Cool-Weather Wall Clouds

So there I was, driving down I-96 toward my mother and sister's house in Grand Rapids this afternoon, when I saw what at first glance looked like a wall cloud. It looked like one at second glance, too, and third, hanging off of a cumulus tower in the distance. Severe weather wasn't in the outlook today, and in fact, the afternoon was coolish and not particularly moist, with spotty showers but no thunder or lightning. I was unaware of any reason to be on the lookout for abnormal weather, though the extent of the vertical development in the cumulus clouds coupled with their nicely sheared look would have been a tip-off under more propitious circumstances. Anyway, I was intrigued by the cloud formation, but not quite prepared to call it anything more than a lowering at that point. It was falling apart over Grand Rapids by the time I turned north onto the East Beltline. But the show was far from over. Another large towering cumulus several miles to my northwest was exhibiting an even larger, blocky lowering which wasn't showing any signs of dissipating. That did it. It was time to get close enough to this thing to see just exactly what it was. This was a simple matter. The cloud was drifting quite slowly, and intercepting it involved nothing more elaborate than continuing north up the Beltline past 7 Mile Road, then pulling into a small turn-in, where I had an unobstructed view from maybe half a mile away. The cloud was indeed a wall cloud. I could see a weak updraft dragging scud up into it, and even a hint of an RFD. More important, the cloud was circulating--very slowly, to be sure, but unmistakably. As it moved closer, I even observed a small, anticyclonic vortex spinning almost directly overhead. There was obviously enough shear and helicity in the atmosphere to create some interest, and I had a nice front-row seat. Just wish I'd had my camera with me, but as I said, I wasn't expecting anything weatherwise today that would have made me think to grab it. What I was seeing struck me as more fascinating than threatening, but I decided to call KGRR and report it anyway, just for the record. The met who took my information said he wasn't surprised. He told me that the office had already received several reports of waterspouts out on Lake Michigan, plus other reports of funnel clouds. Sounded like a cold air funnel outbreak. My buddy Kurt Hulst called later to tell me that he, too, had seen a wall cloud over Caledonia from where he lives in Kentwood. If I'd been home, it would have been a front door delivery, but of course I wasn't. Seems to me, though, that Kurt said he got some photos. I hope so, because I'd like to see what I missed. Days like today just go to show that the weather does what it wants, when it wants. Maybe the local WFO will offer an analysis of today's conditions. That would be cool. Lesson learned: take my camera with me wherever I go.

June 8: Mini-Supercell in Northern Illinois and Severe Squall Line on the Lake Michigan Shoreline

This is really part two of the previous post. After chasing a potent, monster hailer of a supercell north of Saint Joseph, Missouri, I overnighted at a hotel outside of Des Moines, Iowa. When I stepped outside the next morning, the air was much cooler and drier, a stable atmosphere that wouldn't produce so much as a sneeze, let alone a tornado. But I knew that the SPC had outlooked the area to my east across northern Illinois, and for several days I myself had been eyeballing my home state of Michigan, where the NAM-WRF had been consistently indicating the possibility of tornadoes. With a little luck, I hoped to make it back in time to chase whatever convection might pop up along the warm front. As I approached Davenport, I observedĀ  towering cumulus muscling up through the troposphere. However, I didn't pay them any attention--that is, until Bill Oosterbaan called to inform me that the SPC had just issued a mesoscale discussion for the area just east of me. Even as we talked, I noticed a lowering on a cumulus tower a mile or two to my northeast. When it continued to develop, I decided to investigate. Leaving I-80, I parked across from a truck stop at the Atkinson exit to watch. The next cell to my west quickly grabbed my attention. It had a nice rain-free base, and as I watched, scud began to form and ascend in an obvious updraft, coalescing into a small, ragged wall cloud. Grabbing my camera and getting out of my car, I noticed right away that the air was very different from back in Des Moines--considerably warmer and with plenty of moisture. The wall cloud fell apart before I could get a pic, but the overall structure remained interesting.
A mini-supercell approaches Atkinson, Illinois, just north of I-80.

A mini-supercell approaches Atkinson, Illinois, just north of I-80.

More brief, non-rotating wall clouds formed and dissipated one by one, so I figured I'd head north of town and observe. With surface winds veering and the overall flow unidirectional, I had no expectation of seeing tornadoes, but the mini-supercell made for some fun and interesting viewing.

Ragged, non-rotating wall cloud.

Ragged, non-rotating wall cloud.

Distant wall cloud and back side of main updraft tower.

Distant wall cloud and glimpse of updraft tower.

I was tempted to follow the storm, but decided it was a red herring. If at all possible, I wanted to make it back to Michigan in enough time to chase the setup there, and that left me no time to play around on the western Illinois backroads. So I headed back to I-80 and busted east.

The first Michigan supercell fired up earlier than I'd hoped, and I bit my lip as I followed its progress on GR3 and watched it hit Lansing. If only I had driven east last night for two more hours, or left in the morning two hours earlier... But the previous day's chase had left me exhausted. And you know, one of the downsides of being a Michigan-based storm chaser is, you just don't have very high expectations when it comes to your home state. I mean, it's Michigan. Home of convective table scraps, squall lines, and embedded supercells that don't produce squat.

As it was, I watched several more storms fire up and develop rotation along the warm front that stretched across mid-Michigan. I was making decent progress and still had hopes of catching up with some of the southernmost cells. But by the time I crossed the state line, the action all had shifted well to the east, and it became clear that I wasn't going to see any of it.

Instead, taking fellow chaser Mike Kovalchick's suggestion, I headed toward the lakeshore at Allegan Beach to intercept a short but potent squall line. I'm glad I did. The backdrop of Lake Michigan and its dunescapes lends a breathtaking drama to incoming storms. The following photos depict the progress of the arcus cloud moving in across the waters. What these images can't convey is the full, awe-inspiring sweep of cloud, big lake, and shoreline; of the solemn foreboding of some great event about to unleash itself upon a landscape cloaked in storm shadow; of the shelf cloud moving silently overhead like the furrowed eyebrow of a dark, scowling giant; and of sand spray blowing and trees thrashing in the wind as the gust front arrived.

I'll let the photos tell their story as best they can, and leave the rest to your imagination.

An arcus cloud advances toward the Lake Michigan shoreline at Allegan Beach.

An arcus cloud advances toward the Lake Michigan shoreline at Allegan Beach.

View to the north.

View to the north.

Looking south...the storm closes in.

Looking south...the storm closes in.

Looking north...closer still.

Looking north...closer still.

Almost overhead.

Almost overhead.

One last shot to the north, then it's time to make a dash for the car.

One last shot to the north, then it's time to make a dash for the car.