5/26/07 FCST: WI / MN / IA / IL

[guest]

While I'm very concerned about instability (and I know this setup pales in comparison to this year's many spectacular setups in my old chasing stomping grounds), it looks as though shear will be favorable for supercells in central WI tomorrow. Tornadoes look possible along the warm front. Now if we can just get adequate sunshine and if we can get a region of decent low-level shear - models aren't terribly crazy on that aspect. Anyone else watching this setup? I don't have high hopes, but I'm definitely not ignoring it.

Attn Moderators: Any way the subject line can be changed to include MN/IA/IL? Thanks!

 

[Ross Lazear]

I've been watching this threat for a few days now... And yes, instability certainly appears to be the big issue. If we were talking CAPEs of >3000 J/kg, I think this would be a great setup, with very good shear, SSE surface flow in the warm sector, and a strong westerly upper jet.

The models have been all over the place as far as the speed of the system is concerned, but now appear to be converging on placing the surface cyclone in N. Central Minnesota by 0Z Sunday, with a cold front through E. Minn., and a warm front through NE Wisc. Considering the extremely strong dynamics associated with the impressive upper shortwave, I think it's definitely worth watching. But yeah, Chris, I also don't have very high hopes either!

 

[Jim Zandonai]

Well I hope we get something up here in our region. I love chasing in SC WI. and NC IL. It's been really dry as a bone up here and being this dry doesnt help either when it comes to evaporation and transpiration or whatever and we'll take all the help we can get. Heck I'd do A rain dance if I thought it would help..but pattern and trends sometimes are tough to break. The dry areas get dryer and the wet areas get wetter.
If enough instabilty can develop and that is a big if.. I think we finally have a decent set up here..but lately getting any kind of decent dewpoints even over here has been tough all month.
You may want to include IL in the FCST thread though.
Lets hope for a few good cells !

 

[Derek Weston]

Probably want to make this to include IA, MN and ILL.

SPC hatched a 30% over most of NE Iowa, and a bit of SE Minnesota, SW Wisc, and NW Illinois.

Looking at the models it seems to me our best shear would be up in the Wisc/Minn area, but best instability further south into Iowa... perhaps the area noted will be where things converge the best.

 

[Joel Wright]

The eastern half of Iowa is looking pretty good to me. I think the morning clouds should clear out at least somewhat in this area. The warm front will lift north into MN/WI. By afternoon some areas in Iowa could exceed 80 if enough insolation can be managed. With dewpoints pooling south of the front well into the 60's, I think the instability should be pretty decent.

Any cell that decides to take a right turn in Iowa will have plenty of shear to work with. Mid-level winds are sort of marginal, but still not too bad.

I'm thinking there will be some nice sups in the east half of Iowa by later Saturday afternoon.

Unfortunately I won't be able to chase (which sucks because it's so close to home!) do to prior weekend obligations, but if I were I would make my initial target Waterloo or Marshalltown Iowa.

 

[Brandon Sullivan]

I have a party to go to in NC IL in the morning. I will probably head west afterward. I like the instability and shear combo.. I will try to play the warm front for any tornado potential.

 

[Jesse Risley]

I think we're going to plan to chase eastern Iowa late tomorrow afternoon, pending one more look at morning forecast tools to ensure optimal timing. I'm thinking the area between Iowa City and DVN looks good at this point.

 

[Josh Richardson]

Everything looking pretty decent for a fairly local chase for us tomorrow. I wont rehash what has already been mentioned so I'll just say we will be targeting the Waterloo area tomorrow. Just hoping we dont end up with more multicellular junk...

 

[Brent A. Clair]

I am sticking close to home near IA/IL/MO border, hoping for something to kick off as the front drifts north. Limited indices but some juicy atmos might just be enough for firing. Of course, this being Memorial Weekend, we always get some big storms...just hope it brings some much needed rain.

 

[John Farley]

Looks to me from this evening's model runs that Wisconsin could be better than IA or most of northern IL. Looks like the warm front will be in WI by afternoon, with veering surface winds in the warm sector in IA. Instability doesn't look all that great, however. Overnight and morning precipitation may also further limit instability in IA and northwestern IL.

 

[Brandon Sullivan]

I as well noticed some discouraging things in the 00z models.. But will not even think bout ducking out yet.. Hope tommorow things look good!

 

[Joel Wright]

Despite SPC's latest forecast, I would still target Waterloo/Marshalltown Iowa area by afternoon. This area will have the best combination of instability and wind shear in my opinion. Hopefully the clouds can break up just enough in the afternoon to allow for maximum instability. It won't take too much sun to change things quite substantially.

 

[Derek Weston]

Despite SPC's latest forecast, I would still target Waterloo/Marshalltown Iowa area by afternoon. This area will have the best combination of instability and wind shear in my opinion. Hopefully the clouds can break up just enough in the afternoon to allow for maximum instability. It won't take too much sun to change things quite substantially.

Hopefully, as the instability up in the target zone in Minnesota looks like crap... but we'll see, I guess. I don't think I'm game for central Minnesota. . .

(though, of course, I'm not sure we'll have the wind shear needed in N. Iowa)

 

[Brandon Sullivan]

I as well still like that area. Yes, this May sun is very hot, and can do alot. I will go anyways since I have that party to attend and see what happens. Good luck all

 

[Ross Lazear]

I think if I were to head out this morning, I'd target somewhere in SE Minnesota (somewhere in the middle of the Rochester-Red Wing-Winona triangle). This is some bad chasing terrain, especially as you get within 10-15 miles of the Mississippi River, but I like SE Minnesota, W/SW Wisconsin, and extreme NE Iowa better for this set up, as they are closer to the upper vort. max (and thus, stronger upper jets). I really don't like straying too far from the good upper dynamics when instability is already lacking so much, as it will be today. Plus, there's a lot of convection already this morning in much of Iowa, which probably isn't great news for severe wx. later down there...but I guess I certainly wouldn't rule it out as that whole convective area gradually moves NE into a higher shear environment...especially if N. Iowa is able to get a little bit of clearing mid-day.

Did anyone notice that SPC kept the same tornado-risk area for the 1300Z outlook that they had for the 0600Z outlook? It's funny, because the 5% tornado risk in NW Minnesota (which seems too far northwest to me anyway) is outside of the 1300Z slight risk area.

I'll be here in Mad-town, this morning, and may head WNW to the aforementioned area if things appear to be getting more interesting!

EDIT: After just reading it myself, I highly recommend reading the always amazingly detailed La Crosse NWS (ARX) forecast discussion---it really explains the whole system, as well as supercell chances, nicely.