3/7/09 FCST: OK, KS, AR, MO

[matt patterson]

Havent looked at whole lot, but I just checked out the 18z GFS (yes i know its old news) and it looks rather encouraging for an area in C and NC OK. 850 moisture doesnt look near as bad as it did on previous runs. It is going to change quite a bit between now and Saturday, but I like that we are starting to see some model agreement.

 

[Steve Miller TX]

Well, I'm not writing off the ENTIRE season for ALL of the plains between Mexico and Canada. It's not just "dry" in west/central Texas. It's a very severe long duration drought in a good chunk of Texas into the western half of Oklahoma and into SW KS and SE CO.

There is practically NO ground moisture for most all of the state little alone strong vegetative growth. It's worse now than Feb 10th when that event was preceded by a good large-scale precipitation event across TX/OK 1-2 days prior. The GOM moisture was in better shape including the 850mb level if my memory serves correctly.

So, back to the thread at hand. The moisture creeping into south Texas is very thin. A look at the sounding for BRO and CRP this evening clearly reveal that 850mb is bone dry. Looking at the Mexico soundings including Yucatan, it's very dry as well. Without moisture at 850mb, surface moisture will scour out quickly with daytime heating and mixing....something the models often don't handle very well this far out. Going back to the 2/9/09 event, the models overestimated dewpoints. Instead of lower 50's forecast in advance even 36 hours out, it was mid to upper 40's at best come the day of the squall event.

But, it will be interesting to see what by happens Saturday. I really really hope that I'm wrong because I would love to chase some nice supercells Saturday. All I'm trying to do is to offer up something more than just model forecasts for the upcoming system this weekend.

 

[Bob Hartig]

I get it, Steve, and I think you've given some excellent input. Like you, though, I hope you're wrong! I'm in the area this weekend and I'd sure like to see the moisture show up along with a nice taste of early season convection.

Right now, I'm seeing upper fifties/lower sixties reads from the GOM buoys, with the moisture working its way inland on southeasterly flow. That's great. But I don't know what the Tds look like above the surface layer over the Gulf, around the H85 level, and as you've pointed out, that layer is key. We've got a few days for the moisture to deepen; let's hope it does. With water temperatures ranging from 60 to 70 degrees, I don't see why that can't happen.

Thankfully--or maybe not thankfully, depending--the atmosphere doesn't give a rip about our logic. It just does what it wants to. I'm looking forward to Friday, by which time its whims ought to be more apparent.

 

[Darrin Rasberry]

Still on self-ban for model-checking until Day 2, so I'll extrapolate as much as my sophomore knowledge allows from this thread and from the SPC outlook issued today.

After reading this thread and doing some study, I had to chuckle at the SPS Day 3 outlook for today - the SLGT's southern extension for those portions of EC/NE OK and SE KS is directly over the no-drought area on Miller (TX)'s preceding map for those states. Coincidence?

CC setup may be imminent for the evening for SW IA and "The Hole" in Missouri; it might prove for some lazy night practice should the potential for surface-based discrete sups end up in the dumps completely. It's a cold front setup, so I'm not expecting a whole lot, but it's at least a bump to ease the SDS shakes a bit.

As far as the sitch in general, most of KS and all of Nebraska and Iowa on up are just fine droughtwise; remember last year, sans a couple of chase days in western Texas and the early-May OK bullets (think Picher), was pretty bad through April as far as chasable territory during the day goes - scrolling through the reports for last April yielded lots of "NO REPORTS RECEIVED" days, albeit for different reasons being discussed here. And I also recall beaucoup "buoy checking" for March 17 and March 30th last year, as well - SDS is kicking in too hard to label this the new 2k6.

 

[Derek Weston]

eh... mediocre. Shear is a little too unidirectional, CAPE a little too weak... I mean, in just taking a quick look.

It's something, but nothing I'd drive too far for, as of this latest run.

We shall see... at least something to watch, eh? (probably the last thing we'll watch for a few weeks... if the GFS is right about the next cold air slam)

 

[Ryan Wichman]

Just taking a quick look at the 6Z GFS looks to be overdoing the DPs by about 5 degrees F. While the same NAM run is about 10 degrees F below where dPs are at.
At this point I am not very confident in much more than a linear event, from forecast soundings it looks like the warm sector of this storm will be strongly capped.

