January 2016 in the PNW

[snow_wizard]

I have to say, at the 500mb level this is probably one of the wonkiest looking snow events we have ever had.

 

I was just going to post the same thing.  Fascinating to see how oddball ULL  is directing and enhancing the moisture stream from the southern low.  The models are pretty lost with that relationship.  Looks like the moisture stream may effect this area soon.

[BLI snowman]

The 1,000ft snow level mention seems pretty strange too. Feels like that is their default when things look uncertain.

 

They wanted to go down with their ship.

[bainbridgekid]

Cold air tends to build in places that get little solar heating and that are isolated from bodies of water (i.e. east of the Cascades in the winter). The same mechanisms that build our local cold airmasses are the ones that build the cold airmasses at the poles, albeit on a smaller scale.

 

That's why the term "fake cold" has always seemed so strange to me. Cold is cold is cold. It can even give us snow sometimes, like today!

I always think of "fake cold" as being when we sit under a huge ridge of high pressure with a strong inversion. Seems more appropriate then.

[snow_wizard]

Strongest WWB of the year thus far predicted on the GFS. Might slow down current reversal but due to the nature of the thermocline in a Niño like this, it won't lead to much SST warming.

 

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That's kind of a bummer.  As you say though there is so much cold subsurface water in the picture now it may not due much.

[Phil]

The shutdown in the W-IO/E-MT forcing may be quite prolonged. Going to make it tough to sustain any sort of -PNA.

[MossMan]

Perfect day, I'll I want now is the Seahawks to lose to balance out all this positivity due to snow.

Meaningless game for the Hawks so it won't matter much.

25 degrees here currently under mostly clear skies. A few clouds to the south of me though! Might need to measure the frost on the portion of my deck that doesn't get sun...it's getting quite thick!

[MossMan]

[Phil]

That's kind of a bummer.  As you say though there is so much cold subsurface water in the picture now it may not due much.

It'd be hilarious if this ended up morphing into a multi-year Niño or La Nada for 2016-17. I highly doubt that will be the case, but it'd make for an interesting analoging experience.

[HighlandExperience]

I was just going to post the same thing.  Fascinating to see how oddball ULL  is directing and enhancing the moisture stream from the southern low.  The models are pretty lost with that relationship.  Looks like the moisture stream may effect this area soon.

 

You have to admit after the cold rain last week, the dry weather today is heart breaking. 

 

The experimental HRRR tries to bring a little moisture into the southern half of King County. 

[MossMan]

That cold air at the border coming does look promising, a few more model improvements and western wa might actually be in business for the first time in many years!

[bainbridgekid]

12z also shows widespread lowland snow next weekend with a weak low moving into the South Washington Coast and an arctic high in BC.

 

Details are meaningless a week out, but it's nice to see the potential. Several chances for snow coming up, which greatly increases the odds of one actually working out.

 

[Perturbed Member]

Cold air tends to build in places that get little solar heating and that are isolated from bodies of water (i.e. east of the Cascades in the winter). The same mechanisms that build our local cold airmasses are the ones that build the cold airmasses at the poles, albeit on a smaller scale.

 

That's why the term "fake cold" has always seemed so strange to me. Cold is cold is cold. It can even give us snow sometimes, like today!

 

I understand that, but it is generally hard for us to locally produce air this cold since so many things have to be set up just right, keeping the influence of the ocean at bay for long enough for the airmass to cool this much is itself a difficult thing for us to do. 

 

I know scientifically there is no distinction between us getting cold air out of the north and us cooling our own airmass over a few days of offshore flow and clear nights. "fake cold" is not a true meteorological term but it seems we are kind of using it to distinguish getting an arctic blast from somewhere else vs an airmass that has locally cooled off and is cold especially near the surface. 

[snow_wizard]

I have a bit of De Javu from Feb 2014 here. PDX getting a nice snowstorm while Seattle gets nothing. Completely different setup and SEA actually did get some snow in feb 2014, but considering there is less precip than that storm it reminds me of a less precip version of 2014. 

 

This is far from over.  Have you been looking at the models?

[snow_wizard]

The 12z GFS is freeking amazing!  A full blown snowstorm with strong Fraser outflow.

[snow_wizard]

Why is everyone talking like the Seattle area has missed out on this?

[FroYoBro]

It seems that the Portland metro area is in the exact right spot for this setup. Incredibly lucky and awesome.

 

It has actually turned back to all snow and it is falling pretty moderately here. 

[HighlandExperience]

The 12z GFS is freeking amazing!  A full blown snowstorm with strong Fraser outflow.

 

That is interesting long term. Short term this would satisfy me. 

 

S PRECIPITATION

IS EXPECTED WITH LITTLE OR NOTHING NORTH OF EVERETT. MOST GUIDANCE

SUGGESTS ONLY TRACE TO LOCALLY ONE HALF INCH OF SNOW POSSIBLE

INCLUDING THE TACOMA-SEATTLE-BELLEVUE-BREMERTON AREAS. THIS IS SUB-

ADVISORY BUT WILL NEED TO UPDATE THE FORECAST TO INDICATE A CHANCE OF

SNOW RATHER THAN A MIX BUT WILL NOT BOOST POPS MUCH NORTH OF

OLYMPIA. 

[FroYoBro]

Why is everyone talking like the Seattle area has missed out on this?

 

I wouldn't be surprised to see Washington to do really well in the next few weeks while we are a little too warm down here. I am willing to share the fun! 

[Phil]

Thanks Phil for kicking us Puget Sounders down even more!

You can take solace in the fact that your region is in for a major pattern reversal over the next 2-3 years. I'm preparing myself for an extended blowtorch this summer and beyond, for the time being.

