Black Friday 2024

Given the holiday, we’ll keep this short.  The PNW will be dominated.   Say what?  ☕️

Yep, dominated by High pressure.  A large, stable High pressure ridge will block all threats for precipitation around the entire PNW through roughly Sat night Dec 7.  After that, no more precip until Fri the 13th.  (Exception: the BC coast & Northern Vancouver Island will be quite wet!)  The moisture arriving late Pearl Harbor Day - Dec 7 - will be targeted mostly over the Puget Sound north. 

Generally DRY until the middle of December.  The change back to the normally cold, wet, snowy December weather will begin the weekend of Dec 14,15.  Until then, expect periods of fog & afternoon sunshine probable. 

Thanksgiving week already.  Let’s get right to the outlook.   ☕️Mug is full.

In comparison with many Thanksgiving weeks, this one will be generally pleasant and calm across the West.  Some wx issues face those traveling to the east, as the first, large-scale blast of cold Canadian air drops across much of the eastern half of the Nation.  The PNW will slowly dry-down early this week, then present a calm holiday weekend for all.  Fog possible in the usual locations.

Post-Thanksgiving week - December 2 through Fri the 6th - looks dry, except for the far NW corner of WA & Vancouver Island, southern BC, where it will turn quite WET.  Moderate-to-heavy rainfall is charting for coastal BC & the Alaskan Panhandle.  Windy, too.  For the rest of the PNW, we can expect some showers over the Puget Sound region; generally dry elsewhere.

The weekend of Dec 7,8 trends dry early Sat, turning damp overnight as a weak cold front zooms past the region.  Afterward, it could be dry again for another few days.  Models have toyed with a cold wx outbreak, but that seems to be an outlier solution that some are grabbing onto.  A Yukon Dome of 1040 mb does develop during the next couple of weeks, but drifts in the normal pattern over the lower 48, east of the Rockies.  We always monitor closely.  We will provide an update on Black Friday.

Around the PNW, lots of clean-up and power restoration in progress after the big storm this week.  What weather-card does the end of November hold?  Let’s take a look.

First of all, blustery & damp today, as the last in the current series of strong storms spins north a few hundreds miles offshore.  The atmosphere will ‘calm down’ throughout the weekend, with occasional showers and gradually cooling temperatures - a calming atmosphere, if you will, has we enter the first big holiday week of the season.  An east wind will blow down the Fraser Gap, but nothing of significance, other than a chill factor.

A stable, cool air mass will reside over the PNW next week.  Morning fog possible in the usual locations; frost probable, if the sky clears in your location, esp in the higher elevations & east of the Cascades.  Good news is that there is NO LONGER the chance for powerful east wind outflow from the Fraser Gap or Columbia Gorge during the holiday.  Models now keep the atmosphere rather tranquil for late November.  Most of the ‘winter wx’ will be in play across the plains and eastern half of the nation.  Generally DRY for the extended Thanksgiving holiday, excluding the last day.

The next chance for rain around the PNW is charting for Sunday, the 1st day of December.  Rain will advance north-to-south, covering nearly all of the PNW (including northern CA) by the afternoon.  Nothing heavy, no wind event - just a calm, cool rain.

Mon through Fri, Dec 2-6.  Rain will let up late Mon in most locations, before starting back up again on Tue.  A stronger system will dump lots of precipitation over Vancouver Island & the northern 2/3 of western WA Tue through Wed.  A couple inches possible, with most of OR only getting a small ‘clip’ of rain from that 2 day pattern.  Models continue heavy rainfall over northern Vancouver Island for the balance of the week, as the train of moisture lifts a bit farther north, compared to Mon/Tue.  Showers possible for the Puget Sound, but dry elsewhere around the region.

The weekend of Dec 7,8 is trending DRY & rather mild for early December.  

Upper-level pattern looks to have shifted away from any cold outbreaks in early December.  Let’s see if that holds.  Change is always expected.  

Where do we start?  Wow, lots of impactful weather about to hit the PNW and California.  Extra-size your morning beverage, this will take some time to absorb.  It is important.  Ready?

