February Weather in the Pacific Northwest

[ShawniganLake]

When does most of this fall? Sunday morning?

overnight into Sunday morning for your area. Some higher elevations see snow Saturday morning, possibly the Malahat.

[Esquimalt]

overnight into Sunday morning for your area. Some higher elevations see snow Saturday morning, possibly the Malahat.

It just seems like 4 to 5 inches is a little bit to expect from this arctic front.  I would think amounts of 1 to 3 inches are more believable.  

[tomas]

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[ShawniganLake]

It just seems like 4 to 5 inches is a little bit to expect from this arctic front. I would think amounts of 1 to 3 inches are more believable.

Who knows. Surface low spins up near southern Vancouver Island. Could get some convective showers. Other models have had that feature positioned less favourably

[SilverFallsAndrew]

36 with light rain

[MR.SNOWMIZER]

12z look whats on the north coast.

[Jbolin]

Not that it matters much but the KUIL sounding shows the FL around 1500FT,  0C isotherm is also not that far away in terms of height. I would peg the rain/snow line somewhere just east of Tim's location (Perhaps the Garcia/Olallie State Park area/s). S

[MR.SNOWMIZER]

Stronger low. This run may be the start of something very good. Perfect track down the coast.

[Front Ranger]

I was looking at November 2014 which was a very poor mans version of the pattern coming up and Seattle had afternoon temps in the low 30s on the day of the Arctic outbreak. Low temps later went on to go well below 20 in many places. I this case the 850s will be much colder, the surface gradients considerably stronger, and the cold air mass much deeper. The cold is being underestimated with this as it often is with Fraser River events. I still say the Central Puget Sound will get snow as is normal with Fraser outflow events. I've seen the models show nothing (and be wrong) way too many times to believe it.

I agree with almost all of this. It's just really hard to get sub-freezing highs this late. If everything comes together just right, I could see SEA having a couple highs in the 32-34 range.

 

I think a lot of outlying places will have lows in the 10-15 range.

[MR.SNOWMIZER]

That low remains 1000mb down the coast and fills to a 1003 at land fall. Been awhile since we have had a low take this track with arctic high pressure in bc. Looks like 12z is trending colder for mid week system dropping down as well. Good stuff.

[MossMan]

38 and rain!

[MossMan]

Stronger low. This run may be the start of something very good. Perfect track down the coast.

Flash freeze after 17.5” of snow!

[MR.SNOWMIZER]

Flash freeze after 17.5” of snow!

I think sunday will be pretty good most places. Good chance it trends better for snow now that the models can get a good look at what is going on. 

[SilverFallsAndrew]

Snow mixing in

[MossMan]

I have a hard time believing that we will not see more snow than the models show considering the one-two punch of a low tracking just to the south of us and a modified arctic front moving down the Sound around the same time.

 

I can easily see precip rates being heavier and more broad than what is currently shown.

I agree!

[MR.SNOWMIZER]

I have a hard time believing that we will not see more snow than the models show considering the one-two punch of a low tracking just to the south of us and a modified arctic front moving down the Sound around the same time.

 

I can easily see precip rates being heavier and more broad than what is currently shown.

100% agree. I think it will be much colder than what some of the models are showing for high temps Monday and Tuesday.

[MossMan]

Tim must be flying high towards the Kona low right now?

[bainbridgekid]

100% agree. I think it will be much colder than what some of the models are showing for high temps Monday and Tuesday.

I agree about the snow. The fact all models show at least some convergence and snow along the arctic front suggests there will likely be relatively widespread 1-2" and likely a few lucky spots that get 3-5" under more persistent convective bands.

 

I don't agree about temperatures though. It will be very tough to have highs below the mid 30's Monday and upper 30's Tuesday under sunny skies this time of year.

[Front Ranger]

Tim must be flying high towards the Kona low right now?

 

I see what you did there...

[Front Ranger]

I agree about the snow. The fact all models show at least some convergence and snow along the arctic front suggests there will likely be relatively widespread 1-2" and likely a few lucky spots that get 3-5" under more persistent convective bands.

