December Weather In the PNW

[Frontal Snowsquall]

Very good 12z GFS run. This is just the beginning.

[van city]

Weird year!!!

Jim and Tim!!!

[Jesse]

Weird year!!!

Good stuff! We’ve been awaiting your input.

[TT-SEA]

Weird year!!!

 

 

It actually applies this year!   

[Jesse]

Very true. I was going to say the same thing.

 

Jim said it could happen... but even he was thinking it might just be a warning shot at the end of the ridge. This is way beyond that.

 

Very exciting stuff.

Yeah, I’m not quite sure what to make of it. Hard for me to wrap my head around such a strong block having such longevity. But I’m sure it has happened in the past. Definitely not since I started following the models, though.

[Deweydog]

It actually applies this year!

It'll definitely be weird if it verifies. Hard to put it in perspective.

[Deweydog]

Good stuff! We’ve been awaiting your input.

I'm sure your butt was hurting from the anticipation.

[Jesse]

I'm sure your butt was hurting from the anticipation.

What is your deal lately?

[MR.SNOWMIZER]

Jim and Tim!!!

They are not a Apple.

[Deweydog]

What is your deal lately?

I'm getting into mid winter form! Exciting times ahead!!!

[MR.SNOWMIZER]

The Nws better stock up on Coffee and Advil, Long days ahead for them.

[Gradient Keeper]

I see good, noticeable improvements on Ensembles. Through day 10 mean temp Troutdale down to -7c, Yakima -10c. More colder members too.

[ShawniganLake]

[Jesse]

In other news, it was 24 here this morning. Coldest so far of five consecutive mornings in the 20s.

[Jesse]

 

Looks like a big shift to the cold camp.

[SilverFallsAndrew]

That 12z GFS was absolutely insane. Montana would feel more like Mongolia if it verified...

[Guest Dome Buster]

Phil will be sipping lemonade if that run verifies.

[stuffradio]

Phil will be sipping lemonade if that run verifies.

Lemon Водка

[SilverFallsAndrew]

Didn't Seattle have a major snow storm last February? I don't understand all this whining about "no snow."

[TigerWoodsLibido]

Hopefully the models progress and get less backdooorish and more north southish.

There is plenty of potential for a regional event later this month and into January. At least you get the cold during the backdoor stuff. In N/S events we are in boring southerly flow. Events with a broad and deep trough that digs way down to SoCal are a pretty good indicator of good things for all of us up here.

[Jesse]

Nice ensemble improvement.

 

[bainbridgekid]

Didn't Seattle have a major snow storm last February? I don't understand all this whining about "no snow."

It was major for the hills and especially South and East of the city. Wasn't major Downtown, at UW, or North of Seattle though as temps took forever to fall to freezing.

[umadbro]

My brother in downtown seattle had a few inches with thundersnow.

[umadbro]

It was an impressive convergence zone if I remember right.

[Gradient Keeper]

Near the 20th EPO is now forecast to tank negatively.

[Brian_in_Leavenworth]

Ensemble mean improvement:  10 degree or so improvement (decrease) in 2M temps

 

Last night's 0Z at hour 300:

 

 

Today's 12Z at the same hour (312):

 

[Front Ranger]

If we do end up getting some cold air in the next 7-10 days, it will be an unusual progression. I can’t think of many times that we sat under a strong +PNA ridge for so long only to have it retrograde without a period of westerlies to break things up. Especially during a Niña.

 

No doubt.

 

It happened in 2014, to a certain extent, with a long period of +PNA ridging the second half of January followed shortly by cold air in early February. Same thing with 1985. It even happened in Jan 2009, although the cold air didn't end up all that cold (though still enough to produce some lowland snow and very chilly lows).

[Deweydog]

Near the 20th EPO is now forecast to tank negatively.

Better than tanking positively...

[Gradient Keeper]

[SilverFallsAndrew]

It was major for the hills and especially South and East of the city. Wasn't major Downtown, at UW, or North of Seattle though as temps took forever to fall to freezing.

 

Good info. We had a tremendous amount of cold rain down here that day. As the front slid through it briefly turned to snow IMBY and dropped a couple inches of snow. 

[Front Ranger]

Better than tanking positively...

 

Positively tanking?

[MossMan]

Didn't Seattle have a major snow storm last February? I don't understand all this whining about "no snow."

Almost 3” for me! That melted as fast as it came. Sloppy. Been sloppy slop for the last 6yrs.

[Jesse]

Good info. We had a tremendous amount of cold rain down here that day. As the front slid through it briefly turned to snow IMBY and dropped a couple inches of snow.

The front was originally forecast to stall over the north valley, but instead it stalled over the north Oregon coast and lower Columbia. We drove to Astoria the next day and started seeing a dusting around Kalama. Astoria had 3-4 inches up at the column.

[Deweydog]

Positively tanking?

Negatively spiking.

[Gradient Keeper]

12z GFS 500mb Composite Analogs
Day 6-10, 8-14

 

Looking promising. Correlation score still needs work, but there is plenty of time for that.

 

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

 

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

[Front Ranger]

12z GFS 500mb Composite Analogs

Day 6-10, 8-14

 

Looking promising. Correlation score still needs work, but there is plenty of time for that.

 

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

 

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

 

Hey look, January 2005!

 

Pretty sure 1962 has shown up more consistently than any other -ENSO analog over the past month.

[TigerWoodsLibido]

The front was originally forecast to stall over the north valley, but instead it stalled over the north Oregon coast and lower Columbia. We drove to Astoria the next day and started seeing a dusting around Kalama. Astoria had 3-4 inches up at the column.

That was one of those weird onshore snow events where the precip get heavy enough to bring the snow to the surface because of the evaporative cooling process. Also happened back in 07-08 in Eugene.

[HighlandExperience]

Good info. We had a tremendous amount of cold rain down here that day. As the front slid through it briefly turned to snow IMBY and dropped a couple inches of snow.

Areas of east and south of Seattle had 9-14 inches of snow. But the cold didn’t stick around. Would have preferred to have one week of cold with snow on the ground.

 

We had cold rain for hours preceding the change to snow. Would have been epic if it was colder.

[Brian_in_Leavenworth]

UW-GFS shows some snow for South Puget Sound next week.  This is for the 72 hours ending next Tuesday at 4PM

 

[Brian_in_Leavenworth]

Hey look, January 2005!

 

Pretty sure 1962 has shown up more consistently than any other -ENSO analog over the past month.

December 1990 is there too, that was another great month.  That month has shown up quite a bit.