3/31/07 FCST: TX, LA, OK, AR, MS, MO, IA, IL

[Ryan Pfannkuch]

Hmm..12z NAM is trying its best to draw my attention to the northern MO/southern IA area...just out ahead of the track of the cold closed 500mb circulation. From 18z-0z...the approx. 997mb surface low moves slowly from roughly Manhattan to Lincoln...with the dryline rapidly arcing to the northeast across northern MO/southern IA. The instability axis is depicted along a line from Beatrice NE to east of KC at 18z...and then by 21z along a line from west of Des Moines down to Chillicothe MO. Given the proximity of the -18 to -20C temps with the 500mb low...its not going to take a lot of sunshine to cook up some respectable low level instability.

As always with these situations...the key will be getting some heating within the dry slot...and the NAM shows a nice dry punch into the region noted in the 700 and 500mb RH field. Although the surface features are not as impressive...this is the same basic setup and surface boundary orientation that has resulted in some notable mini-supercell events in this region....such as 4-11-01.

All of this goes for naught if this areas stays grunged in during the day...but at this juncture the I-35 corridor from Cameron MO to Des Moines and eastward toward Kirksville and Ottumwa looks kinda interesting to me if the NAM verifies. A quick glance at the 12z GFS shows a slightly faster progression of the system...with associated surface features a little farther north and east. Gonna be interesting to see the updated Day 2...

 

[Brent A. Clair]

Updated Dy2 paints a nice picture over the Mid Miss. valley with 30% prob. I still cannot get really excited until I know that tonight's convective action will not hamper heating efforts tomorrow afternoon. I do recall, though, that on March 12th 06, the area stayed cloudy the entire day and still got some major action. All models starting to come around to a more convective agreement; now just wait and see.

 

[Jesse Risley]

As models are starting to get a better handle on this situation, a major long track, violent tornado outbreak does not appear likely. However, if we get decent heating tomorrow I would not be suprised to see a respectable number of F0-F1 or F2 reports. Things can and likely will change more by tomorrow. In addition, the parameters appear favorable for a squall line to come screaming through the lower portion of IL (probably well south of I-80) tomorrow afternoon or evening. I'm going to agree that the best tornado paramaters appear likely to remain over southern Iowa and Northern Missouri, unless things change between then and now.

 

[Scott Lincoln]

I am fairly excited about the area in the southern half of Iowa for Saturday as well. These seems like it might shape up as a cold-core type event, and according to some 12z runs I've looked at off of the wxcaster page, that would put alot of the boundary interactions into central and southern Iowa, ahead of the low. Looks like some decent convergence as well. I've seen more shear on events like this, such as the April 11th event that Ryan mentioned, but I definitely see some potential. Of course I have to work so if it pans out I'll be stuck in a tornado-bait grocery store....

 

[cdcollura]

Good day all,

Looking at all this while still at work in Dayton, OH ... Most likely headed out to W Central IL and points westward for afternoon Saturday. Spending night in Chicago, then leaving early tomorrow AM to see what develops. For now at least SPC is forecasting a 30% probablility on Day2 centered right over STL. The boundaries / morning convection / heating will really make the difference come tomorrow. The trend this whole week was these slight risks on Day2 that become hatched MDT risks and fun for many the next day - Look what happened in TX a few days ago! Anway, it's a weekend chase op, so I should be out ;-)

 

[Jesse Risley]

I am fairly excited about the area in the southern half of Iowa for Saturday as well. These seems like it might shape up as a cold-core type event, and according to some 12z runs I've looked at off of the wxcaster page, that would put alot of the boundary interactions into central and southern Iowa, ahead of the low. Looks like some decent convergence as well. I've seen more shear on events like this, such as the April 11th event that Ryan mentioned, but I definitely see some potential. Of course I have to work so if it pans out I'll be stuck in a tornado-bait grocery store....

It looks like a 80-90+ kt jet streak could enhance conditions in this area tomorrow! Hey, it's better than being stuck in a tornado-bait trailer, right?

 

[SteveCarter]

Thinking Quad-Cities to St.Louis. Have family in that area, so maybe I'll go see them, and see what happens. Still a bit concerned about the instability tho. The low itself seems to be deepening, and that may negate any other negative attributes enough to get things going a little. Still, not overwhelmed by this set-up, but at the same time, enough is there that something should happen.

