February Weather in the Pacific Northwest

[Frontal Snowsquall]

 

hmmmm

 

It just misses us. This seems reminiscent of the BC slider that pummeled the southern half of the Willamette Valley back in December 2013. Still 6 days out so plenty of time for this to change and clobber somebody in the PNW.

[TigerWoodsLibido]

It just misses us. This seems reminiscent of the BC slider that pummeled the southern half of the Willamette Valley back in December 2013. Still 6 days out so plenty of time for this to change and clobber somebody in the PNW.

Definitely could be like that Feb, 2014 event too.

[Jesse]

It looks pretty anemic down here. Without much gorge outflow it's going to be tough to stay below 38-39 on Monday.

 

Not feeling the February 15-16, 1956 analog anymore?

[snow_wizard]

A front like December 1990 would blow peoples minds around here. I still remember what this area can do when things are perfect. Been so long.

 

I think the last real flash freeze Arctic front we had was November 2010.  That was the real deal for sure.  This one sure looks like it will be decent with 850s crashing to -13 or so.

[jaya]

What suggests this will be different? This looks like a pretty typical bleed preceded by cold onshore flow.

Most cold air west of the Cascades comes in from aloft (with exception to the small region around the gaps in the terrain.  Air aloft is cold with this system.  It looks cold. 

 

For snow, I want to see a low drop south to the west of the Olympics try to put some warm air advection over the top of a southward advancing cold front. The slower the movement, the better the snowfall amounts.

 

With the cold air aloft and the cooling air from the north, I think that snow-water ratios should be better than 10 to one with this setup (so amounts may over perform what the models show.  I am hoping that Sunday will be a nice and snowy one, and that the snow will stick around for a couple of days or so.  

 

I also like the eastward run to run shift of that next low toward midweek.  Warm air advection into a cold air mass can be good for snow that moves farther into the cold air than models indicate. It will be fun to see how things progress.

 

It looks like things may stay interesting into the first week of March.

[snow_wizard]

Not feeling the February 15-16, 1956 analog anymore?

 

You guys will have to rely on cold coming down from the Fraser, but the air mass looks pretty D**n cold with good upper level support.

[snow_wizard]

Most cold air west of the Cascades comes in from aloft (with exception to the small region around the gaps in the terrain.  Air aloft is cold with this system.  It looks cold. 

 

For snow, I want to see a low drop south to the west of the Olympics try to put some warm air advection over the top of a southward advancing cold front. The slower the movement, the better the snowfall amounts.

 

With the cold air aloft and the cooling air from the north, I think that snow-water ratios should be better than 10 to one with this setup (so amounts may over perform what the models show.  I am hoping that Sunday will be a nice and snowy one, and that the snow will stick around for a couple of days or so.  

 

I also like the eastward run to run shift of that next low toward midweek.  Warm air advection into a cold air mass can be good for snow that moves farther into the cold air than models indicate. It will be fun to see how things progress.

 

It looks like things may stay interesting into the first week of March.

 

The 12z WRF showed a nice snow event a couple of days after the cold air arrives.  I would love to see that after a good 2 to 4 inches with the Arctic front.

[snow_wizard]

Has anyone seen the EPS plumes for snowfall with this?

[BLI snowman]

Not feeling the February 15-16, 1956 analog anymore?

Euro is better than the GFS so we'll see. The trough orientation is reminiscent but that airmass was wicked cold. -18c at 850mb.

[jaya]

Check this page out https://atmos.washington.edu/mm5rt/ensembles/for ensembles. Click on plumes. You can get snow plumes from the MM5 ensembles for several points.  Bad thing is, it is only run once per day, so it will likely be a tad out of date by a cycle or two.

[jaya]

Sorry, but the plumes are only out to 3 days.  No extended...  But, this did do a good job with last night's snow in places like Everett northward. We can get some resolution on Friday?

[jaya]

Euro is better than the GFS so we'll see. The trough orientation is reminiscent but that airmass was wicked cold. -18c at 850mb.

From the standpoint of overall pattern, the ECMWF is both more consistent -and colder and snowier from a pattern look- than the GFS.  The GEM looks quite interesting!  I am liking the ICON more every time I look at this.

[snow_wizard]

Euro is better than the GFS so we'll see. The trough orientation is reminiscent but that airmass was wicked cold. -18c at 850mb.

 

I suppose we could achieve -15 with this, but that would be pushing it.  I was happy to see how much colder the EPS was today 12z vs 0z.

[snow_wizard]

From the standpoint of overall pattern, the ECMWF is both more consistent -and colder and snowier from a pattern look- than the GFS.  The GEM looks quite interesting!  I am liking the ICON more every time I look at this.

 

Any stats on how accurate the ICON is vs other models?

[jaya]

I suppose we could achieve -15 with this, but that would be pushing it.  I was happy to see how much colder the EPS was today 12z vs 0z.

