December 2020 Weather Observations for the PNW

[Brian_in_Leavenworth]

Just now, Link said:

There we go again! Day ten and the Garbage Forecasting System. I'd bet my bank on the Euro instead of wish casting. The amount of 10 day'ers we should've had a LOT more cold then we have had.

Actually the GFS has not been showing much cold at day 10.  Not for awhile.  

[TigerWoodsLibido]

[Link]

Just now, Brian_in_Leavenworth said:

Actually the GFS has not been showing much cold at day 10.  Not for awhile.  

That's when it will happen! Of course! Thanks for the heads up.

[Jesse]

First rain of the winter tonight!!

[Deweydog]

We need to get some warning shots fired off soon, guys.

[TigerWoodsLibido]

46/28 today for a 37F avg A -3.7F departure.

[Gradient Keeper]

If I remember correctly both the extended GEFS and Weeklies show a period of zonal/onshore flow before blocking takes over I think it was around the 22nd-24th and big time cold pattern ensues near/after Christmas Eve. I think that's right.

6z GFS in 5 minutes

[Meatyorologist]

The 06z run is going to send us back to the Younger Dryas era, just you watch.

[TigerWoodsLibido]

Just now, DJ Droppin said:

If I remember correctly both the extended GEFS and Weeklies show a period of zonal/onshore flow before blocking takes over I think it was around the 22nd-24th and big time cold pattern ensures near/after Christmas Eve. I think that's right.

6z GFS in 5 minutes

Let's get the tune-age going!! Got my NFL card to fill out and we are gonna score some points baby!!

[Meatyorologist]

This run is more like the 18z than the 00z so far. Though some key differences: GOA trough is further south, heights over the Bering Strait and extreme eastern Russia are much higher, western Canada is troughier, and AK is a complete reversal. Monitoring for the sake of having nothing better to do... #weenietime

[Gradient Keeper]

3 minutes ago, Meatyorologist said:

This run is more like the 18z than the 00z so far. Though some key differences: GOA trough is further south, heights over the Bering Strait and extreme eastern Russia are much higher, western Canada is troughier, and AK is a complete reversal. Monitoring for the sake of having nothing better to do... #weenietime

Yeah, definitely some key differences.

 

Day 6 (Past 4 runs)

[Meatyorologist]

Splitting away from all other solutions. Into garbage no-chance-to-verify time we go.

[Gradient Keeper]

Day 7 (Past 4 runs)

[Gradient Keeper]

3 minutes ago, Meatyorologist said:

Splitting away from all other solutions. Into garbage no-chance-to-verify time we go.

Yeah GFS run-to-run consistency Day 4-6 hasn't been the best. All blocking patterns and arctic blasts have to start somewhere, right? I mean literally it starts with one model run(EURO usually, but not always) or set of ensembles, and then a trend develops, timing moves forward, and yeah.

[Meatyorologist]

1 minute ago, DJ Droppin said:

Yeah GFS run-to-run consistency Day 4-6 hasn't been the best. All blocking patterns and arctic blasts have to start somewhere, right? I mean literally it starts with one model run(EURO usually, but not always) or set of ensembles, and then a trend develops, timing moves forward, and yeah.

I have a feeling we'll be swirling around in the toilet bowl until 4-6 days out. There is some real potential hidden here climatologically speaking given tropical forcings, and all models, even ensemble suites, are going to be be off. Just give it some time. The PV is strong right now, and models are reflective of that. As it starts weakening, things will clear up in the long range.

[Requiem]

Decent AR this run though!

[Gradient Keeper]

Just now, Meatyorologist said:

I have a feeling we'll be swirling around in the toilet bowl until 4-6 days out. There is some real potential hidden here climatologically speaking given tropical forcings, and all models, even ensemble suites, are going to be be off. Just give it some time. The PV is strong right now, and models are reflective of that. As it starts weakening, things will clear up in the long range.

Yeah that would line up with mid-December, so perhaps by the 12th the models will reflect the weakening PV, -PNA, and pattern flip.

[Gradient Keeper]

2 minutes ago, Requiem said:

Decent AR this run though!

Through Day 8 over 8" of rain central Oregon Coast.

[Meatyorologist]

Just now, DJ Droppin said:

Yeah that would line up with mid-December, so perhaps by the 12th the models will reflect the weakening PV, -PNA, and pattern flip.

That's what I'm assuming. Or we could not realize that potential. Just need to wait and see, but I'm leaning on the former. Probably 75-25.

[Gradient Keeper]

This run is at the very least active with a lot of rain and mountain snow.

[Gradient Keeper]

1 minute ago, Meatyorologist said:

That's what I'm assuming. Or we could not realize that potential. Just need to wait and see, but I'm leaning on the former. Probably 75-25.

I'm thinking it will be before Christmas.

[Meatyorologist]

Heights are higher over the arctic on this run compared to the 00z. Plus they aren't eroding. On the 00z the lobe of lower heights over the Canadian Archipelago was ejecting northward and eroding away heights to the north. This run shows more of a stationary lobe. Extreme NA is frigid by +200hr.

[Gradient Keeper]

6z GFS 10 Day GIF 500mb Height Anomaly

10 Day Rainfall, Snowfall totals

[El_Nina]

Getting a short break in the rain now, up to 0.18" today. 0.21" for December. 

[Meatyorologist]

Geez, that Archipelago lobe is off the charts. Could lower in heights even further. AK is going to get slammed by that in a few frames. Blast to the past stuff for them.

[Gradient Keeper]

Alaska, Yukon, western Northwest Territories going into the deep freezer

[Gradient Keeper]

Jeez. Alaska, Yukon big league cold.

[Meatyorologist]

1 minute ago, DJ Droppin said:

Jeez. Alaska, Yukon big league cold.

That European ridge isn't messing around, either, to say the least. Very amplified run.

[Gradient Keeper]

Seeing the bitter cold finally on our side of the pole... Just need a block and we're going to turn into ice cubes. Expect some crazy model runs ahead.

[TigerWoodsLibido]

12 minutes ago, DJ Droppin said:

Seeing the bitter cold finally on our side of the pole... Just need a block and we're going to turn into ice cubes. Expect some crazy model runs ahead.

Gonna be a fun ride. I'm out for the night. Sleep well.

[Meatyorologist]

All frames are in...

06z was an Arctic spectacle, but not much more; an amplified mess without any significant blocking. However, for the past several runs, we've seen them end off on some variation of the same scenario: copious amounts of cold on the northern end of this side of the pole, with a Pacific that seems poised to form some kind of block. A "loaded gun", if you want.

Will future runs realize this potential, or will this "inevitable" cold snap be delayed further and further out endlessly? We will find out within the next couple weeks. Until then, onto the GEFS, and on to the 12z.

[Meatyorologist]

That is a hugely impressive cold signature for AK into the Yukon and Northern BC. Zonal flow for the lowlands. Logic dictates that *any* sort of blocking pattern would be gold here. Just need to get it... 

[Meatyorologist]

A bit late, but finally some ensemble support now.

[Tyler Mode]

A timelapse of the clouds moving in from the south yesterday, 3pm-4:30 PM.

 

[Brian_in_Leavenworth]

37 minutes ago, Meatyorologist said:

A bit late, but finally some ensemble support now.

Didn't like his next tweet though. 

[weatherwonder]

winter is coming!

you should start to see some significant improvements on tonight’s 00z

[MossMan]

Light precipitation now falling and 45 degrees. 

[van city]

 

[SilverFallsAndrew]

0.74" of rain overnight.

[TT-SEA]

4 years ago this morning on 12/6/2016...