December 2014 Observations for the Pacific Northwest

[SilverFallsAndrew]

I only hit 23 this morning.

 

The clouds really messed with folks up north especially. Most outlying areas south of PDX hit the teens. PDX managed a respectable 21 this morning. Vancouver hit 17. 

[Abbotsford_wx]

20.5F here under calm winds. Not too shabby, but still a little disappointing considering the air mass and time of year. Would have easily been low teens with snowcover.

[SilverFallsAndrew]

This airmass performed respectably in Central and Eastern Oregon. 

[SilverFallsAndrew]

The 15 at the Silverton mesonet station was pretty impressive. Better than anything they saw in January 2013 or Dec 2010. About on par with January 2008 at that location.

[Abbotsford_wx]

This airmass performed respectably in Central and Eastern Oregon. 

 

What else is new.. lol.

[SilverFallsAndrew]

Parallel GFS gets pretty close on the 12z, like it wouldn't take much for at least the N. Interior to see some cold outflow.

[Tyler Mode]

Last sunrise of 2014

 

The high clouds held my low up to 19.  It rose up to 22, now it's back down to 20 a full 40 minutes after sunrise.

 

http://weathercrazy.smugmug.com/Landscapes/Winter-20142015/i-nQsG7MT/0/L/DSC_4181-L.jpg

[MossMan]

Parallel GFS gets pretty close on the 12z, like it wouldn't take much for at least the N. Interior to see some cold outflow.

So is the 12z slightly better than the 6z or about the same?

[MossMan]

Here's a link to Sudden Stratospheric Warming that's a little easier to understand.  If and when one occurs, cold air will go somewhere in the mid-latitudes.  The PNW needs the SSW to coincide with favorable tropic and mid-pattern levels to see the snow/cold.  Our window for that may be closing, although there are plenty of other scenarios that could still deliver the goods. The GFS does seem to be coming on board for a SSW.  I don't have access to the ECMWF.

 

ftp://ftp.cpc.ncep.noaa.gov/long/misc/SSW_Poster_new.pdf

Thanks Chris!!

 

Hit 19 for a second day!

[SilverFallsAndrew]

So is the 12z slightly better than the 6z or about the same?

 

Looks slightly better on the parallel, to me the Operational is about the same.

[SilverFallsAndrew]

Central and E. Oregon have over performed a lot in the past 4-5 years. After about 15 years of generally under performing. 

[Gradient Keeper]

Parallel GFS gets pretty close on the 12z, like it wouldn't take much for at least the N. Interior to see some cold outflow.

Yeah, fairly close.... 12z NAM was heading the right direction and looks completely different from the Op/Parallel at HR 84.

[SilverFallsAndrew]

You know once we get out into the day 7-10 period on the GFS things look pretty Ninoish. Cold east kind of splitty action out west, a lot of cold up in W. Canada, if the pattern was a little more organized and less meandering we could be in business.

[luvssnow_spokane]

Got down to 19.4 last night - dew point of 18. Nice.    Winds light from the NE so it feels like 13. 

[SilverFallsAndrew]

Yeah, fairly close.... 12z NAM was heading the right direction and looks completely different from the Op/Parallel at HR 84.

 

What the NAM shows looks sort of unlikely to me. Its interesting and looks like it has potential, but I'm not sure if the NAM ran out to 180 hours or whatever that it would actually end up anywhere good despite the promise I think it would probably still shunt east...

[westiztehbest]

Traveling to Winthrop .  I was surprised over how NOT cold the Columbia Basin was yesterday.  30-32f through the Gorge, same for the Yakima Valley.  Only cold spots were the passes.  Ellensburg was only slightly colder at 28f when we went through around 3pm. Satus was 16f and Blewett Pass was 14f.  Only places with snow cover were the passes.  Leavenworth was chilly at 20f at 4pm (9f this am) and about 4-5" snow.  Felt like winter there.  But overall it just wasn't cold at all in the basin.  Very little wind  overall in the Gorge yesterday too.  Spent the night in Leavenworth, heading to Winthrop this am.  Currently 6.5f but even there looks to moderate into the mid 20's but at least they have good snow on the ground. 

 

The mildness (during the day) you're referring to is generally confined to the Western Basin.  Last Saturday those areas in NW flow were rain-shadowed while the East Basin Rise saw 2-4" in snowfall.  Much colder over here because of it.  7F currently.

 

Def liking the 6z.  Stays cold with snow chances throughout.

[SilverFallsAndrew]

IDK whether this should make me laugh or cry...

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014123112/gfsp_z500a_namer_35.png

[SilverFallsAndrew]

Really bizarre progression.

[HighlandExperience]

Yeah, fairly close.... 12z NAM was heading the right direction and looks completely different from the Op/Parallel at HR 84.

 

I was pleaseantly suprised by how coolish the NAM looked for northern areas going into the weekend. Might be a bit overdone, but that looks better.