 

I don't agree about temperatures though. It will be very tough to have highs below the mid 30's Monday and upper 30's Tuesday under sunny skies this time of year.

 

Agreed. I'd even go so far as to say someone in western WA will probably see 6"+ on Sunday. That almost always happens in these types of scenarios with a healthy surface low and vigorous front. This is nothing like the multiple, mostly dry Arctic fronts (think Dec 2013, Dec 2009, etc) seen the past 10 years.

[MR.SNOWMIZER]

Agreed. I'd even go so far as to say someone in western WA will probably see 6"+ on Sunday. That almost always happens in these types of scenarios with a healthy surface low and vigorous front. This is nothing like the multiple, mostly dry Arctic fronts (think Dec 2013, Dec 2009, etc) seen the past 10 years.

Port angles will get hammered I bet. 

[Jesse]

Port angles will get hammered I bet.

I will be interested to get reports from my dad in Port Townsend.

[Perturbed Member]

A few thoughts from Mark:

 

"How about the cold?  I’ve checked out the February 2006 and February 2011 late season cold snaps.  A few interesting points…one is that the cold airmass modifies quickly compared to midwinter events.  The other is that with full sunshine and weak Gorge wind, it’ll be easy to get highs up into the upper 30s.  Thus my forecast highs of 38 both Monday and Tuesday.  Both ECMWF and GFS bottom out 850mb temps around -11 to -12 over Portland on Monday.  That’s real cold for this time of year, although not record low.   It’s interesting that we’ve never made it down to -14 over Salem after the first few days of the month.  This is also not going to be a big east wind event for us, even Monday and Tuesday."

[HighlandExperience]

That system coming in midweek looks interesting

[Front Ranger]

A few thoughts from Mark:

 

"How about the cold?  I’ve checked out the February 2006 and February 2011 late season cold snaps.  A few interesting points…one is that the cold airmass modifies quickly compared to midwinter events.  The other is that with full sunshine and weak Gorge wind, it’ll be easy to get highs up into the upper 30s.  Thus my forecast highs of 38 both Monday and Tuesday.  Both ECMWF and GFS bottom out 850mb temps around -11 to -12 over Portland on Monday.  That’s real cold for this time of year, although not record low.   It’s interesting that we’ve never made it down to -14 over Salem after the first few days of the month.  This is also not going to be a big east wind event for us, even Monday and Tuesday."

 

Wasn't someone saying 1956 had like -18C for PDX? Seems hard to believe SLE wouldn't have gotten below -14C with that.

[HighlandExperience]

GFS showing multiple chances of snow over the next 10 days.

 

Sunday

Thursday

Friday

Monday

This week has quite a bit of potential. Looks exciting on GEM too

[SilverFallsAndrew]

One of the best beginning to end model runs I have ever seen...

[HighlandExperience]

WRF much better

 

 

4KM map

 

[BLI snowman]

Wasn't someone saying 1956 had like -18C for PDX? Seems hard to believe SLE wouldn't have gotten below -14C with that.

 

SLE hit -17.2c in February 1956. That airmass actually wound up slightly colder than February 1989 there.

[Front Ranger]

SLE hit -17.2c in February 1956. That airmass actually wound up slightly colder than February 1989 there.

 

You should tell Mark Nelsen.

 

What did Feb 1990 get down to?

[TT-SEA]

Total snow per 12Z GFS through Monday afternoon...

 

[BLI snowman]

You should tell Mark Nelsen.

 

What did Feb 1990 get down to?

 

-11.5c at SLE.

[Esquimalt]

GFS was pretty good, although a little warmer than on previous runs in the LR.  Let's worry about the next week first!! The GEM has some pretty impressive lowland snow opportunities, so that's something to be happy about.  The GEM warms up at the end of the run to daytime highs of around 40. 

 

There's some good and some bad.  

