Forecast calls for snow - but when will it arrive?

Forecast calls for snow - but when will it arrive? »Play Video
A youngster makes a flying leap through Sunday's snow flurries. (Photo by YouNews contributor hmahrt)

PORTLAND, Ore. – A few communities awoke Sunday morning to light snowfall as the first cold snap of the season continued to strengthen its grip on Western Washington and spreads south to Oregon.

The forecast for Monday calls for snow to possibly fall in Portland Monday afternoon just as many people begin to make their way home from work and school. The National Weather Service issued a bulletin Monday advising 1 to 2 inches of snow could fall.

Temperatures are expected to dip all the way to 20 overnight before warming to just above freezing during the day Tuesday. From there, cold but dry conditions are forecast for Wednesday and into the Thanksgiving weekend.

KATU Meteorologist Rhonda Shelby says the temperature in Portland on Monday will drop during the day as cold air moves in and should hit freezing right about 3 p.m. Combined with any moisture, the cold could produce light snow just as the evening commute begins.

Slick roads slowed up drivers in the region Monday morning, especially in Clark County, where several vehicles ended up in ditches or jersey barriers after spinning out on slick roadways. Another accident on the St. John's Bridge in Portland had traffic going west down to one lane.

Around the Portland area, TriMet was taking no chances and had all buses chained up Monday morning. Slower speed limits for the buses messed with some schedules but for the most part buses were running on time.

The first reports of light snow on Sunday came in from Puyallup, Federal Way, Tacoma, Lakewood and Everett Sunday morning. By noon, snow flurries were reported in more locations, including downtown Seattle and as far south as Castle Rock, which is just north of Longview.

By 1 p.m. the snow was falling in Clark County, in the northern town of Hockinson at the 500-foot elevation. The snow also was falling near the Coast Range on Highway 6 and on Highway 26 near the Oregon Zoo.

By 2 p.m., the snow was sticking everywhere from Portland's West Hills to Vancouver, Wash. By around 3:30 p.m. the snow had stopped falling, and had been replaced by scattered showers throughout the region.

View photos of weekend snow from around the region >>>

"The problem is that tonight these roads are going to freeze," said KATU Meteorologist Dave Salesky on Sunday. "It's going to be a zoo tomorrow morning."

Salesky is expecting it to get colder overnight, icing up the roads. Highs in the Portland area could get to 37 degrees Fahrenheit on Monday, with the drive home again returning to cold and icy roads.

"We could have sticking snow downtown beginning as early as Monday evening through early Tuesday
morning," Salesky said. "Cold air Tuesday morning will maintain the snow, in the low- to mid-20s."

He said as much as 1 to 2 inches "tops" of snow could fall in downtown Portland Monday, and up to 4 or 5 inches could fall on Sandy and Estacada in Cascade foothills. Then it's off to a drier, and gradually warming, Tuesday afternoon.

"We have to deal with a little bit of snow tonight, and a little bit more on Monday and Tuesday," Salesky predicts. "But it will be gone in 36 hours."

Behind the weather system
Sunday morning's snow comes thanks to a weak weather system that developed offshore and moved inland overnight. It's expected to move out by midday, and with little moisture in the sky – maybe 1/2-inch at best – snow isn't likely to fall again in those areas.

But it could fall farther south. Some models indicate light accumulations of snow – along the lines of 1 to 2 inches – possible from Olympia south, so factor that in to your plans Sunday.

This comes as arctic air continues to funnel in from the Fraser River Valley, the area north of Seattle in Canada. This arctic air is keeping temperatures in the 30s Sunday.

A second, stronger system comes in on Monday. Most forecast models bring the system into northern Oregon, focusing most of the snow potential there. The northern edges of Monday's storm is expected to spread snow as far north as Olympia.

Right now, we're keeping the "best odds" forecast with snow in Southwestern Washington – maybe 1 to 3 inches depending on how much moisture makes it north. Highs on Monday will likely be in the low 30 degrees Fahrenheit in Southwestern Washington.

So to recap: Everyone be on the lookout for icy roads Monday morning. And for those of you from in northern Oregon to Southwest Washington, be prepared for potential snow on your commute home.

Related links: