February Weather in the Pacific Northwest

[ShawniganLake]

Fwiw, the 3km NAM did really well with the snowfall in the Vancouver area yesterday. It was very much in line with the euro with that.

[pscz1140]

The 06Z ICON is a work of art.

The 12Z ICON now shows 4-5 inches of snow around Seattle on Sunday. It feels like (I hope?) this model pics up the meso details pretty well, but who knows....

[MR.SNOWMIZER]

So far low is stronger on 12z for sat.

[ShawniganLake]

It gets a lot of flack on this board but it's really not as bad as what everyone makes it out to be.

 

I can point to numerous instances where it was more accurate than the GFS for snow events.

Better than the GEM too.

[Front Ranger]

It gets a lot of flack on this board but it's really not as bad as what everyone makes it out to be.

 

I can point to numerous instances where it was more accurate than the GFS for snow events.

Yeah, as far as precip in the short range goes, it's one of the best tools we have.

[ShawniganLake]

Looks like the gfs is trying to dig the trough a little further west this run.

[TT-SEA]

Amazing to zoom in at the snow line. That has always fascinated me.

 

Even more cool when the rising sun is just shining on the snowy part of the ridge...

 

[TT-SEA]

Total snow through Sunday afternoon per the 12Z GFS... focusing on the south Sound again.

 

[HighlandExperience]

Total snow through Sunday afternoon per the 12Z GFS... focusing on the south Sound again.

 

Swamp does well

[MR.SNOWMIZER]

Total snow through Sunday afternoon per the 12Z GFS... focusing on the south Sound again.

 

Must be weak surface low south of that snow line causing heavier totals.

[TT-SEA]

Must be weak surface low south of that snow line causing heavier totals.

 

I think its upslope from the arctic front.  

[Timmy]

It’s looking more like the 00z last night than the 06z

[HighlandExperience]

I think its upslope from the arctic front.

You mentioned that last night as well. Looks like northern pierce and se king county might get decent totals.

[MR.SNOWMIZER]

Cold run so far.

[FroYoBro]

The GFS isn't backing down with the colder solution that it latched onto yesterday. 

[seattleweatherguy]

FXUS66 KSEW 151120

AFDSEW

 

Area Forecast Discussion

National Weather Service Seattle WA

320 AM PST Thu Feb 15 2018

 

.SYNOPSIS...A front will bring rain tonight and Friday. A much

stronger frontal system will bring more rain along with windy

conditions and heavy snow in the mountains Friday night and

Saturday. Fraser outflow will develop Sunday with colder

temperatures and possible lowland snow showers. It will be dry

and cold early next week with offshore flow.

 

&&

 

.SHORT TERM...A few showers will linger today in somewhat moist

onshore flow. A front will bring rain tonight and Friday with some

breezy to locally windy conditions. Advisory amounts of snow look

likely for the Cascades with fairly low snow levels. There will

be a modest and brief lull in between weather systems Friday

evening. A vigorous frontal system will then bring another round

of rain later Friday night and Saturday. This system looks a notch

windier - probably advisory levels for some areas. It will also

be wetter with heavy snow possible for the mountains. Schneider

 

.LONG TERM...A cold upper trough will settle over the area Sunday.

At the same time, strong Fraser outflow will develop, pushing a

modified arctic front south through Western Washington during the

day. There could be some snow in the lowlands, especially along

the arctic boundary that pushes south but it is too far out to

pin down details like timing or accumulations. Dry northerly flow

aloft will prevail Monday through Wednesday. Fraser outflow will

ease Monday but cold air will remain in place. A weak system

dropping down from the north could bring some rain or snow showers

Wednesday. Schneider

 

&&

 

.AVIATION...Northerly flow aloft becoming northwesterly this

morning with the northwesterly flow aloft continuing into Friday.

Rain out ahead of an approaching warm front will move into the

tonight into the early morning hours on Friday.

 

Wide variety of ceilings this morning with mostly MVFR between

Olympia and Bellingham with some isolated IFR/LIFR in the Bremerton

and Shelton and VFR over the remainder of the area. Ceilings will

improve to VFR over most of the area later this morning into the

afternoon hours with ceilings lowering back down to MVFR overnight

with light rain. Local visibilities 3-5sm after midnight with the

light rain.

