The largest severe weather outbreak of the year began in the morning.  The storms activity spread west across Northwest Kansas, eventually expanding into Southwest Nebraska and East Central Colorado.  The first tornado of the day for Northwest Kansas occurred near Hill City.  No damage was reported from the tornado.  The largest hail size reported was golf ball size from multiple locations area.  Some of the thunderstorms did produce damaging wind gusts, which blew down power lines, large trees, and damaged farm buildings.  Flash Flooding occurred over Graham and Gove counties where prolonged moderate to heavy rain that began in the morning, lasted into the late evening.  The flash flooding caused some culverts along Highway 24 to be washed out.  The flooding was so significant water rescues were performed at a trailer park on the south side of Hill City, and 20 cattle drowned east of Bogue.  By the end of the day parts of Graham County had up to a foot of rainfall.

Hail in RAWLINS, KANSAS
From 28-MAY-18 17:30:00 to 28-MAY-18 17:30:00 (CST-6)
Location: BEARDSLEY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in RAWLINS, KANSAS
From 28-MAY-18 17:25:00 to 28-MAY-18 17:25:00 (CST-6)
Location: MC DONALD
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

The hail was measured by a storm chaser.

Hail in LOGAN, KANSAS
From 28-MAY-18 17:27:00 to 28-MAY-18 17:27:00 (CST-6)
Location: WINONA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LOGAN, KANSAS
From 28-MAY-18 16:58:00 to 28-MAY-18 16:58:00 (CST-6)
Location: RUSSELL SPGS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in RAWLINS, KANSAS
From 28-MAY-18 17:25:00 to 28-MAY-18 17:25:00 (CST-6)
Location: BEARDSLEY
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

The hail was measured by a storm chaser.

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 18:54:00 to 28-MAY-18 18:54:00 (CST-6)
Location: COLBY
Magnitude: 70.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Power lines blown down along with large tree limbs on the northeast side of Colby.

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 18:25:00 to 28-MAY-18 18:25:00 (CST-6)
Location: BREWSTER
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 18:45:00 to 28-MAY-18 18:45:00 (CST-6)
Location: COLBY
Magnitude: 56.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Flood in GOVE, KANSAS
From 28-MAY-18 22:00:00 to 29-MAY-18 11:00:00 (CST-6)
Location: QUINTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Plum Creek continues to flow over CR Castle Rock.

Hail in GOVE, KANSAS
From 28-MAY-18 16:21:00 to 28-MAY-18 16:21:00 (CST-6)
Location: GOVE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 18:55:00 to 28-MAY-18 19:04:00 (CST-6)
Location: COLBY MUNI ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Hail in GOVE, KANSAS
From 28-MAY-18 16:22:00 to 28-MAY-18 16:22:00 (CST-6)
Location: GOVE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in THOMAS, KANSAS
From 28-MAY-18 16:23:00 to 28-MAY-18 16:23:00 (CST-6)
Location: COLBY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm Wind in GRAHAM, KANSAS
From 28-MAY-18 12:39:00 to 28-MAY-18 12:39:00 (CST-6)
Location: BOGUE
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A spotter in town measured multiple wind gusts of 60-70 MPH.

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 19:10:00 to 28-MAY-18 19:10:00 (CST-6)
Location: BREWSTER
Magnitude: 61.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Flash Flood in GRAHAM, KANSAS
From 28-MAY-18 15:30:00 to 28-MAY-18 22:00:00 (CST-6)
Location: HILL CITY
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Flood waters were so deep water rescues had to be performed at a trailer park south of the river next to Highway 283 from 5:30 PM CDT to 11 PM CDT.  Highway 283 was closed from Hill City to Wakeeney due to flood waters over the Highway on the south side of Hill City near the trailer park.  The flooding extended thee miles south-southwest from town along the creek channel.

Flood in GRAHAM, KANSAS
From 28-MAY-18 22:00:00 to 29-MAY-18 15:00:00 (CST-6)
Location: HILL CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Photos from the day after the heavy rainfall occurred showed flood waters still in place at the trailer park and adjacent locations.

