05/21/05: TALK: KS/NE/IA

[Ryan McGinnis]

I going to have to look at this one real close when I wake up tomorrow. Still like down here in Nebraska, if for no other reason than it's a lot closer than driving almost to Minnesota, but I'm not going to stick down here if it looks like a sure bust. I don't think it will be; NAM still shows cap eroding by 0Z. But I also would rather not end up chasing a giant squall. Guess I'll see when I wake up to the RUC and the obs.

 

[Anthony Silver]

The greatest potential for tornadic storms will be anywhere in Central, Eastern and Southern Nebraska tomorrow. I think those areas will be the optimal targets. That's where the most instability and shear appears to be. I'll be stuck here in KC tomorrow as I have to be at work at 7PM. :x . Looks like I'll miss the action up north. Good luck to everyone heading up there tomorrow. Unfortunately all I'll be able to do is watch everything from my laptop.

 

[Tony Laubach]

It's just passed 5am; packing up for what is sure to be a VERY long trip today! Shifting my target a hair north into Columbus today in hopes that the cap will hold convection long enough for us to get into position. Would not be surprised to chase into parts of Southwest Iowa or Northwest Missouri today. Figure on eclipsing well over 1,000 miles for this chase before returning home sometime on Sunday for a Front Range day Monday.

Jon Van de Grift and I will be on the road by 6am, which gives us approximately 10 hours to reach our destination; in that time, we could make it as far as Des Moines, IA if need be, so hopefully we'll be all right.

Anyone available for nowcasting, please drop me a PM or an email and let me know. We'll make data stops at the same time we stop for gas, so we'll try and keep up on things; I'll get your PM/email later this morning when we stop the first time!

Thanks and good luck to all out! Gonna be an interesting day!

 

[Philip Flory]

Not a lot of time to post, tired and going back to bed for a while. However, I am growing less and less enthused about todays prospects in SE/S NE.. N KS. Am liking NW IA/W IA better right now, and with a long drive in the cards along with a high-bust risk and things to do around here, today has just become very iffy for me. NAM has been trending towards less and less QPF output every run now for N KS/S NE... and the NAM has seemed to underforecast cap strength if anything this year. NAM also appears to be way-overforecasting TD's by a good 5-6 degrees... yielding less than the advertised 4000 J/KG SBCAPE (to to say 2500-3000 isn't doable). Lower dewpoints also will yield much higher T/TD spreads of 20-25 much of the evening. If the cap was breakable, I would target the Beatrice-Nebraska City area. Im afraid right now that today is just another example of most of the ingredients being in place but one thing is holding us back (gee.. never heard of that before..)

I'll take another looking in 2-3 hours..

 

[Dick McGowan]

As we talked about early yesterday afternoon, still targeting Nebraska city. Eric will meet me in olathe around 10 or so, and will pick up Mike johnston in lee's summit shortly after. Should be in nebraska city around 1. Will analyze from there, and go from there. Let's hope this stays out in rural areas, nothing worse than getting stuck in like omaha, for instance. Will most likely head to into IA, but that's too far out right now. Good luck to all!

 

[Shane Adams]

I am not at all excited about today's prospects after an early morning analysis. Current RUC has triple digits forecast throughout much of Kansas and into Nebraska, which will aid with the cap breaking issue. However, with current progged dewpoints of upper 50s, this isn't gonna get it done. Mid-90s are forecast all the way into NW IA, juxtaposed with low-50s dewpoints - again, not gonna do it. Perhaps the dynamics will create some sups with 5000ft bases for structure fans, but for anyone wanting a tornado, I just don't see it happening. I don't understand the 5% tornado SPC has, I guess they have more faith in the pure dynamics of this system than I do. I just know that 30+spreads aren't what you want to see for tornadoes. There's a band of ENE surface winds currently in AR that seems to be the main fly in the ointment as far as current moisture return is concerned. Once again, there's no pure Gulf fetch being channeled into the target area. Perhaps I'm being too hasty in my analysis but I just don't see why everyone is so excited about today.

 

[fplowman]

Same here.. Nebraska City looks like a 12:30 to 1:00 pm target for Marc Grant and I.

Fred

 

[Ben Prusia]

I really do have a hard time believing what the RUC model depicts for dewpoints, as the model has underplayed dewpoints for almost every severe weather day this year in the Northern Plains States. We had Td's in the mid 60's on 5/10 in NE/IA, when the RUC model forecasted the upper 40's. It's already hard to believe the RUC forecast is right when the 60 degree isodrosotherm has already snaked its way into SC Nebraska this morning (via the SPC Mesoanalysis and 61 degree Td OB at 8AM at Lexington, NE), and the RUC forecasted the upper 40's. RUC model way overplays temperatures from own observations and the such, maybe as much as 10-15 degrees.

I still think that Nebraska City, even up to Sioux City will do for a target today. I am trusting the NAM model more than the RUC model today, so I am hoping it pans out.

 

[Shane Adams]

Perhaps the RUC isn't the solution to believe today:

http://weather.cod.edu/forecast/RUC/SP/ruc...P_0_cape_12.gif

 

[Jeff Snyder]

Ugh! How many times can crappy moisture all but ruin an event this year?!

I was hoping to see >60 tds across se NE and most of KS this morning. Instead, we have low-mid 50s across ne KS and NE. Hmm. The 6z NAM still brings Tds up to near or greater than 70F by 0z, though I'm not sure how much to trust this solution given that the NAM has been overly-aggressive in returning moisture this year. This sucks because it's yet another day with very strong low-level shear (like 3-21, 4-25, etc), yet potentially limiting moisture. It's the 21st of May, how in the world are we still having moisture problems? The strong cap and very high LCLS (with T-Td deficits near 30F) will likely severely limit the tornado threat, unless the surface Tds really do increase to or exceed 70F as the NAM has persistently forecast. I can't imagine not chasing the warm-sector when 0-3km SRH (on the 6z NAM) is in the 350-500 m2/s2 category, which is certainly supportive of strong tornadoes.

The current surface map has cast much doubt on prospects today. Will give it some more time before deciding for sure one way or another.

 

[Jeff Snyder]

Perhaps the RUC isn't the solution to believe today:

http://weather.cod.edu/forecast/RUC/SP/ruc...P_0_cape_12.gif

Shane,

The RUC has had a bad tendency all year to overmix the boundary layer, resulting in much-too-low Tds and much-too-high LCLs. I'd trust the NAM solution over the RUC solution most of the time. That said, the NAM has been too aggressive this year in returning moisture northward into the plains.

 

[Philip Flory]

I think you really have to a take a median between the RUC and NAM. NAM has been overforecasting all spring, RUC underforecasting. That being said, 61-63 td's would be my bet by 0z accross most of E NE/W IA. I see no way we will see the NAM supported 70 tds. I think 2000-2500 J/KG SBCAPE will about do it over E NE.

So in a sense.. numbers accross SE NE around 00z will look something like this:

90/63
2500 J/KG SBCAPE
850 temps around 23 C

I don't know folks, maybe that can get it done, not betting on it though.

Im going to stay in ICT... unless something changes major in the next 2 hrs. I MAY head up to N KS later today if the cap looks breakable and chase some high-based stuff... we'll see.

I agree with Jeff above, what a waste of good shear/dynamics today.

 

[Jeff Snyder]

LOL Well, despite my severe hesitations, I think we're going to try to go. Currently aiming for Hebron, but likely a tad east of there. Latest RUC and NAM both break out precip along (immediately just south of) the KS/NE border and northeastward from there. I'm not sure why the NAM continues to persist on the >70 Tds from extreme eastern NE southward, however. I just can't really ignore the awesome low-level shear. Hopefully we can get something along the KS/NE border, since the 12z NAM shows best shear just south of the border, then NNE into western IA.

 

[Mike Johnston]

Wow, huge difference between 12z NAM and 12z RUC in forecast tds over E NE - as much as 15td. It must be that difference in mixing assumption that has been discussed on the boards over the last few days. NAM has 20% - 40% relative humidities at 850mb over W IA at 00z, but RUC has zip. True, air at 850mb is advecting from the desert southwest, but orientation of height lines and isotachs is pretty similar between the two models. For what its worth, dew on the grass in KC area was pretty heavy this morning, so maybe we will get some help with evaporation. As RUC has been consistently underestimating dewpoints over the last few days, I'm still optimistic we will see sufficient instability to make a NE/IA chase worthwhile on this Saturday afternoon. Earlier than expected clearing over W IA is encouraging. Earl's severe parameters based on 12z NAM should spit out shortly, so we analyze further once we get to Nebraska City.

 

[Chris Hayes]

We're going for an area from Hebron to Lincoln, Nebraska. It was a hard decision whether to make the trip from Wichita to Lincoln to quite possibly into Iowa. I've only got a couple weeks out here in what could be my last year chasing for a couple years, so we're gonna do it. Knowing my luck we wouldnt chase and there'd be some really good storms in the target area. What frequency will everyone be operating on? I'll be monitoring 146.52 and 55. My callsign is KC8OFK

Good luck, everyone.