Colorado Kick-start
Bennett and Limon/Genoa area supercells
11 Jun 10
SHORT: Outflow dominant supercell intercepted E of DIA airport, followed by cyclic complex of supercells from LIC to E of Genoa CO.
LONG:
The previous morning, I got off a night shift at 8 a.m., and Elke and I made a dash toward the NW to see how far we could get toward that day’s (and definitely this day’s ) best storm potential. Unfortunately, she got sick in NW KS and we had to stop in Colby for the afternoon, a couple of hours short of the tornadic Last Chance storm.
To be able to chase at all on the 11th was a blessing, given that Elke had to go to a local clinic to get diagnosed and treated for some terribly painful digestive problems. Not only did we chase, we saw some very interesting storms and met old friends. Elke was cleared to travel, though we had to make reasonably frequent stops for the rest of our vacation so she could stay hydrated and keep the innards moving as they’re supposed to.
I considered two potential target areas — one being a highly conditional potential near the warm front and E of the surface low in north-central/NW KS, where storms might never form, but if they did…look out. The other was the more dependable (for initiation and photogenic structure) but probably not as tornadic upslope region of eastern Colorado. This being our first full day out, and having been unable to get to the Last Chance storm the prior day, we aimed for the Colorado target area.
After meeting the Three Dudes and Two Dogs chase team at Burlington for some pre-storm banter, we headed W on I-70 to LIC, mooching wi-fi from a motel while parked across the road from a lot of V.O.R.T.EX.-2 vehicles. Eyeballs and data showed a nicely destabilizing air mass up and down the Front Range, almost no CINH, lift in the form of heating and upslope winds on the higher terrain, and rich moisture for the altitude, beneath robust deep-layer shear — in other words, a recipe for supercells lacking no ingredients, save the storms themselves.
It didn’t take long. A supercell blew up quickly in the Front Range mountains SW of Golden, where Elke used to live, and started churning NE across the Denver metro. Not wanting to chase in the city, we scooted to a high spot a few miles E of the airport to observe the cycling, already somewhat outflow-dominant storm. A new updraft that went up on the SE side of the storm sported a rotating wall cloud in short order, but that soon got undercut by outflow from the hail-spewing HP mothership. Shortly afterward, several V2 vehicles showed up, including occupants and friends Ken Dewey and Tim Marshall, who looks as if he is about to be struck be lightning in this photo with me. Fortunately he wasn’t, since we both would have been killed.
The storm’s motion began to accelerate as it surfed its own outflow, and we bailed S to I-70 to intercept a younger supercell rolling off the highest segment of the Palmer Divide toward LIC. Along the way, we saw several lowerings, looking S and SW through the core and through precip gaps to the mesocyclonic region, but no obvious tornadoes. We found a nice road a few miles SW of LIC and, for one of the few times so far this year, had the luxury of staying in one spot for awhile and letting the storm move to us.
Our first view from the inflow sector revealed a somewhat high-based, HP storm with a deep core surrounding the mesocyclone area. Sherman Frederickson (former NSSL colleague from the 80s), Howie Bluestein (one of my professors from back then) and several students were occupying a radar truck just up the hill behind us, and Howie was gracious enough to invite me up into the truck for a peek at their live scans of the mesocirculation — impressive, but endangered by heavy precip from two sources…
Things got complicated on the storm scale. A temporary new occlusion with small wall cloud formed ahead of the HP core, but that attempt got short-circuited by cold outflow from a large, heavy shower that formed in the storm’s immediate inflow region (ultimately moving over us and merging with its forward flank). In increasing rain, we decided to get E of LIC near Genoa, E of the messy storm processes unflding, and let things evolve again while moving E toward us.
An elongated supercell complex with embedded mesocyclones emerged from the chaos, while we parked and chatted with the eccentric old proprietor of the uniquely quaint Wonder Tower (“See 6 States”). As the convection reorganized, I shot photos looking over the tower and store and looking N from its back lawn at storm scenes, while Elke toured the antique shop and bought some old bottles.
While I was composing the former shot, I had a friendly yet disturbing encounter with a newbie chaser who had “learned the ropes” (very frayed and thin ropes, as it turned out) on a few years of chase tours. If you’re interested, read more about it in this Weather or Not entry.
Soon afterward, north of the shelf cloud, a violently rotating mesocyclone developed rapidly, in a notch region between core and gust front to its S. This compelled us to wander over to the next viewing spot W of the tower for a closer look. The circulation was spinning so fast, I thought it would plant one any minute. The rotating cloud mass, eerily front-lit from the E, its base atypically low for Colorado and black as night, entirely filled this wide-angle view. The circulation was only was a mile or so away and moving toward us. If a tornado were to form at thus juncture, it would have been be precariously close to I-70 — a most undesirable outcome. I rather would not see a tornado than for one to move down the Interstate, throwing vehicles every which way. Indeed, no tornado developed during this stage, though a quick spin-up did occur between Genoa and Arriba N of the road, as we evacuated rapidly eastward.
By the time we got past metropolitan Arriba, the Genoa circulation either weakened or merged with another to its N, sporting a well-defined mesocyclonic notch — and occasionally, ragged, slowly rotating lowerings beneath a wall cloud, but no obvious tornado. We briefly talked with Al Pietrycha and Pam Varney Murray near Arriba…good to see them again!
The whole complex lined out and weakened, so we headed to Burlington for the night. Visible to the distant ENE: a monstrous explosion of convection out of our reach, in KS, that produced a few tornadoes while remaining nearly stationary, right in my conditional forecast area. I tried some nighttime lightning observing and photography on the back edge of the Colorado line after it moved past us, encountered more inflow moisture and re-intensified, but it was mostly a bunch of in-cloud flashes, diffuse filaments and distant CGs. So it goes…without regrets, we were pleased with the day’s adventures and ready for another.
