A chilly, damp period is ahead, with some areas in the immediate future getting a sprinkle or two of The White.  What about your morn’n Mug location?  Let’s take a gander. This will be complicated, so stick with us, please.

 

Cool week ahead, with periods of showers & snow showers in the mountains.  For Tue & Wed this week, an approaching Low may draw colder air out from the Columbia River Gorge, and when combined with the coldest air aloft compared to the past few days, could bring on The White (1” or so) for a brief spell in portions of the Willamette Valley & higher chance around Hood River.  This system may also sprinkle The White around Chehalis, maybe north into portions of the SE area of the Puget Sound.  All iffy, and short-lived, but fun to witness, if verified.  Bellingham north Patrons should receive some precip, but whether or not stays as snow to the surface is iffy for now.  Any Patron around the PNW sipping their morn’n beverage above 500’ or so Tue & Wed should enjoy a short-shot of The White.  Mountain passes will be definitely requiring tire attention.

 

Thu into Fri should warm at the surface, moving chance for snowfall above 1,500-2,500 ft or so.  The next organized disturbance is modeled to arrive later Fri into Sat.  This will be rain at the surface, heavy snow in the mountains.  Sunday Dec 19 is trending generally dry & chilly; frost if the sky clears in your area.  

 

Christmas Week is beginning to look quite interesting.  Monday will usher in a chance for The White south of Salem before the surface air warms, as a system tracks off the coast of Oregon, drawing colder air in from the E/NE.  An outflow wind is possible from both Gaps - Fraser & Columbia River - but not super strong at this time (definitely could become an issues around Christmas - read on).  Tue & Wed Dec 21-22 are trending relatively DRY & chilly.  Thursday Dec 16 looks damp as a system moves in from the NW.  Not seeing snow risks quite yet, but Nature’s Christmas surprise may be just around corner.

 

Christmas Eve & Christmas Weekend:  the stage is being set - per model scenarios - for a very impactful WINTER STORM event (remember we talked about stages for snow last week?).  At that time, we had NOT been discussing an Arctic Outbreak-type of winter event, but now that is trending as POSSIBLE for the Big Holiday period.  Models hint of a High pressure Dome of 1044-1048 mb developing over the Yukon and moving south.  Should this actually take place, the pressure difference between interior BC and the Olympic Range could be huge - meaning powerful outflow winds from the Fraser River Gap.  (Outflow winds much colder than what we discussed on last Saturday’s Farm Show on KGMI 750 Talk Radio.)  Model runs suggest a rather deep Low pressure cell dropping south, right along the BC/WA coast, at the same time as that cold DOME figuratively drops into place.  As we mentioned in our last report, we all know the drill, if that happens.  Moisture, subfreezing outflow air - SNOW.  Back to the forecast —

 

Fri Dec 24.  Rain & wind increasing from Thu system as the surface Low moves south along the OR coast.  Air will turn snow-cold first over NW WA, Vancouver Is., SW BC as this event gets underway on Christmas Eve.  It is possible for the precip to turn from rain/showers north of Salem to all snow at some point overnight Thu into early Christmas Eve.  Odd movement of that Low - it may shift south near Brookings, then back north again - still off the coast - before literally “parking” itself just west of Vancouver Island.  Oh my, if this verifies, all that moisture will first turn back to rain at the surface, before swinging back to The White as Santa makes his jolly way across the rooftops.  Based on current model trends, SNOW is possible from Eugene all the way north into BC on Christmas Day.  Really?  Remember, just a crazy forecast for now, but seriously, we have not seen this pattern for Christmas on the model charts in years.  Ponder Point for sure.  Some solutions keep the NE cold air flow strong through that weekend; others place the coldest portions of that High Dome east of the Rockies, with enough drawn into the eastern basins of WA/OR to hold snow at the surface as possible after Christmas.

 

Monday Dec 27: another Low may follow a similar path as the Christmas Eve Low, and add to the moisture source, along with increasing E-NE outflow winds for more snow at low elevations, esp for NW WA.  Southerly winds should lift snow up off the surface over Willamette Valley, Portland at that time.  It may set up a FREEZING RAIN event for Salem north into Longview.  Double oh my, if this verifies.

 

NOTE: we do not take this kind of forecast lightly, as long-term Patrons understand.  This could ALL change back to ’normal’ mild Christmas weather, as you know, but it would be unwise NOT to heed what could be a reality, esp given the large numbers of folks traveling about the area during the big holiday.  Any amount of surface snow will challenge holiday travel.  We’ll monitor this closely the next several days.

