5/13/09 FCST: IA/IL/MO/OK

[Kevin Polston]

Interesting day coming up and a challenging forecast. To me....I don't like the central Illinois area for tornadoes. It seems the profiles (based off the NAM forecast soundings) are very moist through a large depth. I also don't like the northeast Missouri into western Illinois area....for several reasons. I do like southern Illinois just to the southeast of STL as this area has good thermodynamics and good shear. Others have talked about Oklahoma and my personal preference for the day would be somewhere in the northeast quarter of Oklahoma. Any further west and the LCL's and bases are too high and the shear isn't nearly as good as further east. So just my two cents but I would target an area in northeastern Oklahoma....somewhere along the I-44 corridor as Shane mentioned earlier yesterday in a post. It will be a late in the day show....towards 00Z I think but that's what I would do.

 

[Derek Weston]

Despite all my critical comments on this event... we could be in for quite a show if we do develop the instability some of the models are projecting over much of Missouri and Illinois. While it remains to be seen how quickly a line is formed off of the cold front... should cells get a chance to stay discrete for a bit, we've got the shear to get the job done. We've got some really impressive shear profiles to work with... lots of good 0-1KM SRH. This could be a high end severe outbreak if the sizable warm-sector evolves favorably... (in my slightly uneducated opinion...a high risk like result in storm coverage and intensity is possible... though I won't predict it... just had to post a "on the bright side" message here so as to not sound too doom and gloom )

 

[Jim Zandonai]

As expected in northern areas the big question is clearing for heating to occur. Current rains moving east but the NE /W-IA complex has to move through yet. This doesnt help things unless it dies out which it doesnt look like it will. Soundings in North IL do not look good either at this time for clearing but we'll see.
Looks like the best bet will be well south...nevertheless I'll still be watching closely but N.IL looks questiionable..Central IL better chance if the current complex to the west doesnt mess things up too bad.

 

[Kevin Crawmer]

Well I get a rare opportunity to get a mid-week chase, so I’m gonna give it a go. The RUC and WRF are making me strongly consider heading to the Columbia to Mexico, MO area today as a starting point. I believe this is the best area with strong enough CAPE to get things going in the daylight. I believe there is a chance that something discrete can pop in this area prior to dark. I also think up towards Kirksville will be ok with the first storms that fire on the line, but I believe the best shear will be a little further southeast. Closer to 00z, I believe the activity ahead of the cold front will build northeast towards the Hannibal area. This will also be in an area of good shear. This discrete activity will likely pop from here on up towards Peoria between 8 and 10pm before being overtaken by the cold front. I think the best chance at seeing a daylight tornado that isn’t imbedded in a line will be between I-70 and I-36 in Missouri. Roughly the Columbia to Mexico to Monroe City line. CAPE at or around 3000 to the southwest of this area, good directional shear in this area, and should pop well before dark.
The only model that throws a wrench in this has been the NAM, which has seemed to throw a wrench in everyone’s forecast. It takes the EHI to nil right over my target area, but the other models support it.

We will see. Heck, it is just a good day to get out and see some storms. Good luck and be safe everyone. I’m anxious to see what comes out of the southern target too.

BTW, I think the SPC did the right think on their first day 1. I thought it was crazy to consider a High Risk like was being rumored. 10%, non-hatched seems appropriate right now given the best instability and shear are having a hard time matching up.

 

[Mike Hollingshead]

http://www.rap.ucar.edu/weather/model/ruc09hr_sfc_cape.gifhttp://www.rap.ucar.edu/weather/model/ruc09hr_sfc_cape.gif

http://www.rap.ucar.edu/weather/model/ruc12hr_sfc_cape.gif

Talk about a 3hr change(time sensitive, already new 10z ruc on 9hr so just a 2 hr change). Current developing MCS building more south than I'd probably hoped for, but doesn't change a heck of a lot. Should move on through and leave a nice OFB somewhere near highway 36. Or least close to there and maybe lifting north. Interesting waves racing ne right behind the line.

http://radar.weather.gov/ridge/radar.php?rid=EAX&product=NCR&overlay=11111111&loop=yes

Probably end up somewhere in the Kirksville to Hannibal line. But I've opted to go the St Joe route rather than through Des Moines to leave the go south option at least open, not that I like se KS at all on this one but if other gets really hosed look it'll be better than nothing.

 

[Ryan Wichman]

Based on current radar and water vapor loop there looks to be a bit of a dry slot working in behind this area of convection just to the east of Kansas City. If the mode stays the same speed, it will move through West Central Illinois by 9am and clearing the area completely by 11. We will have to wait and see how this works out, but this could prove a firing mechanism as it moves through Illinois and lays OFB down.