 

KSEA...Scattered to broken deck around 1000 feet early this morning

will scatter out by mid morning with just mid and high level clouds

this afternoon. Ceilings lowering back down to near 2000 feet after

midnight with light rain. South to southeast wind 4 to 8 knots into

Friday morning. Felton

 

KSEA...

[Esquimalt]

The GFS isn't backing down with the colder solution that it latched onto yesterday. 

Yep it's looking better.  Alaska ridge is a bit fatter at hour 144 on this one though.  Hopefully it doesn't extend too east.  

[Esquimalt]

GEM looking awesome with a coastal slider.  A good 12 hours of light to moderate snowfall with this one.

[BLI snowman]

GEM still a lot more aggressive than the GFS with sending energy down the coast next week on the eastern edge of the block. Pretty similar otherwise. Does look a lot better towards the end of the week.

[MR.SNOWMIZER]

GEM still a lot more aggressive than the GFS with sending energy down the coast next week on the eastern edge of the block. Pretty similar otherwise.

GFS does show some getting closer on this run.

[MR.SNOWMIZER]

Block remains in great spot entire run so far and looks like it will get really good as we approach long range.

[HighlandExperience]

[BLI snowman]

GFS does show some getting closer on this run.

 

Yeah, it has the Tuesday system a bit closer to the coast and develops an extremely weak low off of Long Beach at 168 hours. The models always struggle mightily with these types of systems so it's not going to be relatively clear until a couple days out. Potential is there.

[Esquimalt]

Post the GEM w/b map

Dunno how to.  A widespread 6 to 8 inches throughout the sound and Vancouver Island, including Victoria.  Portland has approximately 4 inches.  Many people have 8 to 10 inches, especially if on higher terrain. I know that the GEM overdoes snowfall, but this is looking very promising.  

[Front Ranger]

You mentioned that last night as well. Looks like northern pierce and se king county might get decent totals.

 

Very possible. But again, models have been kind of all over the place with where they're focusing the heaviest snowfall. And judging from past experience, they usually don't have a decent handle on it until right before the event...and even then, a healthy CZ can totally change things. 

 

If this event does end up having a Feb 2011, Dec 2008, or Nov 2006 type front, it's likely that the actual snowfall will look quite different than what the GFS is depicting.

[Esquimalt]

Low at hour 204 on the GFS looks stronger on this run.  Still rain for most areas but looks like cold maritime air with 850s at around -5 to -10 C. 

[Esquimalt]

Wow.  GFS at hour 240 is truly incredible on the 500mb level!!

[Front Ranger]

GEM still a lot more aggressive than the GFS with sending energy down the coast next week on the eastern edge of the block. Pretty similar otherwise. Does look a lot better towards the end of the week.

 

ICON has a nice little snowstorm for the Willamette Valley/Portland area at that time.

 

[ShawniganLake]

Wow. GFS at hour 240 is truly incredible on the 500mb level!!

In what way is it incredible?

[Timmy]

In what way is it incredible?

its not, looks like a decent mountain snow pattern. Gem is much better.

[Jesse]

Wow.  GFS at hour 240 is truly incredible on the 500mb level!!

 

The stuff at 84 hours is decent too.

[Esquimalt]

In what way is it incredible?

Just looks better than the patterns in that time frame in previous GFS runs.  Lots of cold air in the north of BC.  

[ShawniganLake]

That is some serious maritime polar air in early March.

[HighlandExperience]

 

Interesting little tidbit.

 

What are the chances of a 1" snowfall in Seattle after Valentines Day? In the 74 years of records there have been 42 ( 57% ) 1" or more snowfall days after February 14th but only 4 of the 42 have happened in the last 25 years. #wawx— NWS Seattle (@NWSSeattle) February 15, 2018

Shows you how crappy the last 25 years have been.

[Esquimalt]

That is some serious maritime polar air in early March.

Looks like a massive snowfall in the clown range   

[MR.SNOWMIZER]

Just keep coming in the clown range. This really could be a historic cold stretch. The blocking is just crazy.

[SilverFallsAndrew]

For the love of GOD

 

[MR.SNOWMIZER]

For the love of GOD

 

Andrew special there!!

[Jesse]

Pretty old school look to the upcoming pattern.

[Timmy]

I