These next few days of sunny skies and warm temperatures may make you believe spring has sprung. But keep those garden starts in the green house and keep your puffy coat handy. Cold weather will come back with a vengeance by the end of the week.
The National Weather Service is watching models carefully as temperatures are likely to tumble about 15 degrees from Tuesday’s high to Thursdays, and snow may even fall to the valley floor by the end of the week.
That may seem unlikely as you head out Tuesday under mostly clear skies and enjoy an afternoon high of about 62 degrees. The day may start with some patchy fog, especially south of the metro area. Fog was seen on traffic cams along Interstate 5 in Salem early in the day. Once fog burns away, skies should be mostly sunny, and the high temperature should reach about 62.
Wednesday will also be mostly clear, especially in the early part of the day. Highs may reach near 62 degrees. But a change in the weather pattern will occur later in the day bringing a chance of showers by the evening.
Winter-like weather returns Thursday as a cold system moves into the region from the Gulf of Alaska. High temperatures will dive back into the 40s, and snow levels are expected to sink as low as 500-1,000 feet.
Portland will see a wet day Thursday with widespread showers that will be heavy at times. The heavier showers are likely to contain hail or graupel as cold air aloft and instability kick up stronger showers and possibly thunderstorms. Winds may gust up to 30 mph during strong showers. The weather service warns that some hail showers could cover the ground with the frozen balls of precipitation depending on location. The daytime high should reach about 48 degrees.
The wild spring weather continues in the evening with more chances of thunderstorms and heavy showers. Snow levels will stay low overnight Thursday and into Friday. Snow is likely over the coastal mountains, on the passes over U.S. 26 on the Coast Range and in the Cascades and their foothills. Accumulating snow is possible above about 1,000 feet.
Some models are showing a possible 6-10 inches of snow by early Friday across the Cascade passes. The Coast Range could see 1-3 inches.
Friday offers a strong chance of mixed precipitation even down to the valley floor under heavier showers. Portland could see anything from rain, a rain/snow mix, hail, and graupel. Temperatures are not likely to dip below freezing, so anything that does fall should melt off quickly. The daytime high is expected to reach about 47 degrees.
The extended forecast is showing a cold and sometimes snowy weekend across much of the state with special concerns focused on the Cascades due to additional snow accumulation that may cause difficult winter driving conditions. If you’re planning a trip to higher elevations this weekend, keep an eye on TripCheck.com to see current travel warnings or chain restrictions.