 

[Chris Allington]

http://www.rap.ucar.edu/weather/model/ruc09hr_sfc_cape.gif

http://www.rap.ucar.edu/weather/model/ruc12hr_sfc_cape.gif

Talk about a 3hr change. Current developing MCS building more south than I'd probably hoped for, but doesn't change a heck of a lot. Should move on through and leave a nice OFB somewhere near highway 36. Or least close to there and maybe lifting north. Interesting waves racing ne right behind the line.

http://radar.weather.gov/ridge/radar.php?rid=EAX&product=NCR&overlay=11111111&loop=yes

Probably end up somewhere in the Kirksville to Hannibal line. But I've opted to go the St Joe route rather than through Des Moines to leave the go south option at least open, not that I like se KS at all on this one but if other gets really hosed look it'll be better than nothing.

Was thinking almost the exact same thing. Blue sky is visible through some holes in the grunge here in Omaha... as long as that line moves pretty rapidly I dont see it causing a problem. Dont like the directional shear as much in SE Kansas either but the rediculous instability is kind of hard to ignore. We will more than likely stop around St. Joe for a quick late breakfast and to evaluate more data. Plus, if early convection lays down that OFB a little father south that perviously thought, we can easily drop down to the I-70 corridor. I think we might try that anyway to get a better shear/ instability combo.

 

[Jacob Ferden]

The question over Oklahoma remains the triggering mechanism, but I'll say this: The forecast CAPE by 0z is AoA 5,000-5,500 j/kg per GFS, NAM, and RUC and the hodographs look beautiful. It may turn out to be nothing more than an MCS, but if a tail-end storm can isolate itself and tap into the supply all hell could break loose.

 

[Brian McKibben]

This sounding put a good bullseye on OKC. Look at the CAPE near 4000

 

[Mike Hollingshead]

The MCV mentioned on the latest day one, easily seen on the water vapor loop, bugs me a bit for the ne MO target. Maybe it shouldn't but I never like being between so much stuff. The WRF radar simulator showed that thing pretty well last night. Looks like it would go south of St Louis a ways, I just wonder how early it will fire things and the effects that will have to the north. I sort of wish that thing wasn't there, though surely will help those chasing that far south. Guess game plan is the same, just fearing that thing more than liking it there.

You can see southeast bound rolls on the wv loop too, in ne KS. I guess maybe one could get an ofb just ahead of the cold front further west in MO, not sure you'd have much chance keeping southerly winds that far west, but not sure the southerly winds further east won't get screwed(rained on) by early convection on that MCV. Hmmm. I hate trying to guess where things will be on satellite by the early morning look. Half the time it's better than though, other half, well.

 

[David Draun]

Yeah OK looks good. I don't have the luxury of going there today, so I will play the northern end. My new target is going to be Jacksonville to Springfield and points south of there. There is just too much clouds and rain farther north. And it seems like the I-72 corridor is a good place for an OFB to set up from the current storms. So I will leave for Jacksonville around 10am. I'll be pretty close to the enhanced shear from the mesolow.

 

[Jesse Risley]

I still think the area SE of a KUIN to KSPI line looks like a good play. I would agree that being on anything when it initiates in E. MO would be a good play, keeping in mind any residual boundaries from the convective waves that are firing up north here this morning. The one caveat about E. MO is the presence of the mighty Mississippi, being that there are no river crossings between KSTL and Louisana, MO (U.S. 54).

I am keeping an eye on surface OBS and watching for any areas of clearing to enhance SBCAPE after the next wave of convection clears. That should better refine a final target for later.

 

[Warren Faidley]

Target for today: Southern/SW most **isolated** storm before dark. Maybe a GAG, Woodward to END area, or near the triple point. Have a feeling storms may initiate and propagate S/SW from SE KS as clusters and broken lines of rapidly developing, severe hailers due to extreme instability. Tornado development may need to be intercepted in early stages further NE. Any outflow boundaries would refine target and increase tornado potential substantially. I think this day has more promise further SW than forecasted. We will see.

Good luck to all and be safe.

W.

 

[Michael O'Keeffe]

The RUC us indicating some sort of wind shift line well ahead of the cold front which will likely be the focal point for isolated development in E MO/W IL. If this does verify then I think we could see some interesting things today. The RUC also shows the line of storms north of I70 rapidly moving into Illinois clearing out much of E MO/far W IL by 11am and points east by noon. I am slowly becoming more optimistic about today. However I still have no defined target we will be blasting east on I70 at 9am planning on heading towards Columbia or St. Louis before adjusting.

Edit: After seeing the new RUC it appears Columbia, MO will be the place to be, it breaks out one lone supercell that just sits in C MO all afternoon with CAPE 3000+ j/kg and 70F dews, it could get pretty wild in this area around 2-3pm. I also like to see the cold front hang back in NW MO and W Iowa all day with supercells erupting all along the 'wind shift" line in E MO and far W IL.

 

[Buddy W Bradley]

Well, for what it's worth... I have to plan a short chase so I can be back in Bolivar by 7:30pm for my daughter's graduation. So our plans are to head from Springfield MO up to central MO in the Jeff City to Columbia area. Hoping that things will fire in the mid afternoon up there so I can make it back home in time. There is a possibility of heading south on 63 toward Rolla if something should fire off an OFB or as a result of that MCV moving across nw AR and southern MO. Good luck to everyone going out today and be safe! Bag a 'nader or two.