Although severe weather in the form of hail or damaging winds was not an issue, thunderstorms, some producing flooding rains, were widespread across South Central Nebraska between the evening of Monday the 29th and pre-dawn hours of Tuesday the 30th. By far the heaviest rainfall targeted southern counties, generally between the Highway 6 corridor and the Kansas border, with amounts of 1.50 to 2.50 inches common. A narrow zone tallied even higher amounts of at least 3-4 inches, including parts of Harlan, Franklin, Webster and far southern Adams Counties. A few of the highest measured 24-hour totals included 3.90 inches near Bladen, and 3.80 inches near Republican City. An unofficial report indicated that 6 inches fell north of Macon in Franklin County. As a result, northern and eastern portions of Franklin County bore the brunt of localized flooding issues. These issues included water overflowing a small portion of Highway 10 near Macon, causing a car to go in the ditch, and also the flooding of Thompson Creek. The gauge along the Thompson Creek at Riverton crested several inches above flood stage around 9 AM on the 30th, with water gradually receding through the day.
The majority of heavy rain during this event fell between midnight and 5 AM CDT, corresponding to a period of enhanced warm air advection and moisture transport focused into the area along the nose of a 30 knot low level jet evident at 850 millibars. Although weak mid-level lapse rates likely precluded a severe weather threat, the atmosphere was primed for heavy rain with precipitable water values averaging around 2 inches. In the mid-levels, the main forcing mechanism was a modest shortwave passing through quasi-zonal flow.

Heavy Rain in ADAMS, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: AYR
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 3.68 inches was reported by a Nebraska Rainfall Assessment and Information Network observer.

Heavy Rain in HARLAN, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: ALMA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 3.20 inches was reported by a Nebraska Rainfall Assessment and Information Network observer.

Heavy Rain in FRANKLIN, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: UPLAND
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 3.25 inches was reported by a Nebraska Rainfall Assessment and Information Network observer.

Flood in FRANKLIN, NEBRASKA
From 30-AUG-11 02:00:00 to 30-AUG-11 11:00:00 (CST-6)
Location: MACON
Flood cause: Heavy Rain
Property damage: 50.00K
Crop damage: 1.00M
Reported by: Newspaper

Rainfall totals ranging from 2 to as high as 6 inches were reported across the area.  Just south of the intersection of Highways 10 and 4 north of Macon, water was reported over the road, causing one car to go into the ditch.  Several county roads around the area were affected by running water, causing some minor damage and gravel loss.  This heavy rain eventually ran into the Thompson Creek basin, and the gauge near Riverton rose above flood stage during the morning hours of the 30th.

Heavy Rain in WEBSTER, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: BLUE HILL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Storm total rainfall of 3.38 inches was reported.

Heavy Rain in WEBSTER, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: BLADEN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 3.90 inches was reported by a Nebraska Rainfall Assessment and Information Network observer.

Heavy Rain in HARLAN, NEBRASKA
From 29-AUG-11 06:00:00 to 30-AUG-11 06:00:00 (CST-6)
Location: REPUBLICAN CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Storm total rainfall of 3.80 inches was reported by a Nebraska Rainfall Assessment and Information Network observer.