Before I start this summary off, I'd like to say that first, I can't believe how many people were chasing that storm from NE MO imto Illinois on 5/13. And from "tornado alley", too!
Here are the details....
4,500-5,500 CAPEs. Dryline for convergence; triple point expected near Keokuk, IA (far southeast part of the state) by nightfall. 80 knot 500 MB winds, from the southwest. Southeast winds 20-30 knots sustained. In short, we thought supercell armageddon would occur. And basically, it did.
We took I-88 to I-39 from DeKalb, then to state road 17 to 29 to Peoria. From there, SR 116 W to 41, 41 to US 136W to Keokuk. We got there at 3 PM.
At 3 PM, we called the College of DuPage (COD). Paul said severe storms had popped near Kirksville, in northeast MO. So, based on a trajectory of 240/40, we decided to go north on US 218 to Donnellson, IA. Slow going through Keokuk. We saw the monster storm to our SW. As we got to Donnelson, we called COD again, to see what was going on. As we were talking to Paul Sirvatka, I heard the tornado warning for Scotland Co., MO, just off to our southwest! Well, Karl and I had to decide where to go. I thought taking U.S. 218 back south to southbound 394 would be best. We did so, and saw the storm approach.
At 3:32 PM, we decided to turn west on county road J62, which led to Croton, IA. As we went passed the house at the corner of that intersection, we were on the top of a hill that went into a valley. As I looked to my southwest, the rain free base came into view. "Tornado! Tornado down! Slow down, Karl! I want to get this!" was my next words into the camcorder at 3:33 PM! We did so, and Karl came to a quick stop.
So what did we do? I ran into the back seat, got my tripod, set it up, put the camera on. Took 20 seconds. By that time, however, the tornado was gone! I started yelling at myself for missing it; I have a total of 3 shaky frames of tornado on my videotape. :-( Karl ran back, got his camera, and might have got one picture of it. Time will tell what he got, before it lifted.
But there was now another problem. This storm was hauling butt, BIG TIME. 50 MPH. We turned back on the highway (US 218) and headed south, quickly! We almost got pegged by the mesocyclone as it went to our north by about 1/2 mile. This thing was turning hard right and moving quick!
Well, afterwards, we took U.S. 218 to U.S. 261 to Fort Madison. We lost a heck of a lot of time there. As we headed northeast on Illinois state road 96, we saw BASEBALL hail in Lomax! I've never seen hail that big before! As we were coming out of Lomax, we ran into COD chaser Jeremy Hylka. He followed us the rest of the chase. We caught a brief glimpse of a large tornado near Niota, IL, on my camcorder. Tough to see, but it's there. Karl, after reviewing the video, yep, that which we saw was true!
Basically, though, there isn't any more to tell. We took 94 to US 34 and tried to catch up. But we couldn't. Then we heard about the tornadoes in Fulton county. All we saw for the rest of the trip was heavy rain.
What did we learn? Do not chase in river valleys, and let it come to you when this happens! We would have seen a lot more stuff had we done that. Live and learn, though. We still got two! But what an incredible chase day. Congratulations to all who were there and saw this.