7/18/10 Severe Multicells in Southern Michigan

Chase Stats
SPC Outlook: SLGT
States Driven: MI
Miles: 224
Departure City: Battle Creek, MI
Target City: Grand Rapids, MI
Ending City: Battle Creek, MI
Outcome: Hail (1/8"), Shelf Cloud, Lowering/Downdraft Feature
Chase Pics: Unavailable

This setup did not look spectacular; then again, how often are Michigan setups amazing? Michigan has lately had problems with anvil blow-off, or cloud cover inhibiting surface heating which results in less instability in the atmosphere. We have also had issues with veered flow. Most setups are usually linear with surface winds from the southwest. To create more directional shear, or turning in the atmosphere, it is helpful to have southeast winds-sometimes referred to as backed winds.

Fortunately for us, the models were indicating some backed winds over towards the lakeshore area and northeast of the surface low. Mesoanalysis showed a nice theta-e axis from St. Joseph to Grand Rapids. While the most CAPE was down south, the better helicity, and moisture convergence was further north near the warm front.

We headed off to Grand Rapids, as the terrain that far north could get pretty ugly, but as we also found out, Allegan and Barry County aren't much better. We caught the first little line coming ashore in Holland. Unfortunately, I could not find any beach access around that would permit a view from the car, so I abandoned the line, and headed south towards Allegan, while observing the shelf cloud behind us. When we got into Allegan, we pulled off, and waited a little for the storm to move northeast so we could get a better view of the storm. While waiting, heavy rain began falling as well as some sporadic pea sized hail. It was moving really slow, with its updraft nearly stationary-indicative of low shear.

We finally got moving, and observed what appeared to be a wall cloud, but was more likely a lowering feature exhibiting downdraft characteristics as shown in the video below. Eventually the storm started out-flowing, and dissipated shortly thereafter. With the rest of the storms looking like crap, we headed to meet up with Ben Holcomb, Bob Hartig, and Kurt Hulst in Hastings for dinner at Walldorff's. Nick Nolte also showed up a few minutes later, and we all enjoyed a delicious dinner.