NATIONAL WEATHER SERVICE
Observer staff report
LONG BEACH — A high-wind watch is now in effect for Pacific County and the Oregon coast for late Friday night through Saturday evening.
The National Weather Service in Portland said coastal winds may gust high as 70 mph, with sustained winds of 35 to 34 mph on beaches and headlands. The watch is likely to be upgraded to a warning on Friday.
“An amazingly strong oceanic cyclone will develop and move up the Northwest coast,” University of Washington meteorologist Cliff Mass wrote in his blog Wednesday. At 5 a.m. Saturday there will be a deep (972 hPa) low west of Washington state, with a huge pressure gradient to its south and west. “That means big winds,” Mass said.
Although stronger winds are common on Washington’s outer coast in the late autumn and winter, winds of the predicted velocity are very unusual in early April and may damage tender new spring vegetation.
Offshore on Saturday, combined seas are forecast to reach 27 feet in the afternoon, with gusts to 55 knots. Conditions will be dangerous at sea and are likely to be hazardous on beaches. A gale warning is in effect Thursday for offshore waters.
It’s also expected to be rainy on the south Washington coast during the day Thursday and on Friday night, with up to nearly 3 inches of rain forecast for the Long Beach Peninsula over the next 72 hours.
“Having such a strong storm in April is unusual, but not unprecedented,” Mass said. “But we are in for an interesting period. But one good thing, one can forget about West Coast drought or any water issues for this summer. Our tank is about to be filled, if not overfilled.”
A week ago as they saw this storm developing in the Pacific Ocean, Columbia River hydro-system managers began making preliminary plans to manage a big surge of rainfall. But as it has turned out, the truly gargantuan aspects of this storm are forecast to hit south of us. By late next week, up to 8 inches of rain are forecast to fall in parts of California, including over 2 inches in the usually dry central valley. Mudslides are a distinct possibility in Southern California.
Mass calls this “an extraordinarily strong atmospheric river … A monster that will be one the strongest on record, particularly this late in the season.” An atmospheric river is a narrow current of high moisture values, originating in the tropics and subtropics, that is associated with warm air and heavy rain, particularly when into coastal terrain, Mass explained. In the Pacific Northwest, atmospheric rivers are often called a pineapple express.