December 2014 Observations for the Pacific Northwest

[Snow]

I really don't think the public expects more than 2 days warning for snow.

 

Any significant cold is still 3-4 days out and there is not really any major snow potential so I can totally understand why the TV mets would be conservative.

Yeah hoping we get more clarity with the moisture coming with this initial cold air. With these lows coming from the NW it doesn't take much to produce nice accumulations. If I remember correctly the low that dropped from the NW during the first Arctic blast last winter wasn't all that juicy and Corvallis/Eugene got big amounts.

[MikeInEverett]

How about that Parallel AGAIN!?! http://www.tropicaltidbits.com/analysis/models/gfsp/2014122506/gfsp_z500_mslp_namer_41.png

[bainbridgekid]

How about that Parallel AGAIN!?!

4 straight runs to show something similar to that at day 10.

 

Operational is totally different so it's an interesting battle setting up.

 

http://www.tropicaltidbits.com/analysis/models/gfs/2014122506/gfs_z500_mslp_namer_36.png

[Snow]

[Gradient Keeper]

Parallel was delayed a bit.... but you can see what's coming day 10 and after... major blast

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014122506/gfsp_z500a_namer_41.png

[Gradient Keeper]

I want 507 heights, 494 thickness for PDX by January 3rd-6th lol

[Perturbed Member]

Yeah hoping we get more clarity with the moisture coming with this initial cold air today. With these lows coming from the NW it doesn't take much to produce nice accumulations. If I remember correctly the low that dropped from the NW during the first Arctic blast last winter wasn't all that juicy and Corvallis/Eugene got big amounts.

 

In my experience PDX usually struggles to get any good snow totals as the cold air is arriving. The biggest snow storms here almost always seem to be in the form of overrunning precip from a low coming out of the SW which keeps the easterly gradient going, in all of those cases the cold air is already in place (Jan 2004, Dec 2008, Feb 2014). Not saying this couldn't give us some snow but I doubt that will turn into a massive snow maker here. 

[Snow]

In my experience PDX usually struggles to get any good snow totals as the cold air is arriving. The biggest snow storms here almost always seem to be in the form of overrunning precip from a low coming out of the SW which keeps the easterly gradient going, in all of those cases the cold air is already in place (Jan 2004, Dec 2008, Feb 2014). Not saying this couldn't give us some snow but I doubt that will turn into a massive snow maker here.

Good points, I'll be happy if we can go into this cold air with at least 2 inches.

[Perturbed Member]

Good points, I'll be happy if we can go into this cold air with at least 2 inches.

 

Yeah, an inch or two would be great and would help with those temps. 

 

I think we are nearing the point where the initial cold blast is starting to look like a lock. I think the models have finally agreed on this solution. If the 12z runs show the same thing, I'll feel pretty confident. 

[Gradient Keeper]

*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*.*
*.*.*. MERRY CHRISTMAS .*.*.*
6z GFS Extracted Data for those who don't want to scan through the models. In the short term days 4-8 this was the coldest Op run by far, but not only that, for PDX metro-Clark County-Foothills, a new possible concern is showing up on this run. A possible damaging downslope wind storm Monday through Wednesday. I added a few more cities, because Christmas! Keep in mind GFS Parallel was quite a bit colder at 850mb and thickness values than what is shown here.

[Portland-Troutdale]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KTTD
[salem]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KSLE
[The Dalles]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KDLS
[Moses Lake]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KMWH
[seattle]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KSEA
[bellingham]
http://wxweb.meteostar.com/sample/sample.shtml?run=2014122506&text=KBLI

[MR.SNOWMIZER]

Merry Christmas!

[Snow]

[IbrChris]

Merry Christmas folks!

Figured I'd have a looksie at 00z ensembles since I'm working this Christmas morn. 00z because frankly who looks at 06z anyway? You? Me neither.

00z GFS

D6-10: 70% place ridge near 50N-140W (no real change). NE flow aloft. Chilly but not real cold. 30% center ridge over SE and E Alaska, still N-NE flow aloft.
D11-15: 80% place ridge over western/central Alaska roughly 150-155W. 20% have ridge in mid con with trough in Bering Sea. About 25% suggest a fairly decent arctic blast.
Hour 360: 85% suggest ridging over Alaska (45%) and over Alaska-YT-NWT (40%), 15% trough over Alaska extending into GoA. 35% suggest an arctic blast for PNW.

