Statistics:
| Initial Target: | Macomb, IL |
| Departure: | Bolingbrook, IL 9:30 am CDT |
| Arrival: | Bolingbrook, IL 10:30 pm CDT |
| Intercepts: | Peoria, IL |
| Tornadoes: | 0 |
| Hail: | Severe (0.88 inch estimated) |
| Wind: | Non-Severe (not measured) |
| Features: | RFB, Wall Cloud |
| Miles: | 717.0 |
Summary:
| Left Bolingbrook with Jim Wallin, a new laptop mount, and a moderate risk. Targeted Macomb and picked up Dan Cook at Western. Towers fired at 12:30 east of Macomb when we picked up Dan. Headed east out of Macomb for severe warned cell. Intercepted northern flank of supercell and core punched. Hammered by penny sized hail until under RFB. Observed wall cloud lower then storm disorganized. Stopped for lunch then a futile attempt to catch severe warned convection moving at 60 mph. Called it a chase at around 4:30 and headed for Macomb and then Bolingbrook. |
Video:
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Hail, RFB, and wall cloud video shot by Dan Cook (10MB WMV) |
Crew and Equipment:
| Chase team included Dan Cook and Jim Wallin. Equipment consisted of a NOAA weather radio, TH-F6A Tribander, and GPS/Cell Phone equipped laptop. Photography by Skip Talbot and Dan Cook. Video by Dan Cook. |
Route: route in green, click yellow circles to jump to picture
Details:
| When this system came up on the models, it looked to provide Illinois with the first chase worthy weather of the year. The instability was forecasted to be rather meager at first, but as the surface slowed its path from run to run on the models, conditions kept improving. Speed sheer pushing 80 knots, surface based CAPE up to 1500 J/Kg, 70/55 temps/dewpoint for most of west central IL. SPC confirmed that the day held potential for significant weather when the Day 1 outlook was released. |
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| I had put many hours into prepping the car for the season during spring
break, the week before, and I still wasn't done. With this chase
quickly approaching I found myself "cramming" trying to get everything ready
the night before. I initially thought this was going to be a practice
chase involving a squall line and a bunch of equipment tests. However,
the night before it was obvious that this was going to be the real thing.
Featured here is the new laptop mount, built from a cheap eBay rig, and various parts from Home Depot. Harder to make out are the new DC power outlets, AC power inverter, and new CD deck with aux in Also pictured is my new cell phone, linked to the laptop via USB. I was going to have live, mobile radar on this chase for the first time ever.
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| Joining me on this chase were Jim Wallin, a journalist filming a
documentary on storm chasers, and Dan Cook, storm chaser at Western Illinois
University. I offered to pick Dan up in Macomb, which is quite a drive
from Bolingbrook, but Macomb was the initial target so it worked out.
Jim and I left Bolingbrook at 9:30, breaking out of the cirrus once we passed Ottawa, and hit the cumulus field once we exited 80 near the Iowa border. Towers started going up just as we entered Macomb at about 12:30, perfect timing. Convection northeast of campus:
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| We quickly gassed up, and headed north out of Macomb to look for an eastern route to the towers. Dan rode shotgun navigating with street atlas and working the cell phone data. Radar showed two good looking cells going up, this one being the northern cell. The southern cell was blocked from view by other convection, but I opted for that one given that it was stronger and had an unobstructed inflow. |  |
| As we intercepted the convection, we lost sight of the tower
tops and were in and out of spotty downpours. Our cell connection was
also intermittent, so we lost our grasp on where we were in relation to the
storms. As we drove deeper into what appeared to be mediocre rain
showers, I was worried we were going to miss the show. That's when the
hail started. It was only pea sized, but it was the first hail I had seen
in many months. We got our radar back just in time to see a
beautiful V-notch supercell echo (thanks
Stan). We were on the northern end, and any rain free storm
structure would be on the southern flank. I had Dan plot us on a
southerly course directly into the heart of the beast: we core punched. The hail was pea sized and intermittent at first, but as we got closer to the updraft, the hail grew in size. A barrage of penny sized hail hammered the car, reducing our visibility to almost zero. The sound of the stones hitting the metal roof was deafening and we had to shout to hear each other. |
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Hail, RFB, and wall cloud video shot by Dan Cook (10MB WMV) |
