3-28-07 FCST: SD / NE / KS / OK / TX

[Brian Stertz]

Looking at the latest RUC...it appears there are 2 hard targets later this afternoon/evening. The first target is across WC Nebraska/E. Nebraska Panhandle/extreme NE Colorado. 50 kts. + of 0-3km shear, favorable 0-3km CAPE of 100-200 j/kg and good VGP forecasted suggests a strong tornado threat in this area. The RUC was also painting a pretty good target across the EC/SE Texas Panhandle and WC/SW Oklahoma as well. Low LCL's..a slightly strong but breakable cap, and favorable VGP/CAPE suggest an enhanced threat for tornadoes in this area by early evening. Supercells may remain more isolated in the TX PH/SW OK area with the benefits of a stronger cap. Initiation should occur sometime after 19z across the extreme NE Colorado, NE Panhandle/WC Nebraska, and after 22z in the SE/EC Texas Panhandle.

 

[Adam Atkins]

A couple of observations from this morning. The RUC has initialized the surface moisture well, but has forecast 65+ Td's across much of the Southern Plains by 4pm, which leads me to believe there won't be too much mixing off the dryline in the warm sector. The model has also picked up on a couple sublte surface features that shows up as a wind shift boundary north of OKC and south near the Red River. These features might not fully wash out if limited mixing in the boundary layer occurs. Why not mixing? There's a thick cirrus deck overspreading the region via IR satellite and will keep the boundary layer from fully mixing. The shallower moisture near the dryline will be the first to see full insolation so the strongest instability should develop out west and CINH should erode quickly. The "strong cap" everyone has been forecasting really isn't showing up on morning soundings, however WAA will occur during the day to reinforce the cap.

The big questions will be whether sufficient E-W instability develops off the dryline before initiation and whether storms will fire exclusively off the dryline, OR also develop at the subtle boundaries in OK should they maintain their structure after insolation and mixing. The RUC and last night's 4km WRF initiated storms ahead of the DL in southwest Oklahoma. I've seen this burn chasers before so I plan on staying ahead of the dryline boundary, which is also an area of better backed low level flow, and either waiting for storms as they develop and track NE'ward, or catch something ahead of the dryline (Ie. Throckmorton).

Good luck all.

 

[Mark Farnik]

Well I've made up my mind. This is just too close and too good of a setup NOT to chase today. My target today is Ogallala, NE. Why, you may ask, given the aformentioned convective mode issues? Well, I personally see some very good things about Ogallala. First off, the triple point will be parked almost on top of it around 3 p.m. this afternoon, with the surface low back to the west/southwest, a warm front extending to the east towards Kearney/Grand Island roughly paralleling I-80, and the dryline extending back south to north Texas. As of this early hour, the dewpoint at Ogalalla's Searle Field Airpark was already a juicy 54 degrees, and I believe that 60 degree dews should be in place over southwestern and west central NE by early to mid afternoon. Directional shear is looking quite nice, as surface winds are east/southeast at 15 knots, 850 mb winds are southeast at 30 knots, 700 mb winds are south/southwest at 35 knots and 500 mb winds are southwest at 50 knots. Storms should initiate in the mid afternoon hours in far northeastern CO along the dryline and quickly go severe as they move into the juicier air in Kansas and Nebraska. Tornadic potential will be enhanced along the warm front as is typical in these types of situations, so I'm going to play along that boundary.
This brings me to the storm motion/convective mode issues.
It has been mentioned several times both in SPC outlooks and on this thread, that storm motions in this area will be more parallel to the boundary, which would increase the likelihood of seeding effects and accelerated cold pool formation and speeding up the transition to multicellular modes.
However, while they'll go multicellular more quickly than points further south, the primary convective mode should be supercellular for several hours after initiation.
And plus, it's only a two hour drive to my target, versus an eight hour drive to the southern target. And with gas continuing to skyrocket, it's a much more affordable target. Might not be quite as favorable for significant tornadoes, but I still think there will be a few tornadoes in this area today. I'm so excited! SDS, you've met your match!

 

[Brett Adair]

Unfortunately, I won't be chasing this afternoon since I am some 2000 miles away from this one...LOL. If anyone needs assistance as far as nowcasting goes, you can shoot me a PM and I will provide you with a phone number and I will help anyone I can.

 

[David Wolfson]

Waal -- shoot. After arising virtually in SJT and perusing the RUC, I'm quickly packing up for Dodge City, KS. I'd hoped for some decent split flow and lee cyclogenesis in the FST - SJT area by now. Not happening and not forecast to happen. Moisture axis is displacing north and east. Best dryline push and parameter convergence looks to be DDC and north; my target is the southern end of the favorable jellybean.

 

[Aaron Kennedy]

Concur with Mark. Sadly I woke up with a spring fever, and being in the car all day + sickness doesn't bode well. I gotta sit this one out : (

 

[Lance Maxwell]

A couple of you have hit on this, but I thought I would throw out a couple of the RUC soundings to help illustrate just how impressive the W and SW areas of Oklahoma are looking for this evening.

Clinton (albeit I will play much further west than here, just no soundings available for the Shamrock-Sayre area):

http://beta.wxcaster.com/cgi-bin/parse_skewt_trace.cgi?model=RUC&fcsthr=012&STATIONID=kclk

Altus

http://beta.wxcaster.com/cgi-bin/parse_skewt_trace.cgi?model=RUC&fcsthr=012&STATIONID=kclk


As you can see, the LL flow is now forecast to become increasingly backed leading to 0-3km SRH values in the 300m2/s2 range. Also notice the pretty much outlandish prog'd CAPE values of 3-4k (don't think these will be realized, but impressive for the RUC nonetheless).

