6/01/07 FCST: IA,MO,KS,OK,TX

[Jordan Hartley]

First forcast thread so bare with me...

Frontal boundary extending from the nrn plains swd through wrn KS and sern CO friday. Models at this time suggest a sfc low developing along the frontal boundary in KS then has it lifting newd into the upper ms valley. As the low lifts ne, models show the trailing portion of the front shifting swd into the srn plains during the afternoon.

Biggest factor for tommorow will be the amount of cloud cover over the warm sector from any mcs that is left over from tonights activity. 1000-1500 j/kg cape is forcasted from ern ks through the upper ms valley. SPC wording in their 2 day outlook suggests that low level hodographs and deep layer shear will potentially support supercells with low level mesocyclones as storms advance E and the atmosphere destabilizes. The big question attm is how far will today/tonight's mcs track ewd but additinal storms may develop ahead the mcs if enough destabilization can occur.

I dont know if I will get the chance to chase tommorows setup. Seems like this year I only get to chase when the activity is close to me. If I do go my initial target for tommorow will be Emporia, Ks. This is probley going to change depending apon how far e the mcs tracks overnight into tommorow morning and early afternoon. I know the better stuff will be in MO and IA but theres no way I can make it that far NE in time nor do I have the funds attm lol.

 

[Andrew Pritchard]

This is a really complicated forecast, which may ultimately be my reason for sitting it out. (that and it would require chasing Iowa)

Right now, I think the best chance for seeing any tornadoes is going to be around the Des Moines - Iowa City line and a little north and south of there right around where a pseudo warm front should be located, and where enhanced shear values will exist. Winds may also back ahead of the storms in western Illinois where supercells may also be possible with the main complex, or with any other storms that may try and develop ahead of the first complex. In areas other than that the shear seems a little unidirectional to me.

Instability is a big concern looking at the models, but that may be in part to a ton of convection showing up. Should some clearing take place ahead of the first area of convection there may be enough instability in place for vigorous convection to continue that, should it tap into an area with better directional shear could go supercellular with an attendant risk of isolated tornadoes.

Shear will still be good behind the first area of storms, further back west into western Iowa and northwest Missouri through the day. However, you're really going to be scraping for instability in the areas behind the first complex in that area as the atmosphere should be fairly worked over. Should some instability find it's way over there there may be a chance for a second area of rotating storms in that area, but the odds are against that right now.

p.s.. is it just me, or did the SPC reissue their day 2 early this morning? It came out once at 1 am, and I could have sworn they only had a 15% risk over the area, but now I see they have increased that to 30% and the issuance time is an hour and a half later.

 

[Craig Maire II]

APrichard wrote: (that and it would require chasing Iowa)

Whats wrong with chasing in Iowa?? The area has great chase terrain as long as your not chasing in the far northeast portion of the state. I am happy though about the possibility of that speudo warm from setting up along I-80 though and I'll definitely be ready to chase tomorrow! As long as SPC doesn't issue any PDS tornado watches for tomorrow and doesn't jump to a HIGH risk I believe tomorrow should be fine in Iowa JINX!!

 

[Scott Lincoln]

I have never quite understood the anti-Iowa chase sentiment. Even a guy from the National Weather Center I was talking to about the D.O.W. mentioned that they "just dont go further east than the Missouri river; its not as chaseable". I am dumbfounded. Central and Northern Iowa provide better chase terrain and road networks than Central Oklahoma. When I was out in the Central part of Oklahoma, I was confused as to why its always regarded as such good chase country, yet its alot more hilly and rugged than Iowa. If you want to talk about unchaseable areas.... worry about far Northeast Iowa, as well as some parts of Southern Iowa. Missouri is where the road network degrades and the hills get worse.

As far as tomorrow goes, I think some people will be heading out from here at Iowa State, probably down to near the border with Missouri. I have not done alot of looking into the models, but I think the idea is to be out in front of the surface low, and it seems like the it is projected further south each run.

 

[Michael O'Keeffe]

I agree this is a very difficult setup. The MCS that will through the morning will moisten the air even more then it already is and move out by mid-late morning. I expect breaks in the clouds by around noon and the clouds to totally burn off by around 2pm. This will create some instability to work with and with the good shear will be sufficent for supercells. If we can get discrete cells to form the tornado potential will be greatly enhanced. I also concur that the low is moving south on every model run...so based on the GFS/WRF I think the best area to play would be E KS into MO.


Edit: We wont know how the setup will really play out intill tomorrow.

 

[Jonathan Behle]

Right now I would roughly be targeting around St.Joseph MO and maybe park myself tomorrow afternoon around Holton Kansas. For whatever reason, every system this year seems to slow down more, so I will throw that into my two cents. Right now lets see what the storms do this evening over the high plains, and what influence they may have for tomorrow.

As for the road networking, I don't see how Iowa can get bashed and Missouri does not get any mention. With the exception of a couple of areas, I would prefer to chase in Iowa over Eastern Kansas in the Flint Hills or Missouri anyday. Those of us who have been in Missouri know you have to plot your areas in advance, especially in Central and Southern Missouri. Atleast tomorrow's threat appears to be more in Western and Northern.

