December 2016 Observations and Model Discussion for the Pacific Northwest

[SilverFallsAndrew]

1950 had a couple days near 50 at PDX with SSW winds thrown in there. Note by note redux still on the table.

 

Yeah I think Salem and EUG hit mid 50s at least once. 

[Brennan]

If only the Euro went out to 384.

 

This is likely shaping up to be our best January locally, for snow/cold combined, since at least 1980. That's longer than many of us have lived!

We could easily fall to January 2012, 2007, 2005 and 2004, 1998, 1996,1993, and 1991 here in Bellingham if we don't manage more than a few inches between now and next friday. We managed 6-24 inches in each of those Januaries. 

Seattle could come in behind 2007, 2004, and 1996 as well. I think they had 6+ in both, no?

 

Having said this... I could see SEA easily scoring 12"+ in the first 10 days of the month, blowing any January in the past 30 years out of the water. Still waiting for that big haymaker! 

 

The forecast models past day 5 are going to flux for awhile. These types of patterns are rare and they won't have a handle on it until at least the first blast comes in here early next week. 

[Brennan]

1950 had a couple days near 50 at PDX with SSW winds thrown in there. Note by note redux still on the table.

BLI even had a couple days up there near 50 in Jan 1950... January 1969 was impressive in that the entire month was like a complete landslide. Started in the mid 40's and just got colder and colder all month without any moderation.

[Jesse]

I've been loving watching the 500mb pattern progress here. The cutoff low is about to form.

 

http://www.atmos.washington.edu/~ovens/loops/wxloop.cgi?sat_500+9

[Deweydog]

Not to be a downer.. But it is a little disappointing that we still seem to be having trouble achieving a full on arctic outbreak with a North to South orientation. That is what the Puget Sound area needs for a very snowy pattern. Seems like almost all of our modified arctic blasts have this NE or ENE orientation and everything is just a couple hundred miles too far east to produce a real snowmaker.

 

Having said that, the reloads advertised for next weekend on yesterday's runs were pretty much exactly that.

Yeah, this initial shot is probably as cold or slightly colder at PDX. If more of a battle ground setup occurs, you guys will likely lap most of us.

[BLI snowman]

BLI even had a couple days up there near 50 in Jan 1950... January 1969 was impressive in that the entire month was like a complete landslide. Started in the mid 40's and just got colder and colder all month without any moderation.

 

We had a regional SW flow warmup after the late December 1968 craziness, and then a lot of cold onshore flow until around the 20th of January.

[Front Ranger]

12z GFS shows healthier snow amounts for King County than 06z. More widespread 1-3 inches, with around 4 as you get closer to the Cascades.

 

Looks like solutions are settling around the 1-3 mark in general.

Exact amounts and location of model accumulations still means very little in these Arctic front situations. So unpredictable, but a slightly better guide is probably what happened historically with such fronts.

[ShawniganLake]

BLI even had a couple days up there near 50 in Jan 1950... January 1969 was impressive in that the entire month was like a complete landslide. Started in the mid 40's and just got colder and colder all month without any moderation.

Not sure if BLI has records back to 1916 but for Shawnigan lake that January set the bar for sustained cold. Only 1 high above 35 and that was 46F. Everyday managed a low of 32F or below.

[luvssnow_spokane]

Exact amounts and location of model accumulations still means very little in these Arctic front situations. So unpredictable, but a slightly better guide is probably what happened historically with such fronts.

Agreed! Pretty much every arctic front that I have experience that has had a strong push usually has resulted in better QPF amounts overall. I do think it will be on the higher end of 2-3 inches at least for King and Pierce counties. 

[Deweydog]

Exact amounts and location of model accumulations still means very little in these Arctic front situations. So unpredictable, but a slightly better guide is probably what happened historically with such fronts.

Especially from Chehalis-north or so. This happens every time we see an Arctic front in the offing. Everyone wants to see the high resolution models pick up every nuance days and days in advance. Not gonna happen.

[jaya]

Would be interested in hearing from Phil, jaya, IBR, et al and their opinions on then longevity of the block. They seemed pretty bullish a few days ago.