 

[Scott Weberpal]

So many are worried about the lack of forecast instability. Sfc Based and MLCAPE won't give a good representation of the instability you should be looking at tomorrow. Watch for areas of clearing to enhance the 0-3km CAPE both near the low in Iowa and along the WF in E. IA/W. IL. I can't help but think of 4-20-04 when MLCAPE was very limited, but the 0-3km CAPE was in the 150-200 j/kg range. Forecasting soundings from C. IA to W. IL are indicating 0-3km CAPE in that same range.

Could be interesting in these areas of enhanced low-level CAPE.

 

[Travis Carlson]

I like the west-central Illinois area actually for chasing for this one...I agree setup looks to a degree simliar to 4-20-04. I have lived in this area for most of my life before heading to Dekalb and this is a classic setup for this area for severe wx and tornadoes. I think we might see a moderate risk on the next day 1 outlook for southeast iowa, northeast missouri, and west central illinois. Everything depends on that warm front and clearing tomorrow afternoon. I would like to position myself near the warm front but not too far east. I like an area from Kewanee, IL to Macomb, IL or maybe southeast iowa near Burlington...that will probably change tomorrow morning when I head out I think that region is where I could catch some supercells tomorrow afternoon and evening. It'll be awesome to see the change in weather from DeKalb tomorrow morning driving southwest no doubt Hopefully will be looking into sunshine to my southwest and not clouds...good thing about west-central Illinois is a good road network and great terrain unlike an earlier chase in Wisconsin last sunday

 

[Joel Wright]

Hmm. Very hard to pick a target at this point. It's all very dependent on what's leftover tomorrow morning from tonight's activity.

However, just for fun I guess at this point Ottumwa Iowa is looking like a good starting point. I do believe there will be at least a narrow strip of decent instability just ahead of the trough axis.

I do like that fact that the surface cyclone will be in a strengthening phase most of the daylight hours tomorrow. That always makes me feel a bit better about things.

Really not too much new to add now. Final target decision probably won't be decided until early tomorrow morning right before I head out the door.

 

[Jim Zandonai]

I agree with regards to Saturdays chase prospects, it does appear that NW or WC IL in the Quad Cities region would be a good location. The thing to be concerned about is if clouds from overnight storms clear out in time to destabilize the air enough on Saturday. Looks like mid to late afternoon is the time slot to shoot in that area before moving east.
Shear apparently looks good too. So we shall see what Saturday A.M brings.
That should give us a much better idea before or if we set out for a chase.
Typically this time of year that area is better for supercells then in extreme NC IL. where its typically cooler and lower dew points.

 

[SteveCarter]

Looking at some of the latest models, it appears this low will strengthen even MORE than previously thought. DP's will be awesome, and if the leftover debris will clear out......WOW. The current radar (9PM est) shows a LOT of moisture already to the SW of this area, and some discreet cells already forming well ahead and to the NE of the area. Target area...40 miles SW of Quad-Cities...4PM. Stability still questionable, but there are so many other ingrediants coming into play that this looks pretty good. I'll be surprised if there isn't a MOD risk for this are later on, especially from N of St.Louis up to even Des Moines. The roads are excellent in Illinois for chasing, if that's where you end up.

 

[Scott Weberpal]

I'd be surprised if the are is in a MDT anytime before the 1630 outlook tomorrow, there are just too many uncertainties that likely won't be resolved until that point in the day. I'm going to forget about the cold core with this one and play the IA/IL/MO border area. IF this mornings forecast soundings are correct, this will be a prime area by 00z.

 

[Jesse Risley]

If anyone is interested, PM me as several of us are having a chaser gathering in the Macomb area tomorrow morning around 11:30 a.m. Final details will be hammered out tomorrow a.m., but I'm thinking that the strength of the system and associated dynamics may be able to overcome the lack of instability (if that does happen ) to produce some severe weather anyhow..time will tell.
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[Brandon Sullivan]

Well, we will obviously be chasing tommorow.. Unless something drastic happens.. But if something happens I would expect things to look better.. I hope we see a moderate.. New DVN AFD is nice and ominous.. As Jesse said, couple people will be meeting in town.. Im just gettn the laptop ready..

All eyes on the 0z and 12z data soon to come..

Good luck to everyone!! Bring em home!