3/1: FCST: Monday on Great Lakes

Feb 8, 2004
Detroit, MI
How many of you are gonna be chasing in the upper great lakes region on Monday? It looks like their will be a risk of severe weather from Illinois to Southwest Michigan with the threat being Supercells with tornadoes and damaging winds. What do the rest of you think of this system and are any of you gonna be chasing that far north?


Nick Grillo
FCST: 3/1/2004 Illinois-Indiana border region

The Day 3 surprised me. I hadn't thought about Monday's potential until a few minutes ago and have been scanning the ETA ever since. My first impressions are that the setup looks as good as anything going on in Texas tomorrow, maybe better since there isn't the extreme forcing to hasten a linear mode. I'm a southern plains chaser by training and after two years in Indiana, I'm still trying to adjusting to the unusual shear profiles associated with these ejecting systems. They don't always look pretty, but they do produce tornadoes occasionally.

Monday is interesting. Low level shear and LCL's would seem to favor some rotating storms ahead of the cold front, likely fast-moving low topped stuff. With 48 hours to work on moisture return, I could buy into the idea that theta-e values are underforecast on the 12Z ETA. CAPE projections are based on the massive rain shield ETA exhibits over the region, which may or may not come true. Again, the pitfalls of indices.

The very cold midlevels are a sure thing and attendant steep lapse rates certainly warrant attention. For the acutely storm-starved like me, it's a no brainer if the 12Z ETA verifies. Right now I'd guess a target about fifty to one hundred miles west of the Illinois-Indiana border. I'd probably stay on the interstate as long as possible to keep pace with things.

I'm off on Monday and it's close to home, so why not? 8)

By Monday there should be plenty of low level moisture available for the system to work with. The slight risk extends all the way north into northern Illinois! The southeast half of Illinois and far southwest Indiana look pretty good at this point. Further north the surface winds will be backed more, but so will the mid and upper level winds as well, so not much of a gain in that respect. If we can get enough sunshine to poke through and add some additional energy, this may end up being a fairly decent early season event. :wink:
You might condsider heading south into Kentucky, because there might be a mess of warm-air advection precip over Indiana throughout the day on Monday. But further south into Kentucky you might get some clearing ahead of the on going squall-line, and there will be a squall-line. If you do get some clearing ahead of the squall-line then look for gravity waves to initiate low-topped supercells ahead of the squall-line.

This setup happens quite often in the spring and fall east of the Mississippi River, especially in the Ohio and Tennessee River Valleys. If some cells can initiate east of the squall-line given the intense 0-1 km helicity values these cells could easily be tornadic! Even the squall-line could be tornadic as it moves into the great low-level shear in the Ohio Valley.

I'll pay close attention to Monday, mainly for the reasons mentioned by Simon. I suspect the worst of the weather will remain to my west over the western-most portions of KY and TN, but you just never know. I figure that at the least, I might encounter a night-time MCS if conditions allow it to hold together that long.
I may chase Monday depending on what things look like on Sunday.
I'm go for Indiana over to central Illinois (5 hr drive) if the moisture gets here -dew pts mid 50's or preferably higher. Central Illlinois is a tornado prone area. It is very flat prarie like terrain similar to central and eastern Kansas and they seem to get a higher than normal number of tornadic storms than surrounding areas. Situation seems to be somewhat similar to the Nov 10, 2002 Ohio tornados. - Jon Miller
0Z ETA update

0Z ETA offers little change from prior runs regarding Monday's setup, though it is worth noting that a wise friend of mine took the time to verify initialization and said ETA overestimated Gulf dewpoints as much as 10F. So we'll see. I'm still planning to chase as of now. No specific target yet.

I have classes on Monday and Tuesday, and I will most likely not be attending those on Wednesday (Texas Storm Chase), but I would be up in the Ohio Valley on Monday.

It looks pretty good!
Things definitely look interesting for Monday. This is far from a perfect setup, but it's the FIRST day of March! :shock:
That's right, the 1st Day of March... it's a good omen!!!!

You guys have to go chase to see what occurs!!!

Nick... I live here in MI as well, in Rochester Hills, or about 15 miles east of DTX. I just got done looking at the forecast models (FEB/29 12Z ETA) for tomorrow, and it looks like the best instability and shear combo will be in extreme southern WI/northern IL into extreme southwest lower MI. By the time any storms make it further east than that, it will be getting dark, and sfc low will actually be weakening, so I wouldn't anticipate much in eastern MI.

What catches my eye as well, is later next week in the Wed-Fri time-frame. Most models - UKMET/ECMWF/GFS - are developing a very strong sfc low across TX. One thing is for sure, this system will have more than enough moisture to work with, and depending on the exact track, we could be looking at 2 inches of rain or 2 feet of snow...But thats Michigan for ya! (by the way, Detroits record 24hr snowfall occured on April 6 1886, with 24.5", so it can snow late - http://www.crh.noaa.gov/dtx/1886-1974.htm).
I'm hoping the low holds off on weakening a bit, which would allow it to hang back in Iowa longer. The GFS inicates this, but the ETA fills it in quicker allowing it to propagate eastward more rappidly. I think the GFS is more on track and I look for the low to still be hanging back in central Iowa around mid afternoon. With the dry/warm slot kicking around the base of the low, and with advancing cold air aloft, I think extreme eastern Iowa and northern Illinois could see a nice low topped event. Due to lack of low level moisture, I look for mainly a hail event with some very weak/brief tornadoes where the moisture has pooled the most. Either way I'm very thankful for such an early season event and will enjoy it as much as I can. Especially since it could snow later in the week!! 8)
Ahhh, it feels so good to be writing chase discussions in February. Not that this is very in-depth, but I didn't post my earlier one (sorry, guys).

