Mission Summary 5/16


Multiple-tornado supercell of 16 May
On Tuesday, 16 May, VORTEX intercepted a supercell in SW KS that produced at least four tornadic ciculations. We targeted SW KS because we expected that region to be at the left side of a nose of a strong jet, with the associated deepening of a surface low and backing low-level winds. Further, it appeared that CAPE would be best there because of the clearing of a thick cirrus shield. We gathered a good "INIT" data set on a stationary confluence line (and radar-indicated fine line) near Sitka, KS (SSE of Dodge City) while we were waiting for the surface features to evolve.
A storm formed near a cold front/dryline intersection near Garden City late in the afternoon. It quickly became a supercell and produced its first, large tornado near Garden City before the surface armada arrived (but I think the two research aircraft were already at the storm at the time of the tornado).
The surface armada arrived in time to observe a second, smaller tornado just ENE of Garden City, extending from a very occluded, weakening flank of the storm. The entire storm seemed to weaken temporarily, and then reintensified in the vicinity of Kalvesta where it produced at least one tornado. Several mobile mesonet teams operated near that tornado.
The Kalvesta circulation, or a new one near it, moved to just NW of Jetmore, KS. The surface armada deployed in a north-south section of road north of Jetmore as the mesocyclone moved across the highway about 6 miles north of Jetmore. This was a good deployment, and included all mobile mesonet teams, turtles deployment, and attempted soundings to assess the forward-flank baroclinity.
However, this mesocyclone did not produce a tornado in the same manner as the previous ones had. Instead, as the gust front south of the meso surged over Jetmore, a circulation developed on the gust front. Several teams passed under this gust front in the vicinity of the developing circulation as we maneuvered to get ahead of the storm. This was near sunset, the ciculation was weak and elongated, and there were no suitable road options for data gathering. Operations were officially ended.
Within minutes, the circulation intensified into a strong low-level mesocyclone, and a tornado formed just southwest of Hanston, KS. This tornado intensified and grew in size, remaining on the ground for at least 30 minutes (perhaps 45 or more) as it moved over open country south of Burdett and Rozel. We obtained very exciting mobile scanning Doppler data of this tornado, video from numerous angles, and mobile mesonet data from one team that managed to stay ahead of the tornado. The NOAA P-3 managed to continue collecting data during the tornadic phase as they were providing communications support to the armada.
This should be the most interesting data set collected so far during VORTEX.

Erik Rasmussen
Jerry Straka

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