December Weather In the PNW

[van city]

[MossMan]

Got back from Yakima (brrr) Snoqualmie Pass was gorgeous, now in the car with my wife and daughter right now heading to Christmas dinner number 1.... should I tell them?

[Bryant]

Got back from Yakima (brrr) Snoqualmie Pass was gorgeous, now in the car with my wife and daughter right now heading to Christmas dinner number 1.... should I tell them?

Of course! Lol

[umadbro]

Just got home from work. 33 and still socked in with fog.

[MossMan]

Of course! Lol

Okay I’m telling them it will be a white Christmas!

[Jbolin]

Got back from Yakima (brrr) Snoqualmie Pass was gorgeous, now in the car with my wife and daughter right now heading to Christmas dinner number 1.... should I tell them?

NO

[Timmy]

When are the gorge gradients supposed to turn offshore. Looks like it has been increasing on shore all day

[Brian_in_Leavenworth]

Got back from Yakima (brrr) Snoqualmie Pass was gorgeous, now in the car with my wife and daughter right now heading to Christmas dinner number 1.... should I tell them?

Scott Sistek has a good write up about it at the KOMO web site, so it is public.  Show them that, it is realistic and easy to understand.  Of course, for those who really want a White Christmas, we almost always have one here on the East Slopes, and this year is no exception.

http://komonews.com/news/local/dreams-of-white-christmas-not-so-far-fetched-now-as-snow-chance-pops-into-forecast

[Bryant]

NO

Sorry, beat you to it... I have nothing to lose lol

[Perturbed Member]

Pretty good summary by PDX NWS. Really hope the euro comes through, screw the crappy GFS solution. That secondary southern low on the euro seems key to maintaining offshore gradients and keeping the 925s and 850s just cool enough. Hopefully we start seeing other models showing that.

 

Hail king EURO.

 

 

Sunday through Thursday...With the high amplitude
pattern the models are really struggling to come to any consensus
in the longer term and the ensembles are showing tremendous spread.
All them models tend to bring a shortwave through the ridge position
early Sunday morning. The GFS has a weaker trough and the ECMWF is
stronger. Both models have held onto their respective solutions over
the past several runs. I prefer the ECMWF solution and have trended
the forecast that way. This means precipitation would likely spread
to the coast and even inland by Sunday morning. Temperatures will
probably be below freezing in most of the Willamette Valley. This
brings a threat of freezing rain to most of the valley Sunday but
the ECMWF also has a stronger surface low which moves toward the
central coast of Oregon. This increases the wrap around flow to the
northeast and over the northern Willamette Valley and into SW
Washington with 925 mb and 850 mb temperatures below freezing. This
could bring enough cold air down to keep precipitation as snow or it
could end up being too shallow with freezing rain. A very difficult
forecast at this point. To make it even more complex the ECMWF digs
the secondary low along the Washington coast and over Tillamook by
Monday morning. The enhanced easterly flow could allow for snow to
persist in the North Willamette Valley and Clark county into Monday.
The GFS solution does not have this secondary surface feature and
weakens the gradient which would lead so some warming and little if
any precipitation.

[MossMan]

Was 33 degrees with lowering clouds when I left my house...hopefully there will be snow in the air tonight!

[MossMan]

39 in Bothell, glad I don’t live here.

[Jesse]

39 in Bothell, glad I don’t live here.

The roses there are glad they live there.

[Winterdog]

High of 34 today with a low of 25.  Sitting at 33 waiting for some moisture to arrive, it's going to be awhile.  Not on board at all with the snow chances for Christmas (as if anybody cares) but if both the EURO and GFS continue to show it tonight I'll be close.  Scott's write-up was very good and described the reasons for my skepticism well.

[Jesse]

34/24 here today.

[seattleweatherguy]

36 with a dp of 29 that be snow if it gets colder or holds. I'm in bothell

[wx_statman]

Hard to believe the morning low was 51 just two days ago. 

[Tyler Mode]

High of 34 today and spent all of 1.5 hours above freezing.  Not bad for a day that was suppose to be in the upper 30s to near 40.

[Front Ranger]

I forget how beautiful this area is. Woke up in Everett where everything was bathed in a clingy fog and touched in frost. I also forget how lovely the light is as the sun hangs low in the sky.

 

Poetic.

[TigerWoodsLibido]

32 in Monmouth. Going to assume that temp will have to lower to further saturate the airmass. Frozen drizzle or light snow is likely at some point soon.

[umadbro]

32 in Monmouth. Going to assume that temp will have to lower to further saturate the airmass. Frozen drizzle or light snow is likely at some point soon.

Not quite sure you know how this works...

[Blizzard777]

I’m assuming word is now out as FB post our coming in with snow forecast from local news ....were screwed !

 

Jim

[Deweydog]

32 in Monmouth. Going to assume that temp will have to lower to further saturate the airmass. Frozen drizzle or light snow is likely at some point soon.

Weenie winter science.

[Front Ranger]

The upcoming snow potential is certainly not how you draw up the pattern classically, but as long as there's cold air in place, no reason it can't happen.

[Deweydog]

The upcoming snow potential is certainly not how you draw up the pattern classically, but as long as there's cold air in place, no reason it can't happen.

