4/15/98 Chase Summary by Gilbert Sebenste

From: Gilbert Sebenste 
Subject: Chase summary, 4/15/98: A taxing tax day

Monday night, April 13. I'm at work and looking over the latest weather
data. The 0Z Tuesday runs come in and confirm: Wednesday, all heck is
going to break loose somewhere. If the timing of the NGM is right,
central/southern IL is where we want to be. Excellent
speed/directional shear, good instability, dryline potential, there was
nothing that looked bad. Which throws up red flags for me.

The upper air analysis from 0Z Tuesday showed quite a few waves in the 500
MB flow. This, I knew, will make the models go nuts as they try (sometimes
in vain) to keep track of, or resolve them all. Would the trough dig and
send the low farther north and slow it down? Or would it be more
progressive, and shoot the storm east so that Wednesday afternoon, I'd
have to chase Indianapolis?

Well, I had Tuesday off, so my plan was to get off work at 7 AM, head to
bed, get up at 1 PM, hit the NIU weather office and forecast my brains
out. But those plans were hindered by a 3 hour long lawn-mowing session
outside my window (just what was this guy cutting?), and a newly
constructed building across the street which kept a loud cement mixer
blasting until 3 PM. By noon, I had given up hope for sleep that day. This
would turn out to be a very good thing.

A friend of mine, Mike Falout, calls up and wants to have a cookout down
here. Hmmm, I guess what I can do is have my cake and eat it too! We do
this and at 8:30PM Tuesday, hit the NIU weather office with Brian Fugiel
and others to see what Wednesday would bring.

The models were coming in late (another good sign ;-) ), but by 10 PM,
after analyzing the surface and upper air data, it was obvious the models
were CLUELESS!!! The NGM killed the surface low near Topeka at 0Z
and formed another in central KS by 0Z Thursday. The ETA did the same, but
took the new surface low and shot it to Springfield, MO for 0Z Thursday as
well. No way, I thought, not with a 500 MB vort continuing to spin up the
surface low near Topeka. Furthermore, another wave coming from IA will
keep it going. However, I did not doubt the wave developing in Kansas,
either. So this was going to be a complex situation.

I realized I had several options:

1) Chase the warm front near surface low near Topeka, which I forecast
would be near Quincy, IL at 0Z; this would place north-central IL under
the gun for supercells. But would instability be adequate? The 60 TD
isodrostherm was still a ways off...

2) Chase the dryline/cold front/mid level dry punch coming out of Missouri

3) Chase the low/wave along the front in KS

Distance-wise from DeKalb, #3 was out. But I had the time to do #2, and I
thought that would provide the best chance for long lived supercells.

Here's the twist...no pun intended. My good friend Scott Olthoff and I had
planned to have a get together, since I haven't seen him in 9 months, down
in Champaign. Scott is an excellent chaser too, and well, those plans got
scrapped and I had a chase partner for STL!

Scott called me Tuesday night and it sure looked like STL was in trouble.
I told him I'd call him back in the morning to let him know what gives.

Wednesday, the big day. High risk from Quincy to Lafayette southward.
Moderate risk to the WI/IL state line, for those warm front supercells.
Looking at the 6AM CT surface map, my forecast is verifying beautifully.
We're on!

At 8 AM I leave DeKalb and head down to Champaign. Just about all of the
University of Illinois chasers were ready to go. But there wasn't,
surprisngly, a lot of enthusiasm: many were feeling this wasn't going to
be a great day, perhaps only a fair to good one at best. Looking at the
satellite images from UCAR/Greg Thompson, I could see why. The warm front
was an outflow boundary, essentially, running almost west/east across
central MO and southern IL. South of there, dewpoints were in the low
60's. Alas, south of that, temperatures were not recovering very quickly.
Still, there was good shear there, and STL still looked like a good bet.
But did we want to chase there during rush hour????

We decided to wait to watch events unfold. And wait. Then, SPC issues a
meso discussion indicating that a weather watch would be needed soon
across central/southern MO. Then it goes out. A supercell develops along
the cold front/dryline in central Missouri and tornadoes near Lake Of The 
Ozarks. But that wasn't the only area I was watching. A clear area in
northern and central IL began to rapidly heat and destabilize the 
atmosphere there, and SPC issued a meso discussion stating that a tornado
watch would be issued soon. Where to go?

