6/13/2009 - East Colorado Supercell and Funnel Clouds

Saturday was another upslope play for my brother and I -- we couldn't play the more severe looking threat to the southeast over Texas since he would need to be at DIA at 6 am Sunday. Luckily, this "forced" decision to stay near the Denver region played in our favor -- we were treated with a nice supercell that had rapid low-level rotation throughout its life. We began the day in Colorado Springs, getting a car rental issue figured out and hitting up my favorite fast food - Chick fil a.

Moo!

After a couple chicken sandwiches bathed in Polynesian, we headed northbound to Denver. As we approached Denver, a storm south of Boulder began to look somewhat impressive on radar -- we shot around the outskirts of Denver since I-25 was clogged according to Google traffic. We intercepted the high-based storm just northeast of Denver and followed it east to Prospect Valley. Near this region, a new set of convection formed to the south and appeared to "kill" any structure to the original storm to the northeast. We sat east of Prospect Valley for a bit as we let what was left of the storm slide to the northeast. I finally decided to head south to I-70 to see if anything could form off the Palmer Divide and move into the uncontaminated air west of Limon. As we moved south, a small cell to our north did redevelop -- however, I stuck to my guns and went south. We grabbed a bite to eat at Bennet and waited a bit for storms to reform. Eventually, I decided to head west toward Denver with the choice -- if no storms form soon, go to our Pricelined hotel; or if storms formed nearby, go after them. I thought for sure we were going to be checking into the hotel early. Nope. As we neared DIA, a small storm began to look more impressive to our immediate north. We turned around on I-70 and headed back east in order to intercept the newly tornado warned storm. Unfortunately, the storm moved right of the radar, making radar assessment tough due to cone of silence issues. We headed east to Strasburg and then north where we waited for the supercell to approach.

Supercell north of Strasburg.

RFD-clear slot wraps in -- violent rotation at this point. On the road north out of Strasburg.

Comes close to producing.

New meso formation, with an apparent needle.

The storm slowly rolled toward us, becoming more visually impressive every minute. As it neared us, it really started to rotate in the low levels, prompting me to report a rotating wall cloud on Spotter Network. Despite this report -- and a formal "funnel cloud" report several minutes later -- the BOU NWSFO replaced the tornado warning with a severe t-storm warning. I'm not sure what was going on at the office, but I was quite surprised my reports fell of deaf ears. Oh well, perhaps the video below will reconvince the office that there was indeed strong rotation with the cell. Hmmm. To their credit, they did go on to issue a tornado warning a bit later. Anyway, as the wall cloud rotated to our immediate northeast, we took off, traversing dirt roads, trying to wrap around to the east of the circulation. We stair-stepped north and east along plenty of dirt roads northeast of Strasburg, all the while watching meso handoffs occur -- each meso would tighten up, produce intense rotation with attendant filaments and funnels, before dissipating and reforming a new meso to the northeast. We saw a nice cone funnel, as well as a rope funnel (and possible tornado) a bit later. We were driving at the time of the rope and could not tell if it made it to the surface; however, it was a long rope making me wonder if it briefly tornadoed. We then began to fight a bad, bad road network. In fact, near sunset, as we were trying to get to an "improved" road according to Delorme, we found ourselves on the back side of the hook on a road that had been turned to jello due to the rain. This basically stopped us dead in our tracks as we literally skied to a junction and then turned around and skied back to dry dirt. I thought for sure we were either going to be using AAA or our onboard OnStar system. My brother did a great job driving us out of that mess ... we ended up back at the hotel about 10 pm were we promptly went to sleep. Overall, a day that was somewhat surprising in that we were disappointed with early storms only to be wowed by a supercell with some of the best, long-lived, low-level rotation I've seen this year. I was quite surprised this thing never laid down a big cone -- it would have been an excellent storm for V2 to examine tornadogenesis failure modes.

Funnel cloud between Leader and Strasburg.

Funnel - so close to tornadoing!

Another view of the funnel -- soon after it turned horizontal and dissipated.

Time-lapse of the supercell, illustrating the amazing low-level rotation and funnel activity. A higher resolution video is available for download here.