Bright Sunshine, But a Chilly East Wind

January 13, 2019

7pm Sunday…

What a fantastic January day with a blue sky and bright sunshine.  If we aren’t going to get much-needed rain and mountain snow I’d prefer this over gray skies.  The coastline was quite warm today along with most of us in the western valleys of Oregon and SW Washington

todays observed highs orwa 2017

Strong high pressure is in control over the Pacific Northwest both in the higher atmosphere and down here near sea level as well.  We are still in “inversion season” for about 4 more weeks; meaning the sun angle (although rising) is still too low to allow that sunshine to warm the ground much.  The long winter nights mean cool air pools at the lower elevations.  In fact quite an extensive pool of cool (not cold) air has developed east of the Cascades below about 4,000′.  A late-morning GOES-17 image shows the large area of stratus (low clouds/fog) east of the mountains and mainly clear sky westside

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This weather pattern continues through Tuesday/Wednesday, except we’ll add lots more clouds and even a few showers overhead Wednesday.  This is our classic east wind pattern in the western Gorge and Portland metro area too.  Right now it’s blowing 26 mph at PDX gusting to 35.  It was a windy day across a good chunk of our area; the area in orange shows who was feeling the wind today and continues to get nailed this evening.

warnings gorge and metro east wind

As I mentioned in the post last week, we’re headed into at least a few days of wet weather from Wednesday through this coming weekend.  Overnight temperatures rise up closer to 40 and highs stick to within a few degrees of 50 as we’ll get leftovers of California weather systems.  Take a look at the 6 day rain forecast down there!

ecmwf precipitation accumulation

We should see only around 1″ or so in the next week here in Portland.

Models also appear to be latching on to a pattern change for the 2nd half of January; what was coined the “North American Winter Temperature Dipole” in a recent published study.  We know it as the “Western Ridge/Eastern Trough” pattern.  Warm & drier than normal in the west and cold/snowy in the east.  It begins to show up on all models about a week from now.  Here’s the ECMWF/GEM/GFS for Monday the 21st, showing some sort of strong upper-level ridging developing over or just west of the West Coast

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Then there is surprising agreement it’s still there a week later, on Monday the 28th

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Generally this means a slowdown in weather along the West Coast and lots of high pressure overhead.  If ridging is weak, we end up with weak systems bringing onshore flow, light rain at times,  and mild temperatures over the top of the ridge.

It’s interesting to note both the GFS and ECMWF ensembles have a hint of the ridge backing a little farther offshore.  That would open up the possibility of at least some cold air making it west of the Rockies.  That would be at least 10 days out from now.  So if you’re a weather weenie and concerned there is no sign of winter ahead; there’s still a chance…

 

What does this mean for our day-to-day weather the next 10-14 days?

  • East wind and sunshine continues through Tuesday
  • Wednesday through at least next Sunday we’ll see lots of clouds, rain at times, and mild temperatures
  • NEXT week (starting Monday the 21st), could be much drier but mild temps will continue.
  • There is no sign of lowland snow/ice or real stormy weather in the next 10 days.  Unless something pops up in the last week of the month, this January is going to end up a very mild January!

Chief Meteorologist Mark Nelsen