December 2016 Observations and Model Discussion for the Pacific Northwest

[seattleweatherguy]

00Z ECMWF certainly shows less snow than the WRF tomorrow. Its does not show that heavy snow in north King County either.

 

Generally 1-2 inches away from the water... barely a dusting in Seattle.

 

Total snow through Tuesday morning...

 

Hmmm at least I get an inch.

[Heavy Snow]

Wow, KING EURO has the over-running system more South than previous runs. Moisture doesn't reach PDX Metro until Thursday around 10am. This could potentially keep the cold pool thicker with the East winds having a longer duration to blow in.

[Front Ranger]

Good thing the radars are fixed now, eh?

[IbrChris]

Looking at hindcast-corrected values for the 00z GFS Op there's a pretty nice arctic front Day 9-10 (high/low at PDX):

Mon Dec 12: 44/35
Tue Dec 13: 35/6
Wed Dec 14: 20/12
Thu Dec 15: 26/15
Fri Dec 16: 35/15
Sat Dec 17: 25/16 (reload)
Sun Dec 18: 18/6
Mon Dec 19: 15/5 (would be coldest since Feb 1989)

[Heavy Snow]

Yup, KING EURO showing solid 2"-4" snow for PDX Metro through Thursday at 10pm.

[TT-SEA]

10 a.m. Thursday on the 00Z ECMWF....

 

[Gradient Keeper]

Definitely a stronger system than the GFS is showing.

The notorious model battle of the northern stream v.s. the southern stream has begun.

[seattleweatherguy]

Rigjt now conversion zone over everett?

[Bryant]

00Z ECMWF certainly shows less snow than the WRF tomorrow. Its does not show that heavy snow in north King County either.

 

Generally 1-2 inches away from the water... barely a dusting in Seattle.

 

Total snow through Tuesday morning...

 

Wouldn't you think WRF would handle this situation better?

[Gradient Keeper]

Day 5 ... Look upstream.... block anyone?

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/120/500h_anom.na.png

[TT-SEA]

Wouldn't you think WRF would handle this situation better?

WRF almost always loses when it disagrees with the ECMWF. I watch this all year long.

[Front Ranger]

Rigjt now conversion zone over everett?

 

Yeah, reporting snow and 34.

[Front Ranger]

WRF almost always loses when it disagrees with the ECMWF. I watch this all year long.

 

Yeah, but these snow forecasts are so hard for all of the models to get right.

 

The bottom line is that over the next 30 hours or so, it will be cold enough to snow most of the time for most of the lowlands, and there will be precip around. And convergence zones.

[TT-SEA]

Yeah, but these snow forecasts are so hard for all of the models to get right.

 

The bottom line is that over the next 30 hours or so, it will be cold enough to snow most of the time for most of the lowlands, and there will be precip around. And convergence zones.

 

Yes... and the ECMWF shows that as well.   

[luvssnow_spokane]

Yeah, but these snow forecasts are so hard for all of the models to get right.

 

The bottom line is that over the next 30 hours or so, it will be cold enough to snow most of the time for most of the lowlands, and there will be precip around. And convergence zones.

Accept for the swamp of course

[Bryant]

WRF almost always loses when it disagrees with the ECMWF. I watch this all year long.

WRF this evening was a bummer for whatcom county and my area, especially compared to the run this morning. Euro is a bit better, but would disappoint a lot of people. I have no idea what to expect around my area honestly

[Kayla]

Have to love where the euro is headed at day 6...

[TT-SEA]

WRF this evening was a bummer for whatcom county and my area, especially compared to the run this morning. Euro is a bit better, but would disappoint a lot of people. I have no idea what to expect around my area honestly

 

 

I am almost certain you will have snow on the ground by this time tomorrow.   My guess is 2-3 inches.  

[Gradient Keeper]

00z GFS Composite Analog
Day 6-10, 8-14

 

Quite simply the best pattern and analogs I've ever seen. Just look at the years popping up. One year after another is flat out epic. Look how the block holds in the sweet spot. Done deal.

 

Day 6-10

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_00gfs610.gif

 

 

Day 8-14

 

http://www.cpc.ncep.noaa.gov/products/predictions/short_range/tools/gifs/500hgt_comp_00gfs814.gif

[SilverFallsAndrew]

Looks like our friend Timmy is about to get a very healthy snow shower. 

[The Swamp]

Accept for the swamp of course

Our only hope is a convergence zone. Not very likely in this situation though.

[Gradient Keeper]

Day 6 .... Uhhhh.... Heck of a block!

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/144/500h_anom.na.png

[Bryant]

Everett

[Front Ranger]

Have to love where the euro is headed at day 6...

 

It actually looks like a compromise between the GFS and GEM.

[Bryant]

I am almost certain you will have snow on the ground by this time tomorrow. My guess is 2-3 inches.

I'll let you know, hope you're right

[Kayla]

Looks like our friend Timmy is about to get a very healthy snow shower. 

 

Don't forget about me!!!

[Heavy Snow]

Day 6 .... Uhhhh.... Heck of a block!

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/144/500h_anom.na.png

 

Yeah, the next couple frames is going to be crucial.

[Kayla]

It actually looks like a compromise between the GFS and GEM.

 

Much better looking than the 12z run though.

 

Edit: Definitely trends away from the GEM at day 7

[Gradient Keeper]

Day 7 . Amazing agreement with the GFS.. MEga block, PV pivoting SW

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/168/500h_anom.na.png

[Dave]

Didn't you guys do pretty well the last few years though

Ha.  I just realized you weren't talking about the Oregon ducks.  Yes, we've done well until recently.  March 2012, Dec 2013, and Feb 2014 were all incredibly special.  That being said, I haven't seen a single flake since Feb 2014.  

[Timmy]

Looks like our friend Timmy is about to get a very healthy snow shower.

We will see, doesn't look that great to me... I took some sleep medicine too, because I know how this night plays out. Lots of trips to the window. I can't afford that now with a newborn in the house.

[IbrChris]

Day 5 ... Look upstream.... block anyone?

Yeah I like the pattern a lot in the long range.

[Heavy Snow]

Day 7 . Amazing agreement with the GFS.. MEga block, PV pivoting SW

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/168/500h_anom.na.png

 

Stunning.....

[TT-SEA]

Everett

 

Nice!

[Front Ranger]

Day 7 . Amazing agreement with the GFS.. MEga block, PV pivoting SW

 

 

 

It's more similar to the GFS than the 12z, but the block is quite a bit different. The main block is way further west, there isn't that huge negative tilted ridge in AK pushing the PV down and west. 

 

I could be wrong, but I think the main cold (of which there is a ton and it's ridiculous) will go further east this run. Or just stall more to the north.

 

Obviously, either way there's huge potential with this pattern.

[Timmy]

Actually that band is increasing in intensity, I thought it was going to do the opposite. Dumping on 26 west of vernonia.

[Timmy]

Only 780' elevation too.

http://tripcheck.com/RoadCams/cams/US26%20at%20Timber%20Jct_pid2736.JPG?rand=1480920219419

[Jesse]

Actually that band is increasing in intensity, I thought it was going to do the opposite. Dumping on 26 west of vernonia.

 

That band will be hitting most of the metro over the next hour or so assuming it doesn't fall apart.

 

#momentoftruth

[Gradient Keeper]

Day 8 awwww.... Block just not close enough and lifted too far north into Aleutians, Siberia

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016120500/192/500h_anom.na.png

[Bryant]

I could be wrong, but I think the main cold (of which there is a ton and it's ridiculous) will go further east this run. Or just stall more to the north.

 

Obviously, either way there's huge potential with this pattern.

Bingo