8/16/97 chase report by Doug Sefried Although the threat for tornadoes and severe weather was not as likely then the previous SPC outlook(moderate risk downgraded to slight) due to weaker wind fields, this was still a great chase. THE SET UP A surface trough/outflow boundry was ahead of the main cold front and was sitting over northwest Illinois and east central Iowa. Temps were in the upper 80's and low 90's across the area. Dewpoints were pooling to the low 80's with an extremly unstable airmass(CAPE 4000-6000 and LI's to -14). A 40 knot jet streak was forecast to move into the area late in the afternoon. Mark Sefried and I left Peoria at 2:45 and headed west then north on interstate 74 . At 3pm Peoria was reporting 92 degrees , dewpoint 77, and a south wind at 10. Moline had a temp of 88 and a dewpoint of 79. We were getting hungry around 3:30 so we decieded to stop in Andover in westren Henry county for some food. We left Andover at 4:15 with towers trying to form to our north but they were being cut off. Then at 4:20 the CAP was broken and the storms exploded very rapidly of to the north and northwest and ten minutes later one storm had an anvil already! At 4:55 a severe thunderstorm watch is issued for NW IL and easten Iowa. We are north of Cambridge heading north on IL 78 at 5pm. Storm #1 We reached Hooppole at 5:48. The storm is looking very impressive with a back building anvil and impressive new towers on its west side. At 5:58 we are in Prophetstown in southren Whiteside county. A Tornado warning is issued with a rotating wall cloud west of Morrison (about 8 miles NW). The Rock River was a problem though, should we cross knowing that we my get trapped on the west side or head NE along its east side? The storms seemed to be moving slow so we decided to cross. Then Mark said "What is that!?". I had lost my right contact earlier and the sun was glaring so I couldn't see it. He said it was the wall cloud. We were just south of Lyndon and the town/trees blocked the view. He headed on 78 west of town so we could see northwest again. There it was was about 6 miles northwest of us. It spun of several funnels and spotters near Morrison also reported funnels. You could see the whole meso. We decieded to a little west then north to get a closer look. It was quite a site and the updraft was very strong with some rotation. I thought it was going to go but then the whole thing quickly fell apart in two minutes. The time was 6:36. We chased a few more miles east but then gave up..for there were more storms moving in from the west. Storm # 2 With Storm # 2 building in form the west I deceided to take country roads instead if interstate 88. What a bad decision. The winding, unmarked, gravel roads gave us headaches as we wasted time trying to figure out were the heck we were. We finally made it to Fenton at 6:54 with a new Tornado warning issued for Whiteside county. We then crossed 88 and took a road that ran SW along it. A Tornado warning was issued for Rock Island county at 7:11. We could see the new wall cloud to the storm that was now Northwest of us and was turning right but moving very slowly. This was actually a new storm (I think) so lets call it #3. Storm #3 Anyway the wall cloud was spinning off small funnels as we heading east just west of Erie. Then the Rock River problem came into play again. There was a road the went south-east and crossed the river and there was a road went north-east along the west side of it that took you back to Lyndon. I wanted to take the road that ran SE but the road structure is very poor and we got lost even with detailed street maps. We spent 5-6 minutes in the town (with the wall cloud heading for us) I said we better just head back to Lyndon for safety reasons. This was around 7:30. Then spotters reported a wall cloud with funnels near Morrison form storm #2, we tried to catch up with it but we couldn't. Then the Tornado warning was extended with a tornado detected by radar 15 miles SW of Sterling (Storm #3) . We were now north of Lyndon so we turned around and headed back south as it was getting dark. At 7:56 a tornado was reported 2 miles south of Prophetstown (form the earlier Erie wallcloud) As we headed south on 78 from Lyndon we could see a new storm with overshooting tops WSW of us (storm 4) and a new tornado warning was issued for Rock Island county at 7:50, I may have been able to see the lowering form storm 4 but being 15-20 miles east it was hard to tell. Spotters were reporting a rainwraped wall cloud with funnels in storm #3. We arrived south of Prohetstown around 8:05 and storm #3 was now just of to the south-east as we headed south on 78. We could see a possible rainwrapped cone shaped funnel form the wall cloud as what little light was left was reflecting of it. We then t it was now dark so we headed back home south on 78. A tornado warning was issued for Muscatine county in Iowa from a nice looking storm to the SW. Storm #4 As we headed home south on 78 a tornado warning was issued for Henry county at 8:23 for a possible tornado 4 miles west of Galva. Spotters reported a rotating wall cloud just west of Galva at 8:40. At 9:04 we reached Kewanee with street flooding in the city. Then as we continued south we could turn west on 91 towards Galva or continue south on 78. We tried to go west but we ran into heavy rain and some hail and since it was now dark it was too dangerous to chase, we headed south on 78. We got south of the storms and we entered Peoria county. The storms were in a line now (that when I checked the radar stretched form New York to Kansas!!) We arrived back in Kickapoo around 10. There we several reports on Tornadoes across northren Peoria county by the public. We had a great view form the backyard looking north..just funny looking rain shafts. Last time I checked the only confirmed reports of tornado touchdowns were in Iowa. I give this chase an "B+", no confirmed touchdowns but plenty of excitment and a good lightning show.
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