February 2021 PacNW Weather Discussion

[Requiem]

That outflow is no joke, Portland and Bellingham are in for quite the windy late week.

[Jbolin]

Depending on how strong the outflow is, especially north, could freezing spray be an issue?

[Requiem]

1 minute ago, JBolin said:

Depending on how strong the outflow is, especially north, could freezing spray be an issue?

I know our dear friend Jaya mentioned that a couple minutes ago on his Twitter.

[bainbridgekid]

3 minutes ago, TT-SEA said:

Keep in mind the ECMWF is still not showing much snow through Wednesday morning... but does on Wednesday.    The ECMWF has temps in the 40s with a SW wind on Monday and Tuesday.   I am not expecting much if any snow until Wednesday.

 

Yeah the Euro is a little slower with the cold air and keeps South winds going longer which keeps the CZ mainly North of Everett.

 

[Frontal Snowsquall]

00Z UKMET trended way COLDER! SCORE!!!!!!!!!!

[Kolk1604]

1 minute ago, bainbridgekid said:

Yeah the Euro is a little slower with the cold air and keeps South winds going longer which keeps the CZ mainly North of Everett.

 

Fine by me. Temps start to drop on Wednesday and then the fun begins. Maybe the 00z will move that up a bit. 

[smerfylicious]

I...don't think I've ever seen such pretty colors in the believable range...is this real life? Can I put on my "It's Happening" shirt and prep the bunker?

[Frontal Snowsquall]

00z UKMET days 5 and 6. 

[Jbolin]

3 minutes ago, Requiem said:

I know our dear friend Jaya mentioned that a couple minutes ago on his Twitter.

F***-A, yes he did. 

[MR.SNOWMIZER]

There was massive freezing spray on any road with northern exposure in 1990. Pretty amazing to see ice cycles hanging off the power lines from sea spray. 

[Omegaraptor]

GEM has -40F in the Warner Mountains and Surprise Valley in far NE CA at hour 180.

Close to 0F on the Willamette Valley floor and -10F in The Dalles at the same time. Absolutely insane.

[wxmet]

UKMET has an inch of snow in Seattle then the deep freeze sets in.

[Frontal Snowsquall]

Better view of the 00z UKMET pattern at days 5 and 6.

[GHweatherChris]

7 minutes ago, smerfylicious said:

I...don't think I've ever seen such pretty colors in the believable range...is this real life? Can I put on my "It's Happening" shirt and prep the bunker?

There is no unbelievable pretty colors in the believable range, yet.

[Jbolin]

5 minutes ago, Omegaraptor said:

GEM has -40F in the Warner Mountains and Surprise Valley in far NE CA at hour 180.

Close to 0F on the Willamette Valley floor and -10F in The Dalles at the same time. Absolutely insane.

GTFO here

[wxmet]

My guess is the ECMWF gets even colder in its 00z run

[TT-SEA]

2 minutes ago, wxmet said:

My guess is the ECMWF gets even colder in its 00z run

Maybe less snowy as a result too. 

[TT-SEA]

12 minutes ago, smerfylicious said:

I...don't think I've ever seen such pretty colors in the believable range...is this real life? Can I put on my "It's Happening" shirt and prep the bunker?

Prep the bunker for highs in the 30s!   

[Jbolin]

1 minute ago, TT-SEA said:

Maybe less snowy as a result too. 

I'm cool with that

[wxmet]

1 minute ago, TT-SEA said:

Maybe less snowy as a result too. 

I’m hoping we get enough from the Arctic front to prepare for the possibility that all the storms get suppressed to the south due to the TPV.

[SilverFallsAndrew]

UKMET, GEM, ICON go full arctic. The WARM GFS gets arctic air into Seattle at least. 

[MR.SNOWMIZER]

Just now, TT-SEA said:

Maybe less snowy as a result too. 

Yeah pretty hard to get both. My guess is Seattle area will get a few inches with arctic Front convergence and areas south will get snow with undercutting systems.  Probably a region wide overrunning Event in the end.

[TT-SEA]

Just now, wxmet said:

I’m hoping we get enough from the Arctic front to prepare for the possibility that all the storms get suppressed to the south due to the TPV.

That is my thinking as well... best to get the snow right away in this situation.  

What the GFS shows would not be very memorable.   What the 12Z ECMWF showed would be legit batsh*t crazy.  

[paulb/eugene]

 Not that I really expect anybody to care, but I’m totally on board for cold but have my doubts about snow as we don’t know where or when moisture will enter the picture except in those favored PSCZ areas.

