December Weather In the PNW

[Phil]

A massive blizzard in the upper Midwest next week on the GFS:

 

Yikes. That screams ice storm here.

 

Freezing rain w/ temps in the teens is one of the scariest weather experiences possible for a metro area. People still talk about 1994 & 1999 around here as if it were yesterday.

[MR.SNOWMIZER]

My son at Snoqualmie Summit today... invincible!  

 

https://vimeo.com/248230240

Hell yeah!

[MR.SNOWMIZER]

My son at Snoqualmie Summit today... invincible!  

 

https://vimeo.com/248230240

Me a few year's ago on my 300hp snowmobile. Yes 300hp.

[MR.SNOWMIZER]

My invinsable feeling went away when my wife passed. Before that i was crazy on dirt bikes and snowmobiles, 2 years ago i jumped my polaris razer utv 102 feet down at the oregon dunes. Love seing pics like that Tim. Man to be 16 again!!!

[wx_statman]

Serious torching in Alaska this month, the result of all that N. Pacific ridging. Anchorage is running a +12.4 departure. Also had 4 straight days with maximums of 45+ (12/10 to 12/13). First time that's happened in December. That stretch also featured a low of 37 on the 11th, tying the monthly warm record. 

[Frontal Snowsquall]

12z EPS for KSEA and KPDX show the ensemble mean sitting right at one inch of snow for Christmas Day.

 

http://wx.graphics/models/ecmwf/2017122012/city/KSEA_2017122012_forecast_EPS_precip_360.png

 

http://wx.graphics/models/ecmwf/2017122012/city/KPDX_2017122012_forecast_EPS_precip_360.png

Wow, a white Christmas is certainly possible now.

[Jbolin]

Me a few year's ago on my 300hp snowmobile. Yes 300hp.

What's that "white stuff" in the background?

[weatherfan2012]

Yikes. That screams ice storm here.

Freezing rain w/ temps in the teens is one of the scariest weather experiences possible for a metro area. People still talk about 1994 & 1999 around here as if it were yesterday.

sure does also would scream niña almost to a tee as ice storms and change over events are a bench mark in a lot of winter's here isolated with la niña years.

[Gradient Keeper]

In the short term all eyes on the Alaskan shortwave now seen on IR/WV Loops. If we want any chance of a last minute sudden change it's to hope this strengthens as much as possible as it would then dig nicely down the BC Coast. I will say at first glance it looks "decent" right now. System looks okay. Sharply defined front hmmm. Not expecting anything, but I will keep an eye on it.

 

00z GFS in 2 hours 31 minutes

6z NAM in 6 hours 49 minutes

 

Loop> http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=dev/lindsey/loops/alaska_realtime_ch4&image_width=1020&image_height=720

 

 

http://rammb.cira.colostate.edu/dev/lindsey/loops/alaska_realtime_ch4/20ch4.gif

[Geos]

18z GFS just a tad too warm for snow even here. Roughly showing a 37 degree rain right now. Just need the next few runs to come in a tad colder each time. 

 

NAM showing snow north in the lowland at least for Friday.

 

[TigerWoodsLibido]

This is the most uncertain forecast 3-4 days out I can remember in a long time.

[HighlandExperience]

This is the most uncertain forecast 3-4 days out I can remember in a long time.

 

Something big is coming. Something we haven't seen since 1950

[MossMan]

Down to 29 already!

[Geos]

34 here already. Going to be in the 20s tonight for sure. 

[TigerWoodsLibido]

Still 40 in Eugene. With northerly flow we should get down to freezing.

[SilverFallsAndrew]

37/31 here today. Back at the house tonight. Talked to the people at the store, they said we got about 1/4" of snow early this morning. Drive up on the ridge this afternoon and there were a couple inches up there around 2000'. 

[SilverFallsAndrew]

Still 40 in Eugene. With northerly flow we should get down to freezing.

 

Fox 12 is predicting a high of 35 at SLE and EUG tomorrow.

 

NWS predicting

 

SLE 34

EUG 33

[Perturbed Member]

3km NAM shows Friday as starting with a mix or some ZR briefly before going all rain around PDX.

 

[snow_wizard]

Talk about one of the worst cases of model teasing and taunting that I've ever seen.  Past experience tells us that if this keeps up long enough something big will eventually materialize.  The ECMWF might be onto something that would cause a huge pattern shakeup.  It depicts a strong MJO wave emerging in region 2 by early January.  One possible reason the ECMWF wants to de-amplify the pattern during week two is the fact the current MJO wave gets quite weak and shortcuts through regions 8 and 1.  If the forecast of a strong wave emerging in 2 is correct we could be looking at a very desirable strong wave in regions 2 through 5 for a good part of January.  Many of our great cold waves come with a strong wave in region 5.

