December 2023 Weather in the PNW

[Gradient Keeper]

Sorry I have been too tired to run my fb group model riding there and also here. Usually I can without any problem, but not the past several evenings. That is a monster jet for sure developing around Day 8 over the western Pacific. Day 10-16 it becomes very consolidated nearly stretching across the entire Pacific. Maybe a real active period hammers us before and after Christmas. I would much rather see that jet being held back retracted well west of the dateline/180 W and a big ridge over Alaska. Maybe that'll happen. I believe it could. I could foresee this progression in 7-10 days. Another thought is jet suppression. We would likely have strong high pressure over us, so a big cold pool could be in play with many days of east winds. Just add moisture after that point to make things interesting.

6z GFS in 1 hour 40 minutes

[Cascadia_Wx]

Managed to sneak down to 34 here by midnight, for a 46/34 spread today. Some frost out there at the moment.

[ShawniganLake]

Down to 33F earlier but up to 36 now.  Too warm. It’s over.   

[Gradient Keeper]

00z GFS, GEM, ECMWF

Check this out. This is the 250mb jet stream at Day 10. How's that for consistency? All models are in solid agreement showing a very strong, consolidated jet over the western Pacific. Even other features such as the deep low over the western Aleutians and central Pacific ridge are so similar I can only find minor differences at best. I can't remember ANY other time all the models were in agreement long range this far our. The historic December 2008 arctic blast and snowpocalypse was a first and uncanny as most models came into solid agreement 7 to 8 days out. BUT to see this at Day 10? This is bizarre. Let's see how models handle this powerful jet stream over the next 5-7 days.

[Gradient Keeper]

Pineapple express anyone? Textbook.

[Cold Snap]

Down to 31 here.

[TigerWoodsLibido]

33F and partly cloudy.

[Deweydog]

Had to turn on the deFROSTer this morning!

[TigerWoodsLibido]

31F. 14th freeze of the regular season.

[Gradient Keeper]

Radar Update
12/9/23 5:57 am

A wall of moderate to heavy rain lurks just offshore.

[Phil]

18 hours ago, TT-SEA said:

That is not summer-like.   

It is in north bend.

18 hours ago, Front Ranger said:

Certainly possible. Generally, mega +PNA is not great for CA/SW storminess.

It can be very good w/ an augmented STJ. Depends how far east the AL is. 

15 hours ago, MossMan said:

We weren’t quite to this current level just yet, but things were very bleak here in January 2019…And Phil was keeping us updated regularly on the hopelessness…Just like right now.

That SSW caught me (and all of you) off guard.

That was barely a niño, though. This one will be harder to overcome.

[TT-SEA]

3 hours ago, Deweydog said:

Had to turn on the deFROSTer this morning!

At 3 a.m.?   

[TT-SEA]

5 hours ago, ShawniganLake said:

Down to 33F earlier but up to 36 now.  Too warm. It’s over.   

41 here this morning.   

[SilverFallsAndrew]

28 minutes ago, Gradient Keeper said:

Radar Update
12/9/23 5:57 am

A wall of moderate to heavy rain lurks just offshore.

More blessings

[SilverFallsAndrew]

Got down to 30 here. 

[RayRay]

33 here

[TT-SEA]

It's 38 at SEA now... but the ECMWF shows only mid 30s by early afternoon.   And then mid 40s late this evening.   Going to be a strange temp progression today.   The complete opposite of normal with the coldest temps in the middle of the day.

[Phil]

14 hours ago, Deweydog said:

One thing worth mentioning is the fact there was a PV split/major warming event in January 2003…

Tbf it was so transient I don’t consider it a SSW. It only registers as a wind reversal because the PV was displaced so far off the pole..it remained intact the entire time.

[The Winter Warlock]

I am looking forward to the snow today.

[Phil]

11 hours ago, Cascadia_Wx said:

I appreciate that, but it’s best to just avoid adding fuel to the fire period.

To be fair it was the first niño since the 19th century to go nuts in February. I certainly didn’t have that on my calendar.

Of course that was barely a niño so I should’ve been open to the possibility given the prolific SSW. As you said, hindsight is 20-19.

[Ray]

33 degrees this morning and frost starting to form on the grass.  As much as I would like to see snow I just don't think it will be realistic today.

[TT-SEA]

5 hours ago, Gradient Keeper said:

Pineapple express anyone? Textbook.

This is sort of the opposite of the AR event earlier this week though where it was very warm ahead of the moisture and during the heavy rain and then got colder afterwards.    The precip with this event also moves south like the one earlier this week but it gets warmer... tomorrow is in the low 50s.     Sort of strange but its happened before.   I would expect the precip to be moving from south to north given that temp progression.

[TT-SEA]

Latest GFS and ECMWF snow maps... if the GFS is right even central King County is going to see accumulating snow.   Worth mentioning the GFS has been trending snowier as the event approaches.

[Phil]

9 hours ago, RentonHill said:

Nice jet extenze-ion

 

Putin’s cold (SHD) is what’s accelerating the jet. 

8 hours ago, ShawniganLake said:

We will see what happens when it retracts.  

A blizzard at my house, hopefully.

7 hours ago, snow_wizard said:

I have to say the ECWF is playing with fire on this run.  The later part looks like a very Ninoish pattern.  The odd thing is it's so early int he season.  Usually that pattern doesn't set up until the second half of the winter.

