February Weather in the Pacific Northwest

[High Desert Mat!]

Too bad this all this didn't show up in the heart of winter.

[Perturbed Member]

PDX NWS on the Wednesday system:

 

"ECMWF continues to show a low sliding down the coast on Tuesday,

though it now is coming in Tuesday evening. The GFS continues to
show a low much farther offshore. If the ECMWF proves true, there
will be the potential for some snow along the coastline mainly late
in the day on Tuesday. Will have another system drop down out of
British Columbia on Wednesday, but low confidence in the details
with this system because the ECMWF is now showing a defined low
pressure system with more moisture, while the GFS continues to show
a weak shortwave with limited moisture. The main concern if we do
get a system like the ECMWF is showing is what track it will take
coming down the Coast, with the potential for another round of low
elevation snow, at least at the start."

[Geos]

With how nice the long term upper level pattern appears and how many snow chances the models have been consistently showing, it'll be very sad if we come out of this with nothing to show for it. Just 2-4 inches regionwide isn't too much to ask for right? 

 

No it's not too much

[Geos]

18z RGEM

 

[seattleweatherguy]

National Weather Service Seattle WA

358 PM PST Fri Feb 16 2018

 

.SYNOPSIS...Windy conditions and heavy mountain snow are expected

Saturday as a deepening surface low tracks southeast down

Vancouver Island and then across to northeast Washington. On

Sunday, a modified arctic cold front will move southward through

the area, bringing the possibility of lowland snow, as well as

strong wind. It will be followed from late Sunday through Tuesday

with dry weather but some of the coldest air so far this winter.

Another system could slide in from the northwest around next

Wednesday or Thursday.

 

&&

 

.SHORT TERM...Active and potentially impactful weather coming up

this weekend, first on Saturday in the form of wind and heavy

mountain snow, then on Sunday with the potential for lowland snow

and strong northeast-north Fraser Outflow wind. Coldest air mass

of the winter is expected from Sunday night through Tuesday

morning.

 

On Saturday, a deepening low pressure center will move southeast

down Vancouver Island, then track east near Vancouver B.C. and

continue deepening as it moves to northeast Washington. At it

closest approach, the central pressure of the low will be near 998

mb. Strengthening or deepening lows typically come with more lift

and greater impact. The low will be preceded by a large swath of

warm advection lift, while northwest flow aloft is a great

direction for enhancing orographic lift and snowfall totals over

the Cascades, including the main highway passes. Some of the

heaviest snow totals in the passes come in this type of pattern.

A Winter Storm Warning has been issued for the Cascades from late

tonight through Saturday night. Nearly two feet of snow is

forecast at the passes in 24 hours. Avalanche danger will be

elevated given the the heavy amount of snow and strong wind in

exposed locales.

 

Southwest gradients will really pick up as the low makes it

closest approach around mid-day Saturday. Models bring the HQM-SEA

gradient to around +4 to +4.5 mb, and the UIL-BLI gradient should

reach near +5 mb around mid-day Saturday. 18z GFS MOS peaks the

sustained wind at Shelton, Tacoma Narrows, Tacoma McChord, Sea-

Tac, and West Point (Discovery Park) at 33, 28, 30, 27, and 34

knots respectively around mid-day Saturday. With 925 mb winds of

40-50 knots and cold advection during this period, wind gusts of

45-50 mph are totally reasonable for the South and Central Sound

regions. Further north, a strong westerly surge is expected

through the Strait during the afternoon. NW flow aloft favors such

surges impinging on land areas on the U.S. side of the Strait and

the Admiralty Inlet area. Given all these things, have gone with

a round of Wind Advisories for tomorrow. Would not be surprised if

one or two zones pick up a few stronger gusts.

 

After the low exits east on Saturday night, a cold front will

spread out of B.C. into Western Washington on Sunday morning,

aided by strong Fraser Outflow wind. The Bellingham to Williams

Lake gradient could exceed -20 mb on Sunday morning, making this a

strong outflow event. May eventually need a High Wind Warning for

Western Whatcom County on Sunday. This pattern will cause a sharp

modified arctic cold front to slip southward. The air aloft will

be cold, so low-level convergence near the frontal boundary and

some instability could support snow showers as the front moves

south. On average up and down the I-5 corridor, the official

forecast has about 1 inch of snow centered around Sunday morning.

In reality, some places will see more, and others will get none.

GFS ensemble mean has about 1 inch of snow at SEA early Sunday.