 

[Brian Stertz]

12z NAM still looks to be in bullseye agreement for a target between Pratt-Hutch-Wichita area late Sat. afternoon/evening. Looks like the cap will bust before sunset. Hmmmm do I make the Turnpike trip? I will keep a close eye on things....shear is pretty dang strong and steep lapse rates. May not need a Td of 60 on this event.

 

[Ted Keller]

There is an interesting bullseye of 0-3km EHI along the dryline OK/KS border area at 00Z Sun from the 12Z NAM. And the low level helicity is favorable in eastern Kansas but will any storm be able to tap it? And it will be mostly dark.

Still, it's a Saturday, it's close, I have new equipment to check, it's dark, I'm wearing sunglasses, well, you know the rest.

 

[Skip Talbot]

Based on the 12z WRF:

The cap is going to have a lid on things until near 0z (except further downstream on the cold front). SPC is pessimistic about the setup because of the capping issues. The WRF however has holes on the cold front, and minimal CINH down the dryline to the OK border at the 0z hour. I think we might be able to get something up near the triple point, and possibly a little further south of there given the lift on the boundaries and great dynamics. I think this setup definitely has chase potential, including surface based supercells during a relatively narrow window around the 0z timeframe. Low level CAPE is high here and LCL's are low enough as the cap erodes during this hour. I'd play near the triple point between Salina and Russel. That target will adjust as the models settle on where the triple point will actually occur. With the cap poking around and marginal instability to begin with, if this setup degrades any before it arrives, it won't take much for this to turn into a weak/elevated event.

 

[Sean McMullen]

I wouldn't get too worried about the drought conditions as this area is no stranger too it. Here's some encouragement. Just look at the drought conditions in 1999. It's from August but when it comes to drought a couple months doesn't really matter.

http://drought.unl.edu/dm/archive/99/drmon0831.htm

For Saturday, it might be best to look at it as if it were May. If you saw 50 Td's at best with a 1000 CAPE's and most of the action on the cold front what would you think? Not too good huh? If I lived in the area I would probably go out just for the sake of getting out but it certainly isn't something I would put 100's of miles on my car for.

 

[Andrew Stoller]

I agree McMullen. I looked over skew Ts for all of Kansas and saw nothing to write home about. Hardly saw one model sounding with surface winds east of south. In addition, there's precip all day according to both the NAM and GFS despite indicated capping. Looks like a front induced mess.

 

[Jared Farrer]

Yeah it has a real linear look to it. Most of the convection should be concentrated along the cold front, but there maybe something along the dryline. But most of the warm sector will be to heavily capped for any real development before frontal activity. I think the models have this one pretty well resolved. Looking over temps and dews I think they are down playing cape a tad. But it looks pretty linear. With morning convection hampering any real surface insolation. As far as I see it, not worth driving out for.

The upper levels look good on sunday though!

 

[Darrin Rasberry]

I don't have anything else to do Saturday and I can pick some gas money from the tree in my backyard (read: I'll regret the $75 hit on my bank statement ... later) but with Sunday in my FRONTyard in Indiana the jury will be out for me until tomorrow night, when I can use my meager skills on the way things actually are (i.e. how "wet" 850mb actually is) and so on.

I'll target the DL/CF triple point, see if the SFC low itself can poop something out in NC Kansas before the inevitable cold front marching band lines up 2008-style. More thoughts tomorrow when I can give more than a cursory look at things.

 

[AndyGabrielson]

I realize this is going to be mainly linear but I think it may be worth chasing. All it takes is to get one discrete super cell. Right now it looks like it'll be squal line city come 7 or 8pm but if something could get going early (but not too early) I certainly wouldn't rule out an isolated tornado. It's still 2 days out yet basically but by tonight we will all have made up our minds.

 

[Andrew Ryan]

I wouldn't totally discount tomorrow, just yet.

Looking at the 12z soundings, the 850s are nearly as dry as they were 36-48 hours ago, especially at OUN. Moisture is quickly moving northward with 60F Tds in southern TX. So, it's a not a real stretch to have 50F Tds in the warm sector tomorrow.

The 12z breaks out precip around 21z, which is discrete at first but quickly becomes linear after dark. Decent helicity overlaid with modest instability on the KS/OK border increases the chances of a couple of a supercells tomorrow afternoon.

Not the best situation, by any stretch of the imagination, but worth a shot if you are in the area.