2012-05-25 FCST: TX/OK/KS/NE/MO/IA

[Jeff Duda]

I think the severe weather threat is a little greater than what SPC is currently giving it credit for. The main fly in the ointment is that the region will be between two strong upper level disturbances, and thus upper-level support will be lacking. However, model progs have been consistently showing a very unstable air mass developing especially across N OK, E KS, and W MO, with surprisingly little CIN near the dryline and warm front. However, CIN increases dramatically away from the boundaries, so storm coverage will probably be pretty light during the day. Deep layer shear appears to be marginally supportive of supercells, but we've seen high CAPE make up for marginal shear before. It also appears there will be 15-20 kts of 0-1 km shear, so given the steep lapse rates near the surface, I don't think a tornado can be ruled out. Given the lack of upper-level support, I think the best play will be near the triple point invof Salina.

 

[Andy Jackson]

The 0z NAM reflectivity has a decent amount of precipitation breaking out around SC/SE NE as the warm front surges north. This seems to be in response to the mid level disturbance. The thermodynamics shows ample CAPE with CIN eroding by 4pm. After looking at a skew-t sample south of Lincoln I see a good potential for tornadoes with High 0-3km SRH blanketing the area under some strong mid level shear. I would probably target SE NE pretty early and see what happens.

 

[Ben Toms]

I completely agree with what both Andy and Jeff discussed in their posts. According to the NAM, the optimal target should be somewhere in the NE KS/SE NE/NW MO area where cooler 700 mb temperatures, moderate convergence along with a slight disturbance, and generous 0-3km helicity values will reside. However, I'm still keeping an eye on the triple point for a secondary target.

The NAM has been hinting at a minute mid-level disturbance kicking straight through the triple point somewhere between the 21-00z time range which, in combination with low CIN values and moderate low level convergence, should kick off a few supercells. However, the current runs of the RAP bring in much hotter 850mb temperatures which would effectively cap off anything trying to form, but the RAP hasn't impressed me much lately so that will be left to be seen how that pans out tomorrow. SPC is definitely underplaying this one, though. I would have expected even a slight risk with the mid-day 2 outlook. If a storm blows up on the warm front or the triple point, there should be at least some very large hail, if not a couple tornadoes to go with it (especially along the warm front).

 

[Chris Wilburn]

I have to agree about the warm front in SE NE/NW KS area as well. I have been noticing a potential play here for a couple days now. Tonights 00z run of the NAM erodes the CAP a bit more than previous runs. Plenty of moisture and instability along the front so that is no issue at all. Tonights NAM still shows quite a bit of CINH for the triple point target. Targeting the SE NE/NE KS area could be very rewarding tomorrow. Will need to look over the lates 00z NAM more.

Edit: 700 mb temps in extreme NE KS and SE NE are in the forecasted 10-12C range while the triple point area in western KS shows 12-14 which is hard to overcome. There is going to be quite a bit of moisture pooling along the warm front in the areas I have mentioned earlier close to 70 dews. This along with 3,000 SBCAPE may be enough to erode the CAP like the NAM is showing. Both the surface winds and 850mb winds back nicely. The 0-1 SRH in this area isn't exceptioanl, but 100-150 can be enough. 0-3 SRH is insane showing over 500. Just my thoughts for tomorrow.

 

[Bill Hark]

I was not planning on chasing today until I looked at the00Z data last night. There is decent but not too high SW flow at the 500 mblevel along with backed surface and 850 winds. Dewpoints in Oklahoma arealready in the upper 60s to 70 and that should shift northward into Kansas. The12Z NAM has CAPE to 4000 in central Kansas by 00Z and the RAP has the CAPE to2500 by 18Z slightly to the north in Kansas. I am expecting some nice stormsahead of the dryline. The RAP has an area of precip breaking out by 17Zslightly south of the Wakeeney area while the NAM shows an area of precip moreto the south, maybe near Kinsley and additional areas in western Oklahoma. Mybiggest concerns are the high 700 mb temos and that the WRF is only picking upon the precip in western Oklahoma. I am currently in Lawrence and will likelyhead west to Hays and drop south to a target of Kinsley of course depending onadditional data checks.

BTW, I am very happy that UCAR now has the RAP!

Bill Hark

 

[Sean Ramsey]

Since I have to work a normal day today I was looking at the NAM and RAP and starting to like what I see a little closer to home. Plenty of CAPE available at 3k+ and just enough 0-1km helicity (150+) in front of the dryline to make it interesting near the OK/TX border, with capping looking like more of an issue with RAP...NAM says otherwise. I figure since I'm not able to get out early to chase KS today I'll cross my fingers and hope things work out a little further south and head towards Sayre/Shamrock later today.

 

[Mike Johnston]

Convective initiation! Convective initiation! Indicated about halfway between La Crosse, KS and Hays, KS. Looks to be right astride the warm front. Plenty of instability, deep layer shear as well as helicity in the immediate region. SPC seems to not be that impressed with the parameters, though.

 

[Jeff Duda]

Unless that storm puts on the brakes immediately and turns right, it's not going to remain in the warm sector long. The most recent Hays ob (almost directly under that storm) was 75/66. With 12-13 C at h7 and mid-20s at h85, that kind of thermodynamics means SB parcels are going to struggle mightily and probably will not be able to break the cap. That storm is probably going to become elevated as it's flying northeast. The composite parameters just at and north of the warm front are very high indicating a strong conditional threat for significant tornadoes. However, the amount of CIN increases dramatically as one gets north of the front. Along with that, lapse rates are very poor and there is almost no 0-3 km CAPE. That storm doesn't have long to do something before it no longer poses a tornado threat.

 

[Jeff Duda]

Looks like the storms hit a brick wall at I-70. They did exactly what they needed to in order to produce. Good for them.

 

[Kelly Sugden]

Looks like the storms hit a brick wall at I-70. They did exactly what they needed to in order to produce. Good for them.

Looks like they are still producing wedges.

 

[Michael Snyder]

Spotted 4 tornadoes today just south of Hays to just west of Lacrosse.
The wedge at sundown was epic, I was inside 100 yards of it at times.
The town of Lacrosse didnt hit the sirens until about 30 minutes after the +FC was on the ground.
Police had 183 blocked off and they said there was damage to buildings.
Ill have pictures soon, just got back from watching LTG lit wedge tornado for the last hour or so, a beautifull thing.