 

The Port Angeles area is most likely to get snow, given

northeast wind upsloping along the north-facing side of the

Olympic Mtns. The official forecast has 1 inch of snow near the

water there, but 3-6 inches above 500 feet along the Strait.

 

With all of the cold, dry continental air pouring out from the

interior of B.C., the air mass will dry out quickly later Sunday,

and the last showers will end over the Cascades on Sunday night.

Coldest air mass of the winter is expected, with Monday night

being the coldest. Should be a widespread hard freeze.

 

.LONG TERM...Northwest flow aloft will continue from Tuesday

through next Friday, keeping temps below normal. A system will

dive southeast around Wednesday or Thursday. The air mass will

moderate a bit as clouds and precip spread in, and weak onshore

flow develops. Still, a rain/snow mix is forecast over the

lowlands. QPF is modest, so only minor snow accumulation is

expected on higher hills near the Cascades. Haner

[MR.SNOWMIZER]

Huge earthquake in mexico. 7.5.

[HighlandExperience]

I see NWS Portland put out a Special Weather Statement regarding the potential for lowland snow. Why didn't the NWS Seattle do the same?

 

I feel like us Sounders always get left out of the pro-met-weenie excitement.

Poor portlanders

[Front Ranger]

I see NWS Portland put out a Special Weather Statement regarding the potential for lowland snow. Why didn't the NWS Seattle do the same?

 

I feel like us Sounders always get left out of the pro-met-weenie excitement.

Heh heh. This oughta trigger an oldie but a goodie.

[kokaneekidz]

I see NWS Portland put out a Special Weather Statement regarding the potential for lowland snow. Why didn't the NWS Seattle do the same?

 

I feel like us Sounders always get left out of the pro-met-weenie excitement.

We are closer to Canadia so snow is expected and if you don't know how to do curling or drink Kokanee beer you should go back to weather weenie ville (keep portland weird) !!!

[DareDuck]

Too bad this all this didn't show up in the heart of winter.

This won’t be very special for you and me. Cold and dry? That’s normal. Sounds like just slightly cool nights are ahead. We reached 7 under a warmer airmass last week. Nothing is even showing us reaching that again.

[Deweydog]

Huge earthquake in mexico. 7.5.

Has to be a good sign for Sunday.

[HighlandExperience]

Pretty nice that the 850 temp anomaly at day 11 is still -7/-8c on the GEFS.

 

Even better, look at the Midwest/East Coast torch! Yippee!

 

Earth changes occurring. Earthquakes in Mexico and inland USA flooded with warm gulf water.

[seattleweatherguy]

I see NWS Portland put out a Special Weather Statement regarding the potential for lowland snow. Why didn't the NWS Seattle do the same?

 

I feel like us Sounders always get left out of the pro-met-weenie excitement.

They want to deal with the windstorm first.

[Perturbed Member]

The SWS seems pretty reasonable to me.

 

 

"...LOWLAND SNOW POSSIBLE LATE SUNDAY...

...COLDEST TEMPERATURES OF THE WINTER LIKELY EARLY NEXT WEEK...

- Snow expected to mix in with rain showers down to sea level on
Sunday for all areas including the coast and interior
lowlands...including the Columbia River Gorge and Hood River.
Any accumulation expected to remain 1000 feet and above during
the day Sunday.

- Light snow accumulations are possible Sunday night, but
showery nature of precipitation will lead to scattered areas of
accumulation and no accumulation.

- Temperatures will fall quickly Sunday night which will likely
cause wet roads to refreeze, even where snow does not fall.

- Temperatures expected to fall into the low 20s in the cities
and into the upper teens in the outlying areas on Monday night.
"

[Blizzard777]

No Tsunami warning, Tim is safe

[TT-SEA]

No Tsunami warning, Tim is safe

Whew!

 

82 with a dewpoint of 64 and partly sunny at my location.

[Deweydog]

Whew!

 

82 with a dewpoint of 64 and partly sunny at my location.

I'm confused.

[wxmet]

One interesting thing to note is that the hi-resolution regional models like the NAM and RGEM are colder than the ECMWF on Sunday.

[MR.SNOWMIZER]

Whew!

 

82 with a dewpoint of 64 and partly sunny at my location.

Yuck. To hot, you will melt.

[TT-SEA]

Yuck. To hot, you will melt.

So wonderful.

 

Heaven.

[Phil]

Pretty nice that the 850 temp anomaly at day 11 is still -7/-8c on the GEFS.

