January 2024 Weather in the PNW (Part I)

[Sunriver Snow Zone]

If 1 hour of the forum being shut down did that much, imagine what a week would do. Fred shut us down, cyall in a week!

[SouthHillFrosty]

1 minute ago, Phil said:

Rossby wave break.

Ah o ok. I got no idea what that means but I got google!

 

Rossby wave breaking (RWB) is a mechanism that causes waves to mix potential vorticity and permanently change the mean flow. It's also defined as the irreversible overturning of potential temperature contours on the tropopause. 

 

Climate.gov

Rossby waves are large, undulating movements of the ocean that stretch horizontally across the planet for hundreds of kilometers in a westward direction. They are so large and massive that they can change Earth's climate conditions. 

 

In a potential vorticity (PV) framework, Rossby wave breaking can be diagnosed from the formation of elongated PV filaments, referred to as PV streamers. These streamers can eventually split off from the main stratospheric (tropospheric) air reservoirs over the poles (tropics), known as cutoffs. 

 

Rossby wave ridges often cause above average temperatures on the ground and generally bring fair weather. Rossby wave troughs bring below average temperatures and potentially stormy weather. 

[LowerGarfield]

1 hour ago, SpaceRace22 said:

You realize Los Angeles has had measurable snow before, right?

In the hills yes. I think 1949(?) There's a semi famous photo of a few inches at UCLA.

[RentonHill]

Euro is missing a bunch of cold air in canada

[Kolk1604]

EMCWF vs GEM 

[Doinko]

Day 6

[LowerGarfield]

46 minutes ago, Front Ranger said:

These are the two prettiest maps tonight. Hopefully dom daddy Euro will follow suit.

It prefers King/Queen (Euro) titles

[lowlandsnow]

Euro is looking worse than the GEM and GFS so far

[Phil]

Dr. No living up to his name.

Will be an improvement but nothing like the GFS.

[Slushy Inch]

5 minutes ago, RentonHill said:

Euro is missing a bunch of cold air in canada

Blocking is improved

[Brian_in_Leavenworth]

38 minutes ago, Brian_in_Leavenworth said:

Kunyu model.  No joke BTW.

And here is the Kunyu "legacy".  Don't ask, I don't know

 

[Kolk1604]

1 minute ago, lowlandsnow said:

Euro is looking worse than the GEM and GFS so far

Through hour 150 they look the same 

[lowlandsnow]

1 minute ago, Kolk1604 said:

Through hour 150 they look the same 

Less cold air in Canada at a 500mb level they are pretty close though

[Doinko]

Day 7!

[Kolk1604]

Changes... theme of the night 

[RCola]

Good agreement between all three major models to hour 150. Honestly, that's what you want to see. Whatever happens beyond that will oscillate between various solutions depending on newly ingested initial data and numerical errors that accumulate in these models. I fully expect Euro will not be as extreme in the long run as the GFS or GEM, but if it's in lock step with the GFS and GEM for the first five days, that should be encouraging for us PNW folks that love colder, snowing weather. 

 

TLDR: Don't sweat it if the Euro doesn't provide the goods beyond 5 days. 

[Mid Valley Duck]

Euro trending the right direction

[Front Ranger]

12 minutes ago, RentonHill said:

Euro is missing a bunch of cold air in canada

500mb pattern still looking improved, though.

[Slushy Inch]

2 minutes ago, Doinko said:

Day 7!

Blocking massively improved on all runs.

[snow_wizard]

Big improvements on this ECMWF run as well.

[Phil]

The ECMWF is much farther east than the GFS w/ the RWB/Kona low. Not even remotely close when you extrapolate it.

[Doinko]

Day 8

[Doinko]

Just now, Doinko said:

Day 8

Lot more cold air nearby compared to other runs, hopefully that GOA block trends stronger

[snow_wizard]

7 minutes ago, Slushy Inch said:

Blocking massively improved on all runs.

Major Kona low and the connection to the NAO bock.

[Phil]

This run actually does pull off a wind reversal up to 20mb with a big Scandinavia ridge retrograding poleward.

That is a new development. Could increase amplification straight from NAM irrespective of the Pacific differences.

[Front Ranger]

4 minutes ago, Doinko said:

Day 8

Tremendous. Very close to GEM/GFS.

[Doinko]

Huge improvement
 

[Cold Snap]

If the EPS’s run to run change looks like the GEFS and CMCE that would be very nice.

[Doinko]

Wow, Day 9

[Mid Valley Duck]

Just a little improvement

[RentonHill]

Luv 2 see it

[Front Ranger]

If this works out, gotta hand it to the underappreciated CMC. It's been much more steady the past few runs.

[Slushy Inch]

1 minute ago, Doinko said:

Wow, Day 9

Oh yeah. Euro coming on board!

[MossMan]

3 minutes ago, Phil said:

The ECMWF is much farther east than the GFS w/ the RWB/Kona low. Not even remotely close when you extrapolate it.

Your girlfriend is disappointed that you spent 30 seconds with her, and the rest of the evening on forum telling everyone that it’s not coming. She wants you to go back to her and tell her that it’s coming. 

[snow_wizard]

Big time cold coming into the picture by day 8.

[Requiem]

Pretty marked improvement synoptically 

[Slushy Inch]

[SpaceRace22]

6 minutes ago, RentonHill said:

Luv 2 see it

Excuse me sir, did you not get the memo that this run is a total bust and not even close to anything good

[Kolk1604]

Not as cold as the GEM but getting there 

[snow_wizard]

4 minutes ago, Doinko said:

Wow, Day 9

Wow!