Don't know.  Too far out.  Things do break down eventually. Even in longer lasting cold years (1950) there were brief warm ups following reloads.  Anything goes.

[Heavy Snow]

Don't know. Too far out. Things do break down eventually. Even in longer lasting cold years (1950) there were brief warm ups following reloads. Anything goes.

Yeah exactly.

[MossMan]

Don't know.  Too far out.  Things do break down eventually. Even in longer lasting cold years (1950) there were brief warm ups following reloads.  Anything goes.

Thoughts about say... I don't know...maybe Northern Snohomish Co and snow this weekend? Any new thoughts?

[stuffradio]

You need a proper ratio of teens to adults. Open up invites to all of us and we'll be sure to bore all those teens into leaving.

"Hey kids, HEY HEY HEY, look at these soundings!"

[snow drift]

I noticed the 12z GFS cut my qpf in half for the Sat-Sun system. I expected as much. Backdoor blasts are rarely good snow producers in the Spokane-CdA area.

[Winterdog]

NWS forecast for Seattle has them bottoming out at 23° through Tuesday and no highs below freezing despite the models trending colder in that period. Possible rain or snow showers. Historic!

[Prairiedog]

Yeah exactly.

My opinion that will separate (for good or not) this from other great years will be if any reloads actually happen. I don't mind if there is a brief warm up but it seems to me that the really good winters have one or more reloads that extend the cold and gives us better chances of snow.  If it's a one and done, it can still be a great event (well good event anyway) but to my in MHO will we get hit a second or third time.

[Perturbed Member]

http://maps1.pivotalweather.com/maps/models/ecmwf/2016122912/240/sfcmslp.conus.png

 

 

Can we keep this low south of PDX? Repeat of the December 2008 storm here please?

[Deweydog]

http://maps1.pivotalweather.com/maps/models/ecmwf/2016122912/240/sfcmslp.conus.png

 

 

Can we keep this low south of PDX? Repeat of the December 2008 storm here please?

The 974mb bomb is driving the ship there.

[snow drift]

http://maps1.pivotalweather.com/maps/models/ecmwf/2016122912/240/sfcmslp.conus.png

 

 

Can we keep this low south of PDX? Repeat of the December 2008 storm here please?

That would be majestic! Usually they bomb out and head for Vancouver Island.

[Perturbed Member]

That would be majestic! Usually they bomb out and head for Vancouver Island.

 

Yeah, the current track on the euro looks good but too bad its so far out. I think this is the first run that even shows this solution. 

[Perturbed Member]

The 974mb bomb is driving the ship there.

 

Would be a real heart breaker if we got all of this cold and we transitioned out of it with a quick burst of strong south winds from some low bombing out heading to Vancouver island.

 

We'd better have some snow to show for this -15c 850mb cold we're about to get.

[Heavy Snow]

My opinion that will separate (for good or not) this from other great years will be if any reloads actually happen. I don't mind if there is a brief warm up but it seems to me that the really good winters have one or more reloads that extend the cold and gives us better chances of snow.  If it's a one and done, it can still be a great event (well good event anyway) but to my in MHO will we get hit a second or third time.

 

Yeah good points. What I suspect will happen is a L will track to your south like the 2nd winter storm we had earlier this month but this time more widespread and snowier sending snow even up to SEA/YVR. Behind that colder air will pour in and a reload will take place.

[ShawniganLake]

That would be majestic! Usually they bomb out and head for Vancouver Island.

[Perturbed Member]

The bigger picture...

 

 

http://maps1.pivotalweather.com/maps/models/ecmwf/2016122912/240/sfcmslp.na.png

 

 

Yeah, I didn't notice the real low there earlier.

[Deweydog]

Those solutions are subject to change.

 

-God

[snow drift]

IMG_0440.PNG

There we go! Order is restored. I imagine it would take a monster block to keep that low south of PDX.

[Perturbed Member]

FWIW, the Euro ensemble mean for snow at PDX through the run is about 11 inches now.  Ensembles signaling significant snow sometime between the 7th and 9th of Jan. Out of the 52 members, I only see 2 that have under 2 inches of snow and the vast majority of them have 6+ and quite a few are much higher. 

