Even with the official start of summer less than a week away, many in the northwestern United States will have to deal with raw and rainy conditions that are more typical of late April than the middle of June.
Temperatures have soared to above historical averages in parts of the Northwest following an abnormally dry May and start to June. However, a robust storm system will help bring in big changes to the weather starting this weekend and continuing into next week. In some locations, snowflakes could fly.
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“An unusually cool storm for this time of year will move into the area this weekend,” said AccuWeather Senior Meteorologist Heather Zehr.
Steady showers will begin along the coastal Pacific Northwest on Sunday morning and spread into portions of Idaho and Montana by the afternoon. Generally, rainfall across much of the area on Sunday will not be very heavy in nature. No widespread flooding issues are expected.
Showers will continue along the coast on Monday while rain intensity will pick up along the Oregon coast and southern portions of eastern Washington.
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“Periods of rain and possibly even a rumble or two of thunder are forecast to impact much of the Cascades and portions of the northern Rockies in Idaho and western Montana through early next week,” Zehr said.
Rain in this area can be heavy at times – especially in the higher elevations where snow is possible -Monday evening through Tuesday evening.
“Snow will fall down to around 5,000 feet in the mountains, and snow may mix with rain in some of the mountain passes,” Zehr said.
Although some may consider this early-week rainfall to be a nuisance, it will be welcomed with open arms in portions of Oregon. Any rain that falls in central Oregon will actually be beneficial in nature as much of the area continues to experience severe drought, according to the United States Drought Monitor.
This system will not only usher wet conditions back into the region, but it will also lock in cooler air that will send temperatures to unseasonable levels.
“Temperatures will be near historical averages on Saturday but drop around 10 degrees for Sunday as the storm moves in with some cloudiness,” Zehr explained.
On Sunday, high temperatures across the region will top out at 10-15 degrees Fahrenheit below historical averages for mid-June. High temperatures will generally reach the upper 50s to low 60s west of the Cascades, with highs reaching the upper 60s in the Columbia Basin and mid-50s elsewhere. The higher elevations will be even cooler, with some areas struggling to reach the mid-40s.
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For some cities, the mid-June chill will challenge decades-old records.
“The heart of the storm will be over Washington and Oregon on Monday; temperatures will average 10-15 degrees below average,” Zehr said.
The mercury in Seattle and Portland is forecast to reach 61 degrees in both cities, respectively, on Monday. The record lowest high temperature for June 19 is 57 in Seattle and 61 in Portland. In Seattle, the record for the coldest high temperature on June 19 was set over 100 years ago in 1916.
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