December 2016 Observations and Model Discussion for the Pacific Northwest

[stuffradio]

Have to say, I love the reddish/pink meat on the 12Z GFS. Lots of snow opportunities for us until almost the Winter solstice. Now if only we could tell the weather gods this is the solution we want.

[Front Ranger]

Still seeing that Kona Low. No idea what the NWS/NCEP forecaster is seeing to forecast it dissipates. I wish he were correct.

 

Need that upper level trough off Siberia to back off too. Not going to happen.

A true Kona low is usually a good thing for the PNW.

[van city]

Have to say, I love the reddish/pink meat on the 12Z GFS. Lots of snow opportunities for us until almost the Winter solstice. Now if only we could tell the weather gods this is the solution we want.

Simple... ask Snow Wizard (weather god).

[Timmy]

http://www.atmos.washington.edu/wrfrt/data/current_gfs/load.cgi?images_d3/or_snow48.72.0000.gif

[Timmy]

12z GFS definitely shows a nice little snowstorm for PDX on Tuesday now. 6" of snowfall being shown to fall on Tuesday now after 1-2" falls on Monday. 925s are -3c on Tuesday so plenty cold enough to support sticking snow.

 

Trend has definitely been on Portlands side these last 48 hours!

Wrf isn't as bullish for pdx but still shows snow

[Kayla]

I should add, the 12z sounding for Monday morning does not look good for any sticking snow below 500ft around PDX. 

[bainbridgekid]

First WRF run to show a strong CZ persisting into Monday night.

 

Certainly have been watching closely for this potential. 

 

I'm thinking we may be looking at some sticking snow for many areas early Monday morning, followed by melting and temps in the upper 30's during the day, with some more snow after sunset. It would be this evening snow that would have a chance to stick around.

 

[Kayla]

Wrf isn't as bullish for pdx but still shows snow

 

Yeah I just saw that as well. Definitely looks very impressive for Monday night/Tuesday now.

 

Still think it's overdoing Monday mornings accumulations as it contradicts it's own sounding for the same timeframe.

 

http://www.atmos.washington.edu/wrfrt/data/current_gfs/images_d3/or_snow72.72.0000.gif

[FroYoBro]

Yeah, I would ignore all of the sticking snow before Monday night. There will probably be a lot of snowflakes in the air in the valley, but I don't see it sticking until later. 

[MR.SNOWMIZER]

Things are starting to look good for puget sound. I can see this overachieving. I am real interested in the overrunning potential for the hood canal later in the week. Starting to look like we cool right back down. I have seen this before where the hood canal never transitions to rain and gets buried. Looks to be a good upslope flow up the Olympics.

[bainbridgekid]

MM5-NAM isn't nearly as cold Monday into Tuesday but also has a lot of moisture.

 

Spits out a ridiculous ~1.5" of liquid QPF for the San Juans and Southern Vancouver Island from 4 PM Monday to 4 PM Tuesday.

[bainbridgekid]

The warm nose and warm air advection isn't nearly as strong for the overrunning event on the Canadian.

 

Nice snowstorm for everyone North of about Salem is the result with snow sticking around Seattle into Thursday night.

 

Still pretty chilly at 4 AM Friday. This would be a dream:

 

 

EDIT: WAA is actually much weaker on the 12z GFS than the last several runs as well.

[bainbridgekid]

That shows like 9-10 inches for my part of the island.  I don't even know if we have snow plows on Bainbridge very often.  I haven't lived here since before the snow stopped falling in Western Washington.  I don't mind being stuck at home!  

 

I would love for this to prove out.

They barely do.

 

Couple pickup trucks with temporary blades and the real plows get to the highway but that's about it.

 

Even the busy roads stayed completely compact snow and ice in 2008 for well over a week after the 18th.

[ShawniganLake]

MM5-NAM isn't nearly as cold Monday into Tuesday but also has a lot of moisture.

 

Spits out a ridiculous ~1.5" of liquid QPF for the San Juans and Southern Vancouver Island from 4 PM Monday to 4 PM Tuesday.

Yea, it went a bit nuts with the outflow snow in that area.  I hope it verifies obviously.  I think the wrf was nearly totally dry during that timeframe.  We don't really know any more about Mondays potential now then we did about 3 days ago, IMO.  Gonna be a waiting game, watching satellite and radar, following surface obs Sunday night and Monday. 

[snow_wizard]

Things continue to trend colder a very tiny amount in the home stretch. I'm really liking the prospects for week 2.

[snow_wizard]

Yea, it went a bit nuts with the outflow snow in that area.  I hope it verifies obviously.  I think the wrf was nearly totally dry during that timeframe.  We don't really know any more about Mondays potential now then we did about 3 days ago, IMO.  Gonna be a waiting game, watching satellite and radar, following surface obs Sunday night and Monday.

There really is nothing to support the NAM. Obviously that solution would be bad for most of us.

[luvssnow_spokane]

[Kayla]

The 12z GFS meteogram goes bonkers showing 9" of snowfall for PDX (26" at Cascade Locks in the Gorge!) over the next 120 hours.

 

One neat thing is seeing the overnight surface temps dropping in reaction to the forecasted snow cover now.

[SilverFallsAndrew]

The 12z is the most bullish yet for snow at my location. The GFS also gives my location another couple inches in the onshore flow Friday night.

[snow_wizard]

The ECMWF control model has us below normal in temps for the next two weeks with another solid cold shot at day 11. Loving the trend!

 

Pretty amazing to see every run of every model indicating lowland snow in the Sunday night to Monday evening period.

[Phil]

Every 12z GFS analog year on the CPC site (except one) was a +QBO year. As research continues to pour into the literature networks, it's now very difficult to deny the importance of the stratospheric background state in seasonal forecasting, IMO..

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_12gfs814.gif

[Front Ranger]

The NAM continues to be the Debbie Downer of models this time around, with very little accumulation south of the border through Monday evening.

 

 

[SilverFallsAndrew]

KING EURO running!

[Front Ranger]

48 hrs.

 

 

[Farmboy]

Those forecasts are probably computer generated.  Nobody is thinking and making a forecast for 100's of thousands of cities around the world. 

Well I guess they need some better software, huh?

[Front Ranger]

Euro is a little weaker with the BC shortwave and a little slower with colder air vs the GFS.

[Farmboy]

I hope this warning shot will be enough of a warning for everyone of the ensuing snow-pocalypse coming for the remainder of December....

[Front Ranger]

The good news is, at day 3 the Euro continues to have the approaching offshore low a little weaker than GFS.

[ShawniganLake]

There really is nothing to support the NAM. Obviously that solution would be bad for most of us.

I didn't say I believed it. 

[snow_wizard]

The NAM continues to be the Debbie Downer of models this time around, with very little accumulation south of the border through Monday evening.

 

get_orig_img.gif

 

Thank God it's the NAM!

[Front Ranger]

Euro just isn't all that cold, at least in upper levels, with -7C 850s from Vancouver, BC down to Portland at 72 hours. Pattern looks pretty good though.

[snow_wizard]

I hope this warning shot will be enough of a warning for everyone of the ensuing snow-pocalypse coming for the remainder of December....

 

In all seriousness warning shots this time of year are historically very good news in a neutral or cold ENSO situation.  High chance of big things later on.

[snow_wizard]

Every 12z GFS analog year on the CPC site (except one) was a +QBO year. As research continues to pour into the literature networks, it's now very difficult to deny the importance of the stratospheric background state in seasonal forecasting, IMO..

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_12gfs814.gif

 

Nice to have another tool to add to the box.

[Front Ranger]

Euro just isn't all that cold, at least in upper levels, with -7C 850s from Vancouver, BC down to Portland at 72 hours. Pattern looks pretty good though.

 

By day 4, however, Vancouver is at -10C, Seattle -9C, and Portland still -7C. Offshore low is still weaker and further offshore than GFS, less progressive pattern. Euro sticking to its guns in the short/mid range.

 

 

[SilverFallsAndrew]

Latest RPM Monday morning. 

 

[Gradient Keeper]

A true Kona low is usually a good thing for the PNW.

Yeah, if the pattern is retrogressive or not progressive and it remains in the true Kona location, near/northwest of Hawaii.

[Gradient Keeper]

12z GFS Composite Analogs

 

As I posted early this morning the Canadian Ensemble showed marked improvement of the upper level pattern in the 6-10 day range. Now today's 12z GFS has latched onto this idea and has improved dramatically. I know the operational has yet to show this, but we do see the Ensembles improving some. You have to love the positive anomaly and mean ridge position. Also the orientation of the cold trough and cross polar flow. 2008 is popping up quite a bit. Perhaps something to keep an eye on if models begin to show something similar.

 

6-10 Day

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_12gfs610.gif

 

 

 

8-14 Day

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_12gfs814.gif

[luvssnow_spokane]

Euro sure has been consistent.

[Front Ranger]

Yeah, if it remains in the true Kona location, near/northwest of Hawaii.

 

Exactly. That's why I wouldn't call that low that develops north of Hawaii in this pattern a real Kona low.

[Phil]

12z ECMWF very similar to the GFS overall, actually has lower 500mb heights over the NPAC/western Aleutians compared to the GFS and GGEM.