PNW December 2022 - Part II

[TigerWoodsLibido]

23 minutes ago, SilverFallsAndrew said:

His forecast high is 9 degrees higher than the NWS on Tuesday and actually makes sense. 

He has improved a LOT since his Dec 2008 blunder.

[RentonHill]

2 minutes ago, Meatyorologist said:

Hate how shadowing is becoming an increasing concern for Tuesday. Weaker system means weaker lift and more meridionally oriented precip direction, and downsloping off Olympics.

Puyallup express

[snow_wizard]

5 minutes ago, SnowWillarrive said:

Heaviest snow of the night here. Already surpassed an inch. Pretty amazing out! 

I'm at about a half inch here.  Looks wintry!

[RentonHill]

[snow_wizard]

4 minutes ago, Meatyorologist said:

Hate how shadowing is becoming an increasing concern for Tuesday. Weaker system means weaker lift and more meridionally oriented precip direction, and downsloping off Olympics.

Most places still get plenty of precip.

[Requiem]

Good luck to Camas/Washougal folks if forecasts pan out. Pretty much a freeze-dry type of wind Wed-Friday. Chapstick galore!

[Prairiedog]

34 minutes ago, Perturbed Member said:

What is the PDX NWS smoking here? What warming trend?

Models through the
latter part of the week continue to show a wide spread of solutions,
which is still causing a fair amount of uncertainty within the
forecast. So, have continued to lean towards NBM model solution.
Even with a fair amount of uncertainty, an overall warming trend is
still being observed starting Thursday and continuing into the
holiday weekend.

...

However, both deterministic and ensemble models have
started to become more narrow in their solutions. Still, snow with
some freezing precipitation is expected for areas in the Northern
Willamette Valley, SW Washington and the Columbia River Gorge/Hood
River.

 

850's will be warming Thursday with freezing levels rising considerably.  GIve or take a day, much of the valley will scour or start to scour out.  I guess their definition of warming is if it's not snow then it's a warming trend.  Any other form of precip would indicate warmer air moving in.  Kind of stretching their definition.  Most of us live under incoming warm air.  Technically they're probably right saying that while we shiver.   If our precip stays as snow, then it's not a warming trend in my definition. 

[FroYoBro]

13 minutes ago, Rubus Leucodermis said:

Obviously it will never go above freezing again. Ignore the models, this cold snap is permanent. Welcome to Narnia!

You seemed confused about what people are discussing. They aren’t wishcasting. They are making a good point that the NWS discussion is really strange. 

[Cascadia_Wx]

3 minutes ago, Perturbed Member said:

 

No. Here is the EPS trend for max and min temp for Thursday and the following days. Can you show me the warming trend? I'm pretty sure if anything it is a cooling trend. 

 

You're confused about the point I'm making. The PDX AFD implies that there is a warming trend for the end of week event. This is absolutely wrong as I showed above. In fact it would be wrong even if you were talking about the weekend.

I think you are talking about the eventual warm up by this weekend. There was never any question that there would be massive WAA after this. Models have been advertising a torching 50F Christmas for a while. There is no new trend there. If anything they scaled back on that a tad. The PDX NWS is speaking nonsense no matter how you slice it.

He’s just being a pill. One of those posters you’re better off ignoring.

[KingstonWX]

Temp: 31

DP: 30

Snow seems to be letting up now, but judging from visual observation we got about half an inch or so on the ground. 

[Rubus Leucodermis]

2 minutes ago, TT-SEA said:

ECMWF shows that the it dries up the CZ overnight.  

Thank you. I was going to answer “virga,” but was afraid that would trigger an IP ban from Fred for being negative (i.e. realistic).

[snow_wizard]

The CZ ended up south of ECMWF expectations tonight so that might bode well for the next couple of days.  It seems to be understating the degree of northerly push a bit.

[VancouverIslandSouth]

1 minute ago, RentonHillTC said:

Looks worse for almost everyone even though it takes a southerly track.

[Deweydog]

22 minutes ago, Perturbed Member said:

The surface level cold with this is looking pretty top shelf no? You mentioned 2004 had 850s around -2c, seems like even on the coldest models we are 0c to start with right now. Would be nice if we could magically get those mid and upper levels a bit cooler. 

Cold air damming due to the gorge, significant wet bulbing from just how crazy dry the outflow is, hopefully some of this stuff can keep the WAA aloft at bay for a bit. 

The frontogenic properties of the gorge mouth no doubt helped a ton in 2004. WAA was stout and stalled nicely with thicknesses teetering right around the magical 540dm mark or even a little above as most places stayed snow for 8-10 hours. I doubt very much we could evolve to that protracted of a frozen column given that this will be almost entirely a low level advection while 2004 had a bit of a beefier upper level tap.

As for the surface temps, it’s hard to say. There’s some serious moving parts to getting things advecting at a low level that effectively, but the air mass and surface pressures currently shown are really prolific. Timing is gonna be key as just as we begin to see any real sign of cold continental air the mid and upper levels are trucking toward a warm frontal dynamic. Gonna be a fun few days to track it, but at the very least it’s the first event in quite a while where the PDX metro has a legit shot to be the coldest of the two big cities when all is said and done.

Edited December 19, 2022 by Deweydog

[snow_wizard]

1 minute ago, Rubus Leucodermis said:

Thank you. I was going to answer “virga,” but was afraid that would trigger an IP ban from Fred for being negative (i.e. realistic).

Usually dry air injected into a CZ causes moisture to be wrung out of it thus increasing the potential for more snowfall.  Obviously after that process it eventually dries up.  I've been around long enough to see a few of these!