[seattleweatherguy]

Forecast Discussion

National Weather Service Seattle WA

311 AM PST Fri Feb 16 2018

 

.SYNOPSIS...A weather system will move onshore today with rain

changing to showers. A stronger system will reach the area later

tonight and Saturday resulting in windy conditions and more rain.

Cold air will push into the region Sunday with the snow level

falling to sea level. Dry conditions are expected for the first

part of next week.

 

&&

 

.SHORT TERM...A front is currently moving onshore with rain and

mountain snow. Advisory level amounts of snow are expected for

the Cascades today. There will be a brief and relative lull in

between weather systems this evening then the next front will

arrive. This system is a notch stronger that the one today. Windy

conditions are expected many areas - advisories will probably be

needed for some zones. Heavy snow is expected in the mountains - a

winter storm watch is currently in effect.

 

A cold upper trough will settle over the area on Sunday. At the

same time, strong Fraser outflow will develop, pushing a modified

arctic front south through Western Washington during the day.

Snow levels will fall to near sea level. Accumulations of an inch

or two are possible for parts of the lowlands. Highs will probably

occur early in the day for many areas with steady or even slowly

falling temperatures during the day. Schneider

 

.LONG TERM...Monday and Tuesday will be dry but chilly with

northerly flow aloft. Fraser outflow will ease but modified arctic

air will linger over the area. Highs will be mostly in the mid to

upper 30s and lows will be in the 20s with some teens in spots.

Some of this will depend on if there is any snow on the ground

from Sunday. A weather system will drop down from the north later

Wednesday or Wednesday night for another chance of rain or snow.

Schneider

[seattleweatherguy]

Wind Advisory

URGENT - WEATHER MESSAGE

National Weather Service Seattle WA

916 AM PST Fri Feb 16 2018

 

WAZ504-509-511-556-558-559-170615-

/O.NEW.KSEW.WI.Y.0005.180217T1500Z-180218T0300Z/

Southwest Interior-Tacoma Area-Hood Canal Area-

Bellevue and Vicinity-Seattle and Vicinity-Bremerton and Vicinity-

916 AM PST Fri Feb 16 2018

 

...WIND ADVISORY IN EFFECT FROM 7 AM TO 7 PM PST SATURDAY...

 

The National Weather Service in Seattle has issued a Wind

Advisory, which is in effect from 7 AM to 7 PM PST Saturday.

 

* WIND...South to southwest 20 to 30 mph with gusts around 45

mph.

 

* SOME AFFECTED LOCATIONS...Shelton, Bremerton, Olympia, Gig

Harbor, Tacoma, Federal Way, Seattle, and Bellevue.

 

* TIMING...Peak winds will occur from late Saturday morning

through the afternoon.

 

* IMPACTS...Scattered power outages and minor tree damage can be

expected.

 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

 

A Wind Advisory means that winds of 35 mph are expected. Winds

this strong can make driving difficult, especially for high

profile vehicles. Use extra caution.

[SilverFallsAndrew]

GFS was pretty good, although a little warmer than on previous runs in the LR.  Let's worry about the next week first!! The GEM has some pretty impressive lowland snow opportunities, so that's something to be happy about.  The GEM warms up at the end of the run to daytime highs of around 40. 

 

There's some good and some bad.  

 

This is not to bad though...

 

[bainbridgekid]

GEM is interesting. Takes longer for the cold air to bleed in on Sunday, but it also keeps some convergence zone snow going into Monday.

 

These surface lows along the arctic boundaries often take longer to slip South than modeled. That can be a bad thing for areas further South, but often results in a sweet spot getting stuck under convergence zone snow much longer than modeled.

[Front Ranger]

-11.5c at SLE.

Despite all the jokes, 1990 is looking like a D**n good pattern/air mass analog.

[Blizzard777]

On another note, pretty breezy day on Saturday.

Looking forward to an active weekend of weather!

 

Jim

[Lisa0527]

Thoughts on the 12Z Euro? Doesn’t look like it’s backing off on the cold and snow...but I only have Tropical Tidbits:(