December 2023 Weather in the PNW

[snow_wizard]

Just now, Front Ranger said:

OLM up over 3.7" storm total now.

This definitely turned out to be a pretty decent AR.

[AlTahoe]

24 minutes ago, Phil said:

That’s because we haven’t seen the deposition of westerly momentum into the STJ yet. That should change as we go through the month.

And overall +dAAMt to +AAM trend is now present across guidance.

Welp with no precip being shown for Southern Cal through mid Dec there has never been a El Nino wet winter when it starts this late. Maybe this will be a first but I doubt it. For Los Angeles they are on pace for the driest Oct - Dec recorded followed by 2017 and 1990. Very un El Nino like. 

[ShawniganLake]

21 minutes ago, snow_wizard said:

Another very interesting GFS run.  Always a good sign when it keeps coming back.

What are you seeing that interests you?  Pretty dreadful looking with respects to any legitimate cold before Christmas.  

[Deweydog]

31 minutes ago, snow_wizard said:

Another very interesting GFS run.  Always a good sign when it keeps coming back.

Every six hours!

Very similar to December 2008 but also very similar to 2002 .

[Phil]

27 minutes ago, Brian_in_Leavenworth said:

Good news is there will be more snow in the mountains this weekend and Leavenworth and large parts of Eastern Washington are also supposed to get snow.  Southern third of Eastern Washington probably wont, save for the hills.  May not last long, but it's something. 

How's your back doing?

It’s not great, but not getting worse, at least. Thanks for asking. Numbness has begun to subside slightly, thanks to corticosteroid injection, but am going in for a second injection on the 12th since portions of the pain and numbness were untouched by the first one.

Started PT last week, seems to be helping somewhat but honestly at this rate the recovery will take 6+ months and I don’t know if I have the patience for that.

If I have one more setback, doc will recommend surgical options. Because it’s a threshold case as is.

[Phil]

18 minutes ago, AlTahoe said:

Welp with no precip being shown for Southern Cal through mid Dec there has never been a El Nino wet winter when it starts this late. Maybe this will be a first but I doubt it. For Los Angeles they are on pace for the driest Oct - Dec recorded followed by 2017 and 1990. Very un El Nino like. 

Warm pool convection will start a bit later thanks to +IOD forcing such an expansive area of subsidence over the IPWP.

[RentonHill]

D**n 2008/2009 had a crazy SSW

[van city]

19 minutes ago, ShawniganLake said:

What are you seeing that interests you?  Pretty dreadful looking with respects to any legitimate cold before Christmas.  

Dreadful sums it up pretty good. 

[ShawniganLake]

12z euro dialled back the lowland snow tease for this weekend.   

[Phil]

12 minutes ago, RentonHill said:

D**n 2008/2009 had a crazy SSW

That event was so wild because it occurred via the inverse of typical conduits..basically the NPAC high amplified so much that it coupled to the stratospheric NPAC high, and with Eurasian help, it produced the most prolific SSW on record.

Basically that crazy Dec 2008 pattern caused the SSW. And it’s why the pattern reverted back to cold in Feb 2008 following the ridge in January.

[the_convergence_zone]

I can't possibly be disappointed by this winter because I figured I would get zero snow. Even a single flake would be an overperformance. 

Just hoping for no drought and decent mountain snowpack. It seems like we're checking the 'no drought' box. Mountain snow is going to be trickier but maybe we can at least get to 75% of normal in the Cascades. 

[Timmy Supercell]

6 minutes ago, the_convergence_zone said:

I can't possibly be disappointed by this winter because I figured I would get zero snow. Even a single flake would be an overperformance. 

Just hoping for no drought and decent mountain snowpack. It seems like we're checking the 'no drought' box. Mountain snow is going to be trickier but maybe we can at least get to 75% of normal in the Cascades. 

A winter like that was due. I grew up with strings of them in a row.

I think a couple dustings wouldn't be unreasonable still. And yeah the cascades hopefully shouldn't be hurting for it.

[Skagit Weather]

2 hours ago, MossMan said:

Seeing reports from my FB friends that live near or on the Stillaguamish River and they are saying that it’s much higher than predicted and is taking them by surprise. I just drove over it on I-5 in Arlington and yeah it’s as high as I have seen it in a while. Going to be interesting. 

Looks like it's at 20.04' at Arlington currently which puts it as the 6th highest crest on record and only a foot below the all time record. And it's still going up pretty rapidly. There might be a chance for it to set a new record crest.

[Deweydog]

12 minutes ago, Phil said:

That event was so wild because it occurred via the inverse of typical conduits..basically the NPAC high amplified so much that it coupled to the stratospheric NPAC high, and with Eurasian help, it produced the most prolific SSW on record.

Basically that crazy Dec 2008 pattern caused the SSW. And it’s why the pattern reverted back to cold in Feb 2008 following the ridge in January.

Monster.

[TigerWoodsLibido]

64F and still waiting on the rain to arrive.

