04/09/11 FCST: OK, KS, NE, MO, IA, MN

[Chip Redmond]

Surprised the SPC didn't act on the models placing the warm front further south. Going to position just south of Omaha as 500 mb vort max is developed just west of here and is progged to trigger initiation via the past two runs of RUC.

Will be interesting to see what the newest NAM and GFS say with the warm front, altough I don't forsee to many changes.

Chip

 

[Jeff Piotrowski]

Today: NE/IA significant tornado’s possible near and north of the I-80 corridor after 4:00 PM.
Per the latest 12Z RUC/HRR/ models have the WF along and just north of the I-80 at 21Z lifting north from DSM-OMA-GRI where the DL/WF double point. The area outline LNK-OMA-SLB-SUX-LNK is in the greatest risk between 21Z-3Z for all modes of severe including significant tornados.
The 12Z RUC sounding LNK/OMA/SUX/SUB.
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=RUC&STATIONID=sux
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=RUC&STATIONID=OMA
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=RUC&STATIONID=SLB
http://beta.wxcaster.com/cgi-bin/parse_skewt_trace_all.cgi?model=RUC&STATIONID=LNK

 

[Zach Chappell]

One thing ones gotta notice is the low clouds hanging around SE SD and NE Nebraska ones gotta wonder if models are not taking that into account if all goes well i to would say SUX is a good target im just concerned with the overall clouds hanging around and the forecasted instability not being realized.

 

[Jeff Duda]

One thing ones gotta notice is the low clouds hanging around SE SD and NE Nebraska ones gotta wonder if models are not taking that into account if all goes well i to would say SUX is a good target im just concerned with the overall clouds hanging around and the forecasted instability not being realized.

Those clouds are burning off fairly rapidly. I think the northward progression of the warm front and thus the instability will indeed verify.

 

[Mike Smith]

I've looked at the 12Z NAM, current data, and the HRRR from 14Z: I'm still liking south central Kansas.

Note: I'm not saying the northern target will not pay off: It will. I believe there is a risk of significant tornadoes there.

That said, for those who do not wish to drive to Nebraska or Iowa, I think there will be supercells with tornadoes in south central Kansas especially if what appears to be a weak boundary (perhaps from last night's convection) between PTT and GBD comes into play.

 

[Andrew Stoller]

The precipitation from last night has really boosted the dewpoints in southern KS/north central OK into the mid/upper 60s, although they'll likely mix out later today. I think the HRRR is picking up on this (the 4KM WRF is not - it has initiation at 06Z Sun) because it's initiating storms by about 22z, even before initiation occurs in the northern target area around Grand Island! Directional shear is pretty decent with 200+ m2 1km helicity.

I wouldn't get to far into IA for the northern target; the RUC has the dryline and triple point into south central NE around I-80 by 00z. Seems to be slowing the system down. That location is right where the HRRR has initiation.

 

[Andrew Ryan]

This is what has me worried for the southern target. The moisture has been slowly mixing out. The high dewpoints along the KS/OK look like they are starting to mix out a little bit. I wonder if the heavy rainfall from last night will lessen the impacts of mixing. That's something to watch. Hopefully, as the surface low deepens, the sfc winds will back and advect some of the better moisture to the southeast.

 

[Darren Addy]

I'm nailed in Kearney with sick kid today, but I would be sitting in West Point, NE watching mesoanalysis & short fuse. Lots of good road options from there. The 0z RUC model skewT for Norfolk, NE looks like proverbial Loaded Gun.

 

[Matt Hunt]

The HRRR seems to like the dryline a little better now. I'm anxious to see how this plays out... and I'm just sitting at home in Indy!

 

[ChristianTerry]

http://www.twisterdata.com/index.ph...nding=n&output=image&view=large&archive=false

Good grief!!! These storms are going to explode in a hour or two. 3000+ Joules of CAPE in Kansas.

 

[Michael Riedl]

Dewpoints are definitely mixing. Td has dropped from 69 to 62 here in El Dorado. Most days it might not be a big deal but ocnsidering its 87 out it can definitely make a difference.

 

[Chip Redmond]

HRRR 17z run is also hinting at a sup to go up around Sioux City again and turn into a monster. It has been all over the board today and I am officially throwing it out. Heading north a bit more where LCL's along warm front are lower and a decent boundary exists. Cap is winning thus far however.

 

[Andrew Stoller]

19z RUC shows initiation around Omaha, so my initial target was too far west. Moisture convergence is better near Omaha as well along the warm front east of the surface low where winds are backed.

Looking at a satelite loop, there's a nice cumulus field that has gone up in eastern NE. Doesn't look like there's towering cu, but this might be initiation for the northern target as this moves into western IA.

 

[rdale]

Very strong cap at 900mb over north-central Iowa. Here is a Omaha sounding from this past hour -

 

[Matt Hunt]

HRRR has been all over the board today, but that area north of Omaha looks to be where the convergence is with the swly LLJ colliding with winds going every which way. Considering the strength of that jet, I'd expect the cap to be broken in the next couple of hours. CAPE is exceeding 4000 j/kg just across the border into IA, so these storms will fire quickly and be severe warned probably within 20-30 mins. If I were there I'd be heading north of Omaha a little bit, maybe 45 mins or so.