July 2, 2004

Summer has usually set into the southern Plains by early July, with warm temperatures and weak winds aloft keeping the severe weather threat to a minimum. Not this year though, as the jet stream remained unusually strong and far to the south even in July. Thunderstorms had hit the Norman area seemingly every other morning for the past few weeks, with this morning being no exception. This morning convection left an outflow boundary oriented in a northwest to southeast fashion just south of town. By late afternoon, an isolated thunderstorm was forming along this boundary southeast of town....and the NWS issued a severe thunderstorm warning. What really caught my attention was the call to action statement "severe thunderstorms can and occasionally do produce tornadoes with little or no advanced warning.", a statement they usually tack on to warnings when radar detects persistent rotation in a thunderstorm. At around 7:20pm, I looked off to the southeast to see the massive supercell with a flanking line extending towards its northwest. Seeing that it wasn't that far and we still had plenty of daylight, I gathered my camera and maps, and by 7:45pm I was out on the road.

As I left Norman, new cumulus towers were going up all over the place. All of these towers were tilting in a southerly fashion, evidence of the strong northwest flow aloft. I went south on I-35 to Hwy 59, which I took east towards Wayne. I began noticing some interesting things with the new towering cumulus - such as one drawing in a long inflow band from the south. The lowering sun illuminated tufts of precipitation falling from high up the side of the updraft a pinkish color - which remained suspended about 20,000 feet or so above the ground even after the updraft dissipated. Although interesting, this was not what I was out there to see. My sights were set on the supercell which continued to rage to my southeast. Fortunately it was not moving too fast, so I made up some good ground on it as I took Hwy 59 to Hwy 133, then took Hwy 133 to Hwy 19. As I got closer, I noticed the width of the updraft tower was shrinking smaller and smaller. I also noticed the updraft was to the northwest of the precipitation shaft. The storm's anvil also displaying some incredible mammatus as well. So as I approached Stratford from the west, I kept an eye on the shrinking updraft tower, which spit out some staccato lightning and even produced a small wall cloud around 8:39. After I turned south on US 177 in Stratford the updraft rapidly began to fall apart. However, the anvil and precip core persisted for some time afterwards, and even produced lightning. As darkness was setting in, I decided to turn around and head back to Norman, enjoying numerous fireworks (manmade, not nature) displays along the way.

For a day with northwest winds aloft and southwest winds at the surface, this certainly wasn't a bad day at all. Usually northwest winds aloft aren't favorable for supercells since the winds blow the precip into the storm's inflow region - but that wasn't the case today as surface winds were out of the southwest. And yes, southwest winds at the surface usually aren't favorable either since they tend to mix out moisture and have a drying effect, but that certainly wasn't the case today with the deep moisture over the region.....before I left Norman I measured a dewpoint of 79F!!!! And with the storm apparently riding the old outflow boundary, you have yourself a rather unconventional setup for a classic/LP supercell.

Total Mileage: 132 miles
Total Driving Time: 2 hours, 22 minutes

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