EF3 Tornado — Fillmore, Nebraska

2014-05-11 · near Grafton, Fillmore, Nebraska

Event narrative

This is the continuation of the EF3 tornado that started in Clay County northwest of Fairfield.

This tornado was reported initially as a multi-vortex tornado for several miles before taking on a more traditional look south of Saronville, where it was described as a wedge tornado. Based upon reports and video, it appears the entire mesocyclone of the storm was near ground level southwest of Sutton. It was one of the strongest tornado of the day in south central Nebraska, rated an EF3 with the peak wind estimated to be 150 MPH. Rear flank downdraft winds resulted in damage on the south side of the tornado track and in addition to the damage to Sutton itself, areas east of Clay Center, southwest of Sutton through northwest of Grafton were affected. Power poles and trees were damaged or snapped, irrigation pivots were overturned, and a few homes and outbuildings suffered damage.

Damage from this tornado was first noted north of Fairfield, where large tree limbs were knocked down and power poles broken. The tornado shifted mainly east across Highway 14 south of Clay Center, with additional tree damage as well as irrigation pivots overturned. It then started to move to the northeast, crossing Highway 41 east of Clay Center and Highway 6 a few miles west of Sutton, but powerful rear flank downdraft winds of 100 mph hammered Sutton and areas south-southwest of town, causing widespread property damage. Moving in between Saronville and Sutton, the tornado then started a more east-northeast path, crossing Road 6 north of Sutton before dissipating approximately 5 miles northeast of town.

As the tornado approached and crossed Highway 6 it intensified to it strongest point. Damage peaked a few miles north of Sutton, where the EF-3 rating was assigned, resulting from the destruction of a home. Elsewhere along the path, a few other homes sustained less significant damage than the one north of Sutton, and a number of other outbuildings and grain bins were also damaged or destroyed. Many trees were damaged, destroyed or contained debris (mainly from destroyed grain bins), irrigation pivots were overturned and power poles broken.

Wider weather episode

Multiple thunderstorms formed along and southeast of a line from Red Cloud to York on this Sunday afternoon. However, most of the severe weather was produced by a single supercell. This was the first and most intense storm of the day and it formed over Webster county around 2:30 p.m. CDT. This storm took full advantage of an extremely favorable environment, quickly becoming severe and producing at least one brief, weak tornado just southwest of Glenvil. The storm continued northeast producing several more tornadoes, two of which resulted in a maximum damage rating of EF-3. One of these tornadoes occurred over Clay and Fillmore counties and the other subsequently occurred over Fillmore and Seward counties. The first of these EF-3 tornadoes was on the ground for nearly 22 miles. Damage surveys, photos and video confirmed that this storm produced at least 6 other tornadoes, 3 rated EF-0, 2 rated EF-1 and 1 rated EF-2. One of the EF-1 tornadoes was anticyclonic and touched down just north of Fairmont. To the left of these tornadoes, severe hail was common. The largest hail observed was the size of tennis balls in Glenvil. Large swaths of damaging winds, from the rear flank downdraft, accompanied the tornadoes to their south and southeast. Tornado and wind damage was extensive to trees, power poles, farm buildings including grain bins, and a few homes. Over 200 irrigation pivots were overturned and/or twisted. Multiple farmsteads also endured damage, including the loss of a new machine shed. By 5:30 p.m., this storm had moved into eastern Nebraska. Other storms developed in its wake, but produced no severe weather.

A very long surface front extended from New England, through the Ohio Valley, across the Central Plains and into the Desert Southwest. Portions of this front were stationary while others were being modulated by several waves of low pressure. The front lifted northward to the Kansas-Nebraska border by daybreak. One low ejected out of Colorado and moved east along the front through northern Kansas during the day. This supercell formed just northeast of this low on the immediate cool side of the front. The upper-level flow featured an amplified western trough and eastern ridge. A closed low was at the base of the trough over the Four Corners region. These storms initiated with the aid of a shortwave trough that ejected into the Central Plains ahead of this low. A strong 100 knot jet streak was at the base of the trough at 300 mb, placing the Central Plains in the favorable left front quadrant. An expansive stratus cloud deck, on the cool side of the front, resulted in a substantial temperature gradient across the front, with afternoon temperatures in the 40s and 50s across much of Nebraska to the mid 80s and low 90s over northern Kansas. This resulted in a tight instability gradient with MLCAPE of 2000 J/kg right along the front. Winds were strong throughout the column. The ejecting low pressure center, combined with the front, resulted in significantly backed winds, enhancing low-level shear. 0-1 km SRH was roughly 300 m2/s2, with 0-3 km SRH 400-600 m2/s2. The environment was very favorable for severe storms and tornadoes.

View location on OpenStreetMap → (40.6407, -97.8247)

Source: NOAA Storm Events Database, event_id 510468. Narrative written by the NWS forecast office that issued the report.