Convective Addiction

June 15, 2009 Kinsley, KS

Summary:

During the afternoon of June 15th a trough was located over the western United States with a developing surface cyclone on the lee of the Rockies. On-going convection early during the day made forecasters a bit weary of strong afternoon convection potential. But it became apparent by mid-morning that the convection would exit well to the east allowing maximum destabilization to occur in western KS.

The trigger for afternoon convection was a dryline which had retreated into Colorado during the overnight hours. To the east, moisture (dew points in excess of 65 degrees) was plentiful and modest low level winds advected in more moisture. A deepening area of surface low pressure centered in southeastern Colorado and southwestern Kansas allowed surface winds to back to the southeast, although hodographs from Dodge City were less than impressive during the 12z sounding.

Environment:

As previously stated, moist air to the west of the dryline allowed for strong destabilization of the atmosphere. By 20z Most Unstable Cape values (derived from SPC mesoanalysis) show that values were in excess of 3,ooo j/kg with CinH dropping below 25 j/kg, effectively opening up the atmosphere to thunderstorm initiation.

Despite the relatively unimpressive hodographs early on in the day, bulk shear values were in-line with established organized supercellular storms. The values were enhanced by mid-level and upper-level jet streaks that created speed shear in the atmosphere and allowed for strong upper level divergence in the storms.

Kinsley Supercell:

The first towers initiated near a dryline bulge near 1900z. Deep convection did not occur until an hour later when the towers entered the tropical-moisture rich air on the eastern side of the dryline. Two storms initially developed from these towers to the east of Dodge City, KS and quickly the southern storm became the dominate storm and would eventually become the Kinsley Supercell. Storm motion was initially to the northeast but as the storm rounded to the north of DDC, it started to make a classic right hook.

There were many interesting boundary interactions that occurred during the Kinsley supercells life. The first and perhaps the most important to many storm chasers that day was an outflow boundary the storm developed near Cimarron, KS. The storm was apparently unable to contain its downdraft and produced a rather pronounced boundary on the W-88D from DDC.

As the storm moved into an area with richer moisture, its inflow from the southeast was constantly being harassed by this boundary. This created an almost chaotic storm appearance from the ground with the storm quickly transforming between outflow dominant and classic supercell modes.

By the time the storm reached the Kinsley, KS area the main mesocyclone was position right along the outflow boundary..

Based of videos of storm chasers who were in the area, the storm produced a very weak and short lived tornado. There were no doubt numerous reasons for the short life of the tornado but one of the reasons which will be addressed in this writing is the outflow boundary. Shortly after the storm had drawn in enough warm, moist and unstable air, the updraft was cut off by the relatively cool and less buoyant air behind the boundary.This is a video from CA’s Skip Talbot and Adam Lucio from this tornado.

Shortly before and during this time frame a weak cell developed to the south of the Kinsley supercell just to the west of Kinsley itself. Based on the location of the storms development (to the east of the outflow boundary) it was likely initiated by an anvil shadow boundary

When this storm merged into the meso of the Kinsley supercell it acted to reinforce the initial outflow boundary. The two cells merging resulted in a large gust from the rear flank of the storm that created a lot of blowing dust, making it very difficult for chasers to pick out specific features of the storm from the ground. Below is a video of the RFD from CA’s Scott Weberpal.

After the weak tornado the Kinsley storm appeared to cycle, with the mesocyclone weakening and turning completely into an high-precipitation supercell.

Very shortly after the storms first meso weakened it quickly developed another and based on radar, stronger meso. Once again, during this same time another cell from the south merged with the Kinsley supercell. The likely initiation factor this weak cell was likely an anvil shadow boundary.

Unlike the last merger which seemed to enhance the Kinsley storms ability to produce outflow, this merger appeared to strengthen the meso. The collision did not disrupt the reorganization of the storm and it developed a very strong updraft and well defined meso.

An EF-2 tornado was produced from the storm this time around, but was a very difficult grab for many chasers. For the few that were able to keep up with the meso, heavy rain curtains obscured views of the tornado until it was very close.

From this point on the Kinsley cell was overtaken by a line of efficient rain producing cells that effectively ended the chase and turned the storms into a large complex of thunderstorms.

-Ryan Wichman

*I would like to thank Rich Thompson for his personal insight and his contributions to this work.