5/1/08 FCST: KS/MO/OK/AR/TX/NE/IA

[Mark Manchester]

I don't particularly like the way he puts things ("retarded moisture returns"?)

After reading it I believe he meant it as the slow return of moisture as opposed to alluding to a mental capacity. Regardless, I'm also surprised at the 5% tornado risk with the upgrade to Moderate. Maybe they're thinking things will go linear rather quickly.

 

[cstrunk]

I'm not much of a forecaster, but here's my two cents for my target area of NE KS.

Moisture looks like it will be a concern, and we may struggle to reach 61-62F dewpoints. If we can get to 62+ I will feel a lot better, but at this point it looks doubtful. Low 60's are still down on central/western/southern OK as of 8:30 AM. 63-64 might be a possibility in southern KS, but daytime initiation is my concern for that area and farther south.

I will be chasing with Scott Bell late this afternoon. We will depart around/after 4 PM from the St. Joseph/Maryville MO area. My initial target area is between Marysville, KS and Manhattan, KS. We will choose a final target later this afternoon (and probably as we are leaving).

Here's to hoping we get some better moisture by this afternoon into KS for my first "real" chase!

 

[BrandonWhittington]

As it looks right now, I plan on playing with the dryline further south into OK. TDs are already approaching the mid 60s in southern OK, and the cloud cover will be almost completely eroded off alowing for good mixing. I honostly dont think the cap will be as big as a problem as i was first thinking it would be, the moisture return in a lot deeper and not shallow, temps are increasing nicely as well.

Im going to target the stillwater, ok area this afternoon, and evening. The Dryline should set up shop in the area and if anything retreat bit further west which is my next concern. I hope that the dryline does not start to retreat after storm ignintion..

 

[Mike Hollingshead]

I'm leaning more and more towards the northern target.

http://www.rap.ucar.edu/weather/model/ruc12hr_sfc_cape.gif
http://www.rap.ucar.edu/weather/model/ruc12hr_sfc_sreh.gif
http://www.rap.ucar.edu/weather/model/displayMod.php?var=ruc_sfc_wind&hours=hr09hr12

I think that is going to be just too big of a tease to keep me up here. Both areas have their issues and I'm just not sure which is a safer bet. I think both are just as scary to not go to. I do not like that strong sw-ne orientation firmly back on the NAM with the sfc front to the south, and almost think it'd be better to be in OK.

 

[Jason McKittrick]

Yeah some of us are crazy, looking for that wall of good juice(not March) that will ride the dynamics from that "April" cyclone north, and reside under 6c at 700mb in the afternoon(that'd be a breeze in June ).

BTW, 42002 now at 66.4 dew, up 6 in 4 hours. I'd say the wall is near there.

And as for 60 TD in se KS. I'd think you could look at midnight and see those.

Mike, First 60 dew appears in KS at ICT 8AM. I still think moisture is a serious problem for everything north of I40. I will admit that the moisture return yesterday was very impressive, and if you look at surface loops of the big events i.e. April 3rd 1974 there is usually incredible moisture return on the best days. It really hacks me off to waste such a great setup, reminds me of May 29th 2004. I think there may be a decent play today near the triple point especially if cap can prevent widespread storm development. Hebron, Beatrice, Falls City 59 dews at 9AM I will be targeting the triple point today along the KS/NE border. Still worried that LCLs will be too high for any good tornado action.

 

[Mike Hollingshead]

Yeah when I said that I wasn't thinking about the winds staying up and not letting the temps drop and dews come up. Even at that, the moisture return has been less than I thought would happen by now.

http://www.spc.noaa.gov/exper/mesoanalysis/s6/850mb.gif

That westerly 850 flow can't be of much help.

Some good dews can still make se KS but that is going to need to let up really soon.

If I had to name a target right now, I'd say very near Sioux City.

 

[Mitchell Daszewski]

I'm not in a position to chase today but have been keeping an eye on the setup for the past few days, however I am realy intrigued by the new 12z NAM showing a possible supercell day in and around the Houston area this afternoon (my back yard).

Last night's runs of both the NAM and GFS showed decent PVA rotating across the area around 18z-0z and a psuedo boundary setting up below 850Mb. The new 12z NAM is stronger with this feature with locally backed low level winds and decent convergence. Models break out precip near the boundary. With upper 60's DP's and deep layer shear in the area, supercells would be likely.

I'll be curious to see if the GFS follows suit and whether or not SPC deems this noteworthy and extends the slight to Houston.

 

[Mike Peregrine]

Well, I will probably be chasing in the dark tonight. If this thing were just a couple hours earlier and the lid wasn't as strong, I would be much more content. As it is, I'll be targeting the vicinity of Hiawatha, KS to Falls City, NE, into NW Missouri. I didn't want to get into this area due to cell coverage issues, but I'm going to try to maximize potential. I'm not sure why NW Missouri isn't included in the MDT, but wonder if it might be due to questions of storms lining out quickly as they cross the state line. I may still shift to either EMP or STJ as starting points, but that's just where things are at for the time being. Hopefully something happens during daylight.

 

[Van DeWald]

Still shooting for southeast Kansas here. Somewhere near Eureka or Chanute KS. Have no doubts that there might be something for the northern targets up in Nebraska, but think the better, chaseable storms would be south with better overall potential.

Although, am sitting in the repair shop at the moment trying to get an intermittent starter problem fixed on my car. Don't want to have a supercell bearing down on me when my car won't start, or get stuck hundreds of miles from nowhere in the middle of dirt road when the car won't start. Burning daylight here with every passing minute for drive time south, but what else can you do. At least I've got lot's of time to pinpoint my target sitting here in the service center. Ha. Plus, it will probably be an evening party for southeast Kansas, so I do have some time to work with. Good luck to all those that are chasing today. Stay safe! But, if my car repair takes too long, I'd settle for what I could get here locally.

** Edit, ignition module and IAT sensor on my car. Ouch. Well, at least I spent most of my tax rebate just like they wanted me to. Anyhow, will probably try to target northeast Nebraska now and hope for some triple point action, and will likely bail on southeast Kansas. :\

 

[Mike Johnston]

I still believe the SE KS / NE OK area holds some potential, perhaps even during daylight hours. Models seem persistent in development of a secondary surface low, although there is considerable uncertainty re: its latitude. At 00z, the RUC has it centered over W Central KS, while the NAM has it over the TX Panhandle. Either way, it should open the possibility for a wave along the dryline.

Re: initiation, the 12z models try to break out convective precip by 00z; the NAM in an area from Coffeyville, KS swwd through central OK, and the RUC in a much more localized area in vicinity of Coffeyville to Parsons, KS.

If we do have initiation and storms move into SE KS, the enivornment looks very decent, especially w/ the LCL's ~ 700 meters and some impressive instability and helicity overlays.

Given the opportunity, I would set up as far east as the intersection of U.S. 69 and U.S. 400 - just south of Pittsburg and monitor development westward of there.

 

[Donald Giuliano]

Although we got some good moisture return last night, moisture continues to be a sticking point with this system as strong westerlies are presently scouring some of it out. Based on visible satellite it currently looks as though the northern extent of the best juice is near Waco, TX, with a second moisture surge likely to occur late this afternoon and evening as the low-level wind field backs in response to the main upper support moving in. How far north this surge can make it and when it can do so is the big question right now, but it looks as though it may come in around/after sunset. I'd say 00-04Z is the time frame to be most interested in this evening--I wish it were earlier, but I'll take what I can get.

 

[Alex Lamers]

Anybody notice the 12Z NAM? It develops things ONLY in Oklahoma before 00z. Kansas is dry. That's interesting. In fact it develops more precipitation than the RUC, which is not something you see every day.

EDIT, also the 3km WRF ARW fires off a line of stuff around 4pm from SE KS into OK right along the boundary...that may do something briefly. It then redevelops stuff about 2 hours later farther west. Look out NC OK into SC KS. Like the SPC WRF this develops a lone supercell in that neck of the woods. Interesting...

http://www.wrf-model.org/plots/realtime_3kmconv.php

AJL

 

[Scott Lincoln]

Anybody notice the 12Z NAM? It develops things ONLY in Oklahoma before 00z. Kansas is dry. That's interesting. In fact it develops more precipitation than the RUC, which is not something you see every day.

AJL

It actually is surprising me that its doing that. Most model runs I've seen dont show the dryline moving at all that far south, and I'm just not seeing much convergence until the cold front moves in. That latest run is alot different I think than the 00z. It came in while we were doing our chase weather discussion here at Iowa State. We were excited to see a model really start pushing the dryline east and keep the northern low dominant, but at the same time not much precipitation looked to form with that eastward surge. Regardless, I think a majority of us are going to head out and go to either far southeast Nebraska to be near the low or to east-central Kansas to be near the better moisture returns.

Alex: I was looking at the NSSL WRF run also and it doesn't form anything until dark or just after, all along the cold front in central OK. I wish the models could make up their mind 8 hours before the event!

 

[Mike Peregrine]

My other question now has to do with what the RUC appears to be doing with TDs between 15z and 21z. It appears at least that it is choking the flow off a bit to everywhere but NW Missouri and SW Iowa in the northern target areas. I am now wondering if the southern SFC low may initiate sooner in SE Kansas and this could potentially disrupt clear flow of moisture further upriver along the dryline. Will SE Kansas steal the juice?

Edit - definitely revising targets to SE Kansas now. Looks like most favorable combination, better data coverage, and all around safer bet at this point.

 

[Kenny Drake]

Okay (1) I'm throwing the WRF out of the window. 20 km, 12km, 4km, I don't think higher resolution is fixing the problem. I'm not quite sure where the problem is within the WRF but it's not due to spatial resolution concerns. Not one model has been consistent to my liking, however the GFS has been the MOST consistent. ECMWF also aligns fairly nicely with the GFS. The GFS progs a nice vortmax to move across N. TX/S. OK later this afternoon and GFS still fires convection in C. OK'ish (same as last night's 00Z run.) W/V imagery verifies that what the GFS is seeing as a shortwave at 500mb is in fact there. 12Z NAM now picks up on this and since observations are verifying with the 12Z NAM and GFS, I'm going to sit here in Norman and bank on something going up along I-35 in the C. OK area'ish. I believe the s/w is going to arrive fairly late and initiation will occur around the 4-7pm timeframe. I am really hoping for a 19-20Z'ish sounding from OUN to verify that the 850mb winds begin to back to the south like the model progs and also to diagnose the cap. The problem of course will still be the CAP, even with the enhanced forcing from the s/w. The cap will be less of an issue in KS however storm rotation parameters are much less favorable. Everyone in C. OK needs to turn on fans and aim them upwards.

PS: There is a good chance I'll completely bust, but hey I'll learn that the cap was too strong for the s/w.