This Sunday afternoon and evening featured a rather localized-but-significant flooding event within primarily central and northeast portions of Furnas County, including the community of Edison, which was ground zero for flooding rains and also a brief bout of severe wind gusts estimated up to 65 MPH, along with hail up to quarter size. According to a trained spotter two miles southwest of Edison, an unofficial rain total of 5 inches poured down in a 90-minute span between 3:30-5:00 p.m. CDT, washing out part of a driveway. In Edison itself, the NWS cooperative observer recorded a slightly lower storm total of 3.74, but this was still more than enough rain in a short time to cause significant flooding of several roads and some structures. Some of the worst damage occurred at Ag Valley Coop, where a shallow depth of water infiltrated much of the first floor office. Even after the last drops of lingering light rain vacated Edison around 9 p.m. CDT, impactful flooding persisted well into the morning hours of the 17th. Although the Furnas County flooding situation was the big story from this event, radar data suggested that other pockets of flooding might have also occurred in portions of eastern Gosper and western Phelps counties, where rain totals of at least 2-3 were also fairly common.
For the vast majority of the 16th, all the way from the pre-dawn hours through midnight, at least isolated to scattered showers and mainly weak thunderstorms affected at least some portion of South Central Nebraska, primarily within counties northwest of line from Franklin to York. While most of this convection was fairly disorganized and weak, the mid-afternoon through early evening hours featured a noticeable uptick in storm coverage and intensity, especially in southwestern counties such as Furnas, Gosper, and Phelps. Within this area, an initially weak cluster of convection rapidly intensified between 3-6 p.m. CDT, morphing into a nearly solid, southward-sinking line of slow-moving strong to severe storms. The primary synoptic scale trigger for this event was a very slow-moving, southwest-to-northeast oriented surface cold front roughly bisecting Nebraska during the afternoon and evening. Considerable moisture pooled in the vicinity of this boundary, featuring surface dewpoints in the mid-60s to low-70s F and precipitable water values averaging 1.50-2.00. In the mid-upper levels, forcing was rather subtle and weak, with southern Nebraska positioned well-south of a primary shortwave trough shifting from the Northern Rockies into the Dakotas. Around the time of the most intense Furnas County convection, mesoscale parameters featured at least 2000 J/kg mixed-layer CAPE, but weak deep-layer wind shear only around 25 knots, helping promote slow storm motions.

Thunderstorm Wind in FURNAS, NEBRASKA
From 16-AUG-15 14:42:00 to 16-AUG-15 14:44:00 (CST-6)
Location: EDISON
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 2.00M
Reported by: Law Enforcement

Wind gusts of 60 to 65 mph were reported both from law enforcement two miles north of Edison, and also a trained spotter in Edison.

Hail in FURNAS, NEBRASKA
From 16-AUG-15 14:44:00 to 16-AUG-15 14:44:00 (CST-6)
Location: EDISON
Magnitude: 1.00 
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flood in FURNAS, NEBRASKA
From 16-AUG-15 21:00:00 to 17-AUG-15 05:00:00 (CST-6)
Location: EDISON
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Isolated flooding continued across parts of eastern Furnas County through the night, especially in the Edison area. The NWS cooperative observer in Edison reported a 24-hour rainfall total of 3.74, most of which fell between 3-5 p.m. CDT on the 16th.

Flash Flood in FURNAS, NEBRASKA
From 16-AUG-15 15:30:00 to 16-AUG-15 21:00:00 (CST-6)
Location: EDISON
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Multiple roads were under water in and around the Edison area due to flash flooding. In Edison, Ag Valley Coop sustained some of the worst damage as flood waters infiltrated the first floor office. Other homes and buildings in and around Edison were also flooded. As of 4:25 pm CDT, 4.25 inches of rain was reported to have fallen two miles southwest of Edison (fell in one approximately one hour) and washed a dip in a driveway 2 feet deep. By 5 p.m. CDT, rainfall at that location was unofficially up to 5. In addition, the NWS cooperative observer in Edison reported a storm total of 3.74.