8/9/09 Chase Recap

Large cells had exploded in IA that morning, and were headed our way. My Dad and I left around 5:30PM and went towards Kalamazoo on I-94. The squall line that had just come ashore didn't look very impressive on radar. I looked at the velocities, and noticed the storm coming ashore near Grand Haven. We didn't have much time, so we quickly headed toward Grand Rapids.

Just north of Grand Rapids, it began to get really windy. Trees were blowing like crazy, and you could hear the wind hitting the car as we cruised down the road. Debris started to fly across the road, but luckily it was only leaves, and small branches. We were now in the bulk of the storm, but not quite far enough in front like I planned.

I was hoping to get far enough ahead of it for a little bit so I could pull off the road, and get some wind measurements. By the time we could get anywhere remotely in front of the storm, it had started to die out.

We began to head back towards Muskegon to check out the damage that was starting to be reported. North of Sparta through Kent City seemed to have gotten hit the worst. We encountered numerous trees down, telephone poles snapped off, and power lines down. Big trees were draped across the road in some spots, so we had to backtrack a little, but we finally made it towards the outskirts of Muskegon. It was dark by then, and I couldn't see many trees down compared to the small cities east of Muskegon. As one could see from the velocity radar data, the downed trees and damage were caused by straight lined winds.


Base Reflectivity loop


Base Velocity loop. The darker blue colors represent possible 60-70mph winds.


This is Echo Tops off the Level II data from the NWS in KGRR. You can see here the storm that came ashore in Muskegon appears to have two distinct updraft cores, which eventually merge into one. It also shows the approximate storm tops (specifically the precipitation echoes) at ~50k ft, indicating a strong updraft.


Shown here is a 3D cross section of the storm showing a tilted updraft (a good indicator of speed shear, which helps blow the precipitation downstream, and out of the way of the updraft. This leads to a storm which lasts longer.)


A huge pine tree completely uprooted.