Not much to say on this day. Winds were largely unidirectional, with our only hope for discrete supercells being that there was speed increase with height and any boundary interaction. Supercells and tornadoes were possible early in storm evolution, and one discrete cell did form for about an hour, but it was near the river and thus almost completely unchaseable, although many tried anyway.
Nate Williams and I traveled north to where I-74 and I-80 intersected, but I wanted to get a little further east to get away from the terrain of the river, so we headed to Geneseo and went a little north out of there. We watched as several updrafts tried to do something; most didn’t until one cell that was semi-discrete presented itself in the form of a gust front and some decent rising motion under the updraft as it tried to form a wall cloud. Although it remained unimpressive, we traveled a few miles east to see what it would do (gusted out quickly), and after some debate of whether we could get in front of the bonafide supercell in Lee County, we eventually headed south on IL78 in an attempt to get ahead of the forming line and head in the general direction of home.
This turned out to be a good decision as many chasers who were flying toward it quickly abandoned the cell, and we were able to get a head start on the line which was swiftly overtaking us. We got to Annawan and noted some stronger winds as we reached closer to the leading edge. About two miles south of town, though, I noted some rain curtains FLYING east across the corn field directly to our and had literally just enough time to only say, “OH %#!*†and get into a small driveway so that we weren’t completely exposed to winds coming across our side. Luckily, we had just gotten south of power lines that ran parallel to 78 on the west side, as the winds were some of the strongest I’d witnessed.
I reported estimated winds of 70mph as the event was ongoing (I’ve never been great at estimating winds, though, to be fair -- I tried to not overestimate in my report), but after the wind died down we drove around the immediate area to see what kind of damage had been done. The corn in four fields around us had been almost completely flattened, and in a yard near our position, there was a foot-and-a-half diameter tree snapped off a foot above the ground, among other things. We reported all this damage to the NWS, and checked other reports from the area. A spotter in Annawan, two miles to our north, reported 80mph winds (estimated), but interestingly, chaser friends Mark Sefried and Jarrod Cook reported only 50-60mph winds (and no damage) about 15 miles to the east.
My guess, then, is that we got caught in an embedded microburst, because our winds were no doubt much stronger than 60mph. In fact, in a later text to Jarrod, I compared the winds in our location to those in the RFD that I witnessed on the supercells that produced the Wakita, OK tornadoes earlier this year and the Glen Elder, KS tornadoes in 2008.
A rough (albeit fun) chase for a photography-based guy like myself, but as I sit here writing this account, two opportunities may present themselves Tuesday and Wednesday of next week in the Northern Plains. I may go.