Well, by 2:15PM, after looking at the surface data, the best chance for
long lived activity was along the now well-defined outflow boundary by
STL. We know we have several things going for us, if you're
superstitious: the STL 88D will be out for the entire event, AT&T is
having problems so data is being delayed, and Scott is going.
(Thankfully, ILX/Lincoln's radar overlaps with STL, so they still had
radar coverage there and all the warnings went out very timely and with
apparently no problems from the end-user side). We decide to head out.
Before we do so, we see the supercell continues to head for the south side
of STL, and then thunderstorms begin to pop in eastern IA. We leave
Champaign at 2:30PM (19:30Z). We miss the convective outlook, as it comes
out late on our data circuits. In the lead car is Brian Jewett, Tim Shy
the radio guy (and driver, who would give a stellar performance of keeping
everyone updated and calm during this hectic chase), and Jason Boyer. In
car 2, yours truly, Scott Olthoff (driving) and Jeff Van Dorn, reunited
after our 1997 week in the plains. In car 3, Ed, driver (another veteran
of ours who chased with Scott and I in 1996); Noah and Brian all connected
via CB radios. Car 1 can monitor and transmit on the ham bands.

I pop on KMOX 1120 from St. Louis, and the familiar voice of Charles Jaco,
veteran CNN reporter, now talk show host, comes on. He will handle this
outbreak magnificently. He provides the warnings every few minutes on the
storm approaching STL. At 3:15PM, with the storm a good hour plus away
from St. Louis, Charles breaks into a network feed announcing that all
sirens in St. Louis and St. Louis county have been activated, and the news
person and Charles have "no clue why...we're trying to find out". They
bring an ESDA person on the air minutes later, as he tells everyone that
he wants all to know this storm is coming. You can almost hear Charles'
exasperation! Although I'm all in favor of warnings, this was pushing it.
Jaco tells people to get out of their basements in St. Louis, it was just
sounded to let you know there would be possible severe storms coming in an
hour and a half. 

Well, we decide to stop for a gas/bathroom break at 4:45PM 40 miles
east of STL near Highland, IL. I get out my video camera and begin to do 
my usual introcutory narration of the people and the setup involved,
when suddenly my camera goes dead! After 3 months, my 2 hour camera
battery had lost it's charge! I reach into the case for the hour long
battery, and realize it only has 40 minutes of juice on it at best! Bad,
bad Gilbert!!! You know better!!! Thus, I will have to film
conservatively, getting the most important shots in, and keeping the
camera off at all other times. At any rate, at 5:03 PM, we leave the
station, and four minutes later, warnings started to fly for St. Clair and 
Monroe counties in IL; a tornado had just been reported at Festus, MO,
right on the Mississippi River about 30 miles south of St. Louis. Little
did we know that the storm was splitting at that point, and the right
mover was the one we wanted!

We headed south of SR 160 from Highland and then we hit it. Grunge city.
The outflow boundary had pooled moisture...lots of it...into the area.
Dewpoints were in the low 60's. Unfortunately, temperatures were barely
warmer than that! Good visibility was now less than 4 miles.

Then we hear of a warning for Randolph county with a tornado on the ground
near Red Bud, IL. Arrgh! What can we do? Well, the storms are moving fast.
We decide to take I-64 east to SR 127 at about 5:30PM. I hate driving away
from a storm, but we had no choice, really, if we wanted to see something.

Then things started getting hairy. We enter Nashville, IL, at about
5:50PM. And I stop hearing warnings. Hmmm, what's going on? What? The
warnings for St. Clair and Monroe counties have been cancelled? Why? No
mention is given on the station from St. Louis I was listening to (and it
wasn't KMOX, who were busy dealing with new warnings in the city, plus the
signal was starting to get weak). We needed a thinking session. We pull
off the side of the road and brainstorm.

