6/17/06 FCST: KS / OK / TX

[Mike Peregrine]

I keep coming back to see if anyone has started a thread about today yet, and since no one has, here it is.

Basically the SPC seems to have a bit more confidence than I do today, but it's worth taking a look at. An eastward moving MCS has propagated across Kansas, Oklahoma and Texas overnight. In its wake strong daytime heating combined with decent moisture will contribute to strong instability along the dryline across south-central Kansas, central Oklahoma and north-central Texas, which could re-ignite convection by mid afternoon. Questions concerning shear and UL support (surprise) cause me to wonder if it will be worth the $100+ in gas alone to get to Pratt and back today - but worth keeping an eye on throughout the morning anyway. My batteries have been charging since 8:00 a.m. just in case.

 

[Kiel Ortega]

LOL...so I am loving the forecast soundings from the RUC...all would support anticyclonic storms in C/SW OK. RUC develops a line of precip from OKC towards the SW...any station along or just behind this line has half circle hodographs that are counter-clockwise turning. Considering the good moisture around the area, the forecast soundings and left over boundaries from last night's convection, OK might be fun to watch--chase????

 

[Kathryn Piotrowski]

I like todays setup outflow boundry across southern oklahoma it intersects the front over SW OK. It looks like SB cape over 3000 over same area. 500 flow wsw at 35 knts with -13C 500 mb temp over TX Panhandle. I think a couple of tornado's are likely over SC, SW Okla & NC & NW TX today. Watch out for the hail could be larger then baseball in a few storms.

Target area SW of OKC.

PS. Kansas also looks good today target ICT.

Jeff Piotrowski

 

[Mike Mezeul II]

Even as small as the chances are for today, I'm heading out of here at around 11:30 for Wichita Falls right now. It's too close to home not to at least try, so I figure head up to Wichita Falls and hang out there at the library for a bit. Keep the fingers crossed on this one today

 

[Shane Adams]

Wind fields are screwy, which is the one thing that's got me pulling my hair out on this morning's analysis. Instability is there, dewpoint depressions are in the tornadic range, but the models are varying on the wind fields. A check of profilers doesn't really give me much hope, as the best h5 flow is currently located in western OK and might be through the target area before the main heating of the day. Tucumcari and White Sands show dead winds, so the psuedo speed max currently showing up in Vici looks to be all we can hope for. The rest of the profilers show 20-25kts max, which will be marginal. The upside is if we can get the clearing we need, the instability should somewhat compensate for the lack of shear. I agree S OK looks best, maybe into N TX. Right now we're thinking Ardmore to Gainesville.

I hate to be pessimistic, but I'm guessing the SPC tornado will drop to 2%, owing to the crappy h85 wind field. I was wrong already once today, so hopefully I'll be wrong again.

 

[Jeff Snyder]

Another interesting forecast! The trough/low appears to be more progressive in this morning's 12z model runs, which is a little disappointing since the situation doesn't look quite as good (to me) as it did on last night's models. The cold front / wind shift will come through faster than earlier thought, yielding a backing-with-height low-level wind profile. However, strong instability remains behind this wind shift, yielding an interesting situation. As Kiel noted, the RUC forecast hodographs for much of OK show significant anticyclonic curvature across much of OK... The hodographs look pretty nice actually, though they loop the "other way". For example, look at http://www.wxcaster.com/ruc2skewt.php3?mod...&STATIONID=KOKC at hour 12. That's a very nicely-curved hodograph, with strong instability. Given an east or northeast storm motion, there would be significant negative helicity, which would argue for the very real possibility of isolated anticyclonic tornadoes and scattered anticyclonic supercells. I'll take 3000 j/kg CAPE with -300 0-3km SRH. I haven't found any graphics yet that would show negative SRH, unfortunately. Looking at the RUC hodos, though, and giving a northeast storm motion (which seems possible given flow above 600mb across central and northern OK, particularly for a 'left-mover'), I can guesstimate that the SRH is about -300 0-3km.

The NAM isn't quite as bullish about anticyclonic supercell threat, but still indicates potential for such a storm mode this afternoon. Farther south (south of the Red River), the mid- and upper-level flow veers at the base of the trough, resulting in a more 'classic' (though relatively short) cyclonically-curved hodograph. Deep-layer shear from the 12z NAM isn't anything to write home about, particularly in OK (where 0-6km shear is progged to be <30kts). Again, the RUC is more bullish, suggesting 30-45kts in OK. Regardless, with the OFB in southern OK, things may be interesting. I wish the trough would slow down more, so we don't end up east of I35 by late afternoon. Regardless, CAPE should be 2500-4000 j/kg (RUC more bullish than NAM), with the potential for only 15F dewpoint depressions where dewpoints can remain in the 68-70F range.

 

[Angie Norris]

Looks like a backyard chase today. Winds are weak, but there is decent shear, along with backing, and there looks to be some moisture pooling in the southern part of the state where the outflow boundary lurks.I was a bit pessimistic at first given the cloud cover, but that looks to erode shortly so there should be some decent surface heating here in a bit. Going to head out shortly for the Sulpher area.

 

[Dan Dawson]

Looking at sfc obs, FDR and TLX VWP, and SPC mesoanalysis, I think those cells near the Lawton area may have a chance if they can move further NE into the better moisture and backed surface winds. Right now they are in the worst possible place they could be as far as instability and shear are concerned. The low-level shear, effective deep-layer shear, and instability all increase rapidly just to the NE of the Lawton area and SW of Norman. The KFDR VWP shows completely uniform WSW at 20 kts from the surface all the way to 22 kft, but the TLX VWP is much better in comparison, with good low-level veering with height and some decent speed-shear to boot (40 kts at 7000 ft). Robin Tanamachi and I are thinking of heading out soon to sample some of the small cells forming in that area. Maybe we will get some boundary magic today.