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. 

http://dlvr.it/SzfsQz

Nat’l Wx Service, TV, Radio and private forecasters are all speaking out about the large, region-wide high water event that will unfold between now and next Wed.  HEED Alerts, Watches & Warnings!  The amount of rainfall is modeled to cause rapid rise in streams, creeks & rivers over the next 5 days.  Wx models have yet to settle on which areas west of the OR, WA Cascades, and SW BC will be hardest hit, but the charts do indicate nearly everyone west of the mountains will have HIGH WATER problems - be that standing water in low-lying areas or that running down streams & rivers.  If you live or drive in a flood-prone area, be prepared to fight high water issues.  Per the Nat’l Wx Service: “Most coastal rivers will have a 40-60% chance of minor flood stages and 20-30% chance of reaching major flood stage.”  Their words, not ours.  Be Prepared.

Rather than specific details, we will present the broad picture of what will unfold the next several days.  Two to three storms (atmospheric rivers is the current phrase used) will hit the PNW starting now, with each one having the potential to present HIGHER amounts of precip than the one preceding.  They may NOT all hit in the same location (thankfully).  SNOW in the mountains, above 3,000-4,000 ft, will be measured in FEET between now and Saturday night.  Late Saturday, THAT precip will likely be melted when the heavy rains strike overnight Saturday - with freezing level jumping up over 6,000 ft.  Combine snow melt ‘water’ with inches of rain on top and, wham, flood potential down stream.  

Valley level rainfall 3” to 4” range, higher in the coast ranges.  Rain will be moderate-to-heavy starting later on Saturday through much of Sunday.  Another drenching storm or two is modeled to hit the PNW the first half of next week.  Yikes.  Urban flooding concerns are also in play - help, when safe to do so, to keep your local storm drains clear of leaves. 

Overall, things should calm down a bit by late Wed or early Thu, Dec 5,6.  It could turn totally dry for 3 days.  In fact, the latest model scenarios for next Fri through the second weekend of Dec (9,10) call for a dry spell, although chilly, weather, with a return to showers/rain sometime Mon Dec 11.  The week of Dec 11-15 has presented as a mix, with a wet day or two, separated by a dry days.  We’ll see.

The last week for the month will be rather ‘blah’ in the weather dept.  That will change.  Let’s take a look ahead.  Morn’n ☕️ Mug time.

Frosty mornings (low 20s here in the Albany area) will continue much of the week, although temps should begin to tap up a few degrees overnight.  Air quality will continue to deteriorate because of the surface cold air layer trapped under a warmer air ‘blanket’.  By Thursday the 30th, the wx pattern will shift back to the seasonal storms of fall.  Or so the models resolve at this time.

Expect showers to develop sometime during the day Thu, as the first of 3 systems arrives from off the eastern Pacific.  A 'step-up' storm with a bit more moisture and wind action will arrive Fri Dec 1.  Wet day.   The weekend looks damp, as Sat will present more rain/showers and blustery conditions.  Overnight Saturday, a 2nd 'step-up' stronger storm will move rapidly over the PNW.  WINDY.  Sunday looks blustery, chilly & damp at times.   Sunday night presents yet another system, for added precipitation & wind. Top step storm, if you will.

The first work week of December looks VERY WET & STORMY through mid-week; turning showery on Thu.  Colder, with snow levels dropping below the passes.  Fri Dec 8 is trending as the driest day of that week.  Chilly.

Models have shifted back & forth as to the weather over the weekend of Dec 9,10.  Some solutions indicate a break in the wet pattern for a couple days, before a major turn into several days of very drenching rains; other scenarios keep rain over the PNW that weekend, then a drying period thereafter for a few days.  This will get sorted out before the period arrives.  Either way, what follows warrants attention.

For several days now, model runs have presented a string of super wet storms pushing into the PNW, with heavy rainfall across the western region & down into northern CA, as well. It is the timing that varies; not the impact.  WIND will be notable as it accompanies the seemingly unending steady rain.  We’ll have to wait for verification.  Localized flooding will be likely.  

Bottom line: the dry spell of November is coming to an abrupt end.  Various model cumulatives of precip for the first 13 days of December top 6” in the valleys; nearly 10” in our foothills & Cascades; --> as much as 15 inches in the Siskiyou Mountains.  Possible, not definite.

Our pleasant holiday weekend will continue.  So, too, will the ‘run' of dry days.  Got your Mug ready?

Frosty mornings in many locations - if the sky clears - will be the play for a few more days.  Sunny, chilly, late fall afternoons.    Fog may pop in for areas mainly north of Portland, as Columbia Gorge winds will push fog aside for a few days here in NW OR.  NO RAIN is charting through the rest of November.  The weak system we noted last time for next Tue evening is going to remain offshore, tracking south into CA for some light precipitation there, primarily south of the Bay area.  While there is a chance for light showers over the PNW next Fri, as the month of December arrives, we are forecasting that the transition back to a rainy PNW will take a day or two longer — so, we’ll go with continued dry wx through all of next week.  A wet, chilly pattern should return Sat and/or Sunday, Dec 2,3.  

Starting next weekend, Dec 2,3, models suggest a weak system approaching OR from the west, with increasing clouds, slightly warmer temps and some precip.  A much stronger storm is charting to arrive later on Sunday the 3rd.  This could truly 'open the atmospheric door' for a series of storms moving in one right after the other for a week or more.  NOTE: it is possible that 1 or 2 of these storms will be WIND PRODUCERS - so we’ll monitor closely.  Also, they will be carry lots of moisture into the region, so expect lots of moderate-to-heavy rainfall once the pattern sets up by Monday Dec 4.  The good news for the snowpack is that colder air will be associated with the storms, yielding FEET of snow in the Cascades and Sierra Nevada range.  Yep, the lovely holiday break is over.

It should be noted that several model scenarios keep those wet systems offshore, tracking them into CA (think El Niño) instead of the PNW.  That said, for now, we’ll stick with the latest model runs which indicate a return to seasonal weather pattern for early Dec.  Rain, mountain snow, & windy systems from Dec 3 through at least the 15th.  

Repeat quip: “It’s quite obvious that what makes some people tick needs winding."

Well, the weekend storm was a wee bit underwhelming, but most areas did pick up some rain, with a coat of snow in the Cascades.  The holiday week is upon us, so here’s what we can expect from the sky.

Dry week ahead, aside from a weak system that will bring rain/showers after dark Tue evening (a tad earlier for Vancouver Is.).  The system does looks a little damper than suggested earlier, so Patrons in western OR can also expect wet pavement overnight Tue into early morning Wed.  This system will be a snow producer as the Low moves into the Rocky Mtn states over the holiday.  Not a super rough storm.  Holiday travel will be smooth, excluding any ’self-induced’ airline issues.

Thanksgiving Day, Black Friday, weekend:  very decent holiday weather.  Fog could be in play in the usual locations, but rain is off the charts.  Temps will trend cooler than the past few days.  Light frost possible, if the sky clears in your area, esp heading east.

The next outside chance for showers looks to be Tue Nov 28th, but that may be limited to NW WA, if that.  More likely, rain may arrive sometime Thu Nov 30, although model trends have been for that storm to become a California event, with showers possible west side for OR & WA.  We’ll get a better projection of that system after Thanksgiving.  Either way, the early days of December 2023 are looking CHILLY, wet, seasonal.   Could be a dry period after Dec 4, with an E-NE wind.