In only a few hours' time between the late evening of Sunday the 28th and the early morning of Monday the 29th, a nearly stationary cluster of thunderstorms drenched much of southern Adams, northern Webster and adjacent small portions of Franklin and Nuckolls counties with 3-7 inches of heavy rain, at least temporarily halting a worsening drought (more on this below). Extensive flooding ensued along the Little Blue River and its tributaries (including Ash Creek) and numerous rural county roads/bridges were flooded out/damaged, some of which remained barricaded for several days. The overall-worst flooding concentrated within south central Adams County, including the Crystal Lake Recreation Area and campground located just north of Ayr along the Little Blue River. There, extensive damage occurred to electrical boxes, buildings and picnic tables, and the park remained closed to the public for over two weeks before reopening in mid-September. Along the Little Blue itself, flood waters quickly worked downstream from Ayr, reaching the Pauline area on the morning of the 29th and the automated river gauge near Deweese by early evening. At this gauge site, the river crested around 11 feet (one foot above minor flood stage) during the overnight hours before falling below flood stage on the morning of the 30th. Minor flooding likely continued along the river through much of northeastern Nuckolls County, but no flooding was reported farther downstream into Thayer County. This event was all about flooding, as thunderstorms otherwise remained sub-severe and yielded no reports of large hail or damaging winds.
This was likely the most notable flooding event to strike the Adams/Webster County line area in several decades, especially considering that the majority of accumulation occurred in only a four-hour period between 10 p.m. and 2 a.m. CDT. Some of the most impressive rain totals featured: 7.27 two miles northeast of Blue Hill (NeRAIN observer), 6.62 four miles southwest of Blue Hill (NWS observer), 5.60 four miles south-southeast of Roseland (NeRAIN), 5.50 in Blue Hill (personal weather station) and 3.81 five miles south-southeast of Deweese (NeRAIN). In an ironic twist, leading up to this event the southern Adams/northern Webster locale had been one of the driest places in the entire state of Nebraska for the summer, having recently been placed in a Severe Drought (D2) category by the U.S. Drought Monitor. As a striking example of this sudden transition from drought to flood, the NWS cooperative observer near Blue Hill tallied merely 2.77 of rain from Jun 1-Aug 27 (roughly 25% of normal) and then received more than twice this amount (6.62) on this single night!
Taking a closer look at event timing and evolution, things got underway between 9:30-10:30 p.m. CDT on the 28th as thunderstorms erupted along a northwest-southeast axis extending from western Adams County down into Republic/Washington counties in Kansas. Over the next several hours, the northwestern edge of this initial activity evolved into a quasi-stationary storm cluster that essentially anchored itself over the southern Adams/northern Webster area. By 2 a.m. CDT on the 29th, convection finally began to diminish in intensity/rainfall rates, leaving only lingering lighter showers that dissipated completely by 5 a.m. CDT. This was a rather sneaky mesoscale flood event, as although low chances for thunderstorms were in the forecast, computer models (even in the very short term) were not spotlighting the potential for significant flooding. Not surprisingly, forcing aloft was rather nebulous, not uncommon by late-August standards. In the mid-upper levels, the Central Plains resided under fairly weak south-southwest flow, directed between broad ridging over the southeastern CONUS and a slow-moving trough to the west anchored by a modest closed low over New Mexico. Parameters were not conducive to severe storms given deep-layer wind shear averaging well under 30 knots and weak mid-level lapse rates. However, favorable factors for slow-moving, heavy rainers included: the presence of subtle mid-level waves, precipitable water values averaging over 1.5 and slightly-enhanced flow between 850-700 millibars during the night, resulting in increased deep moisture convergence. At the surface, there were no notable features to speak of, although dewpoints averaging in the mid-60s F were indicative of the moist airmass.

