Potent storm to blast northwestern US with rain, severe weather

An unusually strong storm for the summer will spin ashore in the Northwest with areas of rain that can slow travel and severe thunderstorms that can cause damage. Gusty winds will raise the fire risk.

An unusually potent North Pacific storm for mid-August will slowly swing ashore in the northwestern United States and will produce areas of drenching rain, gusty winds and severe thunderstorms this weekend, AccuWeather meteorologists say.

"This storm will bring rare severe thunderstorms to western Washington and Oregon," AccuWeather Meteorologist Brandon Buckingham said, "It's not only rare for the summer, but any time of the year along the Interstate 5 corridor."

"In addition to the risk of hail and damaging wind gusts, numerous burn scars will be in the path of these potential thunderstorms," Buckingham said, "Within the vicinity of these burn scars, mudslides will be possible as the dry, sun-baked ground will not be capable of soaking up all of the moisture."

The threat of severe thunderstorms will extend through much of the Cascades and the mountain passes.

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Even outside of the main severe weather threat zone into Saturday night, there can be locally heavy, gusty thunderstorms into northwestern Washington and perhaps farther to the south in Northern California.

August is typically a rain-lean month for the Northwest, including the coastal areas. Seattle and Olympia, Washington, average less than 1 inch the entire month. Portland, Oregon, tends to pick up just over 0.50 of an inch with less than 0.40 of an inch for a historical average in Eugene, Oregon.

Enough rain will fall along the I-5 corridor to create slick conditions and possibly cause ponding in areas that drain poorly. The combination of water and oily residues that have built up on the highways can make for extra slippery conditions and may lead to an increase in vehicular accidents.

Little to no rainfall is expected from the incoming storm east of the Cascades. However, gusty winds will make the effects felt, fanning ongoing flames and posing a risk for new fire development. The gusty winds will extend well to the south as well with areas east of the Sierra Nevada being at a high risk of wildfire ignition this weekend.

"A multi-day stretch of windy conditions are expected across the mountainous terrain of California and a majority of the interior Northwest and Great Basin into next week, leading to a prolonged risk of wildfire activity," Buckingham said.

If any new fires ignite, firefighting conditions could be very difficult because of the wind and low humidity levels.

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