Fairly dry week ahead before plenty of rain arrives.  Mug up time.

A moderately weak Low pressure cell west of the northern CA coast will slowly work its way north, off both the OR & WA coasts today & Tue.  The result will be increasing chance for showers for the west side up into BC, mild temps and clearing, from the south, later on Tue the 19th.  Dry conditions return Wed & Thu.  Fog, too.

Late Thu night Dec 21 a system will move in from the NW.  This one will be supported by cold air aloft, so snowfall can be expected in the mountains (finally) and maybe a dusting in the coast range.  Other than a few showers Fri afternoon, the main impact will be chilly temperatures, with snow east of the Cascades.  Christmas Eve continues to trend DRY and chilly, with a brisk east wind.  A good day to put on that Christmas scarf.

🎄Christmas Day 2023:  The heavy-hitting storm pattern mentioned in our last report is being delayed a few days by the models.  Meaning, the early hours of Christmas will be dry, with increasing clouds and rain as the day unwraps.  The much-weaker-than-expected system, will move in from the west, so it is possible for freezing rain or snowflakes to fall in the eastern portions of the Columbia River Gorge Christmas night into Tue Dec 26.  Breezy west side.  The heavier rainfall will be centered on northern CA Tue.  The PNW will miss the early portion of the heavy rain, as the first half of this stormy period focuses on CA.  

Wed Dec 27 should present a very stormy night, with a Low center pressured storm at 978-982 mb moving northeast up along the coast of OR & WA.   Weather models have struggled with locations, depths, and timing of a series of strong storm centers developing along the battle zone of warm & cold air masses over the Pacific.  Let’s just say that there will be a stormy period during the week following Christmas, with WIND, rain, Cascade snow and chilly temperatures after each storm front.  This pattern is likely to remain in play through the last weekend of 2023 and early 2024.  More on this in our next report, Fri Dec 22.

Interesting that December may end up with a 'wet close', just like November.  

Yeah, ten ’til Christmas.  And, ten days ’til Nature tips the ‘bucket’ over the PNW again.  Let’s take a look ahead, shall we?  ☕️

Overall, the region will be dry through this weekend, Dec 16,17.  Biggest issue will be dense FOG, esp south of Salem and portions around the Puget Sound.  An east wind will kick-up during the weekend, keeping Portland area sunny & bright (although chilly with the wind factor); coastal areas will be absolutely stunning --> sunny & mild.  

Next week will present a few showers around the PNW as a fairly weak storm moves into California, or north along the OR coast.  Our moisture will spin up from the south.  By late Tue, it should dry out again, as the CA storm shifts farther south.  Rain likely in San Diego, late week.  We will continue dry into the big holiday weekend, other than a quick shot of clouds & showers overnight Fri for WA/BC border area.  Sunday, Christmas Eve, is trending dry.

🎄 Christmas Day.  My, oh my, will the wx change quickly.  The dry cycle will turn to heavy rainfall across the PNW as Christmas Day unfolds.  By the evening, heavy rain and blustery winds will dominate the night.  The wx will be audible -> rain on the roof, winds howling.  Buckets of Rain. Tue & Wed Dec 26,27 will be extremely WET & stormy, with the heavy rain expanding from the Bay Area in CA up into Canada.  We may get a tiny, few hour break from the steady rainfall early Wed the 27th, before what could become a MAJOR WIND EVENT Wed night into Thu, along with a return of heavy rainfall.  

For a week now, models have presented a deep Low developing far to the west of northern CA, sweeping NE to the west of OR & WA sometime the 27th-29th.  Latest model solutions continue to indicate a very deep Low (962-965 mb !!) approaching the PNW before ‘filling in’ before landfall well north of Vancouver Island.  Lots of variants to be concerned with here, mainly the track.  The system - should it verify - will be SO LOW in barometric pressure, that the wind field will be large & powerful.  If it remains well off our coast, we’ll be getting wet but not blown away, figuratively speaking; should it track closer Vancouver Is or NW WA, well, it would produce significant, powerful wind gusts.  Too early to formalize a forecast, just a ponder point for now.  We have a week or so for the computers to nail this down.  Be aware for now.

Either way, RAIN will continue ‘by the bucket’ around the PNW through the week after Christmas.  Oh, and it will turn much colder, as well.  The air mass modeled to set-up over the Gulf of Alaska could be the coldest of the season, ushering in low elevation snows around the PNW & northern CA.  New Year’s Eve could be interesting.

Repeat:  “A guy whose troubles are all behind him is probably a school bus driver.”  

Greetings from Canyonville, OR.  Fair weather ahead for much of the next 2 weeks.  Mug ☕️ ready?

Indeed.  Decent December wx ahead through much of this week and on into the weekend of Dec 16,17.  There will be a weak front pass over the PNW late Wed evening.  Most, if not all, of the precip will fall after sunset over the Olympic Range, Vancouver Is & the NW corner of WA.  Snow in the northern WA Cascades.  That system will yield to a dry Thu & Fri, with the exception of the north 1/2 of Vancouver Is.  EAST WIND really get craned up out of the Columbia River Gorge starting overnight Thu.  That wind will help mitigate fog in some locations west side.

The weekend of Dec 16,17 is now trending totally DRY for the entire PNW, with an offshore flow.  As a system moves into the region from the SW on Mon Dec 18, expect those east winds to be making a play.  Rain should return to start that week around the region.  Drying from north-to-south on Tue Dec 19 afternoon.  A large Pacific Low (trough) will settle in west of the CA coast through the rest of the week Dec 18-22.  There may be increased PNW cloudiness on Fri Dec 22, if that Low moves east over northern CA. 

For our Patrons in the Golden State -> your turn for a wet cycle.  As noted above, the large Pacific Low will spin rain fields over ALL of CA on & off from Dec 18 through Christmas.  A windy system may hit the Bay area Christmas Eve, before a deluge arrives for a very stormy Christmas Day.  A 2023 El Niño gift.

Patrons in the PNW will also get back into the wet mode sometime during the Christmas Eve weekend, depending on the track of the Low mentioned above.  Earlier model solutions pushed the storms into the PNW; but the later runs drive them into CA.  We’ll lean that way, for now.

White Watch.  🎄Christmas Day:  breezy & wet, with heavy rain & strong winds in CA, much less so over the PNW.  We’ll nail this down later, but for now, no White Christmas is charting this year, as of Dec 11.  That said, there are indications of a colder air mass working its way over the Gulf of Alaska, and eventually into the PNW (?).  We will watch closely, but there is a chance for low elevations snowfall late Dec.  Also, a wind producer may develop for the 29th.  Will that storm hit CA or the PNW? 

Overall: looks like 10-11 out of the next 14 days will present dry daylight hours for the PNW . 

We’ll catch a break from the steady rains, as systems spread out more over the next 2 weeks.  Grab your morn’n beverage.  Here goes—

Generally dry, cool day to end the week.  Another storm arrives tomorrow (Sat Dec 9).  Decent shot of rain & mountain snow, with the system moving rapidly to the east.  Sunday should be mixed, with a few showers early, then clearing by late afternoon.  Flooding issues should be minimal, given the rain break today.

Dry Run.  Looks dry & rather pleasant (for December) starting Mon Dec 11 and lasting through the entire week.  It will be chilly, with an offshore flow helping to mitigate fog issues.  Thursday could present few more clouds, and then the E-to-NE wind will increase notably on Fri, esp through the Columbia River Gorge - powerful east wind there to end the week.  Why?  A Low pressure system will be approaching from the SW, tightening the barometric gradient from east-to-west and setting up another wet Dec weekend.

The weekend of Dec 16, 17 has been trending as a ‘repeat’ of our immediate weekend.  Rain Sat, turning to showers on Sunday, with clearing.  NOTE!  There have been several model solutions indicating the potential for a fairly strong WIND PRODUCING center of Low pressure forming to the SW of OR, then moving northeast, up along the OR coast, inside of the 130º, Saturday morning.  As a result, in OR, it could be quite windy before sunrise Sat until around noon, Dec 16.  (Plenty of time for models to pin down this potential.)  Sunday should begin a clearing period, and it will be CHILLY.

Huge variation in model scenarios for the week before the long Christmas weekend.  One group of solutions suggests showery & Cool Mon Tue Dec 18,19, turning to light, steady rain for OR, heavy rain for NW WA & BC to end the week; the other indicates a dry run developing after Wed.  We’ll see.

White Watch.  (Our term for monitoring for the potential of a White Christmas around the PNW.)  As of Dec 8, there’s no indication for snow at the surface Dec 24,25.  Updates later.

There will be many days of rain coming this month.  Looks like we’ll make up for the dry November.  Flood issues remain elevated for the next several days.  Stay alert when out and about.  Here’s the run down.

Heavy rain returns later today and tonight for OR (already started in NW WA, BC) and continues through Tue.  Wed & Thu will also be quite wet, although the amount of precip will lessen after tomorrow.  Cooler air moving in later this week, which will ‘hold’ some of the precip up in the mountains as snow (which is melting fast today & Tue). Inches of precip this week.  Best pick for a mostly dry day this week would be Friday.  

The coming weekend:  more moderate rain on the way Saturday Dec 9 and continuing over much of western WA & BC through Monday Dec 11.  Oregon should experience diminishing showers Sunday & Monday, esp south of Salem.  Tuesday Dec 12 looks to be the driest day for the entire PNW.  Rain returns again Wed Dec 13.  Thu will be showery throughout the region.  

Friday Dec 15 is trending as the first of several consecutive days of moderate-to-heavy rainfall.  This time, colder air will begin to work into the picture, setting up heavy SNOW across the mountains, with a decent amount over the coast range, as well, by Monday Dec 18.  We may also see a rain/snow mix at the surface, early the week of Dec 18-22., as the models indicate a cold, moist air mass.  We’ll see.

Overall, expect plenty of rain - and flood issues - across the PNW over the first 20 days of December.  Models have been quite variable as to timing and location of the heaviest rainfall, but all show a wet cycle.  You will hear a lot about atmospheric rivers this month. 

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