 

 

 

Lots of impactful weather on the way.  Mug up.

 

A large pool of cold air, that we have been discussing here, is beginning to settle in over the eastern Pacific / Gulf of Alaska.  The resulting broad Low pressure trough will spawn several surface Lows over the next several days, most of which will track south towards CA and southern OR.  But first, a powerful storm will arrive this weekend.  WIND will be strong - steady at 35-45 mph in places, esp over western WA, 25-35 mph over western OR.  Gusts, both regions, will likely top 45-50+ mph - meaning power outages are probable.  Plan ahead, Patron!  Rain will be heavy, with anywhere from 1.5” - 3” possible in the lowlands between now and Monday afternoon.  SNOW in the mountains will be measured by the FEET.  A range of 2 ft - 6 ft of snow is being forecast, depending on elevation.  For Patrons traveling over the passes, beware, this is NOT a joke - have winter gear with you at all times.

 

Next week will remain on the damp side, with occasional low elevation snow (500-1,000 ft) or mixed snow/rain at the surface, esp north of Seattle.  More snow in the mountains.  Wed, Thu and/or Fri Dec 15-17 mornings could be ICY, if the sky clears in your area.  Do not rule out surface snow in the Bellingham/Lynden/Abbotsford areas anytime between thisSunday and the end of next week, as a weak outflow from the Fraser River Gap could enhance that chance.

 

Mixed chance for cold showers and dry conditions for the weekend of Dec 18,19.  It will continue on the cold side.  Models have differed on the solution for Christmas week, but for now, expect conditions to remain chilly, and maybe even turn colder because of increasing COLD outflow through the Gaps (Fraser & Columbia Rivers).  Another large cold air mass will reform over the eastern Pacific, setting up increase in offshore winds at the same time as Pacific moisture rolls in — yes, the classic set up for snow and/or freezing rain.  Either way, it looks WET most of that week.  Note that some solutions place a Low pressure cell just off the coast of WA, along with a dramatic pressure difference because of COLD High pressure over inland BC.  NW WA Patrons know the drill — strong outflow, freezing temps and moisture. 

 

Christmas Eve / Day:  trend is for chilly-to-cold weather to continue and for the chance for SNOW for NW WA & BC (see above).  For SW WA, OR and portions of northern CA, very wet period on Christmas Eve; damp Christmas Day.  Snow level around 1,500-2,500 ft.   Hood River area may have frozen precip issues.  Any mountain travel will require chains/snow tires.

 

In Summary: lots of rain, wind and feet of mountain snow on the way for all of the PNW; the chance for periods of surface snow or a rain/snow mix cannot be ruled out, esp for Patrons in the far NW corner of the region.  Yep, December.

 

 

Adjustment.  Modification.  Change.  That’s what you expect when your morn’n Mug is refilled, and you settle in to read the latest forecast outlook.  Well, here goes —

 

A dusting of snow did fall over the lowlands of NW WA last Friday, as the first tease of The White arrived up north.  Will the rest of us receive snow soon?  That’s part of the modification today.  Models are pooling the cold Alaskan air over the Gulf, but dropping it farther south, OFF THE COAST, rather than turning it inland over OR & WA.  At least that has been the model run trend the past 2 days.  However, overall pattern continues to follow our previous forecasts, with that ‘less change of snow at the surface’ adjustment.  

OK, the details.  Rain today will let up later today over OR, drying out up north, too.  It will be December cool on Tue.  The next system arrives from the NW before sunrise Wed, with rain, wind, mountain snow and cooler conditions by Thu.  Don’t rule out another shot of The White north of Seattle late Thu into Fri Dec 9,10 as the pattern is quite similar to last week.  Temps over Oregon will also trend lower, so foothill snow showers are definitely possible overnight Thu into Fri.  Patrons located above 800-1,200 ft could get decent dusting of snow, esp from Salem north.  Rain/snow mix at the surface remains possible south to Eugene.

 

The weekend of Dec 11,12:  A much stronger storm, from the NW, is charting to rapidly roll into the PNW overnight Fri the 10th.  This will be a WINDY storm, so hold on.  Right now, the chance for low elevation snow after the cold front passes has lessened, as the coldest pool of air will remain offshore (heading towards CA - see below).  Snow in the mountains above 2,000 ft will be HEAVY.  NE wind is possible by Mon Dec 13, but the air mass east of the mountains is not going to be super cold (as this is not a classic Arctic shot event).  That said, as moisture moves in from the west, snow showers or rain/snow mixed will definitely be teasing lots of folks west side of the mountains, esp above 800 - 1,000 ft.  As the colder air moves south off the coast, the NE winds will let up as the PNW will dry out a little before the next storm.  Frost & Icy roads possible Wed morning, Dec 15.  The rest of that week is charting as showery, with snow above 1,000 ft and snow/rain mixed down to surface in the heavier showers remaining possible.

