During an 18-hour stretch between noon CDT on Tuesday the 4th and 6 a.m. on Wednesday the 5th, two fairly distinct rounds of widespread thunderstorm activity soaked much (but not all) of this six county North Central Kansas area with 1-4 inches of rain, and localized pockets as high as 6-8. Not surprisingly, short term flooding of rural roads and fields ensued within the zones of highest rainfall, along with minor flooding along the South Fork Solomon River in southern Smith and northeastern Osborne counties. Although a few storms exhibited radar signatures indicative of marginally severe hail and/or wind, there were no confirming ground truth reports. As a result, flooding concerns took center stage in an environment characterized by precipitable water values averaging 1.50-2.00.  The primary swath of 2-4 amounts (and locally higher) was roughly 10-20 miles wide and oriented northwest-to-southeast through most of Smith and Mitchell counties, along with adjacent portions of northern Osborne, southwestern Jewell and far southeastern Phillips counties. Within this broader zone of highest totals, there were mainly three smaller-scale maximums of at least 4-6. The largest of these zones included much of the northern half of Smith County, and particularly the northwest quadrant, where radar estimated a small zone of (unverified) 6-8 amounts. The majority of rain within Smith County fell during the overnight hours, and the highest-known ground truth report was 4.02 from the NWS coop observer in Lebanon. There were at least a few rural roads washed out within the county. The second zone of enhanced rainfall was a small, roughly 5x5 mile section of southeast Mitchell County, featuring a CoCoRaHS total of 6.15 six miles northwest of Barnard. However, rain here did not fall all at once, and was a combination of both afternoon and late-night activity. The third area of primary interest was a tiny, likely no more than 4x4 mile portion of extreme southeastern Phillips County south of Kirwin, where an unofficial total of 5 accumulated in 2-3 hours during the afternoon, resulting in water over numerous rural roads. Given that Smith County bore the brunt of excessive rainfall, much of the runoff steadily worked its way into the North Fork Solomon River upstream of Waconda Lake. At the automated gauge near Portis, the river breached minor flood stage of 15.0 ft. on the morning of the 5th and crested at 16.9 ft. on the morning of the 6th, before slipping below flood late that afternoon. In sharp contrast to the aforementioned pockets of heaviest rain within the six-county area, the majority of Rooks County along with central portions of Phillips and Osborne counties received well under 1, if hardly any at all.
Focusing on timing of this multi-part heavy rain event, round 1 was centered between 1-8 p.m. CDT on the 4th as various clusters of multicell convection traversed the area, largely tied to convergence along a quasi-stationary surface front stretched across the heart of northern Kansas. During this time, the only notable flooding was the localized deluge south of Kirwin. Following a relative minimum in storm activity for a few hours, round 2 got underway around 11 p.m. CDT and persisted through the remainder of the night before vacating local counties shortly before sunrise. This round, which featured repeated development of storms within a northwest-to-southeast axis centered through Smith and Mitchell counties, was largely driven by classic warm air advection/moisture transport along the nose of a modest 25-30 knot low level jet evident at 850 millibars. In the larger scale scene of the mid/upper levels, this entire heavy rain event was instigated by a slow-moving, elongated shortwave trough gradually sinking from northwest-to-southeast through the Central Plains.

Heavy Rain in JEWELL, KANSAS
From 04-AUG-15 14:00:00 to 05-AUG-15 06:00:00 (CST-6)
Location: IONIA
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

The NWS cooperative observer in Ionia received a 24-hour rainfall amount of 3.20.

Heavy Rain in MITCHELL, KANSAS
From 04-AUG-15 07:00:00 to 05-AUG-15 07:00:00 (CST-6)
Location: CAWKER CITY
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

CoCoRaHS observers reported 24-hour total rainfall of 6.15 inches six miles northwest of Barnard, and 5.61 ten miles south-southwest of Beloit. Also, a 24 hour total of 3.45 was reported by the NWS cooperative observer in Cawker City. These amounts occurred from multiple rounds of heavy rain.

Flood in OSBORNE, KANSAS
From 05-AUG-15 14:51:00 to 06-AUG-15 17:08:00 (CST-6)
Location: PORTIS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Minor flooding occurred on the North Fork Solomon River near Portis between the morning of the 5th and the late afternoon of the 6th. The crest of 16.89 feet occurred on the morning of the 6th (flood stage is 15 ft.).

Flash Flood in PHILLIPS, KANSAS
From 04-AUG-15 14:30:00 to 04-AUG-15 18:00:00 (CST-6)
Location: KIRWIN RES
Flood cause: Heavy Rain
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Numerous county roads had water rushing across them, especially in the area south of Kirwin Reservoir. As of 3:30 p.m. CDT, an unofficial rainfall total of 5 inches was reported three miles south of Kirwin.

Flood in SMITH, KANSAS
From 05-AUG-15 07:00:00 to 06-AUG-15 07:00:00 (CST-6)
Location: KENSINGTON
Flood cause: Heavy Rain
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Culverts were washed out one mile north of Gaylord and also two miles northeast of Smith Center. Twenty-four hour rain totals as of 7 a.m. CDT on August 5th included: 4.02 inches in Lebanon and 3.26 in Smith Center (NWS cooperative observers).