When one thinks of autumn, precipitation isn’t the first thing that comes to mind. However, during the second half of September, rainfall was frequent. On September 30^th heavy rain affected southeast Nebraska and central Kansas.  The Lincoln Airport experienced nearly 2” of rain in a single hour, receiving 1.92” on September 30^th, 2026, at 2200 LT. This was the 8^th highest rainfall received in a single hour in the past 50 years for Lincoln Airport. Furthermore, the Lincoln Airport reported 3 consecutive hours in which rainfall exceeded 1”. The Omaha Eppley Airport received 2.7” of rain in a single hour on September 30^th, 2026, at 2300 LT. This was the 2^nd highest rainfall received in a single hour in the past 50 years for the Omaha Airport. Additionally, several streams and lakes situated across southeast Nebraska experienced rapidly rising water levels on September 30^th. The graph below shows the stream gauge for the Salt Creek along 27^th Street in Lincoln. Water levels at the Salt Creek rapidly increased in the evening hours of September 30^th, reaching the maximum (or crested) at 25.86 ft on October 1^st 0600 LT. In other words, the Salt Creek experienced minor flooding and almost experience moderate flooding.

Several lakes in the Omaha area also experienced minor flooding. For example, the Standing Bear Lake and Dam reached up to 1,109.87 ft, beating the previous record of 1,109.1 ft, shown in the graph below. The Wehrspann Lake (not shown) crested at 1,104.86 ft, beating the record of 1,103.2 ft.

This September has proven to be among the wettest months on record for much of southeast Nebraska. Days that featured precipitation were numerous for places in southeast Nebraska such as Lincoln and Omaha. The map below shows the monthly precipitation for September 2026. Precipitation totals exceeding 5” were present for southeast Nebraska, eastern Kansas, and isolated places in southeast South Dakota and North Dakota.

A “binary switch” effect had taken place starting in the middle of September, where weekslong hot and dry weather turned into wet weather with cooler temperatures. This is shown in the graph below, which shows the departure from normal temperature, departure from normal precipitation, SPI, and SPEI for the Omaha Eppley Airport. Departures from normal temperature rose from just under 2 °F to 5 °F above normal, dipped slightly to 4.5 °F above normal on September 15^th, then returned to 5 °F or greater above normal for the rest of the month. Departures from normal precipitation were between 0.5” and 2” above normal from September 1^st to September 22^nd. For September 29^th and 30^th, departures from normal precipitation rose to nearly 9” above normal. Additionally, SPI and SPEI values rose steadily after September 8^th, reaching 1.8 and 1.5, respectively, at the end of the month.

The map below shows the SPI values for the month of September 2026, with the appropriate scale, for Kansas and Southern Nebraska. Much of southern Nebraska and north central Kansas were in the W2 to W4 range due to the received rainfall across the month. Furthermore, many of these same places have experienced an increasing trend in SPI, shown by the upwards pointing triangles.

Lastly, the month of September 2026 ranked among the wettest Septembers for many places such as Lincoln, Omaha, and Falls City in Nebraska, and places such as Manhattan in Kansas, as shown in the tables below. Lincoln, NE, received a total of 11.49” of precipitation, which is the highest monthly precipitation for the month of September for Lincoln. Omaha received a total of 11.92” of precipitation for the month of September, which is the 2^nd highest monthly precipitation for September. Falls City in Nebraska experienced its 4^th wettest September, with a monthly total of 10.23” for 2026. Manhattan, KS, experienced its 2^nd wettest September, with a monthly total of 7.77” for 2026.