 

 

[SilverFallsAndrew]

3km NAM shows Friday as starting with a mix or some ZR briefly before going all rain around PDX.

 

 

I could see almost everyone getting a dusting at some point in the next 7-10 days.

[Blizzard777]

Just read the last four pages and the best thing I got out of it was “ there's something Big out there, something we haven’t seen since 1950!”

 

The rest of the pages had....

 

Dude

 

Sweet

[High Desert Mat!]

In the short term all eyes on the Alaskan shortwave now seen on IR/WV Loops. If we want any chance of a last minute sudden change it's to hope this strengthens as much as possible as it would then dig nicely down the BC Coast. I will say at first glance it looks "decent" right now. System looks okay. Sharply defined front hmmm. Not expecting anything, but I will keep an eye on it.

 

00z GFS in 2 hours 31 minutes

6z NAM in 6 hours 49 minutes

 

Loop> http://rammb.cira.colostate.edu/templates/loop_directory.asp?data_folder=dev/lindsey/loops/alaska_realtime_ch4&image_width=1020&image_height=720

 

 

http://rammb.cira.colostate.edu/dev/lindsey/loops/alaska_realtime_ch4/20ch4.gif

Strengthen....... to go down the coast.

Hmmmm

Usually they strengthen and curve north, is there toad venom at play?

[snow_wizard]

Another comment about the MJO...The recent wave that went through region 5 had a pretty weird result with the blocking setting up much further east than would normally be the case.  That could be due to the fact the wave emerged in 4 instead of over the Indian Ocean and then progressing to the Maritime Continent.

[wx_statman]

Already 31 at OLM. 

 

1 at Cut Bank, MT. 

[TT-SEA]

Already 31 at OLM. 

 

1 at Cut Bank, MT. 

 

OLM seems very warm now that you made that comparison.  

[Gradient Keeper]

00z NAM HR 45 cold/arctic air backed into BC a few notches further west than 18z, 12z

 

Here was 12z

and 00z tonight - Very noticeable you can see the contours clearing digging back

[Geos]

Down to 32 here with frost on my car windows already. 

[Deweydog]

Talk about one of the worst cases of model teasing and taunting that I've ever seen. Past experience tells us that if this keeps up long enough something big will eventually materialize. The ECMWF might be onto something that would cause a huge pattern shakeup. It depicts a strong MJO wave emerging in region 2 by early January. One possible reason the ECMWF wants to de-amplify the pattern during week two is the fact the current MJO wave gets quite weak and shortcuts through regions 8 and 1. If the forecast of a strong wave emerging in 2 is correct we could be looking at a very desirable strong wave in regions 2 through 5 for a good part of January. Many of our great cold waves come with a strong wave in region 5.

I've said it before and will say it again. Epic winters are a lot easier to call months in advance rather than weeks/days.

[Gradient Keeper]

HR 57 bit more noticeable now.

 

Here was 18z

 

and 00z

[liquidsnow]

There's the word "notch" again.

 

*Drink*

[Deweydog]

00z NAM HR 45 cold/arctic air backed into BC a few notches further west than 18z, 12z

 

Here was 12z

and 00z tonight - Very noticeable you can see the contours clearing digging back

#notchwatch2017

[BLI snowman]

00z NAM HR 45 cold/arctic air backed into BC a few notches further west than 18z, 12z

 

Here was 12z

and 00z tonight - Very noticeable you can see the contours clearing digging back

 

 

NAM definitely looks more favorable for wet snow in SW WA. It has a tendency to get a little carried away....

[Gradient Keeper]

HR 57 bit more noticeable now.

 

Here was 18z

 

and 00z

Edited. Correct images in now. Very noticeable now.

[Jbolin]

#notchwatch2017

Tis' the season #NogWatch2017

[TT-SEA]

Edited. Correct images in now. Very noticeable now.

 

 

Its just playing catch up to the GFS and ECMWF... its more of an awakening than a sign of a coming adjustment across all models.   

[MossMan]

Tis' the season #NogWatch2017

Drinking Nog watching notch watch!

[Gradient Keeper]

Edited. Correct images in now. Very noticeable now.

Cold air was 200-250 miles further west, but the base of the block doesn't hold far enough west to allow it to fully dig over us, but as I said with my IR Analysis earlier, this bares watching.

[snow_wizard]

00z NAM HR 45 cold/arctic air backed into BC a few notches further west than 18z, 12z

 

 

 

 

It seems there has been a favorable trend today.  Given the situation just tiny changes at the 500mb level could make a big difference for how much cold air we will get in here.  I will be interested to see how the possible cold shot the 18z GFS showed for next week is looking on the 0z.

[SilverFallsAndrew]

I truly believe the next two weeks will give us a few surprises. 

[Gradient Keeper]

Check out HR 66. Quite a shift to the west tonight

 

12z

and now 00z