 

A brisk NE-E wind will pick-up through the Fraser & Columbia Gaps through the weekend of Dec 18,19 - and continuing into the start of Christmas week.  This will not be a strong outflow, but definitely one to help keep the fog bank away.  

 

Christmas Week: early peek now indicating the chance for a quick shot of rain, Tue Dec 21, then drying for a couple of days.  Could be a bit warmer, too. 

 

California:  Your turn.  Lots of RAIN, wind and relatively low elevation snow is charting for several days - beginning overnight Sunday Dec 12.  Nearly continuous blustery, WET weather through the whole week of Dec 13-17, and portions of the following weekend.  Inverted umbrella time.  Localized flooding probable.  Heed Nat’l Wx Service alerts.

 

☕️ Second Cup:  it would only take a couple hundred mile shift in the cold air over the Gulf of Alaska & eastern Pacific to bring us valley snow between now and Dec 20.  Let’s see how all this develops.  There will be FEET of snow for the Ski Resorts, bringing smiles to all those that love the Slopes. 

 

 

Waiting - for Christmas, for snow.  One we are sure of, the other, well, let’s give it a try.  Challenging forecast to ramble through, so better fill that Mug.  Ready?  

 

Mild conditions across much of the PNW will yield to a much colder, typical December pattern soon.  It will happen in stages.  First, to the relief of many in NW WA & BC, the incessant rains have let up, yielding time to repair, replace, rebuild.  That said, a weak system will move onshore Saturday, ushering in some precip, mainly north of Portland.  As that Low moves SE, colder air will fill in, setting up the chance for snow above 1,000 ft, and a snow/rain mix at the surface north of Seattle.  It will continue mild over Oregon.

 

The next, much stronger storm, will arrive from the NW by Monday morning.  This Low will generate a fair amount of rain & wind for WA & OR; the Coastal Mountains of Canada will likely get a good shot of snow.  By Tue, it will dry out during daylight hours.  

 

Second stage, in a manner of speaking, starts overnight Tue - this one will drop the freezing level rather low, esp over western WA, so expect snow showers mixing down to 1,000 ft by Wed night, and even though showers will diminish by Thu, the freezing level may drop lower still.  Portions of western WA could get some snow in the foothills, although the ground will not be frozen to hold very long.  A weak trough may arrive Thu night Dec 9, drawing in more cold air and dropping snow levels to sea level or very near so in many west side locations, esp north of Portland (or even Salem).  Not a lot of moisture with this disturbance, so rain/snow mixed at the surface will be light on Fri Dec 10; should be all snow in any showers north of Chehalis.  If not foggy in your location, a hard frost is likely Saturday morning, the 11th.  

 

Third stage.  Pooled, cold air over the Gulf of Alaska will sag south even more by Monday Dec 13.  The transition could be Sunday the 12th, with increasing chance for rain as a surface Low moves south along the coastal waters.  If the Low turns inland early (as some model runs suggest), the air mass will be cold enough for very low elevation snow, esp western WA; a few model runs track the Low farther south into the San Francisco area, keeping much of the PNW on the narrow, warmer edge of the broad upper level Low for an extra day or two.  We’ll see.  Rain and showers will persist on/off through Tue Dec 14.  

 

Middle-to-end of the week, Dec 15-17:  Fourth stage: heavy rain over central/southern OR as another push of cold air arrives from the NW.  This one may have the needed cold air aloft to spark SNOW at all elevations from Eugene north.  If not, snow will be everywhere on one’s path west, south, north or east over any terrain over 500-1,000 ft.  Chain time.  A weak series of fronts may push in from the NW, each with enough cold air support to threaten low level snow or rain/snow mixed for all areas west of the Cascades as the week ends.  

 

The weekend of Dec 18,19 is trending chilly, with snow or rain/snow mixed depending on elevation.  Precipitation could be heavy at times, which could drive snow down to the surface periodically.  

