Thursday, July 30, 2015

07/16/15 Monmouth, IL Tornadic Supercell

A tornadic supercell moves east along U.S. 34 in west-central Illinois near Monmouth, IL

On July 16th, I was working till 2:00pm in Peoria, IL but I kept close tabs on the weather. A couple days prior I was "eyeballing" a potential "sleeper warm front setup" in west-central Illinois after observing several runs of various numerical weather models. Once I got off work, I noticed the atmosphere destabilizing toward the Mississippi River near Burlington, IA along the warm front as morning convection had already dissipated. I originally targeted the area near La Harpe, IL during the evening. After grabbing some lunch in Monmouth, IL I ended up waiting for storm initiation during the evening south of Burlington, IA. The atmosphere pretty much was primed for tornado potential in this area. I was actually quite surprised how the "risk" seemed downplayed after watching the mesoscale ingredients come together throughout the afternoon. This area featured 4,000J/kg of CAPE, 0-6km shear at 40kts, a supercell composite of 16, the significant tornado parameter at 3, and a very moist boundary-layer with dew points near 70°F. All we needed was a storm to develop and by early evening storm initiation took place around 5:00pm in northern Missouri thanks to a shortwave trough. These storms were too far away and I knew if I was patient something would go kaboom in this area at some point. By 7:00pm, a supercell initiated over Burlington, IA and this storm would be quite a wicked supercell during the evening as it progressed east. I ended up south of U.S. 34 near Stronghurst, IL on a country road off IL Rt. 116. I watched this supercell's updraft explode into the vertical at this point. I pulled over and began snapping some shots of the structure as it was spinning rather nicely! I was quite surprised to observe some insane storm structure as I would expect to visually observe this kind of storm structure in the central Great Plains rather than west-central Illinois . After being mesmerized by the storm structure and CG lightning barrage I tracked this supercell till dusk as it progressed farther east. This supercell did drop a few tornadoes and a tornado that damaged areas near Monmouth, IL and Cameron, IL. I was on U.S. 67 at this time trying to blast north to get a closer view due to the high-precipitation (HP) nature of this supercell. Unfortunately, traffic was being re-routed so I couldn't head farther north due to the on-going tornado and had to find some alternate routes. I never got a really good view of the tornadoes, but after snapping the several structure shots of this supercell I knew their had to be a tornado back in there wrapped in the rain. It was really hard to get a view from my southern vantage point unlike other chasers that were farther north. This storm was a beast and meant business though! It shouldn't surprise anybody though since the environment where this supercell formed and tracked was primed for tornadoes on this evening. This chase turned out to be a storm structure-fest rather than a tornado-fest for myself however. I've added several photos of this wicked supercell below:

The supercell's powerful rotating updraft!
A wicked supercell looking north toward Monmouth, IL 
 Deadly CG lightning nearby kept me mostly in the car and mobile on this chase...
"Tilted rotating updraft"
 Yikes, a very strong storm at this point...
An absolute insane storm on this evening!
Lightning illuminating the base of this massive supercell!
Another cool shot!
This storm sure didn't disappoint!
A little farther east looking north toward Monmouth, IL again...(you can barely make out a possible rain-wrapped tornado back in there) So hard to tell though...
Supercell slowly becoming outflow dominate, but putting out more great storm structure!
A HP mess of a supercell at this point!
Too close for comfort as I head back east near sunset...

This was another great chase day. Thanks to some good forecasting on my part and realizing that I needed to head west after work I scored quite a monster supercell so close to home. I also was on vacation a week or so ago in the Northern Plains. I will slowly be getting caught up on more photography posts and storm chasing posts and will update in the near future.