LONG BEACH — The National Weather Service has issued a high-surf advisory for 10 a.m. Friday to 4 a.m. Saturday for the south Washington coast and much of the Oregon coast.
Seas will build rapidly Friday afternoon, reaching 20 to 22 feet by Friday evening. These energetic waves will start to decrease late Friday night.
Exercise extreme caution along beaches. Unpredictable and destructive waves may wash over beaches, jetties and other structures with no warning.
Meanwhile, the flooding threat is increasing for Saturday night through Monday for Southwest Washington and northwest Oregon rivers.
“A strong and deep moist westerly flow will begin crossing the Pacific Northwest coast Saturday morning,” the weather service said. “A very long fetch of moisture is stretching across the Pacific with origins west to the South China Sea and has above average potential to bring heavy rains to the area.
“As such, this continues to give the appearance of a classic high-precipitation atmospheric river event, where the deep, moist flow will spend a significant amount of time on a nearly perpendicular course against the Coast Range with the Cascades taking a bit higher of the impact.”
Latest forecasts for Friday night through Monday afternoon bring 8 to 12 inches of rain to the Cascades and foothills, 7 to 11 inches for the Coast Range (including the Willapa Hills), 5 to 7 inches along the immediate coast, and 3 to 4 inches along the I-5 corridor.
Given latest data, it appears multiple coastal rivers have a moderate potential of exceeding flood stage.
Keep in mind that details will always be in flux under these scenarios as subtle north or south shifts cold make dramatic differences in which basins receive extended periods of moderate to heavy rain. Continue to follow the latest forecasts and impacts as conditions warrant.