[lowlandsnow]

NAM 3km is better than the 12km

[MR.SNOWMIZER]

8 minutes ago, SnowPlz said:

East kitsap in trouble again 

Will not be a problem for kitsap on Tuesday. 

[FroYoBro]

20 minutes ago, Rubus Leucodermis said:

Obviously it will never go above freezing again. Ignore the models, this cold snap is permanent. Welcome to Narnia!

You seemed confused about what people are discussing. They aren’t wishcasting. They are making a good point that the NWS discussion is really strange.

Edited December 19, 2022 by FroYoBro

[bainbridgekid]

Just measured 1.5” on the snowboard here. Didn’t hardly stick to pavement but it’s enough to be really pretty out and take my season total to 10” so I’m really pleased with things.

 

[Deweydog]

11 minutes ago, Sandy rocks said:

Why is it that it is supposed to take until Wednesday for the cold to get to the Portland area if it is already south of Seattle.  Also, the models never seem right about east Portland and the gorge moderating.  It takes the gorge winds a long time to change. I have seen it repeatedly.

It stalls, and likely even retreats somewhat before the trailing lobe dumps a lot of low level cold into the east side as the Arctic trough ejects ESE. There’s currently no conduit for cold to make it this far south, until (if the models are correct) the floodgates open through the gorge late on Wednesday or early Thursday.

[MR.SNOWMIZER]

9 minutes ago, TT-SEA said:

ECMWF shows that the it dries up the CZ overnight.  

Tim look at the radar, that bullseye spot has had radar over it for a few hrs now. Very close to where models had it.

[SnowPlz]

1 minute ago, MR.SNOWMIZER said:

Will not be a problem for kitsap on Tuesday. 

Shadowing will dry Bainbridge up 

[fubario]

The 4pm image shows the front thru the south sound. it's 37 degrees where i am. What gives?

wxloop fronts_ir 1 (washington.edu)

[MossMan]

2 minutes ago, lowlandsnow said:

NAM 3km is better than the 12km

Around 4” for my place…Better. 

[snow_wizard]

32 / dp 29 at SEA now.  The cold is really flooding in.

[MR.SNOWMIZER]

Ten degrees and a 55mph wind in Oroville.  That is serious stuff. 

Edited December 19, 2022 by MR.SNOWMIZER

[snow_wizard]

2 minutes ago, fubario said:

The 4pm image shows the front thru the south sound. it's 37 degrees where i am. What gives?

wxloop fronts_ir 1 (washington.edu)

South winds.  The north wind has punched down to Tacoma now.

[TT-SEA]

3 minutes ago, bainbridgekid said:

Just measured 1.5” on the snowboard here. Didn’t hardly stick to pavement but it’s enough to be really pretty out and take my season total to 10” so I’m really pleased with things.

 

Nice!    

3 inches here... started at 3:30 so that is an inch per hour.    Probably going to be getting lighter now though.

[lowlandsnow]

Wow 00z NAM is much colder for Puget Sound than 18z 

19 at 7 am Wednesday at Seattle vs 28 on the previous run

Oregon though is a few degrees warmer

[WildrootParable]

I'll say this: it is FRIGID out there. 32 degrees. Currently sharing my office with a potted baby fig tree I'm hoping to plant in the spring, since the unheated greenhouse wasn't doing it any favors. 

[MossMan]

Back down to 25.9 

[TT-SEA]

6 minutes ago, lowlandsnow said:

NAM 3km is better than the 12km

Looks like a similar track now to the ECMWF... but the NAM is horrible at developing lows and it overdoes cold air so not trusting this yet until the ECMWF shows it.  

[Rubus Leucodermis]

Mt. Walker cam should be in that bullseye, yet doesn’t obviously look super-snowy.

 

[Hawksfan2008]

The NAM/HRRR have different totals but where the snowfall sets up is very good for the sound. I think the 00z runs are going to be very good. 

[SilverFallsAndrew]

NAM is significantly warmer for Oregon Wednesday morning,  but it was probably quite a bit too cold on previous runs. 

[TT-SEA]

15 minutes ago, snow_wizard said:

The CZ ended up south of ECMWF expectations tonight so that might bode well for the next couple of days.  It seems to be understating the degree of northerly push a bit.

Its not really a CZ.   Or if it is one... its very disorganized.

And the ECMWF showed a large blob of precip that looks just like the radar.  

[MikeInEverett]

9 minutes ago, bainbridgekid said:

Just measured 1.5” on the snowboard here. Didn’t hardly stick to pavement but it’s enough to be really pretty out and take my season total to 10” so I’m really pleased with things.

 

Crazy how you’re 5.5” ahead of me when we’re technically in the same city

[The Cats Meow]

35 at my back door.  Lots of moisture showing up on the radar over my location but nothing falling out of the sky.

I keep squinting and looking out at the street lights.

[KingstonWX]

1 minute ago, TT-SEA said:

Its not really a CZ.   Or if it is one... its very disorganized.

And the ECMWF showed a large blob of precip that looks just like the radar.  

Eh, how is not a CZ? It may not be our typical CZ but it's definition a convergence zone IMHO. Maybe I'm dumb though. 

[TT-SEA]

1 minute ago, KingstonWX said:

Eh, how is not a CZ? It may not be our typical CZ but it's definition a convergence zone IMHO. Maybe I'm dumb though. 

Not the traditional CZ... which is a thin line of intense precip.    This thing is spread out from Everett to Olympia.   I am sure there is convergence... but its definitely not focused.