Well, we knew the storms were there; we were seeing plenty of lightning to
our distant northwest. If one extrapolates the storm from Festus to Red
Bud, the supercell is basically moving due east. And now, as we were
talking, we can see the left edge of the rock-hard updraft now coming into
view. That helps a ton! At first, Brian wanted to stay put and let the
storm come to us. But I pointed out that it's getting late, darkness is 90
minutes away and with the clouds obscuring the sun, it's less than that. I
suggest we head west on a road that goes to  We decide that we need to
head to Swanwick, and intercept the tornado on SR 13. The consensus:
that's a good idea, and we head just south of Rice, IL, to an unnamed
access road which will take us there.

We hit that access road at 6:05PM and head west. At 6:08 PM, we can
clearly see a low level inflow band whipping north towards the storm.
By 6:15PM, we pull over in an open field with a good view, and stop and
watch. Odd. Whatever is there seems to be farther north than where we
thought it would be. The sky is very dark north and northwest; inflow is 
only about 10 knots, and it's actually *chilly* out here, which is not
conducive to good storms! We get out of the car, watch the storm for a
bit, and then we all realize that we need to head north. But this road has
no north options, so we must go back to SR 127 to accomplish this. Grrr.
Ah, the fun of a bad road network!

We got back to 127 and drove until we were 3 miles north of Rice. We
pulled over, and just sat and watched. Winds were southeast at less than 5
MPH. I'm flipping through the dial searching for weather
information, annoying the heck out of Scott. Suddenly, my tuner lands on
99.9FM from Carbondale. They break in with a tornado warning and
states that a tornado and baseball size hail should be hitting Rice right
now!!! Stunned, we turn around in our seats and look south and
see....SUNSHINE! People then instinctively look straight up, only to see
anvil. What the heck?!? (Had we caught the entire warning, we likely would
have heard that it was for Washington county (where we were), the meso was
heading for Rice, and the DJ misread the time of arrival of our storm).
Brian has had enough, and since no one is back in Champaign to watch the
radar for us, he calls a friend of his in Colorado who has a live radar
feed for an update. The approaching supercell is indeed there, and it has
an "awesome notch on it!"!!! 

Well, we return to looking at our storm. It's pitch black north and
northwest of us. Brian breaks in on the radio and announces he wants to go
north. Scott and I are against this! But Brian insists, and we
(along with car 3) hesitatingly follow him north.

What happens next was amazing. The winds, virtually calm all along,
are increasing. In less than 5 minutes, they go from southeast at 5 knots
to southeast at 40 sustained! Then we begin to make out a rain-free base
off to our west. At the north edge of this base, a cluster of low clouds
indicates the area we need to watch! At 7:00PM, we can now see the wall
cloud due west, rotating and with a clear slot wrapping around it!!! We
pull off to the side of the road to watch. Suddenly, the rear-flank
downdraft (RFD) south of the mesocyclone surges east, and it carries with
it white streaks of nasty baseball-size hail. What are our east options?
NONE! OK, hurry up and tornado before we have to run!!! We alternate
between watching the RFD and the meso. A few minutes later, at 7:05PM, a
barely visible funnel cloud descends from the occlusion. But the hail/RFD
are almost on us. Darn it!!!! I grab the CB radio. "We need to bail!
Bail, bail, bail!!!" We quickly turn around and head south on 127 again.
Homes, trees and hills now block our view of the meso. I point the camera
in the direction of the meso, hoping I catch something. I do. At 7:03PM, a
20 second viewing opportunity opens up, and a nice elephant trunk tornado
reveals itself, about 4 miles southwest of Nashville! After that, a white
curtain of large hail and heavy rain wrap around the funnel, obscuring it
from our view for the rest of it's life.

But we don't give up. We head east on an access road just south of Rice
(seen on the Rand McNally maps) to U.S. 51, and we come out at a small 
town called Dubois. We head north on 51. An incredible lightning show
commences off to our northwest. We head north and then east to Ashley, and
then 51 turns north again and we stop at a frontage road at I-64 and U.S.
51. It's now 7:30PM, and it's almost completely dark.

