Multiple rounds of strong to severe thunderstorms lifted across this six-county area on this Friday. Although the afternoon hours primarily featured several reports of hail up to half dollar size in the Osborne and Mitchell County area, a brief EF0 tornado tracked across far northern Phillips County, with no damage reported.
Breaking down the timing of this event, strong thunderstorms lifted across parts of the area during the morning hours, but remained below severe limits. Then between noon and 2 PM CDT, a narrow arc of storms gradually intensified, especially over Osborne County. Between 2-4 PM CDT, this line of storms swept across Mitchell and Jewell Counties before quickly departing to the east. Although it initially appeared the severe threat had dwindled by this point, additional small, seemingly weak thunderstorms developed directly under the center of the mid level cold pocket between 4-5 PM CDT, with one of these spawning the brief Phillips County tornado as captured on video by a storm chaser.
Aloft, this event was driven by a well-defined, negatively tilted mid level shortwave that passed directly overhead as it tracked from near the Kansas/Colorado border in the morning, to eastern Nebraska by late evening. Although this mid level wave did not necessarily feature a true closed circulation at 500 millibars, the Phillips County tornado nonetheless possessed the characteristics of most cold-core tornado events. This included a parent low-topped storm with rotational signatures difficult to detect via radar. At the surface, a strong low pressure center deepened to around 996 millibars over the heart of North Central Kansas by mid-afternoon, with a well-defined warm front extending southeast into southeast Kansas, and a sharp dryline surging into central Kansas from the west. Mesoscale severe weather parameters during the early to mid-afternoon time frame featured a narrow tongue of surface based CAPE between 500-1500 J/Kg, in the presence of around 40 knots of deep layer vertical wind shear.

Hail in OSBORNE, KANSAS
From 27-APR-12 12:03:00 to 27-APR-12 12:03:00 (CST-6)
Location: COVERT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in OSBORNE, KANSAS
From 27-APR-12 13:14:00 to 27-APR-12 13:14:00 (CST-6)
Location: OSBORNE
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in MITCHELL, KANSAS
From 27-APR-12 13:44:00 to 27-APR-12 13:44:00 (CST-6)
Location: CAWKER CITY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in MITCHELL, KANSAS
From 27-APR-12 14:08:00 to 27-APR-12 14:08:00 (CST-6)
Location: GLEN ELDER
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in MITCHELL, KANSAS
From 27-APR-12 14:33:00 to 27-APR-12 14:33:00 (CST-6)
Location: BELOIT ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in MITCHELL, KANSAS
From 27-APR-12 14:47:00 to 27-APR-12 14:47:00 (CST-6)
Location: BELOIT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Tornado in PHILLIPS, KANSAS
From 27-APR-12 15:43:00 to 27-APR-12 15:52:00 (CST-6)
Location: WOODRUFF
Tornado F-scale: EF0
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

This tornado touched down approximately 7 miles east of Woodruff and lifted approximately 10 miles east of Woodruff.  No damage was reported with this tornado.

Hail in MITCHELL, KANSAS
From 27-APR-12 14:06:00 to 27-APR-12 14:06:00 (CST-6)
Location: GLEN ELDER
Magnitude: 1.25 
Property damage: 50.00K
Crop damage: 500.00K
Reported by: Law Enforcement

Hail in OSBORNE, KANSAS
From 27-APR-12 13:16:00 to 27-APR-12 13:16:00 (CST-6)
Location: OSBORNE
Magnitude: 1.25 
Property damage: 50.00K
Crop damage: 500.00K
Reported by: Law Enforcement