During the afternoon and evening of June 9th 2011, storms developed in central and south central Kansas and moved northeast and east. A series of storms moved northeast from Herington to Manhattan to near Seneca producing quarter to golfball size hail.
Storms that developed near Wichita and areas to the northeast moved eastward across south central and southeast Kansas. While the National Weather Service Topeka County Warning Area did not receive much directly from these storms, strong downdrafts developed just north of an area of light rain to north of the storms. These downdrafts produced damaging wind during the evening hours along and north of Interstate 35 from Emporia to Melvern Lake to Ottawa and Wellsville. Around the time of the strong winds in these areas, temperatures rose and humidity dropped. For example, the temperature was 85 degrees at Emporia at 8 PM and the humidity was 55%. By 951 PM, the temperature had risen to 93 degrees and the humidity was 15%. All during this nearly two hour period, winds gusted from 40 to as much as 66 mph at the Emporia Airport. When this occurs, meteorologists call it a "heatburst". Something similar, but more extreme, happened the previous night near Wichita.
Below is a radar picture at 951 PM showing the light rainfall across far southern Lyon county while the wind was gusting to 49 knots (56 mph), the temperature was 93 degrees, the dewpoint was 39 degrees and the relative humidity 15% at the Emporia Airport.
|Observation at the Emporia Airport at 951 PM CDT June 9th 2011. The temperature had risen to 93, the dewpoint had dropped to 39 (with a relative humidity of 15%). The wind was from the south at 35 mph gusting to 56 mph (49 knots).|
Also below is a time trace of temperature, dewpoint, wind and pressure from the Emporia Airport from 6 PM to 2 AM CDT . Note the dewpoint dropped when the wind first gusted above 40 kts. Note again the gusts just before and after 10 PM where the temperature rose and the dewpoint fell.
|Time series of observations of temperature, dewpoint, pressure and wind at the Emporia Airport from 6 PM to 2 AM CDT. Heat burst was evident around from 8 to 9 PM, then peaking again around 945 and 1005 PM. Thanks to Daryl Herzman, Assistant Scientist at the Iowa Environmental Mesone,t for this 1 minute data.|