May 28, 2013, Tornadic Supercell by Grand Ledge, Michigan

Tornado season is now long past, and the sting of missing great storms either through bad targeting or having to head home one and two days before two major events has eased. Maybe next year will be better. Besides, the show's not over till the snows fly. Meanwhile, I'm looking back to my most interesting chase of the year, documented by the video at the bottom of this post. Ironically, I logged around 6,000 miles to and from Oklahoma and Kansas with little to show for it, while my humble backyard of Michigan gave me an enjoyable and productive bit of action. On May 28, a warm front lifted up through lower Michigan, ushering in decent moisture and instability along with a good boundary for them to work their mojo with. The thing that seemed to be missing was adequate shear for storm organization--but I ignored conditions farther east of me. I just didn't take the setup seriously enough, and when Kyle Underwood, the WOOD TV8 meteorologist, inquired which of the TV8 chasers planned to head out, I said that I didn't see much potential. If something came my way, I would grab it, but otherwise, I didn't want to waste gas. That was understandable: money was tight, and I planned to chase in Kansas the next day. Still, geeze, what an idiot (me, not Kyle). Let us pause momentarily while I give myself a retroactive dope slap. I have come to a conclusion: in Michigan, when a warm front shows up with good CAPE present and any kind of bulk shear to speak of, even anemic bulk shear, chase the front. Never mind what the models have to say about storm-relative helicity; helicity will take care of itself if a storm manages to organize in the vicinity of the frontal boundary. Just get out there and chase the stupid front. Particularly farther to the east. Storms in Michigan often have a way of intensifying and organizing near and east of I-69 and, north of Lansing, US-127. That was the case on this day. My first clue was when I glanced at the radar later and noticed that Kurt Hulst was on a storm off to the southeast. Kurt knows what he's doing, and the storm looked decent--in fact, it was tornado-warned. Okay, I thought, I missed that one. Probably it'll be the only one. So I sat tight and watched the radar as other storms formed. They looked like a convective mess to my west, but they clearly were moving into a better environment as they progressed east. Finally, I'd had enough. I grabbed my laptop and cameras and headed out. I locked onto the most intense-looking cell in my vicinity and tracked with it toward Portland. But another was following on its heels, and given the way that the storms were behaving, I thought I'd be better off dropping the one I was on and letting the new one come to me. Presumably, it would get its crap together on the way, and that is what happened. As it approached Grand Ledge just west of Lansing, this storm developed a most amazing streamer of scud sucking into its updraft base from the east. It appeared to originate near ground level--hard to tell with trees constantly interrupting the view--and rocketed toward the storm, leaving no doubt that this storm had impressive inflow. Driving into Grand Ledge, I found myself under the area of rotation, with crazy, low cloud motions. Turning around, I headed back north and parked by the airport, then watched and filmed as the storm headed east into Lansing. It looked very close to spinning up a tornado; in the video, you can see it trying hard, and eventually it succeeded. But I had to drop the chase. My friend Steve Barclift and I planned to chase the next day in Kansas, and I had to meet him so we could hit the road for the long drive west. As it turned out, the storm I was on provided a better show than anything we saw along the dryline. My buddy Rob Forry managed to catch this storm at its tornadic phase and got some nice video. My original hi-def shows the motion of the inflow streamer nicely as I enter Grand Ledge. Regrettable, this YouTube clip doesn't render the details as well, but you'll at least get a feel for the motion. The storm was an interesting one and fun to chase. It would be nice to get another one like it. It's only August, so the door is far from closed.

