April 30, 2019

From my morning chasecast email:

"I'll be on the warm front in Illinois. Currently looking at I-55 from Springfield to St. Louis depending on how far north the front makes it, and then points east. Was initially looking southwest of SPI, but encroaching bands of precip now over Missouri may throw a wrench in that. Good clearing coming up from the south, sun in southern Illinois already. Warm front looks nice a diffuse on the models, which is great. Litchfield and points east toward Vandalia might be an initial target. But I'm going to take this one as it comes and just try to adjust to where the most discrete storms are coming up in the clear air warm sector. So watch that vis sat for robust open warm sector development. The line coming in from the west is going to be crap and is not the main play. We need isolated stuff out ahead of it. HRRR hinting a dive southwest toward Effingham might be necessary.

The big Plains tornado play I would probably put on a triangle between Lawton, OKC, and Ardmore. Somehwere between 44 and 35 and you're hopefully trying to get more of a Tail End Charlie on the southern end of that as it looks like a sloppy mess down there on the models. No cap, lift on the cold front, the whole thing may go up. Get on a discrete storm around 5pm-ish and you should be good. Might be a frustrating crapshoot with ugly storms, but best chances of seeing a tornado here probably.

Abilene still in play for pretty supercells if you're way down there, and models hinting the Caprock may be as well. Structure show here, less chasers. The conventional tornado target is probably going to feature grey ugly storms, so this might be an overall more enjoyable chase if you don't need the tube. But let's be honest, most of us need the tube."

Becky Gould was sponsoring me for the Chicago Marathon by donating to the ALS Chapter of Greater Chicago. To say thanks I invited her and Megan on a storm chase. April 30 looked like a good day to stay in state and try our luck on the warm front, away from the chase hordes and fugly terrain in eastern Oklahoma. Storms had initiated by the time we left Springfield, and we got a mature, tornado warned supercell northeast of St. Louis. It was already in a high precipitation state when we arrived, but we could see a dark lowering from the inflow notch, so we were hopeful we might still bag a tornado. Sirens sounded while we watched with a few other chasers parked nearby.

We started stair stepping on the grid, staying within the storm's inflow notch, which got exciting for a few moments. A new wall cloud developed behind us while the storm's RFD core took on brilliant green and turquoise shades.

The RFD gust front bowed out, but a large portion of the inflow band was occluded behind the RFD gust front, which is a textbook location for a tornado.

Panoramic shot showing dramatic supercell structure including the inflow band on the right, occluded gust front in the background, RFD gust front in foreground, and striated updraft tower above. We were in a great position, but the storm did not produce.

We continued east as storms began to fill in and become more heavily rain wrapped. This made me a little pessimistic about our chances of finding a tornado, so I started playing the storm less tight than I should have. We finally bailed on it, heading for new development to the east in clear air. This storm managed to squeak out a brief tornado after we left it.

Chasing new development to the east, we were greeted by a sight I don't often see in Illinois: a low precipitation supercell. The small twisting updraft was the kind you'd usually see out in eastern New Mexico or Colorado.

The small cell was pretty for a few mintues, but it too started to fall apart. We called the chase and headed back, stopping for dinner in Springfield before Becky and Megan continued on toward home.