05/10/05: TALK: NE/IA/IL

There is definitely a risk for severe thunderstorms tomorrow....

I'm loving NE Nebraska for tomorrow. There is somewhat of a large dew point depression across there (10-15F), therefore, I'm somewhat expecting high-bases on some of these storms. I'm still expecting a few tornadoes tomorrow, especially soon after initiation, and my current target is Norfolk, NE...

We'll probably leave Norman tonight...
342 AM CDT MON MAY 09 2005


My Brothers and I leave from So. Cal at 6am to arive in OKC at 12:30. We will be racing north ASAP..

See ya out there.
Originally posted by nickgrillo
There is definitely a risk for severe thunderstorms tomorrow....

I'm loving NE Nebraska for tomorrow. There is somewhat of a large dew point depression across there (10-15F), therefore, I'm somewhat expecting high-bases on some of these storms. I'm still expecting a few tornadoes tomorrow, especially soon after initiation, and my current target is Norfolk, NE...

We'll probably leave Norman tonight...

Nick, agreed on high bases, i don't expect initiation until around 20-21z. I have the day off, so we're thinking of heading to NE nebraska tomorrow also. Good luck to all those out there!!!
I'll be getting a late start tomorrow due to class til 2...So I'll likely play further downstream on the wf in eastern Iowa/western Illinois. If I had more time, I'd play NW Iowa...but...western Illinois will have to do, and doesnt look horrible either.
I think chances are slim all over this setup, but just as good as another pending where you're at in this system... a small group of us from Colorado will be heading out early in the morning for SW Nebraska to play the front in this area... think it'll be a crap-shoot for everyone tomorrow and hopefully will pay off well for everyone chancing this system. See ya in the field tomorrow!
That group from Colorado just got bigger by one more. An hour ago my management was wanting me to stay put and work on a "critical" software bug but now they want to throw the whole thing out and rewrite it which means it will not get done tomorrow! So I am back on the chase, seeing pea size hail tomorrow could make me a happy camper! :D :D
Tomorrow could be good, but perhaps further east than I want to go given Wednesday. That's not a great way to chase, but in this case I feel like it's the way I should think. Mainly because even further east, upper level support is marginal, though with the instability and low level shear, I think the tornado chances are pretty fair. Further west along the boundary, moisture and instability is an issue of course, and I'm looking at LBF and perhaps just north and east of there, depending on how little sleep I want tomorrow night.

Another marginal chase day, but perhaps better days are in store later. We'll see.
Left Meridian, TX a few hours ago after chasing that monster hailer and am heading N on I-35 about to enter KS. I am not to sure about tomorrows chances but I am running out of chase days and will not go home w/o bagging at least one tornado this year. So, I am looking at SE NE and SW IA. SPC was a little more optimistic in their 6z outlook than I was after looking at the 0z NAM so I am likely to head, at least initially, to where they are marking down a 5% tornado risk.
Another marginal event that could easily become an elevated hail-fest, but I'm chasing this time ... let too much get in the way over the weekend, and this will be close to home. Have fun everyone.

EDIT - looking at a few parameters near Omaha ... feel a little encouraged after taking a look at NAM for 0z ...

TD = 64
Sfc CAPE = 2796.4
L.I. = -7.6
SWEAT = 623.3
Storm Dir = 253 degrees
Speed = 20 kt

While I still wonder about potentially high LCL and LFC numbers, the current target looks to me to be north of Omaha right on the NE/IA state line ... near Sioux City. Will have to watch the boundary closely tomorrow ... storms that develop right on and just to the north of the WF will be the ones to play, IMO. May revise the target further south tomorrow depending on various factors.
As last night, I stilll like North Platte to Ansley, hopefully no further east and north of there. 12z RUC holds the front in place optomistically for us; I don't want to get far north of I-80 unless absolutely necessary. Forecasting as well a very tight temp gradient by 0Z. Storms moving along that boundary might be very interesting. Agree that OAX area looks good too. Checked their VAD profile (too impatient for the sounding), and showed excellent low level turning at 13z. Good luck all.
Leaving the house in about an hour for Ogallala. Encouraged to see SPC fall in agreement with me and the target further west. Will head up I-76 for Ogallala and stop there for data, lunch, and maybe a brisk jog! Good luck to all out there as I still think this remains a crapshoot! Never did well in Vegas, hopefully the Plains will luck me better!
We're heading towards York in about a half hour... I'm currently near Topeka, KS...

I feel really encouraged about today and it's supercell/tornado potential...
I'm very discouraged by this setup, mainly by the huge model differences in moisture available for today for eastern Nebraska and western Iowa. RUC has only progged up to 50 degree dewpoints for that area at 0Z Tuesday, while the NAM has progged 65 degree or higher dewpoints. I have a feeling that this will turn into an all out hail-fest for eastern NE into western IA (LCL too high-with high temps reaching near or at 90) with better chances for tornadoes out west nearer to the surface Low. However, there is good moisture convergence along the front so I will continue to monitor throughout the day, and should conditions change, Omaha is only a short 2.5 hour drive from here anyway.
Well, I'm simply playing the warm front location now. Monitoring for as long as I can here in Lincoln, but likely I'll be hanging out on the I-29 corridor from Co. Bluffs to Sioux City. I'm still contemplating being on the Nebraska side of the river, because the earlier the better on these storms. And crossing at Blair seems logical given the progged location of the moisture convergence.

Agreed with Amos.....wind fields at OAX look encouraging this morning.


Moisture convergence RUC at 0z sticks out like a sore thumb from North Platte/Cozad to Norfolk to Harlan, IA. Be on it, either west or east portions, and it looks like it could be gravy.


Good luck, kids!! Should be an interesting day.
RUCing what I'm seeing?

