Flash Flood in Osborne County, Kansas

Persistent thunderstorms with heavy rain rates led to heavy rainfall and serious flooding in Osborne County during the early morning hours of May 16th. Highest rainfall totals included 8.16 from 1 WNW Codell, mainly between 1-4 AM CDT, 4.19 from 1 S Plainville, 4.11 from 13 SW of Tipton. The axis of heaviest rainfall occurred at the head of and alongside the Paradise Creek, which ultimately led to serious flash flooding of Natoma, Kansas in extreme SW Osborne County. The mayor stated that approximately 120 homes had moderate to severe damage, with another 15 likely a total loss. Approximately 22 businesses had water damage. Many people were displaced and had to be rescued from their homes. Comparisons were made to the flash flood event in 1993.

The upper level pattern consisted of diffluent and active zonal to southwest flow, with strong divergence noted in the right entrance region of 90kt 300mb jet streak running from the northern Plains into the Ohio River Valley. A strong 35-45kt low level jet developed during the late evening of the 15th and continued into the early morning hours of the 16th, with strong convergence noted on the nose of the low level jet over central and northern Kansas. The strong low level convergence, coupled with the strong upper level divergence promoted deep lift through the atmospheric column, amidst precipitable water values that peaked near 1.5', which caused heavy rain rates. In addition, thunderstorms trained over the Paradise Creek basin particularly frequently, further promoting heavy rainfall amounts.