(Times in CDT). I had been thinking for a couple days about chasing Tuesday, August 12th on my day off since it appeared to be reasonably close to home. A strong upper jet was forecast to come across the central Rockies and adjacent high plains — around 60 to 70 knots around 250mb. So it was this and the expected decent moisture of upper 50s to lower 60s dewpoints across far eastern CO that perked my interest to chase. The situation just looked promising for good storm photography.
My target was around Lamar, and I left Dodge around 12:45pm or so after attending a going-away luncheon for one of our forecasters. On the mesoscale, I was somewhat intrigued by subtle convergence and baroclinicity between Limon and Burlington. Both Burlington and Goodland were somewhat cool with a 64 dewpoint at 1pm. Cumulus began to form around the eastern reaches of the Palmer Divide, and soon a storm formed near Flagler along the previously mentioned subtle boundary. The storm was small and struggled to fully mature, showing attempts at supercell processes on radar as it drifted slowly south-southeast between Flagler and Wild Horse. I reached Lamar around 3:30 and continued north toward Eads. New storms were forming south of this initial storm extending down toward the Eads area. At Eads I went west about 6 or 7 miles to get a better vantage point of the southern most cell of this cluster. By 4:30, this storm began to take on much better organization to my north. An intense precipitation core developed and spewed outflow with the temperature dropping to about 68 degrees (from 92). A brief roll cloud developed close to the ground, but it didn’t last long.
I had to get south, and instead of going back east to Eads to go south on US-287, I optioned to head south on a graded county road. I took County Road 33 to WW to County Rd 30 which goes into McClave, west of Lamar. During this stretch of the chase southwest of Eads and north of McClave (from ~5:15pm to ~6:00pm) the storm was due north of me the entire time, and I was in the immediate inflow to the storm updraft. Inflow wind was from the east-southeast at 25 to 40mph, and it was a struggle at times to open my driver-side door against the east wind. The inflow temperature was about 86 degrees, and the storm’s cold outflow was not pushing ahead very far at all against such strong storm relative inflow. The surface storm-relative inflow, with a due south storm motion of 15 to 20 knots was from the southeast at probably 45 to 55 knots!
This was very impressive and really allowed this supercell storm to thrive for quite some time. I stopped several times heading south on this county road which was also open range for a good percentage of the drive, and had to slow down for cattle a couple times.
I reached McClave with a decision facing me where to cross the Arkansas River. Do I go west to Hasty to continue south or east to Lamar? The storm did have just the slightest east component to its southward motion, so I made the decision to go east to Lamar. The problem facing me though was the 16-mile construction zone south of Lamar where there would be up to a 30-minute delay with one-lane road and a pilot car. I didn’t want to deal with that, so when I stopped in Lamar to get gas, I took a look at possible graded county road options southwest of Lamar to avoid the US-287 construction. At the time, I didn’t know how far south the construction extended to, so I just planned on staying on county roads as long as the map showed there being any.
Phase 2 of the chase. SSW of Lamar The supercell still had almost a due-south motion as it bypassed Lamar to the west. I got onto graded county roads south-southwest of Lamar and continued the chase. The storm still revealed very nice high-based structure to my north-northwest. The east inflow was still impressive at 35 to 40 mph. Between 6:30 and 7:00pm, the chase was going fine as I was staying ahead of the storm with the graded road working quite alright to the west of Hwy 287. I needed to get back to Hwy 287 eventually, though. But where? One option was County Road L about 20 miles south of Lamar, and the other option was County Road C about 8 miles further south. Driving all the way south to County Road C would requre driving through a ranch that was on Delorme. I felt confident at the time that the graded road I was on would make it all the way to Road C, through the ranch. So that’s what I decided to do.
The above image was taken at 7:10pm on one of the south legs of the graded county road I was following west of Hwy 287 SSW of Lamar. This would be the last time I would photograph this storm from its inflow south side. I saw a "Dead End" sign. I was approaching the ranch. "Floating W Ranch" on the map.
Phase 3 of the chase. Getting cored! Well I got there, and the storm wasn’t far behind. Only thing was, while the storm could keep going, I could not! Now I made this calculated risk because I knew well and good that all the legs of the graded road I was on were very well graded. It was a very good thing. I turned around with a nasty looking core bearing down on me. There was actually a small farmstead I passed only a couple miles before I got to the ranch, so I pulled in the driveway and turned my Jeep into the wind. I was fully expecting at least golfball size hail given its history. North winds up to 60 mph knocked down some tree branches at this farmstead, but hail never got any larger than peas, fortunately enough — but it rained like heck. After about ten minutes of letting the worst of the core go by, I continued the drive back north… at 25 to 30 mph… on the very wet graded county road. It wasn’t bad at all — very hard surface with large pebbles allowing better traction — this is despite at least an inch of rain just falling in the past 20 minutes. I made it back to County Road L, which led east to Hwy 287. The sun was coming out and the rain was still coming down very hard amazingly enough. A brilliant rainbow resulted. Rainwater was cascading everywhere adjacent the road I was on. I came upon a section of this road where some of the water in the adjacent ditch overflowed into the road and was crossing to the other side. I sat there for about 20 minutes for the water to lower so I could pass through. Of course, I did a little bit of photography while I waited!
Phase 4 of the chase. Wake of the storm. The water running through the ditches didn’t take that long to lower, so I continued my merry way slowly east toward Hwy 287. On the way, the sunlight was lowering and the "golden hour" light was just getting better and better. I was treated to absolutely spectacular mammatus and post-storm anvil structure amidst the high plains landscape. The photography of the backside of this storm was just as good — if not better — than from the inflow region. The immediate wake of storms at sunset almost never fails for fantastic photography opportunities. In a serendipitous way, I’m rather glad the circumstances played out the way they did for me. That sunset light was just spectacular — saturated landscape in terms of both wetness and in color with the fading sun!
I finally made it to US-287 shortly after 8:30pm, and the last of the sunlight illuminated the backside of the storm anvil an orange-pink hue to the south. The remnant shaded portion of the mammatus-filled anvil still attained amazing contrast and structure. These were the last images of this chase, and very shortly afterward, I got in line to wait for the pilot car on Hwy 287 south of Lamar. This was certainly one of the more memorable chases in awhile — and definitely ranks in the top 5 of all my mid-late summer (July-August) chases.
-Mike Umscheid