[SilverFallsAndrew]

I can think of a long list of arctic blasts that ended without much snow...

 

Feb 1989

Dec 1990

Feb 1996 (ZR)

Dec 1998 (2" at PDX, but not much widespread and it melted QUICK)

Dec 2009

Dec 2013

[Heavy Snow]

I just noticed the 12z EURO shows that small system drop down the coastline on Thursday. It's very weak though but still manages to drop some light snow across the most western parts of mostly WA but also some in NW Oregon. Looks like a dusting to 0.5" NW Oregon/Puget Sound, 0.5" to 1" North PDX Metro to South Puget Sound and the biggest amounts 1"-2" western WA out to the Coast.

[Phil]

Would be interested in hearing from Phil, jaya, IBR, et al and their opinions on then longevity of the block. They seemed pretty bullish a few days ago.

Still bullish. Should be a 2-3 week wavebreak cycle, perhaps longer duration blocking/troughing should conduit for momentum deposition to PV/NAM remain viable.

[Deweydog]

I can think of a long list of arctic blasts that ended without much snow...

 

Feb 1989

Dec 1990

Feb 1996 (ZR)

Dec 1998 (2" at PDX, but not much widespread and it melted QUICK)

Dec 2009

Dec 2013

Don't forget November 2010 and November 2006!

 

Still plenty to be upset about. It's a good Thursday.

[Heavy Snow]

Still bullish. Should be a 2-3 week wavebreak cycle, perhaps longer duration blocking/troughing should conduit for momentum deposition to PV/NAM remain viable.

 

Glad to hear that.

[Timmy]

FWIW, the Euro ensemble mean for snow at PDX through the run is about 11 inches now.  Ensembles signaling significant snow sometime between the 7th and 9th of Jan. Out of the 52 members, I only see 2 that have under 2 inches of snow and the vast majority of them have 6+ and quite a few are much higher. 

12z or 00z?

[snow drift]

I expect a sloppy pattern here next weekend. It wouldn't be too far fetched. There is still time for things to change though.

[SilverFallsAndrew]

Don't forget November 2010 and November 2006!

 

Still plenty to be upset about. It's a good Thursday.

 

I was just including major regionwide blasts. In fact it is a lot harder to find recent examples that transitioned out with a major overrunning event. The major overrunning events are more "battleground" type scenarios. 

[Perturbed Member]

12z or 00z?

 

00z, sorry should have mentioned.

[BLI snowman]

I can think of a long list of arctic blasts that ended without much snow...

 

Feb 1989

Dec 1990

Feb 1996 (ZR)

Dec 1998 (2" at PDX, but not much widespread and it melted QUICK)

Dec 2009

Dec 2013

 

I would say that December 1998 was pretty widspread, just not much south of Portland.

 

The Willamette Valley is a lot more susceptible to south wind mixing down and 850mb warm tongues of course, so it becomes much more of a guessing game once you get down there.

 

The Portland and Lower Mainland B.C. areas on the other hand are pretty much assured some frozen precip in any juicy transition out of a fully cooked arctic airmass. 

[SilverFallsAndrew]

I would say that December 1998 was pretty widspread, just not much south of Portland.

 

The Willamette Valley is a lot more susceptible to south wind mixing down and 850mb warm tongues of course, so it becomes much more of a guessing game once you get down there.

 

The Portland and Lower Mainland B.C. areas on the other hand are pretty much assured some frozen precip in any juicy transition out of a fully cooked arctic airmass. 

 

December 1998 wasn't that great though. I went to Portland for some last minute Christmas shopping that afternoon and it was pouring rain. 

[Deweydog]

I was just including major regionwide blasts. In fact it is a lot harder to find recent examples that transitioned out with a major overrunning event. The major overrunning events are more "battleground" type scenarios.

The warm nose is already moving it's way of the west slopes toward Silverton.

 

I hadn't really thought about December 1998, we had probably 3-4 inches here with that, but it was a fairly quick transition. That was a bummer too because the models were pretty gung ho with a protracted event followed by a second shot of cold air until about three days out. A little guy known as the body of water on the planet won that battle. She's due for a loss!!!