On April 15, 2016, me and my chase partner for the day (a researcher at the University of Oklahoma Center for Analysis and Prediction of Storms, or CAPS) targeted the Texas Panhandle for a storm chase. We chased two supercells, one of which became dominant north of Amarillo, eventually tracking into the Oklahoma Panhandle where it produced three tornadoes near the town of Eva in Texas County. This was my first storm chase in which I was using my new Nikon D3300, so my photography did not come out the best, but some of my better photos are included on this log.
The morning 500 mb analysis (Figure 1) showed an upper-level low over the Northern Rockies, with deep troughing in place across the western half of the United States. This trough axis moving off of the Rocky Mountains was resulting in lee cyclogenesis over the Great Plains, with a surface low noted near Colorado Springs (Figure 2). Morning dewpoints over the target area were not particularly impressive; only in the upper 40s to lower 40s, but high resolution guidance suggested that these dewpoints would rise into the mid to upper 50s by late afternoon. Mid 50s dewpoints were already noted as far north as North-Central Texas and into the Texas Hill Country, and strengthening cyclogenesis and resultant southerly flow across the Texas Panhandle would allow this richer moisture to advect northwards. Indeed by as early as 1500Z (10:00 AM CDT), mid 50s dewpoints were already making it to the eastern Texas Panhandle, with a sharpening dryline noted across eastern New Mexico (Figure 3).
My chase partner and I departed Norman around 10:30 AM after analyzing 1500Z surface observations, and set an initial target for Amarillo, as this would allow several options to go north, south, or continue west towards the dryline which was forecast to set up along the New Mexico/Texas border. Convective initiation occurred around 2025Z (3:25 PM CDT) as we were re-fueling in Amarillo. The storm motion was expected to be a little east of due north, so the decision was made to track north and west towards Dalhart. The first storm was intercepted just northwest of Dalhart around 2130Z (4:30 PM CDT). This storm had previously been a supercell while it was over Oldham and Hartley Counties, but had weakened as it moved north and off of the dryline. As this storm continued to weaken, attention turned to the storm to the south which had been rapidly intensifying. To avoid the forward flank downdraft of the southern supercell, we had to drive north to Stratford, drop south to Cactus, then follow the storm back to the north on various county roads. By 2330Z (6:30 PM CDT), this storm was exhibiting classic supercell structure with a very crisp updraft, prominent overhang, and a developing clear slot.
It became clear that this supercell was rapidly intensifying from the strong inflow winds into the updraft. As a personal note, the inflow into this supercell is one of the most memorable things about this storm chase. The inflow winds were so strong that they were kicking up large amounts of dust as well as blowing tumbleweeds around. The blowing dust was so intense, and was being lifted so high into the updraft, that some of the features such as where the wall cloud likely was, were actually being obscured by the blowing dust!
The air being ingested into the updraft was very unstable, with temperatures in the low to mid 70s, and dewpoints in the mid 50s (Figure 4). Indeed, the 16/0000Z (15th, 7:00 PM CDT) upper-air sounding from Amarillo (Figure 5) showed surface-based convective available potential energy (SBCAPE) in excess of 2,100 J/kg. The strong southeasterly winds ahead of this supercell combined with a strongly veered vertical wind profile resulted in effective shear to soar to nearly 50 knots. The 0000Z data showed that the environment was becoming increasingly favorable for tornadoes.
As the supercell crossed the border into the Oklahoma Panhandle, it took on an increasingly striated appearance, with a very prominent inflow tail, wall cloud, and clear slot all noted. Moments after crossing the border north of Texhoma, the first reports of a tornado were received. This tornado was soon spotted by my chase partner and I, but was very short-lived and difficult to photograph owing to poor contrast. This supercell would produce three, short-lived tornadoes over the next several minutes before merging with multicellular convection moving out of southeast Colorado. At this point, my chase partner and I decided that we had a good day, and decided to call it.
While my photos did not turnout particularly great since this was my first storm chase using my new camera, it was a great experience nonetheless. The Texas Panhandle has always been my favorite place to chase, and this chase did not disappoint! The strong inflow winds, as well as classic supercell structure (inflow tails, wall clouds, clear slots, etc.) made this one of my most memorable storm chases of all time.