Heavy Rain in ADAMS, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: AYR
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Storm-total rainfall of 7.27 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in WEBSTER, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: BLUE HILL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Storm total rainfall of 6.62 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in ADAMS, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: ROSELAND
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Storm-total rainfall of 5.60 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in WEBSTER, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: BLUE HILL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Storm total rainfall of 5.50 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in NUCKOLLS, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: NELSON
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Storm total rainfall of 3.81 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in ADAMS, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: JUNIATA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Storm-total rainfall of 3.72 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in WEBSTER, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: BLADEN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Storm total rainfall of 3.40 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in FRANKLIN, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: CAMPBELL
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Storm total rainfall of 3.36 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Heavy Rain in ADAMS, NEBRASKA
From 28-AUG-16 20:30:00 to 29-AUG-16 04:00:00 (CST-6)
Location: PAULINE
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Storm-total rainfall of 3.10 inches...all of which fell between 9:30 p.m. and 5 a.m. CDT.

Flash Flood in ADAMS, NEBRASKA
From 29-AUG-16 01:30:00 to 29-AUG-16 07:30:00 (CST-6)
Location: HOLSTEIN
Flood cause: Heavy Rain
Property damage: 225.00K
Crop damage: 350.00K
Reported by: Emergency Manager

Generally 3-7 inches of rain fell across mainly the southern third of Adams County. Extensive flooding ensued along the Little Blue River and its tributaries (including Ash Creek) and numerous rural county roads/bridges were flooded out/damaged, some of which remained barricaded for several days. The overall-worst flooding concentrated within south central parts of the county, including the Crystal Lake Recreation Area and campground located just north of Ayr along the Little Blue River. The Clay County Emergency Manager happened to be camping there that night and reported that the campground was flooding and that nearby Highway 281 was down to one lane in places. At the campground, extensive damage occurred to electrical boxes, buildings and picnic tables, and the park remained closed to the public for over two weeks before reopening in mid-September.

Flood in ADAMS, NEBRASKA
From 29-AUG-16 07:30:00 to 30-AUG-16 07:30:00 (CST-6)
Location: HOLSTEIN
Flood cause: Heavy Rain
Property damage: 225.00K
Crop damage: 350.00K
Reported by: Law Enforcement

Generally 3-7 inches of rain fell across mainly the southern third of Adams County. Extensive flooding ensued along the Little Blue River and its tributaries (including Ash Creek) and numerous rural county roads/bridges were flooded out/damaged, some of which remained barricaded for several days. The overall-worst flooding concentrated within south central parts of the county, including the Crystal Lake Recreation Area and campground located just north of Ayr along the Little Blue River. The Clay County Emergency Manager happened to be camping there that night and reported that the campground was flooding and that nearby Highway 281 was down to one lane in places. At the campground, extensive damage occurred to electrical boxes, buildings and picnic tables, and the park remained closed to the public for over two weeks before reopening in mid-September.

Flood in WEBSTER, NEBRASKA
From 29-AUG-16 07:30:00 to 30-AUG-16 07:30:00 (CST-6)
Location: BLADEN
Flood cause: Heavy Rain
Property damage: 40.00K
Crop damage: 250.00K
Reported by: Law Enforcement

Generally 3-6 inches of rain fell across mainly the northern third of Webster County, resulting in extensive flooding. The rain began around 930 pm CDT on August 28th and ended at about 430 am CDT on August 29th, although the bulk of the heaviest rain occurred between 10 pm CDT on August 28th to 2 am CDT on August 29th.

Flash Flood in WEBSTER, NEBRASKA
From 29-AUG-16 01:30:00 to 29-AUG-16 07:30:00 (CST-6)
Location: BLADEN
Flood cause: Heavy Rain
Property damage: 40.00K
Crop damage: 250.00K
Reported by: Law Enforcement

Generally 3-6 inches of rain fell across mainly the northern third of Webster County, resulting in extensive flooding. The rain began around 930 pm CDT on August 28th and ended at about 430 am CDT on August 29th, although the bulk of the heaviest rain occurred between 10 pm CDT on August 28th to 2 am CDT on August 29th.

Flood in NUCKOLLS, NEBRASKA
From 29-AUG-16 17:00:00 to 30-AUG-16 08:45:00 (CST-6)
Location: ANGUS
Flood cause: Heavy Rain
Property damage: 25.00K
Crop damage: 250.00K
Reported by: River/Stream Gage

The river gage near Deweese along the Little Blue River reported a minor flood, lasting from 6 p.m. CDT on August 29th to 9:45 am CDT on August 30th. The river peaked at 11.06 feet at 6:45 am CDT on August 30th. Flood stage is 10 feet.