 

Second Cup: Various global weather models have been struggling on a consistent solution for the Dec 12-19 period, as we have noted here for several forecasts.  Anyway, we must report that the overall pattern remains on a trend for COLDER air to begin arriving into the PNW from the NW over the eastern Pacific (not from our usual ‘Arctic outflows’ out of the Fraser Gap or Columbia River Gorge).  Snow at the surface in the PNW requires quite a few atmospheric attributes to align just right — a few of these do properly align during the period in question.  We usually lack moisture when the air aloft is cold enough for snow.  The cycle discussed here is right on the edge of ‘cold enough’ while also having plenty of moisture.  We recall December 2008 when a similar combination was charting - and verified.  Will December 2021 be a repeat?  Close call for now.

 

For our California Patrons - heavy rain and surprisingly low elevation snow is possible during the period discussed above.  Be safe!

 

Our quip today reminds us that forecasting is always tough, even for the best of us:  “The phonograph is not of any commercial value.” -Thomas Edison, 1915.

 

 

That’s right, 'The White’ (our affectionately coined term for SNOW) is looking probable for the PNW later in December.  While others may brush aside atypical patterns that extended-range models project, The Weather Café®️ doesn’t hesitate to give Patrons the heads-up and the preparation time needed to get ready for unusual weather events.  Snow, at the surface west side of the Cascades, is, indeed, one of those unusual events worthy of preparation (and fun anticipation, for many).  So, Mug up, Patron.

 

The flooding situation up in NW WA and BC will continue to dominate everything through Wed night this week.  Later Wed, colder air aloft will help ‘hold’ some of the excessive precipitation in the mountains as snow, but still, record breaking rains have sent several rivers above flood stage, yet again.  It will dry out up north late week, as temperatures begin to lower several degrees, esp by the Dec 4,5 weekend .  

 

For a few days this week there will be a ‘zonal’ west-to-east flow of the ‘jet stream' with cooler air over WA (from roughly north of Chehalis) and mild air over OR.  That same flow will train moisture into the far NW, as noted, and keep OR & southern ID on the mild, DRY side.

 

Model runs have generally settled on the first weekend of Dec being relatively dry, as the pattern mentioned above continues.  By late Sunday or early Monday, a relatively strong ‘warm’ storm will move onshore north of Vancouver Island, ushering in a warm southerly WIND and wide-spread rain (freezing level jumps again).  Breezy, showery early Tue Dec 7 - Pearl Harbor Day - then a brief stop in the precipitation late Tue & Wed next week.

 

Now, the interesting transition.  High pressure ridge over the western Alaska (cold up there, with temps in the -35 to -42 degrees F recently), will begin to chill down the air mass over the Gulf of Alaska.  The resulting broad cold trough is modeled to begin approaching the PNW overnight Wed Dec 8.  Current model solutions continue that cold movement all the way south over WA, OR and northern CA as the week of Dec 6-9 ends.  Heavy rain, WIND and a rapidly lowering freezing level will be in play for the PNW.  In fact, by Fri the 10th, the air aloft over from NW OR north looks to turn cold enough for surface snow, esp north of Portland.  If not at the surface, then as least just a few hundred feet above sea level.  Have winter travel gear ready.  Rain over southern OR & northern CA could be quite heavy.  

 

Another pair of powerful Pacific storms may arrive from the NW on Sat/Sun and Sunday night Dec 12.  Initially, southern winds will lift the freezing level for plenty surface RAIN & mountain snow, before turning colder again, with a decent combo of moisture & temperature on the backside of the second storm to drive snow down to near, or at, sea level in many places from Eugene north.  It will be a very windy weekend, as well.  Blizzard conditions for all mountain pass travel.

 

Snow showers, if the whole pattern mentioned above verifies, will continue into Tue night, Dec 14.  Some models solutions set up a strong winter temp outflow from the Fraser Gap and Columbia River Gorge by mid-week.  Any snow is likely to hang around for a few days.  

 

Second Cup:  of course, all of the above is simply a model projection.  However, a cold, possibly surface-snow-pattern has been popping up on the wx models for quite some time now.  A few model runs build a mild High pressure ridge over the west coast, keeping the cold event away from much of the PNW for an extra few days, but none remove ‘The White’ threat completely in the time-frame of Dec 12-15.  Patrons know that over the past 27 years, these long-range projections have been accurate enough to warrant preparations, just in case.  We’ll be a few days closer to said events by our next Mug here, so stay tuned.

 

From an actual Church Bulletin: “On Sunday, a special collection will be taken to help defray the expense of the new carpet.  All those wishing to do something on the carpet, come forward and get a piece of paper."