00z ECMWF

D6-10: Colder look than GFS across the board...ridge centered 50N-140W but not as broad as GFS. N-NE flow.
D11-15: 38% indicate an arctic blast scenario in PNW while 32% place a ridge over the western US as well as over Bering Sea and 30% keep similar pattern to 6-10 with ridge in Gulf of Alaska and cool but not overly cold temps in the PNW.
Hour 360: 56% show ridge in Alaska...24% favorable for arctic blast in PNW and 32% suggest cool N-NE flow and backdoor potential. 44% indicate a trough just offshore with no arctic air risk.

00z CMC

D6-10: Canadian shows strongest ridge out of the three models and also more favorable centering over southern Alaska nearer 145-150W...as a result most members indicate at least a modified arctic blast in NE flow.
D11-15: Split into two camps: 52% suggest west coast ridging and 47% have very favorable pattern for significant PNW arctic blast with block over western Alaska (160W)
Hour 360: 57% have western US ridge, 42% have strong EPO block centered along 160-170W and major arctic blast into PNW.

Still a ways to go but ensembles are keeping hope alive.

 

[GHweatherChris]

Merry Christmas my fellow nuts!!!!!!!!!!

[Bryant]

Merry Christmas all! Hope everyone has a great day with friends and family

[Gradient Keeper]

Merry Christmas fellow weather geeks

[Gradient Keeper]

HR 48 Op

http://www.tropicaltidbits.com/analysis/models/gfs/2014122512/gfs_z500a_namer_9.png

[Randyc321]

Merry Christmas to the forum.

New member here, but I have been a lurking member of the old forum since about the 2006 windstorm I believe.

 

Guys, my son is driving to Anchorage.  Starting Saturday morning.  He has a great strong 4x4 Dodge 1500, chains, block heater, xtra jerry cans of gas and  water, a passenger, AAA, and a big credit limit.  What do you think he should expect?

 

Thanks a bunch.  He's 27 and has traveled the world, is a master diver, and an outdoorsman, but he's still my son.

[Randyc321]

Merry Christmas to the forum.

New member here, but I have been a lurking member of the old forum since about the 2006 windstorm I believe.

 

Guys, my son is driving to Anchorage.  Starting Saturday morning.  He has a great strong 4x4 Dodge 1500, chains, block heater, xtra jerry cans of gas and  water, a passenger, AAA, and a big credit limit.  What do you think he should expect?

 

Thanks a bunch.  He's 27 and has traveled the world, is a master diver, and an outdoorsman, but he's still my son.

Oh yeah, and if some of the Canada boys would chime in, I would appreciate it.

[Gradient Keeper]

Merry Christmas to the forum.

New member here, but I have been a lurking member of the old forum since about the 2006 windstorm I believe.

 

Guys, my son is driving to Anchorage.  Starting Saturday morning.  He has a great strong 4x4 Dodge 1500, chains, block heater, xtra jerry cans of gas and  water, a passenger, AAA, and a big credit limit.  What do you think he should expect?

 

Thanks a bunch.  He's 27 and has traveled the world, is a master diver, and an outdoorsman, but he's still my son.

Based on models he could run into snow as he heads north of Canadian border Saturday early afternoon, then up through BC should turn cold/dry as he gets through central BC.

[Gradient Keeper]

HR 72 Parallel

http://www.tropicaltidbits.com/analysis/models/gfsp/2014122512/gfsp_z500_mslp_namer_13.png

[Guest Winterdog]

It looks like Santa isn't being as generous as we thought. More like Ho Hum instead of HO HO HO.

[Gradient Keeper]

I'm about 15% awake... but 12z Op look a slight touch warmer.. doesn't seem to carve trough out/hold it over us as 00z did.... Parallel is a touch slower, but looks really cold.... run out to HR 114 now

[Gradient Keeper]

Parallel HR 114 might be over water trajectory ....