It really would not take much to bring some really cold air into the Pacific NW.  It has been close by all winter and is still just north of the Canadian Coast ranges.  The upper levels are key, and they look cold.  It will not hit 0 in Seattle or anything like that - late in the winter- but this will likely be the coldest we have seen in a while.

[Phil]

It is almost as if there is some kind of impenetrable geographical barrier preventing cold from reaching us!

Yeah, what could possibly force cold air backwards over the Rockies/Cascades?

 

It’s almost like you need downstream blocking to prevent it from sliding east...

[jaya]

Any stats on how accurate the ICON is vs other models?

 

Any stats on how accurate the ICON is vs other models?

 

 

Not that I can find.  I have just been looking at it over the past couple of months.  Qualitatively, it does look like it performs well, has high resolution, and holds back cold air east and north of the mountains well.  It has also done okay with precipitation amounts for the cases I have looked at so far this year.  If it has a fault, it may be in initialization. I see that it runs earlier and faster than all of the other global scale models. Either Max Planck Institute has a very powerful computer, or they are running the model with a less vigorous initialization scheme than the other models.  ECMWF spends almost a whole cycle time just on its initialization (one factor in their superior performance overall).  I'm still trying to get some info on the model and how it works (from a physics and scheduling standpoint).

[Deweydog]

The NAM is about to be relevant for the first time since last year.

[Phil]

Well, that much is obvious. But he seemed to be inferring that the large scale pattern drivers are finally turning favorable for cold, when if you live in MT or anywhere in the northern tier, you've done just fine this winter without his coveted -NAO/-PNA combo.

 

The dominant factor this winter has undoubtedly been the -EPO, and that's not changing with this upcoming cold period. The main difference is it's finally a more favorable block for the West overall.

 

It may or may not be a direct result of the SSW. Sometimes those lead to good things for the West, sometimes they don't. Regardless, this cold season has had nice blocking since it started, which is why places as close as Montana have had the winter they've had. Not like we're seeing a flip from a 1999-00.

Here’s my two cents:

 

1) It is a direct result of the SSW. This is quantitatively demonstrable, from a physical/observational standpoint, so it’s not really up for debate (IMO).

 

2) Until now, the large scale drivers have not been favorable for PNW cold..it’s been a +PNA/+NAO winter, which has teleconnected well with the broad WHEM Hadley Cells and a NE-shifted warm pool.

 

3) The -EPO won’t be a major factor after Feb 22nd. It’s just a pure -PNA/-NAO constructive interference regime at that point. Much like mid/late 1955/56, 1968/69, 1981/82, 2005/06, etc.

[MR.SNOWMIZER]

The NAM is about to be relevant for the first time since last year.

It's a oldie but goodie like you!!

[Front Ranger]

Maybe I'm missing something. I haven't been paying a ton of attention.

Jaya is on it.

[Deweydog]

It's a oldie but goodie like you!!

Awwwww shucks...

[Deweydog]

Jaya is on it.

[Perturbed Member]

I just noticed that the all important 18z NAVGEM also trended the Tuesday low much further east. 

 

 

[TigerWoodsLibido]

I just noticed that the all important 18z NAVGEM also trended the Tuesday low much further east.

 

 

Thickness values only 534 won't get the job done even if that stalls at Coos Bay

[Deweydog]

Thickness values only 534 won't get the job done even if that stalls at Coos Bay

Need to work on your basic meteorology there...

[BLI snowman]

Thickness values only 534 won't get the job done even if that stalls at Coos Bay

Offshore flow with a residual cold airmass = Good for snow

[Timmy]

Need to work on your basic meteorology there...

Get him! Hit him with that BSF

[Deweydog]

Get him! Hit him with that BSF

Is that anything like ATM?

[TigerWoodsLibido]

Is that anything like ATM?

That's what Arkansas fans call Texas A&M fans

[MR.SNOWMIZER]

Thickness values only 534 won't get the job done even if that stalls at Coos Bay

You are so wrong it actually scares me.

[TT-SEA]

You are so wrong it actually scares me.

 

Really?   It actually scares you?   You are afraid of that?   

[Timmy]

Really? It actually scares you? You are afraid of that?

how much snow did you get this morning?

[Deweydog]

Only two things scare me.... And one of them is nuclear war.

[pscz1140]

00z ICON is a bit cooler than the 18z at HR 69.

 

Ich hoffe das ist ein gutes modell!!

[TT-SEA]

how much snow did you get this morning?

 

Maybe an inch... the wind took most of it before daylight.    It drizzled until mid-afternoon.

[MossMan]

I still have a little snow left over at home! Still had almost an inch in places at work when I left as well.

Currently 34.

And yes I need new blades on my mower...will do that when the big time growth hits in April.

[HighlandExperience]

Only two things scare me.... And one of them is nuclear war.

You need to be prepping better

[wxmet]

GFS 00z looks nice on Sunday:

 

[TT-SEA]

Total snowfall per the 00Z GFS through Monday morning... precip is done at this time.