Tuesday March 15th had that look. A negatively tilted trough with a powerful upper level wave pointing straight at central Illinois, with a deepening surface low forecast to be near the Illinois/Iowa border by Tuesday evening. Colin and I made plans to chase this one together, and ultimately settled on a target in far western Illinois.
There were two favored areas, one in northwest Illinois and the other further south in west-central Illinois, along the Interstate 72 corridor. I favored the I-72 corridor, the southern play, for several reasons. There seemed to be a stronger cap in this area, which was worrisome. Moisture was forecast to be questionable as well, but we'd hoped it would be *just enough*. Surface convergence was forecast to be strong in this area, with a dry punch coming in from Missouri during the evening, and with modest instability and the upper level wave arriving during the evening I thought this would be enough to get storms started. Once they were under way, the environment was forecast to prime and become very favorable for supercell thunderstorms.
We arrived early in Griggsville, along I-72 just west of Jacksonville and sat here for some time. It wasn't long before towering cumulus were visible on the western horizon, and these quickly grew into supercell thunderstorms and crossed into Illinois from northeast Missouri - near the Quincy/Macomb areas. So, the north play was underway and would likely be producing tornadoes soon - with nothing going down south. What to do? A return began showing up on radar to our south and quickly began growing - perhaps this was our show. We quickly jumped on I-72 eastbound to get out ahead of this potential thunderstorm. It quickly succombed to the strong cap and became an orphan anvil and evaporated.
The north play was once again the only thing going. We blasted north through Bluffs and targeted an approached on the northern storms, only to see another new area of convection erupted to our southwest, this time with very crisp and intense convection which quickly developed an anvil. This one had the look visually, and radar quickly agreed. So again, we turned around.
Our intercept took us through Winchester as the storm quickly grew into a hail producing supercell and was given a Severe Thunderstorm Warning. However, our attention was on a brand new storm that was forming on its southern flank. This storm would ultimately ingest the north storm and take over as the storm of the day down south.
We caught a view of it near Roodhouse along Hwy 267. A classic supercell, but fairly high based. Perhaps moisture really wasn't going to be sufficient down here. Incredible lightning, wonderful structure, and the best microburst I have ever seen in person were the takeaway from this initial intercept.
Colin and I likely sat a little bit too long during our first view as the storm did not immediately look tornadic and quickly blew past us to the northeast. Scud began developing quickly and was being ingested into the storms updraft region and it was evident the base was lowering - the show was likely about to begin. Two problems existed - we were now behind the quickly moving storm by 5-10 miles, and the sun was now setting behind the horizon. There are so bad feelings in storm chasing, and being behind a potential tornadic storm while losing daylight is among them.
Colin did a fantastic job quickly navigating flooded highways northbound until we hit Interstate 72 and plowed east behind the storm. We'd come in right behind the updraft region, right where any potential tornado would be.
As we approached New Berlin, I commented that things looked "interesting" out my window to the south, but I did not see anything immediately threatening. Knowing what I know now, I wish I had given it a harder look. But when you're traveling on the interstate at night, quickly escaping a storm that on radar doesn't necessarily scream imminent tornado, you have no compelling reason to slam on the brakes and look at it right that second. Our plan was to get around Springfield and then stop and give it a look. The storm didn't wait a long. A cute little tornado developed just south of the interstate, and likely passed only 1-2 miles RIGHT BEHIND US. We were closer than most, but had no idea. It's eays to not be upset, but then easy to start getting myself upset. It was simply a matter of me looking behind us - but again, if radar doesn't scream imminent tornado, I have no reason to stick my body out the passenger window and look behind us, especially when our plan was to do just that in another 5-10 minutes. I thought we had time.
We pulled off several times on interstate overpasses to shoot long exposure photographs attemting to pick something out of the night sky, but she was a one and done deal.
Perhaps with more moisture this is a bigger day. Perhaps we get daytime tornadoes, and on the other hand, perhaps Springfield is in a lot more trouble. All is well that ends well. I feel for those who suffered damage to property on Tuesday, but on a day with parameters as they were, with no lives lost, you call is a blessing.
Video from the day:
First towers going up to our west:
The initial supercell near Winchester:
And then the eventual tornado producer: