PNW December 2022 - Part II

[Terreboner]

Since us Americans can't make a decent model, what do you say we gather the troops and physically push that Hudson Bay high into Kansas.

[Deweydog]

2 minutes ago, TT-SEA said:

What if the 00Z run notches back?   Then we have to start all over.  

That’s kind of been the theme. Wobbles vs. trends.

[Gummy]

This cooler airmass being modeled is what Seattle needed a few weeks ago when we had our 1-2 inches of 33 degree slush.

[MWG]

Never made it to 40 even with clearing so high of 39F for the day.

[Front Ranger]

5 hours ago, Cascadia_Wx said:

Well there is clearly some reason it’s been over three decades since our last major regional airmass. And it goes beyond blocking not being stable enough or whatever the laundry list of reasons every brush with a major airmass has failed to penetrate in recent decades. I feel like a big issue is airmasses have lost the ability to force the upper level pattern the way they used to. 

I feel like a lot of folks here view the warming climate more linear, like we can still get all the same patterns but they will just be a degree or two warmer. I feel like it’s not too much of a stretch to imagine it would go beyond that and it change the pattern tendencies themselves. Anyway, admittedly a lot of this is above my pay grade, I’m just throwing ideas at the wall. But I don’t think it should be so swiftly dismissed. The proof is in our observed weather and how it’s changed over the decades, across all seasons.

Yeah, I mean there is no way to really prove if or how climate change could be behind the lack of top tier blocking patterns. At least I haven't heard a plausible explanation.

But the fact remains that you still need the same basic ingredients as you did 40, 60, 100 years ago to get a big Arctic blast in the PNW. A stable block offshore to deliver the airmass is a major one. And for whatever reason, the weak and transient block is apparently what we're getting, and that same pattern would not have delivered anything close to a major Arctic air mass in the 1950s.

None of the top 10 CPC pattern analogs Justin pointed to yesterday delivered anything great, and there were quite a few older ones in there - top among them being from 1958.

Had we gotten a much stronger and more stable block, temperatures would have gotten much colder (though probably not as cold as in the 1950s). I have yet to see that type of pattern deliver a result like it looks like we'll see this time around in the PNW.

That much we can say with certainty...a lot of the rest related to climate change (or not) is just speculative.

[TT-SEA]

1 minute ago, snow_wizard said:

Every ECMWF run today has pushed the colder 850s further and further south.  The 18z run gets cold well down into NW OR.  This is pretty real guys.

There have only been 2 runs today.

The 12Z actually notched it north from the 06Z run (using Sunday evening which was the end of the 06Z run) and the 18Z notched it south.    The 18Z is almost identical to the 06Z run so technically it was a wash on the ECMWF today. 

[Terreboner]

18.4 here already but the fog is almost here.

[MossMan]

2 minutes ago, snow_wizard said:

Every ECMWF run today has pushed the colder 850s further and further south.  The 18z run gets cold well down into NW OR.  This is pretty real guys.

Jim, you need to quit your job so you can be on the forum all day to help offset the negative weenies during the day (mostly talking about myself) 

[Cold Snap]

21 minutes ago, TT-SEA said:

Some c-zone snow on Sunday night... 

A lot of models are showing me in the sweet spot for the convergence zone. Including this one from the UW dawgcast.

[Dave]

35 degrees with clear skies. In my somewhat sun sheltered area this time of year, I avoided the horror of a 40+ day.

On a side note, I just took a leak and there was split flow. Probably a sign of things to come. 

[Front Ranger]

8 minutes ago, Front Ranger said:

Yeah, I mean there is no way to really prove if or how climate change could be behind the lack of top tier blocking patterns. At least I haven't heard a plausible explanation.

But the fact remains that you still need the same basic ingredients as you did 40, 60, 100 years ago to get a big Arctic blast in the PNW. A stable block offshore to deliver the airmass is a major one. And for whatever reason, the weak and transient block is apparently what we're getting, and that same pattern would not have delivered anything close to a major Arctic air mass in the 1950s.

None of the top 10 CPC pattern analogs Justin pointed to yesterday delivered anything great, and there were quite a few older ones in there - top among them being from 1958.

Had we gotten a much stronger and more stable block, temperatures would have gotten much colder (though probably not as cold as in the 1950s). I have yet to see that type of pattern deliver a result like it looks like we'll see this time around in the PNW.

