November 2023 Weather in the PNW

[Gradient Keeper]

00z GFS re-cap. 10 Day GIFs: 500mb Height Anomaly, 850mb Temps, 1000-500mb Thickness/MSLP/Precip

[Gradient Keeper]

00z GFS 10 Day Rainfall, Snowfall totals

[snow_wizard]

The control on yesterdays GEFS looks pretty fun in late December.

[Gradient Keeper]

2 minutes ago, snow_wizard said:

The control on yesterdays GEFS looks pretty fun in late December.

Jet suppression!

00z ECMWF in 55 minutes

[SilverFallsAndrew]

Could be a December to remember!

[Gradient Keeper]

Just for fun. 00z GFS Day 10-16 Rainfall, Snowfall totals

[LowerGarfield]

Down to 29F.

[snow_wizard]

30 minutes ago, SilverFallsAndrew said:

Could be a December to remember!

There are some really good Nino Decembers in the past.

1968 and 1972.  Even 2009 had near top tier cold, 1965 had a white Christmas in some places, and 1884 was the all time greatest December.

[Gradient Keeper]

00z ECMWF Day 1

[TigerWoodsLibido]

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Day 2

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Day 3

[Gradient Keeper]

32.7 with fog trying to form now.

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Day 4

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Day 5

[snow_wizard]

It's quite impressive how perfectly this coming inversion episode evolves.  Just the right surface pressure gradients for days to keep most places cold.

[SilverFallsAndrew]

1 minute ago, snow_wizard said:

It's quite impressive how perfectly this coming inversion episode evolves.  Just the right surface pressure gradients for days to keep most places cold.

Yeah I’m not overly excited about some chilly days in late November, but it will be nice, I agree. 

[MossMan]

31! 

[Brian_in_Leavenworth]

Apart from dangerous weather, inversions are the worst.  Who cares about fake cold?  If it's not snowing or stormy, at least be sunny.   We live in a beautiful part of the world, I'd like to see it instead of fog.  

[snow_wizard]

The top 5 analogs from day on tonight's GFS are from La Nina years.  Weird!

[Gradient Keeper]

Day 6

[snow_wizard]

4 minutes ago, SilverFallsAndrew said:

Yeah I’m not overly excited about some chilly days in late November, but it will be nice, I agree. 

This is getting the cold season off to a good start stat wise at least.

[snow_wizard]

1 minute ago, Gradient Keeper said:

Day 6

That low near Hawaii is becoming more of a thing all the time.

[snow_wizard]

2 minutes ago, Brian_in_Leavenworth said:

Apart from dangerous weather, inversions are the worst.  Who cares about fake cold?  If it's not snowing or stormy, at least be sunny.   We live in a beautiful part of the world, I'd like to see it instead of fog.  

Easy for you to say.  I will take cold in any way shape or form.

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Day 7

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Day 8

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Day 9'er

[AbbyJr]

2 hours ago, Phil said:

It can. But doesn’t guarantee it, will need both the Pacific/PNA and NATL/NAO working constructively to drive an arctic airmass into W-Canada this year.

Easier to stumble into such a pattern under a -ENSO LP like the last three years. Now the El Niño base state is so entrenched it’ll probably need to be a hail mary of sorts.

Thanks Phil. The -NOA clearly worked out in 1968/69. But there was also an unusually early SSW event that winter, which as you said, likely was a significant aid in driving the -PNA pattern. The thing about the 1968/69 winter that I find so interesting is just how long the patten was locked in. The initial blast of arctic air came at the end of December followed by a brief warmup in early January. But by mid January, the region was hit with reload after reload of arctic air. Looking at the 500mb reanalysis, it looked like one of the most stable La Niña patterns I've ever seen. That -PNA/-NAO was almost a permanent feature for most of January that year and there was very little shift in the trajectory of the blocking pattern as the ridge bridge remained in place with the polar low settled in over the PNW. It was one of the longest arctic outbreaks in the region. I'm just curious if you have any idea what caused the pattern to lock in for so long? Sure would be epic to see a repeat but unforunately, I'm not expecting to see one anytime soon. The closest we have come were those epic GFS runs back in January 2020. They ended up being an extreme outlier that did not verify, but for nearly a week, they were constantly showing a 1969 pattern. I remember that model ride just hoping the GFS would be right for once and of course it was out to lunch. Darn.

[Gradient Keeper]

Day 10

[BLI snowman]

2 hours ago, Phil said:

I wouldn’t expect much (if any) top-tier cold on our side of the pole this winter anyway.

But what constitutes a torch in central Canada is significant colder than average for a majority of the CONUS. Maybe not in Fargo ND, but most other places.  

True, but the mechanisms that drive central Canadian torching are often the same kind of zonal/Pac Jet fueled patterns that won't be delivering much arctic air south of the border anyways. Obviously the southern tier can still clean up in the absolute right circumstances, like January-February 2010.

Edited November 24, 2023 by BLI snowman

[Gradient Keeper]

00z ECMWF re-cap. 10 Day GIFs: 500mb Height Anomaly, 850mb Temps, 1000-500mb Thickness/MSLP/Precip

[Gradient Keeper]

00z ECMWF 10 Day Rainfall, Snowfall totals

[TigerWoodsLibido]

Down to 31F so we will have ourselves a back to back night and early morning with freezes. Freeze #7 and 8.

[MossMan]

30.6

[Gradient Keeper]

30.2

[snow_wizard]

Already down to 29.8 tonight.

[snow_wizard]

1 hour ago, BLI snowman said:

True, but the mechanisms that drive central Canadian torching are often the same kind of zonal/Pac Jet fueled patterns that won't be delivering much arctic air south of the border anyways. Obviously the southern tier can still clean up in the absolute right circumstances, like January-February 2010.

I have yet to see any signs of a strong PJ this winter.

[Gradient Keeper]

29.7 brrr

[Gradient Keeper]

00z GEFS, EPS - Portland. 850mb Temps, Precip

[Gradient Keeper]

00z GEFS, EPS - Seattle. 850mb Temps, Precip