National Weather Service United States Department of Commerce

Snow & Ice Across the Rockies & Plains; Zeta Forecast to Head Toward the Gulf Coast

Snow and ice will continue over the central and southern Rockies and eastward into the High Plains through Tuesday along with record cold temperatures. Farther west, critical to extreme fire weather conditions are expected in the Desert Southwest, Great Basin, and California. Elsewhere, Zeta is forecast to be at or near hurricane strength as it approaches the northern Gulf Coast on Wednesday. Read More >




Severe thunderstorms developed along and ahead of a dry line across central Oklahoma during the afternoon of May 9, 2016. The storms moved across central and eastern Oklahoma during the late afternoon evening hours. Prior to the storms moving into the area, the atmosphere ahead of the dry line in central and eastern Oklahoma had become very unstable.

This instability, combined with very strong wind shear associated with a strong trough of low pressure that moved into the Southern Plains from the Southern Rockies, resulted in the development of supercell thunderstorms. Several of these supercells produced a dozen tornadoes. Some of these tornadoes were damaging and long-lived tornadoes, and two were also killer tornadoes. One of the tornadoes, the "Katie tornado", killed one person and was rated EF-4.  Another tornado that occurred in Johnston and Coal counties also killed one person and was rated EF-3.

One of the supercells produced multiple tornadoes as it tracked along and near an outflow boundary produced earlier by morning thunderstorms associated with a previous weather system. This outflow boundary had settled across southeastern Oklahoma by the afternoon. The most significant tornado associated with this thunderstorm was the EF-3 tornado which occurred near the towns of Bennington and Boswell.

In addition to the tornadoes in central and southeastern Oklahoma, the severe thunderstorms produced hail up to baseball size and damaging wind gusts across other portions of central and eastern Oklahoma.

Map with damage paths for most of the tornadoes that occurred in Oklahoma on May 9, 2016.