 

[Andrew Pritchard]

Hahaha it's nothing against the terrain... it's just the fact you are chasing in Iowa. It's kinda known as "bust central". I'm surprised you haven't heard it referred to as that. The terrain is fine (though not better than here in Illinois) . I actually agree with you on the plains road networks vs. Illinois and Iowa. Everytime I chase out in the central and southern plains I always long for my Illinois terrain/road networks.

I hope the setup doesnt end up being too far west though. I still think the instability might be too marginal in points further west than the intial area of thunderstorms. But as I said, shear is going to be doable there so if isolated convection can go, it has a shot.

 

[Shane Adams]

I'm not at all impressed with the windfields for the E Kansas/W Missouri plays tomorrow. I'm sure the models are fudging it a bit but it looks fairly unidirectional IMO. What looks intriguing to me (and I have a thing for needles in haystacks) is the southern/SErn TX pan area. Lotta instability and just enough shear to make it interesting. I'll be starting from Dallas so I'll play south anyway, but if that low transpires as advertised, could be fun along the Highway to Heaven 287 corridor tomorrow. It's a bit of a longshot but man if it happens, I could be all alone out there.

 

[Brent A. Clair]

Trying not to get my hopes up, as every single system this year fizzled within 100 miles of home. Just spent a little time on the SREF runs; really paints an impressive picture right along the IA/MO border starting at noon. Slow propagation to the east with a little more heating...could it really happen? Let's just say if it were to happen, it couldn't occur at a more inopportune time. Large school having an outdoor graduation with limited shelter. Can you say "uh oh!"

Patiently waiting for tomorrow's runs. Here's for the best (or worst)

 

[John Farley]

On this evening's model runs, what concerns me more than unidirectional winds is the high LFC levels in central/western MO. Models do show backed surface winds from SE or SSE, with mid-level winds from SW. Granted the surface winds could veer as the front gets closer, but for most of MO the models seem to be keeping them backed. SRH from 100 to nearly 300, depending on model and location. But most of the models are keeping the LFC height up in the 6000-8000 foot range, pretty high for tornadoes. I suppose this might be due to stabilizing effects near the surface from overnight/morning convection (?) Anyway, I will look things over in the morning and decide whether to head out. Could be the best setup within a few hours of the STL area in quite some time, subject to the flies in the ointment noted above.

 

[Andrew Pritchard]

Based on what I see with tonite's model run, unless something changes drastically I'm not leaving the state of Illinois. Iowa and Missouri have "waste of time" written all over them. The airmass in my opinion is just going to be way too worked over with the early convection for anything to fire the rest of the day. I think if I do go anywhere it will be to western Illinois, where I think severe storms may develop on the leading edge of the convection/ofb. This isn't going to be the most ideal set up, but I think it stands a small chance. Wind fields aren't as good as slightly further northwest, but instability will be much higher so getting storms to flare back up won't be hard to do. Probably will be little to no instability in Iowa and Missouri, and the atmosphere being so worked over should suppress any further development in that area the rest of the period.

FWIW, I also think Shane has the right idea in the panhandle, but well, that's slightly out of my way tomorrow.

 

[Derek Weston]

Iowa will remain relatively untouched as the MCS is sweeping through Missouri as we speak...

I'll probably be heading out west towards Des Moines if the mornings run here looks good enough. (not setting up for a huge tornado day, but I'll take what I can get)

FWIW, agree that the E. Kansas/W. Missouri winds looked a little unidirectional. (thought they looked better north and east)

 

[Jesse Risley]

I think the potential limiting factor here in our neck of the woods is the possible lack of sunshine. The round of convection heading towards the area could leave some boundaries for this afternoon, but it appears iffy that we will see significant heating at this point.

I won't be holding my breath to long, but I'll be keeping an eye on things. If clearing can occur I would expect some isolated supercell activity in S IA, NE MO and W IL.

 

[Scott Olson]

Probably going to be playing the cold core today as nice cold mid-level tempatures overspread an area that has been dryslotted. Showing up right now as a nice area of clearing near the James River and to the Missouri. RUC forecast looks even more bullish on cape for this area and current moisture fields look to support increased LLM and certainly new cyclogenesis and a strengthning low won't hurt.

I'll probably head out at 10:30 given the releatively early intiation expected. My second target would be NW IA, perhaps just east of Sioux City. Right now the area is socked in between the clouds of the northern part of the MCV that broke and the weak squall line to the west. So heating is certainly a question here. The 4.0km NMM-EMC WRF seems to have a pretty good handle on the current convective situation and does hint at development here but I think I'll take the cold core possibilities since there is currently an upper 50's Td field advecting towards a cloud free dry slot over -16/-17C 500mb temps.

 

[MatthewCarman]

SPC took E KS and W MO out of the slight risk. The two areas right now are IA/N MO and OK/TX.

IA: I would think this mornings convection would leave alot of moisture so if we can get enough sunshine and instability later I think we could see some nice storms but I am not to sure how severe they will be.

It is raining very hard right now. If this stuff was to move out to fast would that in any way effect our storm chances later today?