Squall line!!!

On Friday we had what looks to be our last day of active operations for at least the next several days. We started the day in Wichita, KS with our target being convection developing along a cold front that extended from Kansas City, KS to the northern TX panhandle. The prospects for supercells were weak, but there was some hope that we'd be able to get some early isolated cells to target before everything evolved into a squall line. We deployed to Enid, OK, where Bill and I launched a pre-storm sounding from the parking lot of a local Wal-Mart. The sounding launched okay, but we encountered a computer problem that caused us to lose some data in the lower part of the sounding. Hopefully we'll be able to get this issue rectified before the end of the project, as this is the second time the problem has happened.
Shortly after our pre-storm launch we deployed north toward Cherokee, OK. Convection as developing rapidly along the front, and rapidly forming a squall line. As a result we broke from our usual deployment strategies and instead came up with a "squall line deployment" where we kept all of the trucks at the same location and rotated between the teams to launch balloons. This allowed us to launch balloons as frequently as every 15 minutes, rather than once an hour or so when we are all deployed to different locations. As a result, we sat and waited about 10 miles south of Cherokee, OK for the line to reach us, launching balloons every 30 minutes. This will hopefully give us a high-resolution picture of how the environment varies as a squall line approaches a location, something that will be useful for my upcoming PhD research!
My team launched twice from this location, one sounding in the pre-line environment, and then another just behind the gust front of the storm, minutes before we were overrun by the heavy precipitation within the line. We hunkered down in the trucks while the line passed, and as soon as the heavy precipitation was done we were back to launching balloons, giving us a full picture of the storm from well ahead of the line, to the cold pool and trailing stratiform precipitation region behind the line of heaviest rain. (For you non-meteorologists in the crowd...this is a very good thing!)
One of the benefits of having all four teams together is that between launches we were just waiting around, which provided plenty of time for pictures, so of course I took a bunch, some of which I've included below:

When we arrived skies were sunny, although we could see the clouds from the squall line off to the west.


Before long, though, the high-level cirrus clouds that make up the forward anvil of the squall line had overtaken our position, with some great looking mamatus under the anvil.


Finally, we began to be able to make out the gust front, the leading edge of the cold air rushing out from the squall line, heading our way. Ominous as it looked, we continued operations right up until the precipitation overtook our location.


Another shot of the shelf cloud associated with the gust front as it passed over our location.


And the best way to end any good chase day is with your truck in one piece, and a nice sunset to watch!