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014122512/gfsp_z500a_namer_20.png

[Phil]

It looks like Santa isn't being as generous as we thought. More like Ho Hum instead of HO HO HO.

[SilverFallsAndrew]

The 06z gfs operational was definitely the coldest opo run yet.

[Randyc321]

Based on models he could run into snow as he heads north of Canadian border Saturday early afternoon, then up through BC should turn cold/dry as he gets through central BC.

Thanks DJ.  I was looking at the Whitehorse forecast and it just look D**n cold.  I will look at the Cascade portion of the drive.  That's a good call.

[MossMan]

Merry Christmas!

Let it snow Let it snow Let it snow!

[Snow]

[Gradient Keeper]

Two things about this run... slightly different 500mb, how trough digs, and timing... Op same timing, Parallel slightly delayed.... You sure don't want to see subsequent runs today/tonight delay anything... could just be minor variances and since Ensembles improved it could be not much of any concern... Op it looks like 850mb -8c to -9c PDX, same as 6z. Parallel looked cold. Initial blast still in the cards. We'll find out if we see a 2nd reload or not.... Day 10 is so far out we can only speculate at this point... HOPE SO!

[SilverFallsAndrew]

Two things about this run... slightly different 500mb, how trough digs, and timing... Op same timing, Parallel slightly delayed.... You sure don't want to see subsequent runs today/tonight delay anything... could just be minor variances and since Ensembles improved it could be not much of any concern... Op it looks like 850mb -8c to -9c PDX, same as 6z. Parallel looked cold. Initial blast still in the cards. We'll find out

if we see a 2nd reload or not.... Day 10 is so far out we can only speculate at this point... HOPE SO!

Seems the cold air is always delayed.

 

But usually hangs around longer than modeled at lower levels.

[Gradient Keeper]

The new 12z GFS-Regular has big time reload and snow potential. ❄

 

http://www.tropicaltidbits.com/analysis/models/gfs/2014122512/gfs_T850_nwus_41.png

http://www.tropicaltidbits.com/analysis/models/gfs/2014122512/gfs_mslp_pcpn_frzn_nwus_41.png

Yeah, we're dangerous close to an incredible blast.... Turns bitter as it is.... and looks like a major clash of air masses begins, so someone is going to get big Snow/Ice.....

 

http://www.tropicaltidbits.com/analysis/models/gfs/2014122512/gfs_T2m_nwus_43.png

[Gradient Keeper]

Seems the cold air is always delayed.

 

But usually hangs around longer than modeled at lower levels.

Definitely

[snow_wizard]

This GFS run certainly looks good for the second wave...at least over WA. The numbers seem to be fairly consistent from run to run now on the first shot of cold with 850mb temps bottoming out at -9 or -10 for SEA. The second wave looks much better for snow prospects assuming the models have any idea what is really going on at the range.

 

Form an MJO standpoint...you couldn't hope to see a much better forecast if you want it to be cold in the PNW. The trend has been for the wave to be slightly slower moving and more robust which can only be a good thing as it moves through regions 4 and 5.

[snow_wizard]

Seems the cold air is always delayed.

 

But usually hangs around longer than modeled at lower levels.

I don't really see where it's delayed at all.

[Gradient Keeper]

Tons and tons of exhausting model riding ahead...

[SilverFallsAndrew]

I don't really see where it's delayed at all.

Haven't seen the run. Just was commenting on what DJ said.

[Snow]

Yeah, we're dangerous close to an incredible blast.... Turns bitter as it is.... and looks like a major clash of air masses begins, so someone is going to get big Snow/Ice.....

 

http://www.tropicaltidbits.com/analysis/models/gfs/2014122512/gfs_T2m_nwus_43.png

Yeah I'm hoping for an early January 1980 repeat where everybody can score.

[Gradient Keeper]

YIKES! Op gives Portland over 2.50" of Sleet or ZR... that could lead to a catastrophic ice storm

 

Again beyond day 10, so can't take it seriously yet....

[SilverFallsAndrew]

The operational gets close with the reload. It is just slightly warmer with the initial push. Closer to the 06z.