Was going to post same as Ben re: RUC. I'm only chaircasting today, but I wonder about the huge diff in the RUC version of events. Looking at moisture in place & the placement and expected development of the CO low, I don't see the RUC justification for the strength and distance of the dryline--make that big dry airmass--progression, nor the lack of northward transport into NE. Even if the northward transport doesn't pan out into NE, it should still be near the NE/KS border at the very least. This western moisture eater scenario I do not buy at all. NAM seems to have a better grip in moisture in place.

Good luck to all the actual chasers. FWIW, my initial target would be Kearney.
With 60 Td's already creeping into Southern Nebraska now I don't think the NAM is that far off. I'll most likely be playing around Sioux City or within 20-30 miles south of there.

EDIT: 12Z NAM is forecasting LCL's between 1400-1600m in Eastern NE. Still pretty high but better than last nights run. RUC13 also now starting to pickup on some convection.
Wow - RUC is showing a much more rapid W to E progression of dry air at the surface over the course of the day than the 12z NAM. RUC also has surface low in E CO deepening to 991mb by 00z. Probably due to this difference in progression during the diurnal cycle, Tds and CAPE values peak much higher on the NAM. NAM also shows lapse rates reaching absolutely unstable conditions of 10 over a very broad area of southern and central plains. Good news on both models is improved upper air support at 500mb. Will be interesting to see how the next SPC outlook addresses the development today... as for me, I am just going to sit tight here in KC area as long as possible. Before pulling out the gas credit card, I figure the more last minute knowledge, the better today.
I think today has the chance to become interesting. NAM is really calling for instability, the RUC is having a brainfart. :wink: Upper level will finally support sups along the warm front today. Low level helicity will be the strongest in the NE area. If I were chasing today, I would play the Warm front. OU finals week....gotta love it!!! :cry:
RE: Chase target for May 10

Denison, IA (about 50 mi NE of Omaha).

Storm initiation 6 PM CDT.

Storm intensity:
Supercells early in storm evolution, with large hail the primary threat. There is also a small chance for tornadoes.

Late this afternoon and overnight, a warm front and strong LLJ will be the focus for severe weather and very heavy rainfall. 14Z SFC analysis showed elevated convection along a 9V9-LLM line, as well as extensive ST N of an ONL-YKN-ALO line. SFC streamline analysis failed to show any well defined boundaries other then some convergence along an YKN to SHL line, likely a result of weak outflow from the precipitation to the north. This boundary should strengthen today as a result of differential heating and surface winds in NE and IA switching around to the S. “Warm sector†dewpoints were only around 50 in NE and low- to mid-50’s in IA.

Latest RUC and NAM guidance agree on position and evolution of the WF, SFC conditions, and QPF location and timing. Later tonight, textbook MCS conditions – ridging in the upper levels, along with a 355K SFC theta-E ridge and a 60kt LLJ nosing into WRN/CNTRL IA. Severe storms will be likely, especially early in storm evolution, where MLCAPE’s will reach 2000J/kG and 0-3km SRH’s will locally exceed 500m^2/s^2. A concern is high LCL’s where T/Td spreads will approach 30F in the warm sector, however areas immediately to the north of the WF should see LCL’s in the 1200m AGL.

- bill
Looking at satellite I don't think you'll have to go north of North Platte. Which is always good as the roads out there SUCK. That cloud cover is a bit scary out there. I guess I might be getting interested in a line from Curtis to Kearney.

The ruc may be right with the dews. You can see the cu field in KS being scoured out quickly from the west. The last 12z eta and 18z eta were showing a lovely veered 850/900 nosing towards Omaha with drier air behind it. I can see that on the ruc now..and the 12z eta today. Will that matter with the very backed flow along the front I'm not sure but I'm starting to think so. This makes me want to wait right here where the nose of the LLJ will be moving over the warm front(when it starts to try and back a bit and has the eastern edge of dews along a n-s line here with the "bulge"). Between 0z and 6z eta continues to go wild with something in western IA. Moisture convergence really increases here between 4 and 7. Ruc has convection on the boundary here at 7 now too. West nearly always seems like the safer bet for initiation and I'm sure there will be some out there. I guess just a few too many things keep me from leaving this target of eastern NE.
think that moisture is going to begin to be a problem here in eastern NE today... looking at my weather station DP's are only 50 degrees now with a temp of 73... Winds are trying to veer slightly with the wind chaging from the SE to the S at around 10mph... well have to see what this afternoon brings tho as i am no expert... Think most of the action will be just North of OAX and mostly elevated supercell hailers with a strong MCS becoming likely as things go crazy tonight...
I been looking at models, in the past few runs, im liking the Norfolk to Sioux City line, right now, however im getting that gut feeling something could happen towards the Fremont to Wayne line ? im going with Eastern NE to Northeast NE , today hope it holds off till i get off work... PRAYING NOW for a good chase GL everyone watch the speed in NE too the State Patrol dont like us chaser's", :eek:
The 12z RUC appears to have some strange solutions so it will be interesting to see if these are resolved for the 15z run out in a half hour. I am liking the set-up in south central Nebraska out ahead of the sfc low currently near the CO, KS, NE intersection. This is the only area with 500 mb flow favorable for discrete supercell development (~ 40 kts) and should be the focus of moisture convergence in the afternoon. That being said, the RUC is consistent with yesterday's NAM in developing precip. in the western IA I-80 corridor. Hodographs turn nicely in this area, but flow is looking weaker than expected aloft. The dramatic temperature and moisture return expected with the warm front drifting north should create some interesting interactions in the late afternoon and should be watched closely.

Target 1: My favorite target of the day would be the HSI area in so. central NE.

Target 2: Western IA along and north of I-80...*storms here will need to move north of the boundary to tap into better helicity and upper-level winds, definitely a target with a lot of "ifs" today.