Bow Echo at Elk Rapids, Michigan

Judging from the forecast soundings, it seemed that northern Michigan stood at least a chance of tornadoes yesterday evening. But the storms that first ignited in Wisconsin quickly congealed into a broken line as they crossed Lake Michigan, minimizing their tornadic potential and fulfilling the predictions of forecast models and the knowledgeable heads at the Storm Prediction Center. I made the trip north regardless of, from my standpoint as a storm chaser, the unpromising prognosis. I hadn't been upstate yet this year, I was itching for a bit of convective violence in any form, and the thought of simply watching a brooding shelf cloud blow in over the beautiful hills-and-water region around Traverse City appealed to me. Given ample low-level helicity between 200-300 m2/s2, I figured I stood at least a chance of getting  some rotation out of a tail-end cell or perhaps a hook-like protrusion. But I was willing to settle for less, which is what I expected and what I got. I headed north on US 131 as far as Kalkaska. Then, with storms to both my north and west, I decided I'd be better off heading west down SR 72 and meeting the southernmost cells moving in toward Traverse City. At Acme, I caught US 31 north, and from then on my goal was to find a good place to park and get some pics. That's easier said than done in a landscape filled with timber. Grand Traverse Bay was almost within spitting distance, and I could see glowering, lightning-laced clouds advancing to my northwest. But, blocked by trees, the clear view I envisioned of a shelf cloud bulldozing in over the bay kept eluding me. Finally I found myself in Elk Rapids. The town was right on the water; there had to be someplace to park with an open view. At a stop sign, I edged out prematurely, then tapped on the brakes as fellow chaser Nick Nolte turned off the main drag in front of me. Cool--Nick was here too. I figured I'd find a spot, then give him a call. As it turned out, Nick found me first a few minutes later in the parking lot of the local marina. "Hey, I just about ran into you at an intersection," I told him. "That was you?" he said. "Jerk!" Our location was probably as close to ideal as possible, given the lay of the land. The cell to our north blew past, but the radar indicated a bow echo making its way directly toward us. I'd never have guessed from the bland-looking sky to the west. But in a few minutes, storm features began to emerge from the nondescript grayness like an old Polaroid photograph developing. A shelf cloud was advancing across the bay, growing more distinct by the second. Nick hopped out of his car and tripoded his camera. I opted to go hand-held--not the best approach, but in this case a practical one. But my camera gave me grief; the shutter wouldn't operate, and by the time I remembered that I needed to turn off the auto-focus, the shelf cloud was overhead. Nuts. I snapped the five shots you see below, then got in my car as the rain and wind descended in earnest. The marina was right in the belly of the bow, and for a few minutes, I enjoyed a nice blast punctuated with lightning and commented on by thunder. Then the line moved off to the east. Nick and I decided to try and reposition in hopes of intercepting the southern end, but our attempt was futile. We ended the chase and grabbed dinner at a Big Boy restaurant in Kalkaska. This time of year, any storm is a good storm--not that I'll normally drive 175 miles just to see a bow echo, but I don't need a Great Plains tornado to make me happy. After multiplied days of remorselessly gorgeous weather, a boisterous round of lightning and thunder always gladdens my heart and gets a shout out of me. ADDENDUM: The tail-end cell, which had consistently displayed a hook-like appendage and shown an inclination to turn right, went on to produce an EF-1 tornado at a golf course near Roscommon, forty miles east-southeast of where Nick and I grabbed dinner in Kalkaska. The low-level helicity delivered after all. If the storms had been discrete, I suspect we'd have seen a few more tornado reports.

The Action Comes to Michigan

Curious about the SPC's Day 2 convective outlook for Michigan, I ran a few forecast soundings. Good grief! I can't remember when I've seen skew-Ts like these in Michigan. The one for Cadillac reminds me of June 5, 2010, in central Illinois, though I think the winds above 500 mbs were stronger in that event. It's late and I'm not about to write a lot. But I have a strong hunch that tomorrow early afternoon I'm going to be heading north on US 131. It's rough chasing in that part of Michigan, but anywhere in this state is challenging, and we don't see this kind of setup very often.

