In the wake of morning thunderstorms, afternoon sunshine heated an already very humid airmass over west central Missouri and eastern Kansas on Tuesday, June 8 2010, creating a very unstable atmosphere over the region. A slow moving cold front reach a Wichita to Kansas City line by late afternoon, rapidly igniting a long line of strong, slow moving thunderstorms. While the threat of damaging winds and large hail were diminished by the vast number of storms that developed along the front, excessive rainfall quickly became a concern. Training, or repeated thunderstorms tracking over the same area, deluged portions of the Kansas City metro into Cass County. Areas from Overland Park to Grandview to Lee's Summit, southward to Peculiar, Pleasant Hill and adjacent communities were hit especially hard as two and a half to four inches of rain fell in just a couple hours. Interstate 435 near the Kansas/Missouri state line was turned into a river at rush hour, while water rescues were conducted near Cleveland, Missouri to the southeast. In addition to the torrential rainfall, these storms were prolific lightning producers, with nearly continuous cloud-to-ground lightning observed well into the early evening hours. National lightning detection network counts showed total cloud-to-ground lightning strikes well into the tens of thousands, but thankfully no damage was reported.
The only severe weather observed in the region was with one of the first storms that developed in western Johnson county Kansas. This long-lived supercell storm track southeast into Cass county and began to show signs of organized rotation as it tracked toward Harrisonville, prompting the issuance of a tornado warning. A brief tornado touched down along the south side of Harrisonville, producing roof and tree damage to a church carport, a commercial business, and a number of trees at nearby residences. An empty tractor trailer was also tipped over. The tornado was on the ground for approximately 5 minutes just before 5:45PM, with a path length of 2 miles and a narrow width of around 20 yards. It has been rated an EF0 with wind speeds between 65 and 75 mph after a National Weather Service storm survey was conducted earlier today.
The pictures/graphics below capture the total event rainfall, as well as damage track and pictures from the Harrisonville tornado.
Daily precipitation map ending 7 AM, June 9 2010
The following is a series of radar images around the time of the Harrisonville tornado. Images are of reflectivity and storm relative velocity)taken between 5:36 and 5:45 PM CDT from the National Weather Service Doppler Radar in Pleasant Hill, MO (roughly 18 miles north). Arrows denote the radar indicated location of the tornadic circulation.
Stats: Path length: 2.1 miles, width 20 yards, peak intensity 65-75 mph (EF0 on the enhanced Fujita scale)
Various Damage Pictures from the southern portions of Harrisonville:
(Location of warehouse denoted on bird's eye view Google map above)
(Location of church denoted on bird's eye view Google map above)
(Location of Casey's General Store is across the street from church denoted on bird's eye view Google map above)
(Location of residential tree damage approximated on bird's eye view Google map above)