I'm going to have this embroidered on a throw pillow.

[Blizzard777]

This looks like it will be fairly difficult to get snow tonight according to what I’m seeing. I assume the system coming in is just light rain so probably won’t be able to pull down much cold air from above. My temperature has flatlined and not falling anymore

[Geos]

39 in Bothell, glad I don’t live here.

 

I think it was 37 when I left work in Bothell at 4:30. Got to the top of my hill a bit ago and it was already 34. Sitting at that now. 

 

Should have no probably cooling off to freezing with a dewpoint of 29. In fact there is some frost still on the north lawn of the yard.

[Geos]

Might be virga, but there is some echoes showing up near Tim already.

 

[Jbolin]

Might be virga, but there is some echoes showing up near Tim already.

 

http://climate.cod.edu/data/nexrad/ATX/N0Q/ATX.N0Q.20171222.0111.gif

It is, very little in the way of actual moisture below 10K 

[weatherfan2012]

Watch this little wavebreak take a small bite out of the North American side of the PV (-60hrs to +48hrs).

That’s the source for the blob of Arctic air next week.

https://www.tropicaltidbits.com/analysis/models/?model=gfs&region=nhem&pkg=Tz10&runtime=2017122106&fh=-60&xpos=0&ypos=440

it is uncanny how alike the over all pattern matches the over all theam of the 2013-2017 period even with the different set ups we have in place.

[Frontal Snowsquall]

Yes, he uses the same GIF's like Bryant said and even gave himself away with a "SCORE!" (note the GIF of the soccer coach and team celebrating. http://theweatherforums.com/index.php/topic/1690-december-weather-in-the-pnw/?p=289309

Classic "Heavy Snow".

I haven't logged on in close to a year and forgot my password. I thought everybody already knew who I was that's why I used those GIFs incase not everybody knew.

[Timmy]

Looks like we will be hard pressed to be helped by a cold pool east side with decent onshore flow currently through he gorge

[Phil]

it is uncanny how alike the over all pattern matches the over all theam of the 2013-2017 period even with the different set ups we have in place.

Yeah, it’s becoming absurd.

[Jesse]

Yeah, it’s becoming absurd.

Almost like the climate is changing/warming.

[Phil]

The average of the last 4 winters’ 500mb anomalies.

 

Jaw dropping.

 

[MR.SNOWMIZER]

Light rain in Olympia. Shelton had mixed precip now light rain.

[Frontal Snowsquall]

Pretty good summary by PDX NWS. Really hope the euro comes through, screw the crappy GFS solution. That secondary southern low on the euro seems key to maintaining offshore gradients and keeping the 925s and 850s just cool enough. Hopefully we start seeing other models showing that.

 

Hail king EURO.

 

 

Sunday through Thursday...With the high amplitude

pattern the models are really struggling to come to any consensus

in the longer term and the ensembles are showing tremendous spread.

All them models tend to bring a shortwave through the ridge position

early Sunday morning. The GFS has a weaker trough and the ECMWF is

stronger. Both models have held onto their respective solutions over

the past several runs. I prefer the ECMWF solution and have trended

the forecast that way. This means precipitation would likely spread

to the coast and even inland by Sunday morning. Temperatures will

probably be below freezing in most of the Willamette Valley. This

brings a threat of freezing rain to most of the valley Sunday but

the ECMWF also has a stronger surface low which moves toward the

central coast of Oregon. This increases the wrap around flow to the

northeast and over the northern Willamette Valley and into SW

Washington with 925 mb and 850 mb temperatures below freezing. This

could bring enough cold air down to keep precipitation as snow or it

could end up being too shallow with freezing rain. A very difficult

forecast at this point. To make it even more complex the ECMWF digs

the secondary low along the Washington coast and over Tillamook by

Monday morning. The enhanced easterly flow could allow for snow to

persist in the North Willamette Valley and Clark county into Monday.

The GFS solution does not have this secondary surface feature and

weakens the gradient which would lead so some warming and little if

any precipitation.

Yeah good write-up by the NWS. If the ECMWF doesn't back down tonight and gives us another good run, then I really like our chances to score. Let's go KING EURO!

[BLI snowman]

Looks like we will be hard pressed to be helped by a cold pool east side with decent onshore flow currently through he gorge

 

The cold air advection into the basin is modeled for Friday night into Sunday morning as the arctic front scrapes northern WA. Tomorrow was never going to have much in the way of low level assistance.

[Phil]

Almost like the climate is changing/warming.

How is that relevant? All the climate ever does is change, and there hasn’t been substantial climate change over the last 15yrs.

 

The fact we’ve been regurgitating the same boreal winter circulation pattern since 2013 has more to do with deep-rooted, large scale, spatially divergent thermodynamic imbalances that have developed in recent years.

 

In this case, the NE-ward explosion of the west-Pacific warm pool is probably the cause, or at least a contributing factor to it.

[Bryant]

I'll have you guys know that I'm down at the Whatcom/Skagit County borderline knocking down this huge wall that is holding back the show for Christmas Eve. The Euro tonight will hopefully reflect my hard work.