Hail in GRAHAM, KANSAS
From 28-MAY-18 11:52:00 to 28-MAY-18 11:52:00 (CST-6)
Location: HILL CITY
Magnitude: 2.50 
Reported by: Social Media

Measured a hail stone 2.25 in diameter.

Hail in GRAHAM, KANSAS
From 28-MAY-18 12:31:00 to 28-MAY-18 12:31:00 (CST-6)
Location: BOGUE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in RAWLINS, KANSAS
From 28-MAY-18 17:25:00 to 28-MAY-18 17:25:00 (CST-6)
Location: MC DONALD
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

The hail was measured by a storm chaser.

Thunderstorm Wind in SHERMAN, KANSAS
From 28-MAY-18 18:00:00 to 28-MAY-18 18:01:00 (MST-7)
Location: GOODLAND ARPT
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

A 4 diameter cedar tree limb blown down.

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 19:25:00 to 28-MAY-18 19:25:00 (CST-6)
Location: MINGO
Magnitude: 59.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Tornado in GRAHAM, KANSAS
From 28-MAY-18 13:19:00 to 28-MAY-18 13:27:00 (CST-6)
Location: HILL CITY
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornadic rotation on radar indicates the tornado tracked northeast, east of Highway 283.  No damage was reported with this tornado.  Estimated the end time of the tornado when the tornadic rotation ended.

Thunderstorm Wind in THOMAS, KANSAS
From 28-MAY-18 19:05:00 to 28-MAY-18 19:05:00 (CST-6)
Location: BREWSTER
Magnitude: 70.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Public

Straight-line winds destroyed an empty grain bin, tore some roof off of a barn and collapsed a second barn.  Structural integrity of the collapsed barn prior to the damaging winds is unknown.

Hail in GOVE, KANSAS
From 28-MAY-18 13:30:00 to 28-MAY-18 13:30:00 (CST-6)
Location: QUINTER
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Golf ball size hail measured at MM 107 on I-70.

Hail in GRAHAM, KANSAS
From 28-MAY-18 14:12:00 to 28-MAY-18 14:12:00 (CST-6)
Location: ST PETER
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail was measured by the spotter.

Flood in GRAHAM, KANSAS
From 28-MAY-18 13:30:00 to 28-MAY-18 17:00:00 (CST-6)
Location: HILL CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A foot of water was reported six miles south of Hill City near Highway 283.  The rain was falling so hard at times that visibility was reduced to near zero.

Flash Flood in GOVE, KANSAS
From 28-MAY-18 14:20:00 to 28-MAY-18 21:00:00 (CST-6)
Location: QUINTER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Over a foot of water from Plum Creek was running over the CR Castle Rock north of Quinter.

Flash Flood in GRAHAM, KANSAS
From 28-MAY-18 16:45:00 to 28-MAY-18 23:30:00 (CST-6)
Location: BOGUE
Flood cause: Heavy Rain
Property damage: 100.00K
Crop damage: 0.00K
Reported by: County Official

Highway 18 from Bogue to Damar was closed due to flooding.  The flooding most likely occurred west of Sand Creek.  Four farmhouses were flooded and 20 cattle drowned where Sand Creek and the South Fork of Solomon River meet.

Hail in GOVE, KANSAS
From 28-MAY-18 14:49:00 to 28-MAY-18 15:10:00 (CST-6)
Location: QUINTER
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

The hail started out as ping-pong size then decreased to quarter size.

Hail in WICHITA, KANSAS
From 28-MAY-18 15:28:00 to 28-MAY-18 15:28:00 (CST-6)
Location: ST THERESA
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in LOGAN, KANSAS
From 28-MAY-18 15:55:00 to 28-MAY-18 15:55:00 (CST-6)
Location: WINONA
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash Flood in GRAHAM, KANSAS
From 28-MAY-18 14:00:00 to 28-MAY-18 23:00:00 (CST-6)
Location: ST PETER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Flooding along the creek channel was reported to law enforcement.  No information was given regarding damage from the flooding.

Hail in GOVE, KANSAS
From 28-MAY-18 16:07:00 to 28-MAY-18 16:07:00 (CST-6)
Location: PARK
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS