2015-06-22 EVENT: IA,IL,IN,MN,MI,OH,WI,


Feb 16, 2014
Norman, Oklahoma
A potential regional severe weather event looks to unfold in the day 3 time frame for the Great lakes region. SPC currently has a D3 ENH risk for much of the area outlined.

Taking a look at observations as of 244CDT Regional Soundings indicate deep moisture is pooled across the OH/MS river valleys. ILX has PWAT near near 1.5 in
Same story from ILN with PWAT 1.5 in and dews in the midd to upper 60's/ low 70s
To the north, PWAT is much lower and temps are cooler. A weak front lies in the area.
The feature will gradually shift south over the next few days as the remnants of Bill exit to the east. On 6/21 SUN the boundary begins to lift north as a warm front ahead of the next upper wave.WV imagery currently shows the wave near the PAC NW coast coming on shore over the next 12 hours.
This wave is also expected to be a player for the previous day 6/21. * See thread on 2015-06-21 EVENT: IA,NE,KS,MO* for updates on that event. As the wave digs over the next few days it should light off quite a few storms. Expect MCS to be ongoing from previous day which should lay down a few OFBS to play with during the day. I also expect the lake breeze to be a potential player.

Diving into model land I like what I see. *Excuse the AWIPS images I'm at work and using some custom color tables. They may not be the best. Still messing with them to get them right.* First up is ECMWF 500 heights and ABS Vorticity Image shows a shortwave trough with smaller disturbances in an area of enhanced flow near and west of the Great Lakes. Main concern is the area immeadiately east of the main shortwave in WI and Mi. Strong shear is going to be present here wich could really get things going if instability is high. A couple smaller disturbances are even visible down near IL IN MI and western OH. Here shear is slightly weaker, but Instability should be more than ample to compensate.

Looking slightly lower at GFS 850 mb we see a strong low level jet response due to the strengthening surface low over WI. 35-55 knots would mean a serious amount of low level shear in play fro almost the entire area. ECMWF is a touch weaker but still has a large area of 35-45 knots at 850 which is contributing to 0-6km shear upwards of 50 knots. Looking ahead at the thermodynamic environment, the NAM 80km has cape greater than 5000 for the entire southern target area and 3500-4500 values for the northern target which seems a little high. This should be more than ample for sig severe. One thing to note is the lake breeze signal showing up in northern Indiana. SPC only has this area in Marginal risk currently. However, with 6km shear at 50 knots oriented perpendicular to the lake breeze and strong instability plus direction shear present, I would expect isolated discrete storms in this area. There is even a slight possibility of a few storms in the warm sector near the warm front over northwestern Ohio by peak heating. Shear is slightly weaker in theses areas, but strong turning suggest a tornado threat is possible. *See sounding B* Looking at the soundings, WI shows very strong instability, strong shear and good turning. Expecting a good chance of TORs possibly strong/sig as well as enhanced wind damage and very large hail. .

Sounding B which is Northern Indiana Western Ohio shows Moderate shear and very strong CAPE. Here I would expect Isolated storms with again all SVR modes possible with an emphasis on hail and wind though I cant rule out an isolated strong tor here.

Sounding A which is Lower Michigan shows very similar traits to Sounding B but with stronger flow aloft and slightly weaker cape. Very strong turning is present with very high helicity values. Expect all svr possible again with signals indicating chances for tornadoes possibly strong/sig.

A lot needs to be watched here as this could be a boom day. However model spreads are fairly high. ECMWF is lower with cape but still strong on the shear side. Lets get some discussion going. If you want chaser opinions, Northern Indiana and NW Ohio are pretty great in the chase terrain department aside from trees.


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Anyone have any tips for chasing southern Wisconsin? lol

Yeah, don't. :p

No doubt some of the ingredients for a major severe weather event will be present across the Great Lakes region Monday. They'll be reaching levels that are pretty rarely seen in that neck of the woods, thus the insane parameters. However, there is also a very impressive plume of warm temperatures forecast to overspread the region at 700 mb during the day. The 12Z NAM has the 14 C h7 contour extending from across S WI to SW MI to the OH-IN border and back west across C IN and into S IL, which I think would effectively take IN and OH out of the play, at least for daytime surface-based storm chances. The GFS is again more friendly in that regard, as it is about 2 C cooler across IN and MI. While there is progged to be something of a warm front extending south and east across MI and into parts of IN or OH, I don't know if the convergence along it or the WAA above it is going to generate enough lift to get storms to fire. Thus I think the triggering ingredient is insufficient for daytime surface-based storms across IN, OH, and the southern half of lower MI.

It looks like there's a much better chance of the ingredients falling into place sufficiently to get daytime surface-based storms in WI. There will be quite a bit of convergence near the surface low progged to be in C WI. That will probably be the best area to go for, as chase terrain in S WI and N IL is pretty bad (if not for the hills, then for the traffic and towns slowing you down). Plus the farther south you go, the more capped things look.

The models aren't too keen on putting out precip anywhere except north of the surface low and along the cold front across WI and IA. The GFS has some precip spread out across what may be the warm front during the day, but it could also be an extension of morning storms propagating southeastward.

Hope for the GFS to be right to see any storms with these ingredients. There may be a nice evening/overnight MCS eventually.
I grew up in SRN WI. This is a great area to chase, but farther west are some hilly / moraine topo areas that are somewhat challenging. Some of the parks in McHenry Co and farther west in Rock, Boone, and in away from the MKE metro in Waukesha and Dodge Co near Slinger and points west have decent farming areas, so vis is ok there too.

Obviously you'd want to stay away from the metros, including Waukesha, Milwaukee, Madison, Rockford and of course Chi. But besides that I may chase a bit. If what the models are pointing to and the SPC is agreeing with verifies, seems like a decent chase day.

One other note as we glance at model parameterizations is that some of the obs may be outdone. 75-80 Tds are kinda high and are probably affecting the composite indices by inflating the CAPE.

Best of luck and anyone chasing between RFD / MSN / MKE / CHI please DM me! (I would think RFD or MSN would be good target areas initially)

I think the last E/F5 tornado in Wisconsin was the Oakfield tor in Fond du Lac area nearly 10 years ago. The Barneveld tornado was featured is this gem from PBS/NOVA:
North central Illinois is fine, obviously northeast is metro / lake and northwest is the Mississippi River valley. But yeah, crossing the Mississippi River could be an issue if chasing around there.
Jeff makes a really good point. I knew there was something I was forgetting and thats the cap. Guess thats what I get for writing this at 3 Am. NAM looks to be slightly overdoing the H7 temps with the Euro and GFS a little bit cooler but still warm with 12-13 C. One thing I am thinking is that this could be quite the significant wind event. Its the time of year and strong params are there. WIll have to see what the cap says about In and Oh still think its a possibility but capping is certainly an issue.
Jeff makes a really good point. I knew there was something I was forgetting and thats the cap. Guess thats what I get for writing this at 3 Am. NAM looks to be slightly overdoing the H7 temps with the Euro and GFS a little bit cooler but still warm with 12-13 C. One thing I am thinking is that this could be quite the significant wind event. Its the time of year and strong params are there. WIll have to see what the cap says about In and Oh still think its a possibility but capping is certainly an issue.

@Ben Holcomb made a good point in a Facebook post that the "Southern Great Lakes Derecho" of 30-31 May 1998 is a top analog for this event on the CIPS page. It doesn't look like a super strong analog, but it's there. That was quite an event. See this page on SPC's site for a look at it: http://www.spc.noaa.gov/misc/AbtDerechos/casepages/may30-311998page.htm
That is the only option I see for playing in Michigan at least... There's no shot of anything during the peak heating.
I confess I'm mystified. Why the skepticism, Rob? I get that the 700 mb temp is hovering right around 12 C, but that's still acceptable for this time of year, and forecast soundings show the cap breaking. Going just by the NAM (COD maps, not the fcst sounding shown here), there's a 75 kt H5 jet max moving into the area, plus a strong (45-50 kt) LLJ, and plenty 'nuff CAPE to get the job done, even if the NAM is overforecasting instability (which of course never happens). Below is the KGRR NAM 18Z run for Monday at 22Z; CAPE--significantly, 0-3km CAPE--only fattens afterward. What do you see to be the limiting factor(s)?NAMM_KGRR 22Z.JPG
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Wisconsin is frustrating but chasing is possible and occasionally rewarding. I'm looking less at the thermo profile and more at the wind profiles which look very strong for June and are well juxtaposed over central Wisconsin. My early guess is a few early tornadoes (some strong) and fairly quick evolution to a fast moving MCS. NAM is very aggressive and scary looking...I expect the next model runs will temper that a bit.
My original limiting factor was that every post I've seen consisted of only the NAM soundings for some reason :) Now that we're in the range of other models (I like Canada) and they also are on board, I'm less concerned than yesterday. I do find it interested that the CIPS still flags 05/31 as the top analog! I don't like the format some broadcast mets use where they actually mention that date publicly, as I'm not sure that's what the intention is of those analogs, but nonetheless it catches my eye!
Quick note on Wisconsin. Roughly from Green Bay North you are screwed. Unless you are on a major highway, you aren't likely to be able to see much. I was on a two mile wide twister a few years ago near Lakewood. I never saw anything except the damage after the fact. It wasn't just because it was rain wrapped as you had to be looking straight down the road or right above you to see anything. The trees damn near cover the road.
On the flip side, the SouthEast quarter of the state is fairly open with a decent road network. Also good cell coverage
I almost posted this yesterday but wanted to wait another run (0Z) and see if the models would collaborate my forecast.. I admit, I'm probably a little off and will adjust some ads usual.. Overall though, I'm pretty excited to see what tomorrow will bring to mid Michigan. And what's not to love? Granted this is based off last nights 0Z NAM run.