 

 

http://www.atmos.washington.edu/mm5rt/data/current_nam/images_d2/slp.72.0000.gif

[SilverFallsAndrew]

Arctic blast hour 384. Done deal.

[Gradient Keeper]

Arctic blast hour 384. Done deal.

Parallel looks interesting after day 8 and you're right, strange progression...

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014123112/gfsp_z500_mslp_namer_41.png

[Front Ranger]

Here's a link to Sudden Stratospheric Warming that's a little easier to understand.  If and when one occurs, cold air will go somewhere in the mid-latitudes.  The PNW needs the SSW to coincide with favorable tropic and mid-pattern levels to see the snow/cold.  Our window for that may be closing, although there are plenty of other scenarios that could still deliver the goods. The GFS does seem to be coming on board for a SSW.  I don't have access to the ECMWF.

 

ftp://ftp.cpc.ncep.noaa.gov/long/misc/SSW_Poster_new.pdf

 

Then again, many PNW cold waves have occurred without SSW, so...

[Front Ranger]

The 15 at the Silverton mesonet station was pretty impressive. Better than anything they saw in January 2013 or Dec 2010. About on par with January 2008 at that location.

 

Pretty lame showing for most of western WA. At least for the major stations and usual cold spots.

[Gradient Keeper]

Lots of potential if you ask me with 12z GFS Op/Parallel...

[MossMan]

Pretty lame showing for most of western WA. At least for the major stations and usual cold spots.

Not sure what Arlington's official low was, but I hit 19. Not terrible, was hoping for mid teens though. If we had snow cover we would have been in better shape for sure. 

[MossMan]

Lots of potential if you ask me with 12z GFS Op/Parallel...

I wonder if NWS Seattle will mention anything during their morning AFD. Last evenings AFD was super in-depth and detailed about the complex pattern which was great to read.

[TT-SEA]

I was pleaseantly suprised by how coolish the NAM looked for northern areas going into the weekend. Might be a bit overdone, but that looks better.

 

 

http://www.atmos.washington.edu/mm5rt/data/current_nam/images_d2/slp.72.0000.gif

 

 

WRF looks about the same for Saturday... unfortunately after this point the warm air is pulled northward.

 

http://www.atmos.washington.edu/mm5rt/data/current_gfs/images_d2/slp.84.0000.gif

[Guest Winterdog]

Hit 19F despite the high clouds.  Currently 20F with the promise of another beautiful day ahead.

[Phil]

Then again, many PNW cold waves have occurred without SSW, so...

True, but it's virtually impossible for the PNW to score with a barotropic PV forcing regimen..it just needs to be disturbed, not obliterated.

 

The biggest winters in PNW history do tend to follow SSW events.

[Guest Winterdog]

Not sure what Arlington's official low was, but I hit 19. Not terrible, was hoping for mid teens though. If we had snow cover we would have been in better shape for sure.

It looks like Arlington came in with a 19F as well.

[TT-SEA]

Sunday per the 12Z WRF:

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.108.0000.gif

[bainbridgekid]

Looks like they saw snow down to 1-2000 feet in San Diego this morning.

 

http://fox5sandiego.com/2014/12/31/cold-storm-brings-heavy-rain-snow-to-san-diego-county/

[HighlandExperience]

Sunday per the 12Z WRF:

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.108.0000.gif

 

 

By Hour 129 the cold air is trying to move southward again, but is shunted off unfortunately. This still looks better than what the models were showing the other day.

 

The good news is that the North Cascades are going to get hammered with snow this coming weekend.

 

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.129.0000.gif

[TT-SEA]

12Z Canadian for Sunday afternoon...

 

http://img.meteocentre.com/models/gemglb_amer_12/GZ_D5_PN_132_0000.gif

[MossMan]

By Hour 129 the cold air is trying to move southward again, but is shunted off unfortunately. This still looks better than what the models were showing the other day.

 

The good news is that the North Cascades are going to get hammered with snow this coming weekend.

 

 

http://www.atmos.washington.edu/mm5rt/data/current_extended/images_d2/slp.129.0000.gif

Yeah if the positive trends continue we might just end up in business. Much better than yesterdays runs and that is what matters!

[MossMan]

12Z Canadian for Sunday afternoon...

 

http://img.meteocentre.com/models/gemglb_amer_12/GZ_D5_PN_132_0000.gif

What does Saturday's GEM map look like?

[TT-SEA]

What does Saturday's GEM map look like?

 

http://img.meteocentre.com/models/gemglb_amer_12/GZ_D5_PN_108_0000.gif

[MossMan]

http://img.meteocentre.com/models/gemglb_amer_12/GZ_D5_PN_108_0000.gif

Thanks! If nothing else it will be quite interesting watching the models try and resolve this weekend and into next weeks weather.

[Gradient Keeper]

Canadian trough digs noticeably southwestward day 8-10

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014123112/gfsp_z500a_namer_41.png

[Gradient Keeper]

Hmmm......