Western Oklahoma: July 3, 2019
Usually in the days and hours leading up to a storm chase, I am closely monitoring weather forecasts and trends. Even though I had an open schedule yesterday with an ability to travel, I was not expecting to chase. I saw that the north-central U.S. had severe threats this week, but that was completely out of range for me. Across Oklahoma and Kansas, a series of MCV features and weak upper level impulses have been pivoting across the region over the past couple of days atop a weak ridge, but shear has generally been limited. Going into yesterday, once again, shear looked weak, but there was the potential for it to increase toward sunset. The only question would be: Would any storms manage to take advantage of the environment?
Early in the afternoon, storms started to fire in north-central Oklahoma and since I had some errands to run in Edmond, I took my camera and headed north. I quickly bailed on the idea of chasing local storms, as outflow was surging south and the sky was very low contrast from my vantage point. There was no point in driving around, aimlessly, with no proper photo opportunities.
I went home and casually looked at data, which was suggesting that the western fringe of this early day convection might become more favorable later in the afternoon, if convective temperatures could be reached. I decided to make a decision by 3 p.m., once I could review new data, as well as radar and satellite trends. The time came and passed, but I was still up in the air about chasing.
By 3:30, I finally made the decision to target northwestern Oklahoma, as satellite was showing attempts at convective initiation. Surface temperatures had warmed into the low to mid-90s, so convective initiation looked more probable than it had based on earlier forecasts. While deep layer shear was still weak, low to mid-level hodographs were enlarged as surface winds backed to southeast. At one point in the afternoon, the VNX VWP sampled about 400 m2/s2 0-3km SRH. That was enough to at least catch my attention.
A few storms briefly organized, as transient supercells formed in far northwestern Oklahoma. One storm in particular near Freedom pulsed up and, for a short time, displayed some supercell structure. Almost as soon as a loosely organized updraft was evident, the storm began to collapse.
The next move was to start heading home to Oklahoma City. On the way there, new convection started to fire just northeast of Clinton, which as a reference point, is roughly two hours west of Oklahoma City. It looked like these storms were on the fringe of strong buoyancy, possibly on or near outflow from earlier storms. This convection rapidly evolved into a bona fide supercell, which was nearly stationary, at first. Not only did I have another storm to chase, but this one looked much more promising than the earlier storms.
I closed in on the storm and a robust updraft could be seen and despite barely marginal deep layer shear (about 25-30 knots, based on mesoanalysis). As I was paralleling the storm to get south of it, I suddenly noticed an appendage lowering from the storm. A funnel cloud appeared to be forming and for a moment, it seemed possible that a tornado might form. The storm must have been interacting with a remnant outflow boundary, as around the time of the funnel forming, the storm changed direction and began to deviate to the south and eventually south-southwest.
Visually, the storm was most impressive at this point. While the supercell continued, daytime gave way to darkness, which limited visibility. At the same time, the storm appeared to gradually be shifting toward more of a slightly elevated, outflow-dominant supercell.
I followed the storm to New Cordell, where it showed some elevated rotation. This was more indicative of hail than any low-level mesocyclone. The storm looked decent on radar, but rotation was not tight and sunset had passed. This storm would soon begin fading away into the night as nocturnal cooling commenced. I moved east to get one last look at the storm before I headed home.
All else being equal, I would consider this a successful storm chase. Was it one of my top chases of the year? No, but factor in that I was not actively planning on chasing yesteday and Oklahoma was far removed from the nearest marginal risk area (which was in northeastern Colorado) and it was a nice little surprise, relatively close to home.
This is why I rarely turn down a chase opportunity. You never really know what you might find while chasing. Some of my best photo opportunities have come during marginal risk days, or in this case, a sub-marginal risk.
