Update Thursday: Low temperatures Thursday also created a traffic headache as the top deck of the Fremont Bridge in Portland was closed while work crews worked to de-ice it. It was reopened about 7 a.m.
Lower than normal temperatures are forecast for Wednesday throughout the state. The lows are expected be in the twenties in the Willamette Valley.
Historically, the average low temperatures for this time of year in the greater Portland area are in the upper thirties. Wednesday’s low is expected to be about 10 degrees lower.
Matthew Colin is a meteorologist at the National Weather Service. He says several factors are causing the cold snap.
“There is a very cool and dry air mass moving into the area and that’s what’s allowing the temperatures to fall. Along the same lines, the skies will be clear and that allows better cooling to occur overnight as the radiation from the Earth kind of is able to escape in the atmosphere allowing temperatures to cool down,” he explained.
Colin says the colder temperatures will extend into the next several nights and may go into the weekend.
The National Weather Service reports that the temperatures may be some of the coldest nights so far this fall.