[Jesse]

Why is everyone talking like the Seattle area has missed out on this?

Missed out on what? It's just been a ZR and sleet storm down here.

[MossMan]

Why is everyone talking like the Seattle area has missed out on this?

Because they have...for today and tomorrow. Next weekend could be a whole different story though!

[Phil]

Ridiculous +AAM surge right now. Man, when this propagates poleward, the STJ will go on all kinds of roids.

 

I think California will finally get their paycheck.

[FroYoBro]

Missed out on what? It's just been a ZR and sleet storm down here.

 

Don't quit your day job. 

[stuffradio]

SW BC has missed out also.

[Phil]

So, poleward AAM propagation --> Pacific jet igition --> Brief warm shot across nation in late January. Overall, the ongoing flip to -NAM/+PNA will sustain, minus a few ups and downs.

[Gradient Keeper]

12z GEM shows what many previous runs suggested. A lot more frozen precip possible Tuesday night-Wednesday morning, probably freezing rain. It looks like a PDX-DLS gradient of 6mb is still going, so cold east wind would keep the lowest levels perhaps near/below freezing. It's not a lock, but we need to watch this closely and see how much we scour before Tuesday afternoon. ... And that's not all. BUT WAIT.... There's more! Interesting system Friday night-Saturday sliding southeast giving PDX Sleet/Snow with cooling aloft. This also suggests what I mentioned in my 12z GFS analysis about suppressed jet. After that system departs a major blast heads south into the Columbia Basin with a VERY strong PDX-DLS gradient. I'll post images below. This is exactly the potential I was mentioning. This is before day 10, yes, still a long ways out, so things can change. Baby steps. Cautiously optimistic.

[Perturbed Member]

Looking like PDX will most likely be able to stay all snow for most of the event. 2-4 inches should be pretty easy to achieve if we can stay snow. 

[TT-SEA]

Moisture does not seem to be slowing down on its northward trek. Very similar to what the 00Z ECMWF showed.

[MossMan]

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE SEATTLE WA

949 AM PST SUN JAN 3 2016

 

WAZ504-032330-

/O.NEW.KSEW.WW.Y.0001.160103T2200Z-160104T1000Z/

SOUTHWEST INTERIOR-

949 AM PST SUN JAN 3 2016

 

...WINTER WEATHER ADVISORY IN EFFECT FROM 2 PM THIS AFTERNOON TO

2 AM PST MONDAY...

 

THE NATIONAL WEATHER SERVICE IN SEATTLE HAS ISSUED A WINTER WEATHER

ADVISORY FOR THE SOUTHWEST INTERIOR OF WESTERN WASHINGTON...WHICH

IS IN EFFECT FROM 2 PM THIS AFTERNOON TO 2 AM PST MONDAY.

 

* TIMING...LIGHT SNOW OR FLURRIES WILL DEVELOP BY 2 PM THIS

AFTERNOON. STEADY LIGHT SNOW IS LIKELY BY THIS EVENING INTO THE

EARLY MONDAY MORNING HOURS. SNOW WILL TRANSITION TO RAIN OR

MIXED PRECIPITATION MONDAY MORNING.

 

* AMOUNTS...ONE TO LOCALLY 2 INCHES OF SNOW IS POSSIBLE. THE MOST

LIKELY TIME FOR SNOW ACCUMULATION WILL BE FROM EARLY THIS

EVENING THROUGH EARLY MONDAY MORNING.

 

* MAIN IMPACT...ROADS WILL BECOME SLIPPERY AS TEMPERATURES WILL

LIKELY STAY NEAR OR BELOW FREEZING. THIS INCLUDES THE I-5

CORRIDOR FROM OLYMPIA SOUTHWARD THROUGH LEWIS COUNTY.

 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

 

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW WILL CAUSE

TRAVEL DIFFICULTIES. BE PREPARED FOR SLIPPERY ROADS AND LIMITED

VISIBILITIES...AND USE CAUTION WHILE DRIVING.

[snow_wizard]

It'd be hilarious if this ended up morphing into a multi-year Niño or La Nada for 2016-17. I highly doubt that will be the case, but it'd make for an interesting analoging experience.

 

With that huge subsurface cold pool that has been building steadily I really doubt it.

[Gradient Keeper]

12z GFS 6-10/8-14 Day Composite Analogs look outstanding

[snow_wizard]

Because they have...for today and tomorrow. Next weekend could be a whole different story though!

 

How do you know this?

[TT-SEA]

New 12Z ECMWF has copious precip for WA... including the Seattle area. WRF and HRRR are just wrong. More precip up here in the end than in Portland.

[SilverFallsAndrew]

New 12Z ECMWF has copious precip for WA... including the Seattle area. WRF and HRRR are just wrong. More up here in the end than in Portland.

 

I agree you can see it pretty clearly in real time on radar.

[BLI snowman]

Starting to pick up here. Maybe a little more than an inch now.

[Phil]

With that huge subsurface cold pool that has been building steadily I really doubt it.

I'm with you on this one, but stranger things have happened.

[HighlandExperience]

[snow_wizard]

New 12Z ECMWF has copious precip for WA... including the Seattle area. WRF and HRRR are just wrong. More precip up here in the end than in Portland.

 

Wow!

 

You can already see a steady stream on the radar coming into the East Puget Sound lowlands.  Interestingly the outflow doesn't seem to be killing it.  It appears the SW quadrant of the ULL is where the big action is.  Some of the models have missed the role the ULL is playing in this.

[Jesse]

Snowing moderately again. This is turning into a nice little event.

[MossMan]

Starting to pick up here. Maybe a little more than an inch now.

Your name still throws me off, keep thinking you are reporting from Whatcom Co.