October got off to an active start within this six-county North Central Kansas area, beginning right away during the late afternoon and evening of Sunday the 1st, as an isolated severe supercell storm tracked from southern Phillips and far northwestern Rooks counties, east-northeastward through parts of Smith and far northwestern Jewell counties before departing into Nebraska. Above all else, it was a prolific large hail producer, yielding several reports of golf ball to even baseball size stones, with the largest reported near Agra. In addition to the hail, a very brief rope tornado touched down in northwestern Rooks County, approximately 13 miles northwest of Stockton, with no reported damage (this EF-0 was the only documented tornado of 2017 in this six-county area). Although a narrow swath of heavy rain fell along this storm's path, its motion was progressive enough to mitigate flooding issues, with the highest ground-truth total consisting of 1.66 six miles east of Phillipsburg.
Breaking down timing and evolution, this severe storm evolved from a convective cluster that initiated in the Oakley area of northwest Kansas around 4 p.m. CDT. By the time it entered the local area along the Phillips-Rooks County line around 6:30 p.m. CDT it was an established supercell with a history of severe weather. Although there were several ground-truth hail reports as it drifted through parts of Phillips into far western Smith counties, there was a pronounced lack of additional reports over northern Smith and far northwestern Jewell counties, despite radar signatures strongly suggesting a continued hail threat.  Eventually this long-lived storm exited into Nebraska around 9:30 p.m. CDT, and while there were no additional severe storms on this night, scattered non-severe convection rumbled through various counties from around 10:30 p.m. CDT until well past midnight.
In the mid-upper levels, this was a rather favorable early-fall severe weather setup, as small-scale disturbances overspread the Central Plains in enhanced southwesterly flow, rotating around the periphery of a large scale trough anchored over the Northern Rockies. At the surface, the aforementioned supercell developed northeast of low pressure centered over eastern Colorado. Breezy southerly winds ushered in an increasingly moist and unstable airmass, with dewpoints climbing into the upper 50s-low 60s F. Around the time this storm entered North Central Kansas, mesoscale analysis featured an impressive combination of around 2000 J/kg mixed-layer CAPE, 50 knots of effective deep-layer wind shear and around 250 m2/s2 of 0-1 kilometer storm-relative helicity (SRH).

Hail in PHILLIPS, KANSAS
From 01-OCT-17 17:53:00 to 01-OCT-17 17:53:00 (CST-6)
Location: LOGAN
Magnitude: 1.75 
Property damage: 25.00K
Crop damage: 150.00K
Reported by: Public

Hail in PHILLIPS, KANSAS
From 01-OCT-17 18:40:00 to 01-OCT-17 18:40:00 (CST-6)
Location: AGRA
Magnitude: 2.75 
Property damage: 150.00K
Crop damage: 150.00K
Reported by: Trained Spotter

Hail ranging in size from half dollars to baseballs was reported.

Hail in SMITH, KANSAS
From 01-OCT-17 18:49:00 to 01-OCT-17 19:01:00 (CST-6)
Location: KENSINGTON
Magnitude: 2.00 
Property damage: 150.00K
Crop damage: 150.00K
Reported by: Trained Spotter

Hail ranging in size from golf balls to hen eggs was reported in and near Kensington.

Hail in PHILLIPS, KANSAS
From 01-OCT-17 18:50:00 to 01-OCT-17 19:00:00 (CST-6)
Location: KIRWIN
Magnitude: 1.75 
Property damage: 150.00K
Crop damage: 150.00K
Reported by: Fire Department/Rescue

Hail up to the size of golf balls was reported. A portion of Highway 9 east of Glade was covered with 1-2 inches of hail.

Tornado in ROOKS, KANSAS
From 01-OCT-17 17:57:00 to 01-OCT-17 17:57:00 (CST-6)
Location: WEBSTER
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A brief tornado touched down in far northwestern Rooks County. No damage was reported from this tornado, which was reported by multiple people in the general area at the time.