60-90kt jet streak coming into the area at 0Z.

Acceptable 700mb temps for June (still under the greater than/equal to 12-13 C threshold)
700mb temps.PNG

Mid 60s to 70s surface dews with a surface Low and lower MI clearly in the warm sector.surface dews.PNG

Excellent but perhaps overdone ML CAPE:

80 plus knots of Bluk Shear....
bulk shear.PNG

1km EHI of over 5..

The NAM shows a breaking cap between 21-0Z also. There a ton of standing water in many places due to our rains we've seen in the past week or so, so PW values are up near 2. I think as this the surface low pivots NE through WI and upper MI, storms will begin to fire in the warm sector a little before dinner time (20-21Z). I'm off in the afternoon and will initially target between Lowell and St. Johns.

Note: sorry for all the slides. I don't have Power Point for the Surface to make this a little more condensed.

What does anyone think about a Extreme Northern IL or Southern Wisconsin target for tomorrow? What's your thoughts on a tornado in that area?

After reading all the expert opinions around the NWS / SPC, and looking at the CAMs, I think that there is definitely a conditional shot at a decent tor in your target area. The main issue with tomorrow will be with morning convection. However, with such strong westerly jet, the debris may exit sooner than later (check your favorite 1 minute vis sat viewer). So, as the usual story goes in this area, the more insolation we get, the better our shot at siggy sever.

Also, this target area (Srn WI / Nrn IL) will have very high precipitable water of nearly 2" (95-99 percentile per local NWS). Thus, watch out for HP supercells and probably some flash flooding (the local area has been very wet the last few weeks).

I hope that helps.

A side note to whoever is chasing tomorrow in SE WI or NE IL, send me a DM today if you think you'd like to participate in our live radio broadcast.
Of course I bet things will change tomorrow morning on the exact target, but good points. I believe the storm debris in the morning is the only question. Hopefully I can get on the storm prior to linear development and HP fully kicks in.
With a raging MCS still ongoing in Iowa this morning (still tornado warned as I write this) the 1998-05-31 analogue may not be far from correct. According to mesoanalysis this thing will run out of CAPE to work with soon, but I'm not sure it will fizzle out. Dewpoints in the upper 60's to around 70 seem present in N IL/S WI/S MI. If it maintains it's current intensity it seems like game over for tornadic supercells unless something can go up ahead of the line and remain isolated.

I'm here in Michigan at the moment but may take a jog south and hope for something on the southern end of that line. We'll see. I'm eagerly awaiting the 12Z sondes from DVN, ILX, GRB, APX and DTX. Would like to see a little better mid level lapse rates, especially over MI (5.5 really?) if we were to get something discrete ahead of this junk.

Tough forecast today, tough target, way too many obstacles. Kind of wishing I had gone home yesterday
Well this has turned to crap. Not at all what I expected... MCS died, new stuff formed over the lake, hoped those would flare but they didn't, now a watch is issued for no reason I can see (other than maybe east of 127). Here's to hoping we get something later today?
The atmosphere here in extreme southern MI has rebounded very quickly with CAPE values climbing above 2500 behind the earlier MCS. I still hold out hope.
22Z HRRR forecasting storms to fire in MI ahead of the CF at 01Z. It was right on earlier with that MCS and its timing, though I was holding out hope for one embedded supercells. We're still in the mid 60s/low 70s for surface dews at 0Z, but mid level lapse rates are pretty stable (5-6) per mesoanalysis.