Rare Tornado Risk Forecast in the Pacific Northwest

A rare tornado risk was forecast on May 28 by the National Weather Service (NWS) for the first time in more than 30 years across three states in the Pacific Northwest as part of a storm system extending across Washington, Oregon, and Idaho.

Forecasters at the NWS’s storm prediction center in Oklahoma predicted a slight risk of severe thunderstorms in the region in the afternoon and night from western Idaho into central Washington and Oregon.

“Scattered severe thunderstorms are possible this afternoon and evening over western Idaho and east of the Cascades in Washington and Oregon, capable of damaging gusts, large hail, and perhaps a tornado,” the NWS said in a weather outlook.

Some locations in Oregon, such as The Dalles, Pendleton, Baker City, and Yakima, are under greater threat for damaging winds, large hail, and have a greater chance to see a twister.

In Washington, Clark County and Cowlitz County, along with portions of Lewis, Thurston, and Pierce counties, have an enhanced threat of funnel clouds or tornadoes. In Idaho, Lewiston, Pullman, Moscow, and Coeur d’Alene are in the tornado risk zone, according to the NWS.

Winds in the region were expected to pick up in the afternoon, mixed with intense sunshine heating the ground and air, and dewpoints in the upper 40s to lower 50s to provide moisture for the clouds to form and grow.

The warm surface air mixing with cold air above are what may create conditions for afternoon thunderstorms, the NWS said.

Possible tornado activity could first develop across southwest Idaho and southern Oregon where a supercell could produce large hail and damaging wind gusts, forecasters warned.

“These storms would continue to pose a damaging wind threat,” the NWS stated.

On May 29, the storm is expected to move eastward across the northern intermountain region into the northern high plains by Saturday. Rain showers and thunderstorms will develop over parts of the region, the NWS reported.

The storm front is expected to advance into the northern and central plains by Saturday, delivering showers and thunderstorms over parts of the northern and central high plains, the NWS reported.

Some of the thunderstorms could include lightning, severe wind gusts, hail and the threat of tornadoes, according to the NWS.

The three-state tornado risk warning was the first possible tornado outbreak in the region since 1997, according to the Western Regional Climate Center. A record six tornadoes touched down in Washington state in one day on May 31, 1997. Before that, four tornados were recorded in 1989 for the entire year.

A tornado was also observed near Lewiston, Idaho, during the 1997 storm.