PNW February 2023 Weather Discussion - Meteorological winter finale

[TT-SEA]

Actually... should mention that Thursday looks windy in the usual places when there is arctic air.    Strong NE wind up north and east wind farther south.    That is going make it feel very cold.  

[Perturbed Member]

Position of the low and precip by early Thursday AM. Models are generally in great agreement now in terms of what happens on the larger scale. The somewhat showery and convective nature of the precip likely means there will be the usual big winners and big losers and it is probably going to be a pain to really nail down what those locations will be head of time. 

On the higher end it seems possible for someone in the valley to end up with 3-6 inch totals with this.

[kokaneekidz]

12 minutes ago, Rubus Leucodermis said:

Southerly flow with entrenched low-level cold banking against the mountains can be very good for metro Vancouver.

I believe this is the WINTER for our entire area. Sit and sip a nice cup while taking it all in. I ran across some nice Graupel en route to the office today around 85th exit on 405 . Was a harbinger of things to come. SNOW!!!

[SnarkyGoblin]

45 minutes ago, RentonHill said:

Looks pretty dark over there! 

Man you must be real close to my work based on this picture.

[Doinko]

2 minutes ago, Perturbed Member said:

Position of the low and precip by early Thursday AM. Models are generally in great agreement now in terms of what happens on the larger scale. The somewhat showery and convective nature of the precip likely means there will be the usual big winners and big losers and it is probably going to be a pain to really nail down what those locations will be head of time. 

On the higher end it seems possible for someone in the valley to end up with 3-6 inch totals with this.

I think the area by Newberg/Sherwood near the Chehalem mountains will do well. WRF shows a bullseye there

[Rubus Leucodermis]

58 minutes ago, ShawniganLake said:

Always like having the HRDPS on board.  Shows strong Fraser outflow with steady snow falling here tomorrow evening and temps in the mid 20s. Would be incredible. 
 

 

And there it is, I’m now in the blue. The first short-term model jumps on board with the Euro/GFS consensus that there will be light snow as the arctic front sweeps in IMBY.

[AlTahoe]

15 minutes ago, RentonHill said:

@AlTahoe ...remains f u c k e d

 

Lots of talk about us potentially beating 2010-2011 winter. So maybe a top 5 Sierra snowfall winter! 

[joelgombiner]

You can spot the moment the Arctic front passed through Williams Lake this morning. The boundary is now moving south in southern B.C. 

[Phishy Wx]

Heavy Snow and 38 lol

need that evap cooling to kick in for anything to stick yet.

 

[TacomaWx]

4 minutes ago, joelgombiner said:

You can spot the moment the Arctic front passed through Williams Lake this morning. The boundary is now moving south in southern B.C. 

Looks like it’s passing through Lytton BC. DPs dropping there and down to 36 with a N wind of 25. 

[Rubus Leucodermis]

5 minutes ago, TacomaWx said:

Looks like it’s passing through Lytton BC. DPs dropping there and down to 36 with a N wind of 25. 

Seems to be running a little ahead of schedule if it’s in Lytton already.

[ShawniganLake]

My official first alert forecast for BC

 

A band of showers will cross the lower mainland near sunset tonight and a couple hours later arriving on the island.  Rain, graupel, wet snow, limited accumulation but it’s going to ice up tonight.  

Later tomorrow a low forms off the Washington coast. Expect some light flurries over western sections of the lower mainland, trace to 0.5”. As outflow increases and moisture lifts north the SE sections of Vancouver island could see a significant snowfall. I think 1.5-4” from the Malahat to parksville. Greater Victoria should see flurries with trace to 1.5”. 

[Prairiedog]

17 minutes ago, Doinko said:

I think the area by Newberg/Sherwood near the Chehalem mountains will do well. WRF shows a bullseye there

A friend of mine lives on Chehalem Mtn about 1,300ft and already had a rain/snow mix.  Basically across the valley a little from Andrew.  They should do well.

[Requiem]

19 minutes ago, Perturbed Member said:

Position of the low and precip by early Thursday AM. Models are generally in great agreement now in terms of what happens on the larger scale. The somewhat showery and convective nature of the precip likely means there will be the usual big winners and big losers and it is probably going to be a pain to really nail down what those locations will be head of time. 

On the higher end it seems possible for someone in the valley to end up with 3-6 inch totals with this.

The morning runs didn't make me feel too optimistic this morning (mostly the EURO), but I still think 2-4 inches is a fair bet for some of us.

[joelgombiner]

12 minutes ago, TacomaWx said:

Looks like it’s passing through Lytton BC. DPs dropping there and down to 36 with a N wind of 25. 

Yep! Moving through. 

[Phishy Wx]

this looks fun and headed SW towards Spokane

 

SNOW SQUALL WARNING
NWS SPOKANE WA
1046 AM PST TUE FEB 21 2023

IDC017-021-211945-
/O.NEW.KOTX.SQ.W.0001.230221T1846Z-230221T1945Z/
1046 AM PST TUE FEB 21 2023
Bonner County-Boundary County-

The National Weather Service in Spokane has issued a

* Snow Squall Warning for...
South central Boundary County in the Panhandle of Idaho...
Central Bonner County in the Panhandle of Idaho...

* Until 1145 AM PST.

* At 1044 AM PST, a dangerous snow squall was located near the north
end of Priest Lake and near Elmira, moving southwest at 15 mph.

HAZARD...Extremely poor visibility in snow and blowing snow. Wind
gusts greater than 30 mph.

SOURCE...Radar indicated.

IMPACT...Dangerous travel.

* This includes the following highways...
U.S. Highway 95 in Idaho between mile markers 473 and 489.
U.S. Highway 2 in Idaho near mile marker 28.

Locations impacted include...
Sandpoint, Ponderay, Kootenai, East Hope, Nordman, Hope, Colburn,
Schweitzer Mountain and Coolin.

[SilverFallsAndrew]

Sounds like its been snowing off and on at home. Splat test positive here in Albany. 

[TT-SEA]

7 minutes ago, ShawniganLake said:

My official first alert forecast for BC

 

A band of showers will cross the lower mainland near sunset tonight and a couple hours later arriving on the island.  Rain, graupel, wet snow, limited accumulation but it’s going to ice up tonight.  

Later tomorrow a low forms off the Washington coast. Expect some light flurries over western sections of the lower mainland, trace to 0.5”. As outflow increases and moisture lifts north the SE sections of Vancouver island could see a significant snowfall. I think 1.5-4” from the Malahat to parksville. Greater Victoria should see flurries with trace to 1.5”. 

Did they use inches instead of centimeters there?  

Or should I say centimetres?  

[TacomaWx]

6 minutes ago, joelgombiner said:

Yep! Moving through. 

Next stop is Hope. It’ll be awhile before it makes it down to the Seattle area though of course. 

[Phishy Wx]

this looks like a true Purcell Trench convective backdoor blast ongoing in progress.

real fun and games should get here later this afternoon/early evening

 

excitement meter up from 4 to 7 currently

 

[Phishy Wx]

[SilverFallsAndrew]

1 hour ago, RentonHill said:

Holy crud. Looks amazing. Hope it comes true... Gotta feel bad for folks down in Harrisburg though. 

[Phishy Wx]

 

arctic boundary just passed Bonners Ferry  you can clearly see it here

 

[SilverFallsAndrew]

Sorry work got busy, just catching up. I see the EURO AND GEM are on board for the Sunday snow. Euro shows 6" IMBY. Looks like the GEM and EURO both have a cold airmass over us at day 10. And of course we have seen what the GFS did in the long range. 

[Cold Snap]

1 hour ago, Perturbed Member said:

Euro still showing overrunning snow this weekend

Hoping the timing doesn’t get moved up on that. Going to be cutting it close with my flight getting in at 8pm that night.

[MossMan]

SPLAT TEST….

 

Negative. 

[Phishy Wx]

Spokane radar also hinting a convergence zone possibly happening over the Spokane/CDA I-90 corridor.  will be cool if it does.  should enhance rates later.  Must be what the NAM 3k picked up on with its higher amounts

[Rubus Leucodermis]

3 minutes ago, MossMan said:

SPLAT TEST….

 

Negative. 

But not for long!

[SilverFallsAndrew]

Solid 12z runs. 

 

Here are the snow totals each run dumps IMBY over the next 10 days:

GFS: 30"

EURO: 26"

GEM: 25"

 

The GFS dumped 58" over the course of its run. Seems ridiculous, but that's about how much snow we got from February 28-March 22, 2012. So while its unlikely, it is possible. 

[thickhog]

25 minutes ago, Prairiedog said:

A friend of mine lives on Chehalem Mtn about 1,300ft and already had a rain/snow mix.  Basically across the valley a little from Andrew.  They should do well.

I see those hills every day from my house. Gorgeous area. Looks like they’re in the bullseye for this. 

[Perturbed Member]

PDX NWS isn't impressed

The picture remains about
the same regarding low elevation snowfall as snow levels fall
below 1000 feet late this evening and then continue to dip to
near the valley floors through Wednesday morning. Probabilistic
guidance still gives about a 30-50 percent chance for an inch of
snow across both the coastal and interior lowlands Wednesday
morning through Thursday morning. Any accumulating snow in these
areas is likely to be highly variable from location to location
given the showery nature of the pattern. Some models are
notably holding onto QPF a bit longer into Thursday morning as
the core of the upper low is slightly slower to clear the area,
which would be more conducive to snow sticking on surfaces
given the colder air expected to be in place by that time.

[ShawniganLake]

22 minutes ago, TT-SEA said:

Did they use inches instead of centimeters there?  

Or should I say centimetres?  

I originally wrote that with centimetres, but I converted to inches for my American friends when I posted it here.  
 

We pretty much use metric for everything except construction supplies. 

[Phishy Wx]

Snow doing its thing 

 

down to 33 with an DP of 31

 

should start to see some Accum soon

[Deweydog]

3 minutes ago, Perturbed Member said:

PDX NWS isn't impressed

The picture remains about
the same regarding low elevation snowfall as snow levels fall
below 1000 feet late this evening and then continue to dip to
near the valley floors through Wednesday morning. Probabilistic
guidance still gives about a 30-50 percent chance for an inch of
snow across both the coastal and interior lowlands Wednesday
morning through Thursday morning. Any accumulating snow in these
areas is likely to be highly variable from location to location
given the showery nature of the pattern. Some models are
notably holding onto QPF a bit longer into Thursday morning as
the core of the upper low is slightly slower to clear the area,
which would be more conducive to snow sticking on surfaces
given the colder air expected to be in place by that time.

Kind of a bummer. Progs look a bit less dynamic than they did 24-36 hours ago. Starting to look like a pretty traditional wringing out of remnant moisture as opposed to a widespread event with sustained isentropic lift. I imagine there will still be some echo training for some lucky folks though. 

[TT-SEA]

9 minutes ago, ShawniganLake said:

I originally wrote that with centimetres, but I converted to inches for my American friends when I posted it here.  
 

We pretty much use metric for everything except construction supplies. 

We really appreciate it! 

[Phishy Wx]

2 minutes ago, Deweydog said:

Kind of a bummer. Progs look a bit less dynamic than they did 24-36 hours ago. Starting to look like a pretty traditional wringing out of remnant moisture as opposed to a widespread event with sustained isentropic lift. I imagine there will still be some echo training for some lucky folks though. 

Yall got NAM'd

[Slushy Inch]

[TT-SEA]

I wonder if we might start coming out of this cold period after the first week of March.    Probably not... but some variety would be nice. 

[Requiem]

I'm curious about the Sunday event at this point-- still a ways off but does that have a chance to potentially be juicier than modeled? It will be interesting seeing an organized front like that move through and drop snow without any hint of offshore flow.

[SilverFallsAndrew]

4 minutes ago, TT-SEA said:

I wonder if we might start coming out of this cold period after the first week of March.    Probably not... but some variety would be nice. 

Yeah, I think we will by about March 10th. Whether it's a lasting pattern change to wetter/milder or we get back into the cool/troughy pattern remains to be seen. What I see on this is a more progressive and variable pattern starting to emerge towards the 10th of March, but not necessarily zonal flow breaking through.