tornado-genesis as temps drop and LLJ kicks in. Perhaps a sleeper day.

 

[Skip Talbot]

Looks like there might be a sweet spot in there right at dusk, with storms walking the tight rope between the cap filling back in after dark and the low level jet intensifying and ramping up the helicity. if a storm can stay surface based and discrete through dusk, I think there's a fairly decent shot at a tornado especially where moisture convergence is maximized at the top of the dryline bulge from southwest KS into the northern panhandles. Looks good enough for me. Brindley and I will see you guys out there.

 

[Tim Nendick]

full disclaimer: I'm relatively geographically limited tomorrow.

With that said, the dryline is certainly the more obvious play. But I do want to bring attention to the composite/warm front that will stretch through Kansas and Missouri as well. The story of this area will be dominated by morning convection as the leftovers from today's storms move through. Evaporative cooling and low insolation will maintain a strong cold pool across northeastern Kansas and northwestern Missouri. This should locally enhance the boundary, providing some additional forcing to the west and south as the clouds burn off and provide differential heating. Along that boundary, the 0z NAM is showing handsome 3km EHI values .

Certainly convection could be messy, and surface based -- especially with the morning convection's impact -- is still a question. Timing, like the rest of the targets, may be marginal as well, with a narrow window of daylight/surface storms. That said, with careful subjective analysis, positioning along the boundary should be relatively doable, and a storm crossing it may well ingest favorably enhanced helicity and be briefly interesting.

It's a conditional target, but it's much closer to home, and one I'll be watching carefully.

 

[Jacob Ferden]

How I approach tomorrow will depend on what kind of moisture actually has managed to return north by mid-morning. The obvious play per GFS, NAM, etc. is SW KS with the dryline bulge / warm front combo. Unfortunately, due to various issues tomorrow, that may be out of range for me. If that is the case, I may opt to play farther down the dryline in western Oklahoma. Mid-60s dewpoints have finally begun to show up in far southern Texas, so much will depend on how well things advect north. Progged LCL heights are not too encouraging, but anything that would develop there would likely be more isolated and photogenic. We shall see.

 

[James Gustina]

I don't have the option to chase today unfortunately (OU exam week, so something good has to happen right?). But the dryline further south towards Hobart/Altus/Vernon looks decent for isolated high-based storms. Like Jacob said though, that T/Td spread means LCLs are gonna be well over 2000 meters. Still, decent H5 southwesterly flow with modest forcing along the dryline should make this an excellent structure day if moisture returns far north enough in time. The 12Z soundings at OUN and DFW didn't look particularly encouraging but that should change when the air mass begins to moisten with the aforementioned moisture return.

 

[Warren Faidley]

Not overly impressed with today, tornado-wise. Have to agree with SPC lowering percentages. Might be a good mega-hail event if you want to place yourself in a sheltered place as the hail bombs you. Could be an isolated risk for a tornado if you pick the right storm based on favorable LCL's.

Stay chasing my friends!

W.

UPDATE:

Looking at the 18-21z HRRR Model Fields, including instability, LCL height and shear, the majority of information points towards Altus, OK. Although signals are similar up north, the south seems to be a better overall choice if you have faith in the HRRR. In addition, the 18Z HRRR Composite Reflectivity has initiation in this area much earlier than up north. Initial target will be around Shamrock, TX.

 

[Derek Weston]

Tough call right now. North vs south. I'd usually go for the DL bulge / surface low area up towards KS, but, parameters look quite a bit better south per latest RAP returns. (SW OK area) Of course, LCLs will likely be higher to the south, and nearer the low should produce better low level shear.

Both the HRRR/4km wrf breakout storms all along the dryline -- picking the winner will be tricky.

I'll probably sit out on 412 to watch the day progress.

 

[Lee Smith-Whaley]

I'll be using Wichita Falls as my target since I'm here anyways. I'm hoping that my basic understanding doesn't steer me wrong as I left all my forecasting books from Jon Davies classes back in KC. One question I do have though. Has anyone else noticed that some radars in Texas come up unavailable in radarscope, but when looking at the status message it says it's operational? With that said, Severe Thunderstorm watch 149 is now posted.