March 15, 2012, Dexter and Lapeer, Michigan, Tornadoes

Thursday's tornadic supercells in eastern Michigan took a lot of people by surprise--NWS and media meteorologists, the SPC, storm chasers, and certainly me. Nothing about those anemic mid- and upper-level winds suggested the potential for even weak tornadoes, let alone significant ones. But there's no arguing with Nick Nolte's fabulous footage of the Dexter tornado, and certainly not with the damage that storm did as it swept through the town. It has been rated an EF-3, the most damaging of the three tornadoes reported on March 15, 2012. Second in impact was a tornado that struck farther north in Lapeer, causing EF-2 damage; and finally, an EF-1 tornado in Ida. Like every other chaser in Michigan whom I know, I had no plans for chasing storms Thursday. True, temps were in the 70s and dewpoints in the 60s; MLCAPE was in the order of 3,000–3,500 J/kg; and the hodograph looked curvy. But curvy alone isn't supposed to cut it, not when the dynamics are as puny as they were: winds around 20 kts at 850 mbs; 20–25 kts at 700 mbs; and 25–30 kts from 500 mbs on up to around 26,000 feet, where they finally began to make incremental but hardly impressive gains. The storms that formed should have been popcorn cells that quickly choked on their own precipitation. But they didn't. At least some of them became classic supercells that lumbered across eastern Michigan at around 15 miles an hour, spinning up strong tornadoes. I was sitting in my living room editing a book manuscript shortly after 5:00 when I happened to glance out the window and saw some impressive, well-formed towers to my southeast. "Dang!" I thought. "Those look nice!" My second thought was to grab my camera and snap a few photos. After all, thunderstorms just aren't something you normally see on March 15 in Michigan, let alone such muscular-looking ones. You can view one of the three shots I took--the last one, time-stamped 5:22 p.m.--at the top of the page. (Click on the image to enlarge it.) Curious, I took a look at GR3. I'd been glancing at it off and on as the afternoon progressed, watching a small squadron of cells pop up across southern and eastern Michigan. They resembled something I might normally see in July or August. But now, one of them looked different--so unexpectedly different that I had a hard time believing what I was seeing. South of Howell and northwest of Ann Arbor, the most vigorous-looking storm of the bunch had transformed into an unmistakable supercell--a regular flying eagle with a little pinhole BWER in the hook. Where the heck did that come from, and why on earth was it there? Pinch me, I must be dreaming. I switched to SRV, and sure enough, there was a couplet, and not just a weak one, either. A pronounced couplet. A scan or two later, the storm was continuing to develop. The pinhole had disappeared, and the supercell now had a classic hook. On radar, it looked as nice as anything you could hope to see out West in May--only this was Michigan in mid-March. Surely the winds had to be better than I had been led to believe. One way to find out. I pulled up the VAD wind profiler at DTX. Ummm ... well, okay. Nothing at all remarkable there. Maybe, given the curviness, enough bulk shear to organize the storm. Obviously that had to be the case; the evidence was staring me in the face, along with a couplet which hinted at the tornadic action that was presently occurring. The last screen capture, just below and to your right, shows both the couplet and the VAD. Enlarge the image, zoom in on it, and you can see for yourself just how meager the winds were and why one would expect storms forming in that environment to drown themselves in their own tears. While I was glued to my radar in Caledonia, across the state storm chaser Nick Nolte was hot on the storm and videotaping the tornado that eventually hit Dexter. After getting out of work for the day, Nick had noticed the storm popping near where he lives. Grabbing his gear, he took off on what turned out to be one of the most serendipitous chases any chaser could hope for. Nick got some fantastic footage of the Dexter tornado. Congrats, Nick--you really nailed it! Rather than steal Nick's thunder by embedding his YouTube video here, I'm going to simply redirect you to his site and let you hunt it up there. I've viewed some other footage beside Nick's that demonstrates a particularly noteworthy aspect of the Dexter tornado, and that is its breakdown into helical vortices. I've seen only one other video that demonstrates this helical structure so clearly, and that is the famous KARE TV helicopter video of the July 18, 1986, Minneapolis tornado. The Dexter footage isn't as dramatic, but it nevertheless depicts the helical effect with stunning and captivating clarity. Nick's video captures it as well toward the end of his clip. It's really amazing to see. Unfortunately, the Dexter and Lapeer storms did considerable damage. If there's a bright side to their human impact, it's that no one was killed or seriously injured. What turned yesterday's anemic setup into a significant tornado-breeder? A weak upper-level impulse provided the needed lift to spark the storms, but it doesn't explain why some of them developed into tornadic supercells, given the lackluster mid- and upper-level winds. I'm no expert, but I'm guessing that the unseasonably high CAPE is what did the trick. I suspect it took what was present in terms of shear and helicity and amplified it, in effect creating the Dexter, Lapeer, and Ida storms' own mesoscale environments--ones conducive to tornadoes. Of course, similar scenarios typically provide no more than single-cell and multicell severe storms. But then, yesterday was an anomaly in some significant ways. After all, this is Michigan, and it's only mid-March. When CAPE of that magnitude shows up in the midst of unseasonably high dewpoints, it appears that all bets are off. ADDENDUM: Lest you should miss reading the comments, check out this satellite loop from Thursday. You can see the storms exploding along an outflow boundary pushing west-northwest from Ohio, and other storms firing along a cold front dropping southeast. Two boundaries, and they actually appear to collide around Saginaw. The OFB accounts nicely for convergence and low-level helicity. Thanks to Rob Dewey for sending me the link.

