December 2015 in the Pacific Northwest

[SilverFallsAndrew]

Me neither really. Low confidence on an actual amplified block...

 

Of course personally I would rather have cold onshore flow. 

[Gradient Keeper]

The 0z ECMWF is quite a bit better than the 12z.  Trends are good right now.  Right now we have solid model agreement on a fairly deep / cold trough around day 8 and 9.  The 12z GFS, 0z GFS, and 12z ECMWF ensemble control all have a major cold snap after day 10.  The 12z ECMWF ensemble showed a steadily cooling during the 11 to 15 day period with strong anomaly centers in the sweet spots.

I agree. Overall the 500mb pattern has improved significantly, we just need better amplification/strong southeast ridge/rising heights over midwest.

[Front Ranger]

Even with the exceptional cold and repeated snowfalls of March 1951, the snow melted pretty quickly (more just kept falling). SEA got over 18" of snow in about a week that month, but never had more than 4" on the ground. However, 7 straight days with snow on the ground in March is pretty remarkable.

[snow_wizard]

Me neither really. Low confidence on an actual amplified block...

 

This graphic makes it look a bit more hopeful.  This being on December 23rd certainly makes me think a white Christmas could still be on the table.  Those are pretty robust anomalies and that big area of minus heights is rapidly sinking southward.  I think there's a 50/50 chance we will go into something quite good in the 10 to 15 day period.

[HighlandExperience]

Even with the exceptional cold and repeated snowfalls of March 1951, the snow melted pretty quickly (more just kept falling). SEA got over 18" of snow in about a week that month, but never had more than 4" on the ground. However, 7 straight days with snow on the ground in March is pretty remarkable.

Imagine that in December/January. This forum would go ballistic

[snow_wizard]

One thing I really like about the day 10 ECMWF is what I like to call a stair step to the W and NW of us.  Those sharp kinks are usually a really good sign.

[Front Ranger]

Imagine that in December/January. This forum would go ballistic

 

I was here in 2008.

[snow_wizard]

Even with the exceptional cold and repeated snowfalls of March 1951, the snow melted pretty quickly (more just kept falling). SEA got over 18" of snow in about a week that month, but never had more than 4" on the ground. However, 7 straight days with snow on the ground in March is pretty remarkable.

 

The numbers were considerably better at Landsburg which is just a few miles from here.  Being away from the water and on a bit of a hill made a huge difference that month.

[snow_wizard]

I'm going to be eager to look at the ECMWF ensemble tomorrow morning.  The improvement was dramatic on the 12z for the 11 to 15 day period, and I hope to see more of the same with this run.

[Front Ranger]

The upcoming pattern, should it appear as modeled, reminds me quite a bit of Dec 2007. After the first half of the month was quite a bit like Dec 2006.

[snow_wizard]

Very interesting to see Jan 2007 showing up in the CPC analogs now.  The 2006-07 analog is progressing nicely.  Perhaps the biggest shocker is the regular appearance of Dec 1988 and Jan 1989.  Obviously this Nino is not business as usual at this point.

[snow_wizard]

The upcoming pattern, should it appear as modeled, reminds me quite a bit of Dec 2007. After the first half of the month was quite a bit like Dec 2006.

 

At this point the million dollar question is how much amplification we will see.  The Nino actually argues against a runaway zonal flow like we had in 2007-08 for too long.  Quite a number of different models have advertised some notable amplification after day 10.

[Phil]

Aleutian high/Siberian trough superimposed on an active EPAC/IO tandem = poor large scale wave driving. I'll wait another 10-15 days before bailing on the Jan 1-10 window, but we want to see at least one of these facets shift.

[Bryant]

Day 10 pattern reset for another cold trough... if only it would amplify

While the PV is strong, progressive will be the name of the game. No time for the kind of amplification we'd like to see. If we're going to score any snow, it's most likely going to be a quick hitting borderline event in my opinion.

[seattleweatherguy]

Just heard thunder and lightning

[snow_wizard]

While the PV is strong, progressive will be the name of the game. No time for the kind of amplification we'd like to see. If we're going to score any snow, it's most likely going to be a quick hitting borderline event in my opinion.

 

I'm not so sure of that.  The 10 to 15 day period bears watching still lots of question marks of course.  The much improved 12z ECMWF ensemble today in the 11 to 15 day period looked very promising to me.