Probably best to break this monster forecast into 2 Parts, as each piece could have ramifications on life & property, depending on your location.  (Remember Patron, our forecast discussions cover BC, WA, OR, CA and ID, so while your specific area may not have a serious impact, another area in our region very well could.)  Enough said.

—> Biggest adjustment since our Saturday Special Statement is that the heaviest rainfall, and thus risk for MAJOR flooding, has been shifted, by the models, farther south into Northern CA, generally north of the Bay area up into the southern margin of OR.  That’s NOT to say the rest of the region will escape lots of rain and localized flooding of small creeks and urban area (leaf blockage of storm drains).  

Kuril Islands Storm - This system is continuing to develop, with the potential for center Low pressure to rapidly fall (hence the term ‘bomb cyclone' used by some) to 941-950 mb by the time it is a few hundred miles west of Vancouver Island.  That is equivalent to a major hurricane.  WINDS will be strong from the EAST, as the storm approaches, but it will NOT make landfall (thank goodness the High pressure Dome will block further eastward movement).  Interestingly, the actual Low will rotate offshore and spin farther West before returning as a weak Low to northern CA a week from now.  

WINDS.  Strong winds along the west coast from Bay area north to BC; inland S winds could gust to 40 mph.  It could be the powerful EAST winds, pushing out from that formerly Yukon Dome as it settles to our east, that could have impact.  The Gaps - Fraser & Columbia Gorge - will be very windy.  Even Cascade passes will be very windy.  Also, as the S wind clashes with the E wind along the western edge of the Cascades, winds will be intense.  Falling trees possible given saturated soils.  Power outages, too.

RAIN.  As noted above, inches of precip is likely for all locations west of the mountains between late Tue and Saturday.  Northern CA could have MAJOR ISSUES with flooding, as models indicated 7”-9” in the period.  To quote Behringer, Nat’l Wx Service, San Francsico, “getting caught up on whether a storm is a ‘bomb cyclone’ or not does not effectively communicate the associated impacts on life and property”.  OR & WA may have dodged the high risk of major flooding this time.  Generally, rain should let up a bit on Fri, except for northern CA.  The weekend is trending damp on Saturday, turning cooler & drier on Sunday.  

COASTAL EROSION.  Beach communities will experience lots of high wave action and beach erosion.  Patrons in these locations must remain alert.

Thanksgiving Week is trending drier but NOTABLY COLDER.  Yukon Domes will continue to have influence on PNW wx conditions, as a ’second’ Dome moves SE out of Canada.  The air will dry beginning Sunday, and an East wind will pick up.  Indications are that by Tue, wind will rush down the Fraser Gap (not severe!), cooling the Puget Sound region.  Not so much out of the Columbia yet.  A weak system from the west could bring rain onshore overnight Tue.  Will it be cold enough for rain/snow mixed at the surface?  We’ll see.  Anyway, on Wednesday, showers will begin to diminish late day, and the Fraser Gap winds will return - this time building into a major wind event for the northern portion of the Puget Sound.  Rain continues over western OR overnight Wed into Thanksgiving Day.

Thanksgiving.  Moderate rain all day in OR, heavy rain all day in CA, and turning COLDER in the Puget Sound area, with the Fraser Gap wind howling.  In fact, Patrons around Lynden, etc should prep for potentially damaging winds & possible power outages overnight Thanksgiving into Black Friday.  We’ll update this, of course.

Strong east winds out of the Columbia Gorge Sunday Dec 1st.  Another very WET week will follow Thanksgiving Weekend.  This time we may NOT dodge the flood-bullet.  More on that in the next report.  

Bottom line:  the blocking High pressure ridge inland is literally saving the PNW from an extremely dangerous wind event.  Potential barometric pressures - in what we have coined the “Kuril Islands Storm” - are way below that of the Columbus Day storm in 1962.  While the storm will not get too close to our coasts, it will have impact, so please heed all the watches and warnings issued by the Nat’l Wx Service. 

⚠️ YELLOW ALERT ⚠️

The “Kuril Islands Storm” (our term - see the Nov 15 discussion) is expected to arrive this Tue night & Wed with strong WINDS & HEAVY RAIN.  It may be the first in a string of storms that could cause MAJOR issues with flooding, both localized & key rivers in the Wed Nov 20 - SAT NOV 23 period.  Localized power outages are likely.  The main area of concern, as of this morning, is western OR & SW WA.  Full details will be published Monday.  A possibility, not a definite.  Plan accordingly, just in case.

As our tag line implies, interesting wx patterns are modeled to unfold in the near future.  Possibly.  Are you interested?  Grab your Fri morn’n beverage and read on - - -

Today, the middle of November already, will present as partly sunny, with a chance for a shower or two, mainly along the Cascades.  Chilly tonight, with chance for frost in the usual cold spots.  Saturday will start out dry, but another wet ‘warm front’ arrives, followed Sunday by a ‘cold front' - with plenty of cold air support -  presenting wet, wind and mountain snow that could exceed 12” by Monday afternoon.  Snow levels could drop to 1,000 - 1,500 ft in NW WA / 2,000 - 2,500 ft in OR.  Pass travelers should gear up for winter travel over “them thar hills”. 

Backstory.  Recall that key ’storm action’ happens when warm and cold air masses clash.  The boundary between the two, which we humorously speak of as ‘middle of the aisle’ being similar to the clash between political parties, is typically where surface storms form and travel along that boundary.  Well, a Low pressure system currently over northern Japan & the Kurill Islands will rapidly cross the Pacific and 'pair up' with a weak Low to the NW of Hawaii to form a POWERFUL deepening Pacific storm as it approaches the PNW.  Cold air over the Gulf of Alaska clashing with subtropical air over the central Pacific.  Remember our last forecast of the Giant High pressure Wall that models suggested would set up from the Yukon south to NV around Nov 20th?  That still develops on the long-range charts, but gets split in the ‘middle’ along its western edge (over WA, OR, northern CA) by the powerful Pacific storm approaching the PNW.   Oh, by the way, models drop the center pressure to 945-950 mb - equivalent to a Cat 3 hurricane center pressure - when the Low is a couple hundred miles west of Vancouver Island Tue night. But, will we get hit?  Sip.

Back to the forecast.  With the info above in mind, we are changing the forecast for next week.  Instead of dry, with a strong east wind, for much of the week, our weather is now charting as wet nearly every day, turning STORMY on Wed Nov 20 as that Pacific storm moves close to the PNW.   —> Fortunately, the Low will NOT make landfall, rather, it will spin around offshore as it ‘fills’ and the pressure weakens, then it will shift backwards farther west, making room for another Low that will move up from the SW.  This one is likely to generate a strong WIND FIELD for coastal WA & Vancouver Is on Fri Nov 22.  Yes, both storms will spin off moderate-to-heavy rain bands, so expect a wet week, in. general.  There will be a brisk east wind in the Columbia Gorge as the Wed storm approaches, less so for the Fraser Gap, although still windy.  South winds will be the main play in west side locations.  

The weekend of Nov 23,24 is trending with rain moving north from CA/OR border on Sat (mostly dry, mild in WA), turning WET & windy for all on Sunday - and Monday the 24th.  Return to chilly conditions, too.

Thanksgiving Week:  another interesting turn in the weather is possible.  Take another sip.  Model solutions keep a Yukon Dome of 1040+ mb forming and reforming throughout the period discussed above.  By Thanksgiving week, a Yukon Dome is modeled to drop southeast, per usual, and this time it may have an impact on the PNW in terms of the coldest wx thus far in the fall of 2024.  Winds out of the Fraser Gap could be strong by midweek; stronger still on Thanksgiving.  Chilly, but too early for forecast temp - think at least frosty mornings.   High pressure ridge of 1050+ mb possible over northern ID on Black Friday, setting up a windy but dry Thanksgiving weekend.  We’ll see.  These patterns often present snow and or freezing rain issues for west side locations.  More next forecast.