August Tornado in Macomb: A Lake Breeze Landspout

Monroe TornadoOn Wednesday afternoon, August 20, 2014, a small tornado spun up beneath a seemingly garden-variety summer thunderstorm and did EF0 damage in Lennox Township on the eastern side of the state. I first became aware of it courtesy of a Facebook post by fellow Michigan-based storm chaser C. J. Postal. He wrote, "I give up. You win, Michigan." Underneath was a photo of  an unmistakable, nicely shaped funnel cruising over the treeline. My first thought was, What does he mean? The photo couldn't have been taken in Michigan. No way. It simply wasn't tornado weather--no ripping jets, no curved hodographs, just weak westerly winds and, here on the west side of the state, beautiful, cloudless skies. Over on the east side, the radar showed just a scattering of small red zits around the thumb and down by Ann Arbor: bland, pulse-type storms capable of squeezing out a few bolts but certainly not a tornado. Yet as you can see from the photo,* one of them did spin up a tube. The National Weather Service logged the following report.
What the heck happened? Michigan happened. Seriously. Not only does this state not get tornadoes when conditions look ripe for them, but it does get them when no one expects them. It happened a couple years ago in Dexter. It happened last month just a few miles from me in Cutlerville. And now, two days ago, it happened over near Macomb. Wind profiles were unimpressive. Bulk shear was negligible. About the only things in place, as I recall, were adequate surface-based CAPE and moisture, but this was by no means supercell weather. "Severe" just wasn't in the picture. However, one easily overlooked element unique to the Great Lakes probably was present and might well have been the culprit. That ingredient? The onshore breeze blowing off of Lake St. Clair. Twenty-six miles long and twenty-four miles wide, with 430 square miles of surface area, the lake is the largest body of water in the Great Lakes region after the Great Lakes themselves. It is easily large enough to generate its own lake breeze. On its western shore, that breeze is an easterly breeze which, backing against an overall westerly wind regime, can enhance low-level helicity or even produce it when none would otherwise exist. That's my theory, anyway, and I think it holds true not just for Lake St. Clare but even moreso for the western sides of Lakes Huron, Erie, and Michigan, where the lake breezes blow inland from the east. Storms moving into such an environment may, under the right conditions, get just the added low-level twist they need to turn an ordinary updraft into a tornado. That, I believe, is what happened last Wednesday. The mechanism was probably that of a landspout. It certainly wasn't that of a supercell thunderstorm. None of the storms I saw on the radar that day looked capable of producing a mesocyclone; they were non-severe little blips on the radar. But they were surface-based. And that combination of an updraft with preexisting vertical vorticity evidently did the trick. I've seen enough other examples of storms in this state that went tornadic, or at least developed rotation, as they approached the eastern coastline to think that the lake breeze plays a role in a good percentage of cases. No doubt the same holds true for the northern Chicago area north up into Wisconsin inland from Lake Michigan. What I'm saying may be nothing new to NWS meteorologists, but I don't recall ever seeing it discussed. Then again, I rarely read KDTX's forecast discussions, so maybe that's why. I'm a KGRR man, but here in West Michigan, while our westerly lake breeze creates convergence, I doubt it contributes to helicity in the same way as the easterly breezes coming off of Lakes Huron, Erie, and St. Clare. I've never seen the lake breeze's possible role in storm rotation and tornadogenesis discussed to any great extent, and I think it merits recognition as a uniquely Great Lakes phenomenon. So I'm throwing it out here, with the caveat that I'm just an amateur forecaster, not a trained meteorologist. It would be great to get the thoughts of professional forecasters as well as other Great Lakes storm chasers who have considered how the easterly lake breeze may sometimes enhance storm severity. ---------------------- * I would like to credit the photographer, but having exercised due diligence, I'm unable to locate that person. If you took the picture, or if you know who did and how I can reach them, please contact me.