Stormy Monday in Michigan?

The Storm Prediction Center's Day Three Convective Outlook has stamped lower Michigan with a "See Text" attended by the following discussion:
A POCKET OF COLD TEMPERATURES AT MID LEVELS...MINUS 18-20C AT 500 MB...WILL SPREAD ACROSS LOWER MI JUST NORTH OF A FOCUSED SPEED MAX. THIS FEATURE WILL LIKELY INDUCE DIURNALLY ENHANCED CONVECTION AS 50F+ SFC DEW POINTS SURGE NWD WITHIN THE WARM CONVEYOR. LATEST FORECAST SOUNDINGS SUGGEST SFC-BASED CONVECTION IS POSSIBLE WITHIN A STRONGLY SHEARED ENVIRONMENT THAT WOULD OTHERWISE FAVOR SUPERCELL DEVELOPMENT. GIVEN THE SOMEWHAT LIMITED BOUNDARY LAYER MOISTURE ACROSS THIS REGION WILL NOT INTRODUCE HIGHER SEVERE PROBS ATTM. HOWEVER ANY UNDERESTIMATION IN LOW LEVEL MOISTURE WILL LEAD TO A MORE UNSTABLE AIR MASS THAT WOULD SUGGEST AN INCREASED RISK OF SEVERE FROM EXTREME NRN IND/NWRN OH INTO LOWER MI.
Hmmm...okay, that's worth looking into, and I have done so. The NAM surface map is more optimistic about moisture than the GFS and SREF, wanting to bring in mid-to-upper-50s surface dewpoints, and therein lies the possibility for severe, from what I can see. Today's 12z 250 mb 4km NAM also shows a 70 knot jet streak moving into the area on top of 35-40 knot 850 mb winds, and GFS is in better agreement with the shear than it is the moisture. Earlier on, I also sampled a few 6z Bufkit NAM soundings using RAOB, and these show impressively curved hodographs--a different story from TwisterData's point-and-click hodos--as well as dewpoints tapping on 60 degrees. That seems pretty exuberant, particularly in the light of other forecast models, but it does give me at least this take-away wisdom: Monday bears keeping an eye on. If, as the SPC states, decent moisture manages to infiltrate lower Michigan, then we could be in for some severe storms. Just for kicks, below are the aforementioned RAOB forecast soundings for Monday evening taken from this morning's 6z NAM run, along with the 4km NAM 250 mb map. The soundings are for Kalamazoo, Jackson, and Fort Wayne. Take them with a grain of salt, but let's see how things shape up (or not) between now and then. KALAMAZOO, MI JACKSON, MI FORT WAYNE, IN 250 MB WINDS (FCST 21Z)