EF0 tornado in Garfield County, Oklahoma

A storm chaser observed a brief tornado south of Bison. An NWS damage survey team found multiple road signs damaged at the intersections of US-81 and Marshall Road. No other damage was observed.

A significant severe weather outbreak, including ten (10) tornadoes, impacted northern and central portions of the WFO Norman Forecast Area during the evening of the 6th into the early morning hours of the 7th. The synoptic pattern across the western half of the Continental United States favored a significant severe weather episode across the region, with a powerful (110-120 knot) upper-level jet streak ejecting across the Central Plains during the evening of the 6th. In concert with robust kinematics in place, extreme instability (pockets of >4000-5000 J/kg of CAPE) promoted an environment favorable for significant severe weather. As such, the Storm Prediction Center issued a rare 'High Risk' of severe weather for portions of central and northern Oklahoma, the first to include portions of the WFO Norman Forecast Area since 20 May 2019.

Initial supercell thunderstorms developed in the late afternoon off an accelerating dryline/Pacific front near the 100th meridian. These initial supercell thunderstorms produced large to very large hail and damaging wind gusts, though failed to undergo tornadogenesis. This may have been due to the propensity for rapid and strong downdraft surges in the vicinity of low-level mesocyclones (among other factors). With time, as storms matured and moved into an environment characterized by richer low-level moisture, and as low-level flow increased, multiple tornado occurrences did result. Additional supercell thunderstorms and thunderstorm clusters developed by the late evening of the 6th across west-central into central Oklahoma. A particularly impactful cluster moved across the southern Oklahoma City Metropolitan area, producing numerous reports of significant thunderstorm wind damage (and gusts) and two weak tornadoes.