My Great 1,600 Mile Chase Bust

Monday and Tuesday this week were the storm chase from hell. It you're looking for a nice, upbeat post about chasing, you'd best skip this one. My feelings about my fiasco in Nebraska may have mellowed down enough for me not to unleash a full-bore rant anymore, but I've still got enough gunpowder left to blow off a few firecrackers. That's the result when impediment piles upon impediment and frustration upon frustration. With my sights Sunday night fixed on western Iowa and eastern Nebraska the next evening, I set my alarm clock for 4:30 a.m. and hit the sack. I was awakened by early morning light filtering through the window. Light? I glanced at the clock. It said 6:30. My alarm hadn't sounded and I was running late. Nuts. But okay, no problem. After a fast shower, I kissed Lisa good-bye, threw my gear into the car, and hit the road. I still had plenty of time to make eastern Nebraska, and that was a good thing because the SPC had bumped the focal point for tornadoes west. No time to analyze models--I just had to trust the Norman weather pros and hope for the best. Off I went. Thirty miles down the road in Zeeland I made a delightful discovery: I had left my debit card in my other pants pocket. This was the beginning of woes. Self-possessed person that I am, I responded calmly and maturely by protruding my eyeballs, depressurizing my feelings constructively using the special vocabulary that I reserve for just such occasions, and, a cat of nine tails not being handy, by rapidly banging my fist on the steering wheel in lieu of self-flagellation. Retrieving my debit card meant losing over an hour. I now was pushing the envelope, but I could still make eastern Nebraska by late afternoon. This being probably my last crack at a good setup in a record storm season during which I've been miserably sidelined, I was determined to try. So off I went again. I wasn't far south of Holland, Michigan, when the disquiet in my stomach became a bubbling, and the bubbling escalated into the kind of tar-pit-like seething that tells you a quick trip to a bathroom will be required in the near future. Between southern Michigan and east of Chicago, I made three pit stops. Another 45 minutes, literally gone down the toilet before I finally popped some Immodium and put an end to the rumblings. By the time I drew near to Omaha, the show was underway. A tornadic supercell was moving up out of Kansas into Nebraska toward the center of the surface low. My friend and long-time chase partner Bill Oosterbaan, who had called me as we both were initially approaching Zeeland and just as my debit card fiasco was commencing, was now far ahead of me and positioning himself for the next storm down. That storm went spectacularly tornadic and Bill got some great footage, probably the best he's gotten so far. But there was no way I could make it that far west in time to catch tornadoes. My show was clearly going to be the pair of cells to my southwest that were heading toward Lincoln. They were my one chance. But they were south of the warm front, and while surface winds were southeasterly, the storms were moving north-northeast. The low-level helicity required for tornadoes was lacking. My hope was that as the storms headed north they would tap into increasingly backed winds. But all they did was backbuild and congeal into a nasty squall line. My hopes were still up as I approached Lincoln; however, as I finally drew near to the northernmost cell along US 77 west of Roca, I could see that I was screwed. The cells had congealed into a pile of linear junk. I had driven over 750 miles to chase a shelf cloud, and it wasn't even a particularly photogenic shelf cloud. True, it had the local media in Omaha screaming about 75 mph winds and flash flooding, but I've seen plenty better right here in Michigan. Linear mess-oscale convective systems are our state storm. No point in prolonging the pain. I started heading home, my idea being to get far enough east that I'd have time to chew on the system's leftovers back in Michigan the next day. Bill had business in Iowa and was overnighting at the Hilton in Marshalltown, so I bunked with him there. He'd gotten four tornadoes in Polk County, and we reviewed his footage. Very nice stuff! He'd gotten close enough to a large tornado to capture the roar. Here's his YouTube clip. Sigh. So near and yet so far. An arcus cloud isn't much of a compensation prize compared to a tornado. Of course there was still tomorrow back home. A warm front looked poised to drape right across Grand Rapids with SBCAPE in the order of 4,500 J/kg--an optimal setup for Michigan, except that the models consistently depicted the 500 mb jet hanging back just to the west in northern Illinois and Wisconsin. Bill and I in fact hooked up again the next day after his business meeting and briefly discussed chasing the low in Wisconsin. But that area is some of the worst chase terrain imaginable, so we scrapped the idea and went our ways. Somewhere around Davenport, out of idle curiosity, I checked out the SPC's mesoanalysis graphics and noticed that the mid-level energy appeared to be nudging eastward toward Michigan. Hmmm...maybe there might be a bit of a show after all. I gave Kurt Hulst a call. He had hung back in town and was planning to chase today, not expecting much but thinking that the big CAPE could compensate somewhat for poor upper air support. I agreed, particularly now that it looked like 500 mb and higher winds might reach the threshold for storm organization. Later VAD wind profiles at GRR showed nice veering with height along with 30 kt winds at 18,000 feet. Not a setup to die for, but it might just work. And it did. A beautiful supercell fired up along the warm front, and Kurt was on it in a heartbeat. He got in some nice chasing on several storms, witnessed rotating wall clouds and a funnel extending halfway down, and did some call-ins for WOOD TV8. Good work, Kurt! As for me, I got delayed by a traffic bottleneck in Joliet, Illinois, and attempting to find a detour proved to be a huge, time-consuming mistake. I finally arrived in Michigan in time to chase storms, but not the ones on the warm front. Once again I had to settle for what I could get as I belted east down I-94 and punched through the line near Marshall. By then the mid-level winds had backed off and I was left with the usual, disorganized Michigan crap-ola. There was a lot of that, though. The warm sector was remarkably juicy, and more storms kept popping up behind the main line. Heading back through Battle Creek, I parked in a lot across from the old Kellogg Museum and watched a couple of cells south and west of me detonate their munitions. I'll say this: The lightning this day was intense, lots of brilliant, high-voltage positive strokes, many of which struck close by. It was an impressive, beautiful, and exciting pyrotechnic display. But now that it's all behind me, my tornado tally for this year remains zero. Between Monday and Tuesday I drove over 1,600 miles and blew through around $200 worth of gas to see nothing that I couldn't have seen by simply sitting in my apartment and looking out the window. It's frankly a bit humiliating, considering what a benchmark season this has been for storm chasers. Family comes first, though, and tight finances in a rotten economy have been a potent regulator. Sometimes all a body can do is choose his attitude. I confess that mine wasn't all that great these last couple of days, but I talk with the Lord about such things. It's the best I can do: put my feelings before Him honestly, then do what I can to adopt a more positive spirit and move on. sure would be nice to see a tornado yet this year. Just one. I don't think that's too much to hope for. Sigh. Maybe this fall.