| As we crossed the Illinois River on 474 we broke free of the hail and got our first view of the rain free base. What a sight: a green core that we just came out of and a churning purple base overhead. Scud was being sucked into the updraft, forming long funnel look a likes. Dan and I commented that the public was probably going to call them as tornadoes, and it was only a matter of time before the tornado warning went out. As a large lowering started to condense we took the next exit and found a place to pull over. It looked like we had a developing wall cloud. |  |
| The wall cloud tightened its appearance, but it was hard to
discern any rotation. Looking west, this was the wall cloud at its
most impressive stage. It really made an attempt to get close to the
ground, while the storm itself had quite a high base. LCL values and
dewpoint depressions were both quite high and I knew this was going to hurt
our chances of seeing a tornado. A car pulled up behind and a familiar voice called out, "Hey Skip!" It was Darin Kaiser, whom I had just recently met at Mark Sefried's chaser gathering. Darin had been following the storm from the south for awhile, and we told him of our core punching excitement. Right on cue, as the wall cloud peaked, the weather radio went off for a tornado warning for Peoria County and the sirens went off. We all intently scanned the sky for rotation or any other lowerings. |
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| The PA system in a nearby office building announced, "There
is a tornado coming, everyone take shelter." After a few minutes of
the sirens wailing, a few suited employees timidly emerged from the building
to see what was happening. The wall cloud soon dissipated but there was still some great motion in the base. Most of it was upward movement but there also appear to be some small scale rotation directly overhead.
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| With the snap of a finger the wind changed from southeast to northwest as the RFD hit. The downdraft was cold and wet, another indication we weren't going to see a tornado. As the storm moved to the north it was clear that rain was falling through the updraft and that the structure was falling apart. Looking north at the core that we had drive through. |  |
| What appeared to be a gust front feature appeared just at
the start of the precipitation core. Initially it had a real pointy
appearance but we dismissed it as being scud, not a funnel. Notice the
dark rain shaft to the right and the brighter, hail shaft to the left. Dan, Darin, and I agreed the storm was looking pretty junky so we said our farewells and split up: Dan, Jim, and I went to get some badly needed food and Darin was off to pick up Mark. |
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| After some greasy KFC, we jumped back on the road to go
after some new cells that were severe warned. The cells were south of
us but booking northeast. This is the backside of the storm we had
just come from, already more than a county away.
Look at that chase terrain! This stretch of road took us right past Roanoke. We got to see the new plant that was rebuilt after being demolished by an F4 that struck July 13, last year. |
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| Weaker, yet pretty convection to our east. Notice how
high the bases had become at this point. This road was the perfect
chase route, no traffic, hills, or trees. We could see in every
direction for miles. As the weather radio announced storm motion to the northeast at 60 mph, we realized we would never catch these new cells so we decided to call it a chase. We caught up with 39 south. |
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| Heading back west to Macomb to drop Dan off, we passed under a few weak cells that were putting down an occasional CG strike. Sun beams through a dirty windshield: |  |
| We were treated to a nice sunset. I was hoping to
catch the setting sunlight on the retreating cells but they had long since
passed over the horizon.
We dropped Dan back off at Western, and Jim and I started our three hour drive home. The low pressure was making for some very strong gusts, but the skies were clear. We could see lightning from the squall that was over eastern IL, far in the distance. |
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| Conclusion: What a fantastic chase for March! After seeing that wall cloud drop, and getting my dose of tornado sirens, and severe hail, I was more than pleased with the chase. It was nice meeting Dan in person for the first time. Without him we would have certainly busted for he knew what he was doing with the radar and navigation software. It was also nice meeting Jim, who after not eating breakfast, put up with us skipping lunch once the storms fired. His documentary should be pretty interesting, as he got to film much of the action and dialogue while Dan and I were busy driving or working the laptop. Lessons Learned:
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