September snowstorms are rare in southwest Kansas. The biggest September snow of the 20th century for the Dodge City county warning area occurred on September 20-21, 1995. Parts of northwest Kansas and northeast Colorado received 6 to 12 inches of snow. Much of the northern, central and western part of the Dodge City warning area received measurable snow. The highest amounts were in Ness and Lane counties where some places reported 6 to 7 inches. Widespread snow amounts of 1 to 3 inches were reported in other areas. Only trace amounts fell east and south of Dodge City. Most of the snow fell between 06 and 14 UTC September 20. In areas north of Dodge City and Jetmore the heaviest snow fell before 10-11 UTC. A record low of 29 degrees was set in Dodge City on the morning of the 22nd (the morning after the snow).
Some folks talk about how warm ground temperatures preclude snow accumulation. This case serves as an excellent example of how heavy snow can accumulate even when temperatures have recently been warm. Here are the highs, lows and average temperatures for Dodge City for September 1995. The coolest minimum temperature leading up to the event was 52F on Sept. 8 and 50F on Sept 19. In fact the 4" soil temperatures at the Garden City Experiment Station were very warm. The minimum soil temperature from Sept 20 at 8 am to Sept 21 at 8 am was 57F. The maximum was 72F. So 18 hrs before the accumulating thundersnow event in Garden City the soil temperature was around 72F. After the event at Garden City the 4" soil temperature was down to 57F.
Here is the radar loop for the event.
For a more detailed meteorological discussion for this event go here.