0Z model runs are out. The Td situation seems to be improving somewhat...although still nothing to jump for joy over. The BUFKIT soundings have improved the low level moisture as a result...and things don't look as bleak now as they did. Hwvr...still xpecting a hail event...but wl not count out tornadoes. Shear looks pretty good...so if some moisture will pool somewhere...brief spin-ups might occur. If nothing else this shud provide a good opportunity to shake the cobwebs out and field test new equipment. The SDS may abate shortly...I await the first rumbles of thunder. How cool would it be to see my first tornado on March 1 of all days?

Tomorrow in Illinois

I still think tomorrow in Illinois is marginally interesting. Tonight, storms
fired in the dryslotted area of southeastern Kasnas and did so near nightfall with 50 temps /upper 40 dps. They were small and weak but one (maybe more--didn't check) went severe, and, more importantly the area cleared out very nicely. I expect much the same effect in western Illinois tomorrow. The line of showers is passing through IL right now, and is very elevated and thus having no effect on BL moisture. Dewpoints behind the showers remain in the 40's and continue to climb.

RUC forecasts clearing skies and with temps in the 60's and dews in the 50's, I certainly think low-topped supercells southeast of the main upper low are possible. I don't know if they're likely or not, but possible, with the very cold midlevel temps of aruond -25C. Deep layer shear should be on the order of about 45 knots and low layer shear is marginally supportive of rotation. SRH values should range around 200 m/s in the area from west central Illinois to the Indiana border. I am thinking the area from Bloomington/Normal to Peoria would be interesting, mainly because it seems the best compromise between promximity to the upper low and access to the better dewpoints. And it's on the interstate highway--built for speed! LOL! Of course I'll look for any boundaries that might remain from tonight's activity, too, and adjust accordingly.

I think storms will fire early, perhaps between 1:00 PM and 4:00 PM, and take off to the east northeast. By 0Z the show will be over as instability disappears after sunset.

I want to chase tomorrow but am currently having a crisis of confidence regarding whether or not I should wait and make a long haul to Texas on Wednesday. Ah, the headaches of spring! :lol:

I think a couple of my gang are going, probably to the same area Amos mentioned. If anyone would like to meet up at some point, feel free to IM or e-mail me with the buttons below. I'm pretty excited to just get out there, regardless if anything ends up happening. Winter in Indiana doesn't have much in the way of SDS relief.
I'll be covering the Macomb area in West-Central Illinois. If things do go big, I can always drag my friend with a car out. :)
Re: Tomorrow in Illinois

Originally posted by Amos Magliocco
I think storms will fire early, perhaps between 1:00 PM and 4:00 PMAmos

Yes, I agree. I think storms will start firing as early as late morning in eastern Iowa and northern Missouri. There isn't much of a cap to speak of, so this is why I expect the early initiation. Low topped events such as this usually fire pretty early in the day. Then as they move further east into Illinois I expect them to reach their peak strength between 2-5pm, especially in the eastern half of northern Illinois. Any tornadic activity will be limited, but an isolated weak one is not out of the question. Look for some reports of hail covering the ground tomorrow as these babies will be hailers, although for the most part marginally severe. Very interesting for this time of year none the less...Good luck to any who decide to chase tomorrow! I want to see some pics! :lol:

Things look on track this morning with clearning developing already in western sections of Illinois and dewpoints reaching the upper 40's with a few fifties. I think the chances exist for a few 64/52 readings in areas along and south of the I-74 to I-80 corridor depending on the amount of insolation. With a negligible cap in the cold-core style regime, storms could fire relatively quickly and move into favorable low level shear. I hope some fire south enough to spend more than an hour or so in the favorable theta-e air--RUC breaks out precip first quite far north. We'll see.

I'm leaving for Peoria in about an hour and hope to see some low-toppers!

As of right now (almost 7am CST) we're still locked in a fairly solid low overcast here in northwest Illinois in the Quad Cities. Dewpoints have reached near 50 as far north as Peoria and Quincy Illinois already. Water Vapor shows the dry tongue nosing right up into Iowa and Illinois. I'm still waiting for the 12Z soundings, but everything still looks on track for an early season event. Storms still look to fire in Iowa later this morning, probably between 10-11am, then push eastward across the Mississippi shortly after noon. I still think northern Illinois is in the prime area, especially the eastern half of northern Illinois. Forecasted CAPE values over 1,000j/kg are VERY impressive for this time of year over northern Illinois.
Right now clouds are breaking up here and the sun is shining. Bring on the instability. 8)

At 10 AM, we've got small cumulous building. According to soundings, CAPE is starting to build.
dews falling western IL

On a less positive note, the dewpoints in western IL are dropping slightly over the last few hours as sfc winds veer a little and drier low level air mixes down from southwesterly 850s.

Where I am, things are okay, but I don't know how long that will hold. Most of the western IL stations that reached 50 or 51F dewpoint an hour or two ago are now in the 48-49 range. I may have to go north to stay in southeasterly flow and chase the narrowing moisture tongue.

I'm in Normal, IL right now, looking up at the cobalt sky and an increasing cu field. May move north towards Peru. I really like this spot because it has five interstate highways radiating in all directions. Imagine if we had that in CDS--wow.

I hope something fires soon!

Dekalb would be a good place to be at this point. A rappidly advancing shield of cirrus is capping the temps here in NW IL now. I'm a little disappointed in the dewpoints. But out to the east they have spiked above 50 in north-central IL. I can see some pretty decent towers going up to the east ahead of the high overcast. Underneath the cirrus deck there are some rather bleak looking cumulus. Out to the west a band of rain showers has formed and is approaching eastern Iowa. So far this has done very little, and looks to have little if any thunder at this point. Dekalb is where I'd be. I wish I could go but I have to work! :cry: Good luck guys!