[Gradient Keeper]

[Model Countdown] 12/14/15

Next up.................

*6z GFS in 1 hour 5 minutes

12z GFS in 7 hours 5 minutes

12z GEM in 8 hours

12z ECMWF in 9 hours 24 minutes

[Gradient Keeper]

00z CMC ENS 500mb anomalies much improved, still maybe slight worse than the GFS/EURO, but far better than previous runs

[MossMan]

Currently a rain/snow mix and 35 degrees.

[westcoastexpat]

Reasonable shot at lowland snow for those inland and north of Everett this weekend... also, looks like the 25-30 period may provide a decent shot at an Arctic blast. Pretty good model agreement of a strong SE ridge.

[Black Hole]

If you guys are bored you can track my storm. Already 10.5" overnight with snow continuing all day at my house, this could have some huge totals when all is said and done. Already the biggest single storm accumulation I have seen here since 2007 when I moved up. 

[SilverFallsAndrew]

Snow advisory for the Coast range with the weak system dropping down the coast this morning. Timmy could score an inch or two at 1500' this morning. 

[Snowman5678]

If you guys are bored you can track my storm. Already 10.5" overnight with snow continuing all day at my house, this could have some huge totals when all is said and done. Already the biggest single storm accumulation I have seen here since 2007 when I moved up. 

I'm going to head out and take some pictures soon! 

[Phil]

Yikes..

 

[SilverFallsAndrew]

I'm going to head out and take some pictures soon!

Jealous

[stuffradio]

I have 38F rain right now. I bet y'all are jealous!

[MossMan]

It's a start!! At my work this morning right at the Snohomish/Skagit border and right along the east side of I-5.

[Timmy]

Snow advisory for the Coast range with the weak system dropping down the coast this morning. Timmy could score an inch or two at 1500' this morning.

Rain just started here, kind of surprised. Was 32 at 3 am.

[Snowman5678]

It's a start!! At my work this morning right at the Snohomish/Skagit border and right along the east side of I-5.

That's cute.

 

 

[Tyler Mode]

Still have yet to see a flake of snow at my location this calendar year.  If it finishes without any, it would be the first time in at least 5 years.

[Phil]

If this verifies, the Jan 1-10 window is shot. Can't get any uglier than this in the stratosphere:

 

[MossMan]

That's cute.

 

image2 57163.JPG

 

image3 57165.JPG

Haha...I will take whatever I can get! Awesome pics!!

[SilverFallsAndrew]

Rain just started here, kind of surprised. Was 32 at 3 am.

 

Well the airmass is not that cold really. 500-1000mb thickness is about 530 right now. That is very borderline for my location with light precip unless it is overrunning some low level cold, which it is not. 

[Snowman5678]

Haha...I will take whatever I can get! Awesome pics!!

Already about 8-9" and it's supposed to snow pretty heavily till Tuesday night. I'm flying back Tuesday afternoon though.

 

NWS grid forecast has 4-8" today and 5-9" tonight on top of the about 7" I woke up to this morning.

[Front Ranger]

Yikes..

 

image.png

Certainly looks like a strong Nino December. But as I've pointed out, some of those anomalies West of the Mississippi will take a big hit this week.

[SilverFallsAndrew]

Already about 8-9" and it's supposed to snow pretty heavily till Tuesday night. I'm flying back Tuesday afternoon though.

 

NWS grid forecast has 4-8" today and 5-9" tonight on top of the about 7" I woke up to this morning.

 

Quite the storm. Are there a lot of delays and cancellations at SLC? Luckily I'm flying into Denver tomorrow night. 

[SilverFallsAndrew]

This would be a snowy Christmas Eve at my location. 

 

http://mag.ncep.noaa.gov/data/gfs/12/gfs_namer_252_1000_500_thick.gif

[SilverFallsAndrew]

The rest of the 12z is not exciting. 

[Timmy]

Well the airmass is not that cold really. 500-1000mb thickness is about 530 right now. That is very borderline for my location with light precip unless it is overrunning some low level cold, which it is not.

 

Precip picked up and I have light wet snow and 34f

[ShawniganLake]

This would be a snowy Christmas Eve at my location. 

 

 

This would be a very heavy wet snow at my location on Thursday morning.