This honestly might be there most perfectly coupled niño I can recall. Atmosphere and ocean are in lockstep.

[GHweatherChris]

 

[SilverFallsAndrew]

Up to 43 at PDX. Speaking of PDX. They are running like 6F ahead of their all time warmest December. 

[Cascadia_Wx]

6 minutes ago, SilverFallsAndrew said:

Up to 43 at PDX. Speaking of PDX. They are running like 6F ahead of their all time warmest December. 

At least they fell to 35 earlier in the night.

This shouldn’t come as much of a surprise, but pretty much every station in the Willamette Valley, NW Oregon and SW Washington just had their warmest first week of December on record. This includes the stations going back to the 19th century. And for a few it wasn’t even close.

Edited December 9, 2023 by Cascadia_Wx

[Andstorm]

3 minutes ago, SilverFallsAndrew said:

Up to 43 at PDX. Speaking of PDX. They are running like 6F ahead of their all time warmest December. 

Yeah it’s rough. And typically when this happens there is some faint eye candy in the models. not this December so far. It’s been years since we had an active January so hoping we get something. 

[SilverFallsAndrew]

13 minutes ago, Cascadia_Wx said:

At least they fell to 35 earlier in the night.

This shouldn’t come as much of a surprise, but pretty much every station in the Willamette Valley, NW Oregon and SW Washington just had their warmest first week of December on record. This includes the stations going back to the 19th century. And for a few it wasn’t even close.

Not surprised at all. It was brutal. It’s tough to get +20 departures in this climate. Especially in the winter, but a few stations pulled it off or at least got very close. SLE actually pulled off a negative departure yesterday. But it’s going to take some legitimate below average weather to pull these monthly means down below all time record levels. Probably more likely down the valley as inversions are more prevalent there. The ship may have already sailed for PDX. 

[SilverFallsAndrew]

15 minutes ago, Andstorm said:

Yeah it’s rough. And typically when this happens there is some faint eye candy in the models. not this December so far. It’s been years since we had an active January so hoping we get something. 

I would love to see the worm turn, but it may just not be our year. That 2014-16 period was so bad I think it bought us a little time, but this is looking like one of those years we rue. A good opportunity to focus on work and our personal lives and regroup for next winter which is looking increasingly likely to be at least a weak Nina. The worm will turn, but probably not this winter. 

[TT-SEA]

1 minute ago, SilverFallsAndrew said:

Not surprised at all. It was brutal. It’s tough to get +20 departures in this climate. Especially in the winter, but a few stations pulled it off or at least got very close. SLE actually pulled off a negative departure yesterday. But it’s going to take some legitimate below average weather to pull these monthly means down below all time record levels. Probably more likely down the valley as inversions are more prevalent there. The ship may have already sailed for PDX. 

SEA ran some impressive warm departures during the first 10 days of December in 2015.    Every day from Dec 1-10  was 50+ degrees and they hit 60 twice in that period.   59 was the peak there with the warm AR event earlier this week.   It happens and also makes getting excessive rain much easier.  

[SilverFallsAndrew]

3 minutes ago, TT-SEA said:

SEA ran some impressive warm departures during the first 10 days of December in 2015.    Every day from Dec 1-10  was 50+ degrees and they hit 60 twice in that period.   59 was the peak there with the warm AR event earlier this week.   It happens and also makes getting excessive rain much easier.  

Cool story  

[TT-SEA]

3 minutes ago, SilverFallsAndrew said:

Cool story  

So it was much colder farther south from Dec 1-10 in 2015?    

Just checked and I see some 60s at PDX and SLE.    SLE had a 62/58 day on 12/8/15 for a +19 departure.   Also had 3 days in a row at 60+ degrees.  

[TacomaWx]

Hadn’t really been paying attention to the snow chances but it Seems like a really odd setup for snow on the I-5 corridor this morning. Probably will snow out in kitsap atleast. 

[SilverFallsAndrew]

8 minutes ago, TT-SEA said:

So it was much colder farther south from Dec 1-10 in 2015?    

Just checked and I see some 60s at PDX and SLE.    SLE had a 62/58 day on 12/8/15 for a +19 departure.   Also had 3 days in a row at 60+ degrees.  

What is your f****** point? Never made a comparison with 2015. Which also is not the warmest December on record at PDX. You may remember there was solidly chilly weather later in the month. 

Edited December 9, 2023 by SilverFallsAndrew

[Blizzard777]

35* & wind calm Federal Way

I’m down in PdX though. Gorgeous sunrise as it undercut the incoming storm clouds this morning.
 Looking forward to the interesting weather reports from you all today….have a good one 

 

[TT-SEA]

9 minutes ago, SilverFallsAndrew said:

What is your f****** point? 

Just a general response to the conversation about it being the warmest early December ever and it was not even close.   And of course this is the type of set up we needed to fill the reservoirs and reduce the drought, but a couple of you talk about it like it was so horrible and brutal.   Obviously now we need to build snowpack.   

[SouthHillFrosty]

Temps have shot up from 34 to 38 last hour. Precip looks good moving onshore!!

[TT-SEA]

6 minutes ago, SouthHillFrosty said:

Temps have shot up from 34 to 38 last hour. Precip looks good moving onshore!!

Up to 44 in North Bend now... not feeling it here but temp can crash fast with heavy precip.

[GHweatherChris]

Splat test confirmed, temp was 37, down to 35.