a supercell merges with a Mesoscale Convective System (MCS)...
On June 16, I was back in Peoria, IL and working till 7:00pm, but I kept close tabs on the weather situation. I had good gut feeling when I arrived at work that morning that we would be in for quite a storm later that evening across central Illinois with quite an unstable air-mass in place. A cold front was also pushing in from the west and the models were hinting at a decent MCS rolling through central Illinois later that evening due to a Mesoscale Convective Vortex (MCV). By 7:00pm, when I got off work I drove to my apartment picked up my camera(s) and camcorder and headed out as convection was already developing to the southwest and a fairly nice MCS was less than a hour away. I setup shop just northwest of Peoria, IL to grab a few photos of the shelf cloud as the MCS began to move into the local-area. This area was characterized by 2,000J/kg of CAPE, 0-6km shear approaching 30kts, and a very moist boundary-layer with dew points at 70°F. By this time, some convection developed out ahead of the MCS to my southwest and had some super-cellular characteristics as it began to move overhead before the MCS would overtake me. There was also a tornado-warned storm with a notch in the MCS just to my north as well at this time. The storm to my southwest though really provided the better photo-opportunities as the shelf cloud was largely unorganized at least in this area. This storm that had developed near Pekin, IL had some nice brief rotation from my vantage-point as it had some "splitting supercell characteristics" probably due to the fact it was attempting to form a "comma head" feature along the northern flank of the MCS. Pekin, IL actually sounded their sirens for this same feature due to the rotation that could be seen. As it moved overhead I had a great view of lots of spin above my location and at times was pretty rapid due to the fast storm motion. It was pretty cool to watch! Anyhow, I eventually got swallowed up by this storm and got pelted with dime-sized hail along U.S. 150 before taking shelter in my garage at my apartment. Torrential rain and vivid lightning at this point kept me in my garage for nearly a half hour. Once I felt conditions were safe I headed back inside calling it a evening as darkness fell. I've added a few photos and some time-lapse video of the shelf cloud below:
Updraft of the storm that formed over Pekin, IL with
a hang-me-down below the base (center)!
Another wide-angle shot of the shelf cloud...
A portrait-shot of the base to my south!
MCS approaching (right) as this storm (left)
is about to merge...
Looking south at the impending convection!
Here comes some rain and hail soon enough...
Circulation a couple of miles to my southeast!
Some spin evident overhead trying to become organized here...
The best photo from the bunch showing the circulation and the
approaching rain/hail shaft (right) to my southeast!
Things calm down a bit leaving behind an eerie looking sky...
I've added a YouTube time-lapse (above)
I can't complain on this "chase day" as I worked nearly all of it and was still able to catch severe convection right on cue as I got off work in Peoria, IL. That almost never happens! That's all for now. Stay tuned for more updates over the next couple of months of local storm chases and photography as well. Until then...
