The outbreak coincided with elevated tornado activity: the period May 19–26 was one of the most intense to date, since the founding of the United States Weather Bureau.

At 00:30 UTC (7:30 p.m. CDT) on May 20, a 75-to-80-knot (86 to 92 mph; 139 to 148 km/h) mid-level jet stream bisected dew points of 65 °F (18 °C), coincident with a 986-millibar (29.1 inHg) low-pressure area and warm front over southeastern Nebraska.

Soundings and surface weather observations indicated a robust, unstable warm sector, showing 3,000 j/kg of surface-based convective available potential energy (CAPE) and the presence of strong wind shear.

A sharp increase in the annual average E/F0–1 count by approximately 200 tornadoes was noted upon the implementation of NEXRAD Doppler weather radar in 1990–1991.

[6][note 3] 1974 marked the first year where significant tornado (E/F2+) counts became homogenous with contemporary values, attributed to the consistent implementation of Fujita scale assessments.

The list below documents information from the most contemporary official sources alongside assessments from tornado historian Thomas P. Grazulis.

Forming near Williamsburg, it moved northeastward through several counties, producing near-continuous damage; a single tornado was likely present for 50 mi (80 km) or more.

[104] A cyclic supercell was likely responsible for this deadly, violent tornado, which probably formed over remote parts of the Mark Twain National Forest.

Hardest hit were schools, businesses, and homes on the eastern side of Fremont, along and near the railroad; these were poorly built, so the tornado was rated F4, but F5 winds could have occurred.