March 27, 2021

Saturday, March 27 was forecast to be another significant tornado event in an already very active March, this time across Arkansas into Tennessee. I wasn't too keen on what looked like a fairly sloppy storm mode, and most of the outlook area was over pretty gnarly terrain. I instead opted to play locally, and catch storms coming off the cold front in western Illinois. Instability was forecast to be pretty meager with modest moisture return ahead of the front, but decent amounts of 0-3km CAPE were forecast to pool on the elongated low, so I thought there might be a surprise or two on the sleeper side of the event.

The HRRR was adamant that a prominent helicity track would pass near Springfield, so I waited around at home to see what would come of that. A storm organized south of Louisiana, MO and picked up a severe thunderstorm warning, so i decided to head it off in Illinois. Storm motion in the warning was very fast, cited at 60 mph. As I approached on 72 there were some laminar, likely elevated, updraft bases in the foreground, and what looked like a big block lowering far in the distance.

I should have cut south earlier, but I wound up trying to take the most direct approach on the fast roads, and so went south out of Jacksonville. Due to the fast storm motion, this resulted in a core punch. A barrage of sub severe hail pelted the vehicle, and the road went white for a mile or so. But the structure I had seen from afar was mostly gone once I cleared the forward flank core and emerged in front of the updraft base. Remnants of some kind of lowering were all that remained, and the storm quickly started to bow, the base retreating like it was going elevated. I made a vain effort to try and keep up with the storm, but the side roads just weren't fast enough even though they were paved. I let the storm go after a few miles and started stair stepping south to catch the next most robust cell, which was coming out of downtown St. Louis. In between, I saw a pretty updraft off to my west. The cell was little more than a shower, and the base was quite high due to the low 50s dews.

I tried to shortcut on the grid by stairstepping ese, instead of meandering on the highways, which all funnelled toward St. Louis. A sign warned me that the road I was on was impassable in high water, and sure enough it was. I got out to check, hoping it might just be a puddle, but there was clearly a small creek with moving water flowing right over the road. This effectively ended my chase. I was out of play for anything ahead of the trailing MCS in eastern Missouri.

A pretty rainbow is what I got after having to backtrack west to the highway when my road was impassable.

I ran east to 55. Everything looked like it was falling apart around me, including the cell I was after, which I had no chance of catching. So I decided to call the chase and make for home.

About half way to Springfield, what were once rather junky looking cells in a line, exploded into supercells just east of St. Louis. Two of them picked up and maintained tornado warnings until well after dark. The cells looked like they tried to cycle but then blasted large amounts of outflow, which made sense given the large temperature / dewpoint spreads and rather marginal instability. I was kind of bummed I was out of position and hadn't attempted a play on these cells, but they seamed to peak over rather congested areas and then became heavily rain wrapped at dusk, so I doubt I would have seen much besides a gnarly gust front.