 

Even better, look at the Midwest/East Coast torch! Yippee!

 

It was 70*F here at 2AM last night. Lol.

 

And it’ll be snowing by tomorrow afternoon. Double lol.

[luvssnow_spokane]

I'm confused.

Down slopping...

[Frontal Snowsquall]

Just posted this is the contest thread:

 

Here's my current thinking. I think the Arctic Front is going to dump more snow than expected. Upwards of 4 to 6 inches in even the lowest elevations. Solid snow cover will keep highs close to freezing on Monday. Then another round on Tuesday night and Wednesday with the BC slider. This isn't my final prediction and I might change it tonight.

 

 

KSEA

 

Sun: 38/26

Mon: 35/24

Tue: 39/26

Wed: 40/33

 

 

KPDX

 

Sun: 42/27

Mon: 34/19

Tue: 40/27

Wed: 37/29 

[Perturbed Member]

00z NAM looks promising so far.

 

Edit: Eh, not too different. 

[MR.SNOWMIZER]

Nam looks dryer to me. Thw precip rates just look anemic.

[MR.SNOWMIZER]

In all the years i have watched weather around here I've never seen a low take thid track with arctic air near by and piget sound not get a decent snowfall in alot of places. Will be very interesting to watch it all unfold.

[Deweydog]

00z NAM looks promising so far.

 

Edit: Eh, not too different.

Nice!!!

 

Edit: Eh.

[Jbolin]

In all the years i have watched weather around here I've never seen a low take thid track with arctic air near by and piget sound not get a decent snowfall in alot of places. Will be very interesting to watch it all unfold.

It'll all end in tears!

[MossMan]

Going to be a fun weekend!!

[Esquimalt]

The NAM doesn't look nearly as good up here.  Was showing 5 to 7 inch totals throughout Victoria but now it seems like the precipitation is centred a little north and Victoria will be dry.  

[Perturbed Member]

The NAM doesn't look nearly as good up here.  Was showing 5 to 7 inch totals throughout Victoria but now it seems like the precipitation is centred a little north and Victoria will be dry.  

 

It's just the NAM though, we can ignore it if we don't like what it has to say.

[Esquimalt]

It's just the NAM though, we can ignore it if we don't like what it has to say.

If only the Euro was like that 

[Prairiedog]

Certainly looks like the best shot at a real snow event but temps look suspect. 

 

us_model-en-087-0_modez_2018021612_129_1256_241.png

us_model-en_modez_2018021612_129_494_155.png

us_model-en-087-0_modez_2018021612_129_494_488.png

May start out as snow but I think southery flow kicks in fairly fast so I'm thinking whatever snow occurs it may be short lived.  Hope I'm wrong but it's usually what happens, esp without Gorge outflow to support the cold. 

[Front Ranger]

36 hrs away from the event, and the models are still all over the place with snowfall. Whaddya know.

 

This is one of the most fun aspects about weather...the times when no one really knows how it will play out until it's go time. Grab some popcorn for Sunday!

[Jbolin]

36 hrs away from the event, and the models are still all over the place with snowfall. Whaddya know.

 

This is one of the most fun aspects about weather...the times when no one really knows how it will play out until it's go time. Grab some popcorn for Sunday!

Xmas even setup ring a bell?

[Farmboy]

Just posted this is the contest thread:

 

Here's my current thinking. I think the Arctic Front is going to dump more snow than expected. Upwards of 4 to 6 inches in even the lowest elevations. Solid snow cover will keep highs close to freezing on Monday. Then another round on Tuesday night and Wednesday with the BC slider. This isn't my final prediction and I might change it tonight.

 

 

KSEA

 

Sun: 38/26

Mon: 35/24

Tue: 39/26

Wed: 40/33

 

 

KPDX

 

Sun: 42/27

Mon: 34/19

Tue: 40/27

Wed: 37/29

4 to 6 inches? Not a bad little frontal snowsquall...

[TigerWoodsLibido]

Well Lindsey took a page from Tiger's book of failures tonight/tomorrow in Korea.

[Esquimalt]

00Z Icon shows a clear convergence zone setting up somewhere just northwest of Seattle.  Some people might get lucky.  

[Front Ranger]

Xmas eve setup ring a bell?

 

Exactly. That was a lot of fun to watch unfold.

[Arctic Front]

Exactly. That was a lot of fun to watch unfold.

If you call missing out on a white Christmas by miles fun, sure.