That much we can say with certainty...a lot of the rest related to climate change (or not) is just speculative.

I'd also add that it's human nature to want to understand the "why" when something goes wrong - or keeps going wrong, in the case of these patterns not working out for top tier blasts in the PNW. Don't blame anyone for that.

Climate change offers a partial explanation for the long term trend and recent lack of very cold air masses overall, but it doesn't offer any logical explanation (that I can see) for why this particular pattern failed to deliver. The answer is simply it was not historically the type of pattern that delivers.

[TT-SEA]

The deeper push on recent model runs early in the week is related to less digging offshore.   Its the digging offshore that creates the modeled snow magic for next week.   The 18Z ECMWF shifted a little east again with less digging offshore.  

The 18Z ICON showed much more digging offshore on Monday and this resulted in a snowstorm on Tuesday when it wraps around.    The ECMWF is not digging as much offshore... so its colder initially but that solution is what robs us of the snowy fun and subsequent overrunning event.  

For the snowy solution... I think we want less depth on Sunday and Monday with the west side of the trough digging well offshore.  

Examples below... the 18Z ICON for Monday afternoon and the 12Z ECMWF at the same time.   The ICON went crazy on Tuesday.

[SouthHillFrosty]

Metro boomin new album is

[TT-SEA]

1 minute ago, NWbyNW said:

It's as if all the local Seattle news channels are colluding to report the same story or something...

 

 

Of course this is all actually true given that Sunday and Monday have trended colder.  Regular folks probably did not see those crazy ECMWF runs and just know its going to get colder and probably snow.    

[TacomaWx]

Is the 18z euro done running already? How’d it look overall through hour 144?

[runninthruda206]

3 minutes ago, SouthHillFrosty said:

Metro boomin new album is

My man

[NWbyNW]

It's as if all the local Seattle news channels are colluding to report the same story or something...

[Nov1985]

6 minutes ago, Cold Snap said:

A lot of models are showing me in the sweet spot for the convergence zone. Including this one from the UW dawgcast.

It's you an me man. A week of hard work to get here, but we'll see some flakes D****T! 

[TigerWoodsLibido]

Looks like a 41F/31F day. Pretty solid.

Down to 36F with more borderline freezing fog likely overnight.

[Winterdog]

31F after a high of 34F.  Had a low of 24.6F.  Pretty chilly out there.

[Terreboner]

17.6 and the fog is here.  It's actually a very cool scene, wish it wasn't all going away.

[SilverFallsAndrew]

8 minutes ago, snow_wizard said:

Every ECMWF run today has pushed the colder 850s further and further south.  The 18z run gets cold well down into NW OR.  This is pretty real guys.

Thoughts. It's nice to see the colder air moving further south. The problem we are dealing with now isn't even the arctic front not moving south, though obviously its not powering south like that crazy run a few days ago showed. Its the energy developing up north or moving north towards Vancouver Island (Depending on your model of choice.), which pushes all the cold air out immediate, and prevents any kind of offshore flow from developing. 

 

[Jbolin]

21 minutes ago, TT-SEA said:

What if the 00Z run notches back?   Then we have to start all over.  

Two steps forward, one step back, 

[TacomaWx]

42/33 here. 

[Front Ranger]

At least some cold and lowland snowfall south of Bellingham still looks pretty likely. 

I'm pretty frustrated with this pattern, too, FWIW. Was supposed to get 2-4" the other night and got nothing, while 10 miles east got hit good. And the models have been promising major Arctic air here 7 days out for 4 days now...keeps getting pushed back.

[TT-SEA]

4 minutes ago, TacomaWx said:

Is the 18z euro done running already? How’d it look overall through hour 144?

18Z run goes through 90 hours.   EPS goes through 144 hours.

[Rubus Leucodermis]

43/30°F for the day here.

[snow_wizard]

The really interesting thing about the 18z ECMWF is the base of the block is stronger at hour 90 than previous runs at the same time.  This still has room for more improvement.

[SilverFallsAndrew]

Wife said it was 28 at 4:30. She's expecting a cold night, I hope so because I'm 2000 miles away.

[T-Town]

1 hour ago, Deweydog said:

Isaac!!

[TacomaWx]

1 minute ago, TT-SEA said:

18Z run goes through 90 hours.   EPS goes through 144 hours.

