Forced by a potent trough and focused along a dryline, these distinct thunderstorms moved northeast through a moist and highly unstable environment.

This outbreak occurred within a transition period for the National Weather Service and proved the value of NEXRAD radars, which were utilized in Oklahoma to provide advanced warning to residents.

[6][7] Through the morning hours, an 850 mb or approximately 5,000 ft (1,525 m) low-level jet of up to 60 kn (70 mph; 110 km/h) overspread regions from south-central Kansas northward into eastern Nebraska.

[8] A surface low-pressure area existed over southwestern Nebraska, supporting a dry line southward into Texas and a warm front southeastward across eastern sections of Kansas and Oklahoma.

[6] Despite early failure at convective initiation, supercell thunderstorms rapidly erupted along the dryline during the afternoon hours as the jet streak propagated into the Great Plains, resulting in a regional outbreak of tornadoes stretching from Texas to Iowa.

At 6:05 p.m. CDT (23:05 UTC), the National Weather Service issued a statement urging residents in Haysville, Derby, and Mulvane to seek shelter.

Around 6:16 p.m. CDT (23:16 UTC), the intensifying tornado began to affect southeastern sections of Wichita and directly struck Haysville.

[91] In eastern Wichita, some well-built houses in the Greenwich Heights Subdivision were completely leveled, indicative of strong F3 to F4 damage.

[92] At 6:24 p.m. CDT (23:24 UTC), the violent tornado struck the McConnell Air Force Base, where it narrowly missed a lineup of 10 B-1B bombers each worth $280 million and 2 of which were equipped with nuclear warheads.

[95] At 6:31 p.m. CDT (23:31 UTC), with the sirens not functional, the police drove through the Golden Spur Mobile Home Park and through the town warning residents to seek shelter.

10 minutes later, the now large wedge-stovepipe hybrid tornado entered southern Andover and began to impact the mobile home park, which ultimately sustained a direct hit.

In this area, it reached F3 intensity, snapping power poles, toppling well pumps, demolishing a house, and destroying oil tanks.

As it neared Interstate 35 and crossed into Noble County, the tornado first reached F4 intensity, flattening a house and debarking many trees.

In this area a University of Oklahoma chase team headed by Howard Bluestein utilized mobile doppler weather radar to analyze the tornado.

[102] Since the Kansas Turnpike video and events on May 3, meteorologists have strongly advised people to avoid seeking shelter under highway overpasses for many reasons.

The National Weather Service therefore notes, "seeking shelter under a highway overpass is to become a stationary target for flying debris, with a substantial risk of being blown out and carried by the tornado winds".

Lastly, motorists who quickly park their cars under an overpass without pulling over to the side first can cause an unexpected traffic jam, that may slow/strand other drivers due to the risk of collision.

American Red Cross and civil defense officials scoured devastated homes and rendered aid to about 370 families affected by the storms.

About 170 construction workers worked double shifts to repair the school grounds, which were tentatively set to reopen on August 12.

[109] The 1991 outbreak occurred during a period of modernization for the National Weather Service and helped highlight the value of radar imagery for detecting tornadoes.

In Oklahoma, the higher resolution radar displayed important storm-scale characteristics such as mesocyclones, some of which were seen over 125 miles (200 km) away in Kansas.