We watch and then at 7:35PM, we see the mesocyclone with a clear slot
(with just enough light getting through it to make it visible!). Then,
Scott spots what he thinks is a funnel cloud; a lightning bolt illuminates
the base revealing that funnel! (It's more than a funnel; the next day
Scott takes my video and goes frame-by-frame, revealing a cone shaped
tornado on the ground, which NONE of us saw. Brian Jewett, a tornado
researcher and veteran storm chaser, yours truly, Scott, and several
others with many years of experience missed that. Gives you an idea of how
difficult and dangerous spotting/chasing is at night!)

We then see an RFD heading for us once again. The funnel has now clearly
lifted, but a new meso has now formed and it is spinning like a top. It
begins to develop a clear slot, but the old RFD is almost on us and we
have to get out of there! At 7:38PM, we head to I-64 and head east.

As we get past the intersection, a few miles down the road, something
catches my eye. I look to the northwest, and suddenly I see green blips of
light that last only a blink of an eye. I grab the CB radio and announce
"power flashes northwest!". Everyone cranks their heads (except the
drivers, of course!), and we see more of them over the next few minutes.
Then, the 2nd and 3rd cars get stuck behind two slow moving semis in
adjacent lanes. But Brian's lead car made it through, and he arrives the
top of a bridge over railroad tracks. As he does so, suddenly, a bright
lightning flash to our northwest...all we see are trees, but Jason and
others in car #1 had an unobstructed view of a cone-shaped tornado!!!!

OK, this is getting wild. It's now completely dark at 7:45PM. We hit I-57
northwest of Marion and head north. It's raining so hard we can't see a
thing but lightning. This is getting scary. We get off of I-57 at exit
103, at the town of Dix. We head into Dix and then head north on state
road 37. Just before we hit the town of Kell, I look northwest. The rain
has subsided, and a lightning flash reveals a HUGE wall cloud to our
northwest. I grab the radio and we pull over in Dix. I announce
unashamedly that we really, REALLY need to head south. We turn around,
get just south of town, and watch for a moment. Another lightning flash
reveals the large wall cloud AND another RFD!!! We book back south to Dix
and then huddle under the I-57 overpass, hoping the baseball hail stays
north. We are hit with modest RFD winds. I head back to my car and turn on
the radio and find out Centralia has been hit by a tornado, and there is
damage on the east side of town. We decide that this chase is over.

After about 10 minutes, we get back on the road. We listen to 100.1 FM
as we get back on I-57 heading north. Suddenly, an urgent report: A funnel
cloud has been reported one mile north of the Jefferson/Marion county line
on I-57 at exit 109, the Centralia exit, which is two miles north of us!
There's lightning to our north and east. We keep heading north. Then a
report of a tornado on the ground at the Centralia exit with damage.
Then we see the road sign: Centralia/Flora exit, one mile!!!

Moments later, we hit that "ionized rain" stuff that every chaser dreads.
I say the only dirty word on the trip: "Oh, S***!". That startles Scott
and Jeff, who know I don't say nasty words unless I am very uncomfortable.
As we get to the intersection, brake lights are everywhere. Passing
underneath the viaduct, looking to our left in the southbound lane, a semi
has been completely flipped and is blocking both lanes of traffic. State
police have just arrived on the scene. Off to our right, my car headlights
illuminate a truck off the road in the grass, flipped over. I look for
tree damage but it's raining too hard to tell if anything else has been
hit. The police are taking care of this, so we drive on and watch for
debris. A new tornado warning is issued for our storm, now to our east, 
and the town of Flora is in it's path. We aren't chasing it. And thank
goodness; Flora was hit badly by a tornado 10 minutes later.

We hit the next rest stop and call home to reassure everyone we're still
alive, and to see if anyone else saw anything. We get back on the road,
and as we drive by Effingham, we see a van in the median that appears to
have flipped over, but is now right side up,  with police attending to it.
We later learn it wasveteran chaser Don Lloyd. At least he is OK.

All in all a successful, but difficult chase for us. My condolences and
prayers to those who were hurt and experienced damage to their property on
this most unforgiving night in the weather. And thanks to my chase
partners for an overall well coordinated, enjoyable chase!


Gilbert Sebenste                                                     ********
Internet: sebenste@geog.niu.edu    (My opinions only!)                 *****
Owner of the Storm Chaser Homepage/SCH Canada                           ***
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