If we do get into the NE upper level flow from Central Canada then there should be no problem getting an exceptionally cold and dry airmass here.  That being said, there is going to be a who lot of mixing going on and it may be difficult to decouple the surface layer on the leeward side of Cascades. Back in December 2010 we were able to eke out some single digits in Eugene without any snow over but that was with optimal radiational conditions.

Best guess is highs in upper 20s to mid 30s at coldest for Willamette Valley.  Colder than that in the gorge. Lows 13-25.

If we can get some snow to fall east of the Cascades, could see impressive cold numbers.  

[Perturbed Member]

The difference from the 12z to 00z UKMET is pretty amazing

[paulb/eugene]

GFS ensemble mean trending colder

[Jbolin]

Just now, nwsnow said:

The difference from the 12z to 00z UKMET is pretty amazing

Nice crisp winter day

[Jbolin]

Hey Tim, wouldn't it be some serious s*** if the GFS ends up being right and your "suspicions" come to fruition?

[Blizzard777]

32 minutes ago, smerfylicious said:

Enough for 2 inches? Perhaps. 

Would be nice to have a low form in the Aleutians and ride down the coast dumping snowy goodness while not totally ruining the arctic temps.

Between 1-2 inches of snow being swirled about by a 30-35mph Northerly wind  !!!

[Jbolin]

I feel like all the other models, GEM, ECMWF, UKMET,  are trying to get the GFS to put the crack pipe down and join them in a nice mescaline induced stupor?

[BLI snowman]

10 minutes ago, hawkstwelve said:

00z GFS ensemble mean shows 850s drop below -5c on Monday and doesn't cross that mark again until 2/16.

Not too shabby at this point. 

 

Something interesting there is how few ensemble members show any precip making it to Seattle at the end of the week. Very good agreement on that offshore energy remaining pretty far suppressed, as you would expect with the PV so close.

[TheNewCulverJosh]

Has to be a new blog post from Marky Mark by tomorrow I would think.

[TT-SEA]

9 minutes ago, JBolin said:

Hey Tim, wouldn't it be some serious s*** if the GFS ends up being right and your "suspicions" come to fruition?

It would be some serious sh*t if anything close to the 12Z ECMWF verifies! 

[bainbridgekid]

9 minutes ago, JBolin said:

Hey Tim, wouldn't it be some serious s*** if the GFS ends up being right and your "suspicions" come to fruition?

GFS still gets pretty D**n cold though. 00z gets down to -12 in Seattle and -14 just North of Everett.

[SilverFallsAndrew]

1 minute ago, TheNewCulverJosh said:

Has to be a new blog post from Marky Mark by tomorrow I would think.

He said he would take another look Sunday night. 

[SouthHillFrosty]

I'll try to make a snowman out of frost!!!

[Cloud]

1 hour ago, weather_fan said:

What does thickness have to do with temperature?

Enjoy! 

A more in depth analysis for those thickness. Ideally for Seattle, we want it to be around 522, so lower the better. There's also some more geeky stuff on there you can look into for more information. 

https://komonews.com/weather/scotts-weather-blog/decoding-social-media-weather-geek-speak-12-20-2015-215542896

 

Quote

 

For Seattle, we start to think snow once that thickness is around 522 decameters or lower (not sure why they picked decameters). Typical winter numbers are around 530-540 (anything under 540 is considered snow at Snoqualmie Pass) To contrast, in summer, our heat waves get to be around 575-580dm, maybe even 585. Anything over 570 is pretty warm.

The forecasting charts show thickness by a dotted line and will denote every 6 decameters. So when you see the 522 line, or even the 516 line, drift on top of our south of Seattle, that's cold enough to start thinking snow on the surface.

 

 

[bainbridgekid]

3 minutes ago, BLI snowman said:

 

Something interesting there is how few ensemble members show any precip making it to Seattle at the end of the week. Very good agreement on that offshore energy remaining pretty far suppressed, as you would expect with the PV so close.

That's a good point. Looks like only 2 Ensemble members give SEA more than about 0.05" with the late week systems. That's pretty remarkable agreement actually.

[Jbolin]

5 minutes ago, TT-SEA said:

It would be some serious sh*t if anything close to the 12Z ECMWF verifies! 

No, that would be some unforgettable s***, at least in this millennium.

[Gradient Keeper]

56 minutes ago, nwsnow said:

Meh, nothing to see. Just your usual -22c 850mb temp over PDX.

-23c actually