ATTM I have yet to confirm my target but it will be in one of those two directions. I think I might lean toward I-40 west to the border though.

 

[Gabe Garfield]

The 12Z RUC just went insaneo drano! Jeepers creepers...

CAPE is still progged to be >2000 j/kg across the entire dryline and >3500 j/kg in W OK! WOW... Not to mention 0-3 km SRH values progged to be >300 m2/s2 along and east of the dryline (including several local maxima approaching 500 m2/s2). To top it off, RUC is highly suggestive of convection east of the primary dryline, which bodes quite well for the supercell mode (at least, for a while).

If this verifies, oh boy...

Gabe

 

[Brian Stertz]

2 areas standing out as southern targets

Looks like some deeper moisture is sliding northward just east of the Caprock...could really make for some interesting times this afternoon on the dryline between Clarendon and Silverton TX. Also of note is a decent theta ridge poking towards the NC/NE Texas Panhandle and E.Oklahoma Panhandle east of the dryline. Looks like this could be a muti-faceted supercell event later on. Strong tornadoes appear to be possible with the increasing low level shear and 2000-3000j/kg CAPEs forecasted.

 

[Jim Bishop]

Yes, it's very interesting that both the WRF and RUC fire convection well to the east of the dryline from Childress into Southwest Oklahoma around 4-5pm. Both indicate backed low level & 850mb winds, with south-southwesterly mid level flow. If this verifies..boy oh boy I wish I could be out there for those tornadoes!!

 

[Ryan Pfannkuch]

"Virtual" 4-county target area in W KS: Wichita, Scott, Kearny, Finney
Including the cities of: Garden City, Lakin, Leoti, Scott City

Well, no chasing for me today as I'll be working the evening shift at WFO Hastings, but if I were free I could see this being an especially tough decision regarding target area. Part of me would want to "keep it simple" and just drive straight west out toward the sfc low and hang out along Hwy 34 in the Wray CO-Benkelman NE area.

However, this just seems like the kind of day where I would want to be take my chances several counties south along the dryline into KS....where things might stay discrete a bit longer and/or fire a little later...but at the same time I'd risk missing a few TORs in my own state (which is hard for me to do!). At any rate, this show just keep focusing farther and farther west.

Thus, the 4-county target above reflects this thinking:

-- for starters, with this much forcing, great kinematics and instability along a long length of the dryline, and lack of a true warm front to focus on...it's harder to really pin down a sweet spot. This being said, with many events over the years, it just seems like some of the "bigger" events seem to focus a solid 100-150 miles S to SSE of the main northern sfc low.

-- interestingly, the southern end of the theta-e convergence max on the 12z RUC seems to correspond fairly well with what I said above.

 

[Mikey Gribble]

I'm late getting out of town this morning. Walking out the door right now. I am sticking to my guns and heading for Hays. The WRF has me nervous about a secondary dryline in western OK. I'll hang myself tonight if that happens. Nice loaded gun sounding at DDC this morning. Good luck to all today.

 

[Donald Giuliano]

The SW OK target is looking more interesting all the time. I'm particularly excited by the RUC/NAM forecasting a secondary jet maximum separated from the main system, and located over W TX this afternoon, with the left exit moving over SW OK this afternoon/evening. A very intriguing feature, and one I love to see.

 

[Brian Swiatowy]

Caprock/Moisture Depth

In my humble opinion, the recent rains/soil moisture combined with the depth of the moisture may very well be enough to slow the dryline in the eastern Texas Panhandle this afternoon. By the time the cap is broken, the dryline may very well be situated farther west than this morning's models were indicating. The 12Z RUC seems to be picking up on this a little bit. This would give the storms more time to get better rooted before heading off into the deeper moisture. It's 11:00 now and the low clouds have yet to break free here in Amarillo. I hope that doesn't last too much longer or we could have an issue with surface heating. All in all, it's shaping up to be a very interesting day. Best of luck to all of you going out today. Be careful and happy hunting.

 

[Glen Romine]

Not much new to add after looking things over. As others have noted, two areas stick out as more favorable - one at the extreme ne corner of CO on the thetaE nose where the surface boundary arcs back to the NW allowing a more favorable orientation relative to the upper level flow (though risk of storms quickly crossing the narrow instability axis). The WF now crossing the OK/KS border seems to wash out in the RUC, though I'd be trying to keep up with it as it sweeps north. South of this, dewpoints are impressive in the TX panhandle for this time of year. Concerned with the shallow moisture not well capped (dry air below main inversion) which could really mix out badly as winds pick up this afternoon. If the moisture doesn't mix out too severely, 700 mb jet max nosing out into central TX panhandle could aid in dryline bulging and focus for storms in the Pampa to Perryton area. Cirrus cloud cover could persist making for a late initiation in this region. Initiation won't be much earlier elsewhere though given 700 mb temps of 6+ C sitting over the entire region. If winds at GDP pick up above 50 knots by early afternoon, then I'd guess things will pan out ok. If I could magically appear anywhere, I'd probably roll the dice with a target of Imperial, NE. A wild and crazy target would be early initiation off the Black Hills of SD.