8/16/97 IL Chase by Doug Sefried
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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