It sure has been a dull few weeks in the Pacific Northwest!  After an active start to winter, things really calmed down after the 1st week of January.  Believe it or not, PDX has seen 4.92″ of rain this month, which is very close to normal.  But most of that came in the first week; for the past 3 weeks there has been less than an inch of total rain.  So at this point you’d be forgiven for thinking it was a “dry January.”

I took a day trip to the Central Oregon Coast last Sunday, thanks to forecasts & models suggesting an especially warm day there.  Sure enough, the high temp at Newport Municipal Airport reached 64F during the early afternoon, before a shift in the wind cooled things back down to the mid-50s.  During the middle of the day I was walking along Nye Beach in nothing but a basketball jersey and shorts, and my car became uncomfortably warm when I parked it in the sunshine.

I also noticed many mature cordyline “palms” in Newport, along with a few (actual) fan palms and several gigantic Phormiums, with their purple sword-shaped leaves.  The Oregon Coast is much cooler than the Willamette Valley or even the Puget Sound in the summertime, making it a popular escape destination during valley heatwaves.  But the same ocean that keeps the coastline cool in the summer, also keeps winter temperatures much milder than in Portland or any of the inland valleys.  Certain plants that get damaged or occasionally killed by valley freezes, survive and flourish better at the coast thanks to the extremely mild winters out there.  The coast is an excellent destination during our “fake cold” inversions during winter, as there is often more sunshine and significantly warmer temps.

Speaking of inversions and “fake cold”…Portland Airport saw its second-coldest night of the season last night, at 26 degrees.  (It was 25 on the morning of January 1).  My Orchards neighborhood saw several nights in the mid/upper 20s this week as well.  The airmass overhead is actually quite warm for this time of year, but lots of cool air has settled into the valleys and basins over the past week thanks to the long winter nights.  Over the past 3-4 days there has been increasing east wind through the Columbia River Gorge…which has lowered humidity levels across the region, decreased fog, and allowed nights to become even colder (except in the areas with really strong wind).

Looking ahead….several days ago the long-range models were suggesting a shift back into a cool and active weather pattern beginning this weekend, and continuing through at least the first week of February.  A few maps even showed arctic air slipping down into the Columbia Basin.  But more recent models have pushed the cool upper-level trough further east, allowing a North Pacific ridge to nudge closer to us.  Today’s 12z GFS shows the ridge reasserting itself by late next week; those brown/red areas represent warmer than normal air in the upper atmosphere.

In the short term, we have one more dry/sunny day tomorrow after another cold night tonight.  Clouds should increase tomorrow night, keeping temperatures a bit milder.  Then Sunday a system brushes by to our immediate north as a trough begins to dig down over the intermountain West.  Most of the rainfall and snowfall is centered over the Washington Cascades, Olympics and Vancouver Island, with only light showers in Portland Sunday evening and early Monday.  Then by Tuesday we’re back to mostly dry conditions across the region as a new ridge over the Pacific blocks any further storms.  Here is the WRF-GFS map for total rainfall over the next 7 days; notice that NW Washington and BC get a soaking while Oregon stays much drier:

Beyond the 7-day, the general picture is to stay dry and warmer than normal, at least in areas not impacted by strong inversions.  Here is the 8-14 day outlook by Climate Prediction Center:

If this prediction holds, then we are looking at a very boring first half of February.  Many more dry days, little to no mountain snow, and temperatures generally on the mild side during the daytime at least (upper 40s to mid 50s in the valleys).  Probably less fog than we saw over the last couple weeks as well, due to the prolonged dryness over our region.  This is very uncharacteristic for a La Niña winter, which usually sees an active jet stream in February and March.  It would also mean that we probably don’t get any more “deep” cold outbreaks this season, with high temps 32F or colder and low temps near or below 20.  It’s very rare to see that happen after Valentine’s Day.  But we could definitely still see a chilly/wet pattern re-emerge in late February and early March, with lots of mountain snow and maybe a little snow at the lower elevations as well.

In any case, enjoy the sunshine tomorrow and plan on seeing more of it in the next couple weeks!  -Karl