Ah I forgot about that well hopefully the EPS improves…but I’m not expecting things to really turn around big on the models the next couple days. 

[Jbolin]

19 minutes ago, TT-SEA said:

There have only been 2 runs today.

The 12Z actually notched it north from the 06Z run (using Sunday evening which was the end of the 06Z run) and the 18Z notched it south.    The 18Z is almost identical to the 06Z run so technically it was a wash on the ECMWF today. 

Grrrrrrr, GOD, I F***ing hate NOT hating you. 

[Cascadia_Wx]

13 minutes ago, Front Ranger said:

Yeah, I mean there is no way to really prove if or how climate change could be behind the lack of top tier blocking patterns. At least I haven't heard a plausible explanation.

But the fact remains that you still need the same basic ingredients as you did 40, 60, 100 years ago to get a big Arctic blast in the PNW. A stable block offshore to deliver the airmass is a major one. And for whatever reason, the weak and transient block is apparently what we're getting, and that same pattern would not have delivered anything close to a major Arctic air mass in the 1950s.

Had we gotten a much stronger and more stable block, temperatures would have gotten much colder (though probably not as cold as in the 1950s). I have yet to see that type of pattern deliver a result like it looks like we'll see this time around in the PNW.

That much we can say with certainty...a lot of the rest related to climate change (or not) is just speculative.

You’re a little late to the party and I really don’t feel like getting dogpiled again but my point was that it’s possible that a warming climate is, for whatever reason, making episodes where the block/movement of the cold airmass evolves favorably for us significantly less likely. Like there is a threshold somewhere and we have dropped off the cliff as far as the odds of getting a chunk of the PV parked over say Hermiston. Ironically I think it was Dewey who said years ago that more anemic cold airmasses don’t have the ability to force the pattern the way they used to. Even when blocking has evolved favorably in recent years we still get these trickle/slow bleeds of cold air regionally. Even events we are pining over the demise of like December 2009 had this problem.

[SilverFallsAndrew]

11 minutes ago, TT-SEA said:

The deeper push on recent model runs early in the week is related to less digging offshore.   Its the digging offshore that creates the modeled snow magic for next week.   The 18Z ECMWF shifted a little east again with less digging offshore.  

The 18Z ICON showed much more digging offshore on Monday and this resulted in a snowstorm on Tuesday when it wraps around.    The ECMWF is not digging as much offshore... so its colder initially but that solution is what robs us of the snowy fun and subsequent overrunning event.  

For the snowy solution... I think we want less depth on Sunday and Monday with the west side of the trough digging well offshore.  

Examples below... the 18Z ICON for Monday afternoon and the 12Z ECMWF at the same time.   The ICON went crazy on Tuesday.

You are 100% right. We actually want the southern energy phased into the bottom of that trough. On a solution like the EURO shows, the stronger low development will be way further north, which will continue the momentum of pushing the arctic air off the the east quicker. 

[Cloud]

35 here at Renton Highlands…. Really plummets after sunset and a cold night on tap.

[smerfylicious]

21 minutes ago, Cold Snap said:

A lot of models are showing me in the sweet spot for the convergence zone. Including this one from the UW dawgcast.

I'm in the dark blue! 

[snow_wizard]

1 minute ago, Front Ranger said:

At least some cold and lowland snowfall south of Bellingham still looks pretty likely. 

I'm pretty frustrated with this pattern, too, FWIW. Was supposed to get 2-4" the other night and got nothing, while 10 miles east got hit good. And the models have been promising major Arctic air here 7 days out for 4 days now...keeps getting pushed back.

Th uncertainty with this is ridiculous.  The models seem confused as to whether to keep most of the cold in Canada or to push it south over most of the US.

[Cascadia_Wx]

42/24 day here today. Very pretty day, frost stuck around all afternoon in the shade. Nice and wintery.

The possible return of the jet stream next week isn’t all doom and gloom, but I think a lot of folks are worried that we are going to torch mercilessly since that’s what usually happens these days after we manage to string together 4-6 weeks of coolish weather. It would be nice if we could get some decent storms and mountain snow without things going off the rails mild and decimating the snowpack/prompting out of season cherry blooms. Then maybe some blocking again a couple weeks down the road, not 6-8 ala 2006.

[MossMan]

Well if anyone wants more sadness and negativity…Head on over to the sports thread, the game is about to start! 

[T-Town]

Nice sunset tonight. First in a while.