[MWG]

49F and fog since last night. Was a bit scary this morning leaving home at 7am. Supposed to be 62 today.

 

[Brian_in_Leavenworth]

1 hour ago, Phil said:

It’s not great, but not getting worse, at least. Thanks for asking. Numbness has begun to subside slightly, thanks to corticosteroid injection, but am going in for a second injection on the 12th since portions of the pain and numbness were untouched by the first one.

Started PT last week, seems to be helping somewhat but honestly at this rate the recovery will take 6+ months and I don’t know if I have the patience for that.

If I have one more setback, doc will recommend surgical options. Because it’s a threshold case as is.

That sounds like a typical progression.  Surgery is if all else fails, or it's an emergency.  And I am guessing this would be the last cortisone injection.

Keep us up to date!

[iFred]

2 hours ago, Phil said:

Nope.

Worst possible pattern for W-Canada cold loading.

Like you said, going to be a massive couple years for you as the multi year Nino rages on. You’ll have your third masters before there is a sustained cold anomaly hanging over the Pacific Northwest during DJF.

[Front Ranger]

1 hour ago, AlTahoe said:

Welp with no precip being shown for Southern Cal through mid Dec there has never been a El Nino wet winter when it starts this late. Maybe this will be a first but I doubt it. For Los Angeles they are on pace for the driest Oct - Dec recorded followed by 2017 and 1990. Very un El Nino like. 

Payback perhaps for what happened in August, their wettest ever.

[MossMan]

Sounds like things are starting to hit the fan in Arlington, they might be closing Hwy 530. 

[Deweydog]

MODERATE RAIN

[Cold Snap]

Looks like the snoqualmie river might not get as high as they were expecting. Looks like it’s going to peak lower.

[snow_wizard]

Looks like SEA is at 2.65" so far.  Very legit event.

[snow_wizard]

4 hours ago, Phil said:

1990? Not gonna happen dude.

Never said it would.  No way to say for sure it won't though.

[snow_wizard]

4 hours ago, MossMan said:

Seeing reports from my FB friends that live near or on the Stillaguamish River and they are saying that it’s much higher than predicted and is taking them by surprise. I just drove over it on I-5 in Arlington and yeah it’s as high as I have seen it in a while. Going to be interesting. 

I remember the Stillaguamish was insane in October 2003.  Maybe it floods worse with lower snowpack situations.

[snow_wizard]

18 minutes ago, Cold Snap said:

Looks like the snoqualmie river might not get as high as they were expecting. Looks like it’s going to peak lower.

Not sure about that.  The peaks around Snoqualmie Pass are way above freezing with 50mph winds blowing.  That will wipe out the snow very quickly along with the heavy rain.

[snow_wizard]

5 minutes ago, snow_wizard said:

I remember the Stillaguamish was insane in October 2003.  Maybe it floods worse with lower snowpack situations.

In response to the question emoji.  I think it's something of a misconception that bad floods don't happen with low snowpack.  October 2003 is proof of that.  I think just a modest amount of freshly fallen snow may be the worse of all though.

[SilverFallsAndrew]

wiz, what do you find compelling about the models right now. They look pretty hopeless to me. 

[Phil]

36 minutes ago, iFred said:

Like you said, going to be a massive couple years for you as the multi year Nino rages on. You’ll have your third masters before there is a sustained cold anomaly hanging over the Pacific Northwest during DJF.

Trollololol.

I don’t control the weather, dude. If I did, every winter would be 1899 on steroids.  

[Phil]

6 minutes ago, SilverFallsAndrew said:

wiz, what do you find compelling about the models right now. They look pretty hopeless to me. 

Except the Euro control run!

[SilverFallsAndrew]

Just now, Phil said:

Except the Euro control run!

Tell me more. 

[Phil]

1 minute ago, SilverFallsAndrew said:

Tell me more. 

[NorthBend RainEnthusiast]

4 minutes ago, snow_wizard said:

In response to the question emoji.  I think it's something of a misconception that bad floods don't happen with low snowpack.  October 2003 is proof of that.  I think just a modest amount of freshly fallen snow may be the worse of all though.

I don't see how that supports that the Stillaguamish River would "floods worse with lower snowpack situations". Maybe there is an argument to be made that deep snowpack would absorb some of the rainfall and lessen impacts? But is that the case in these warm AR events, where the wind, temps, and rainfall are all facilitating runoff? My guess would be if there had been more snow in the Stillaguamish watershed, there would be worse flooding.  

[Front Ranger]

1 hour ago, Deweydog said:

Monster.

Mid January 2009 featured an epic torch here, with five straight 60+ days. 

But then we had a cold spell about a week later with a 13/2 day and another low of -11.

[Mercurial]

38 and rain on top of my snow.  HOW DELIGHTFUL

[Mercurial]

It would be great if wx forecasting worked like the stock market, with sentiment indicators, contrarian signals, etc.  We'd be in for a hell of a winter.  

[GHweatherChris]

Pretty mundane and meh AR event here.

[TT-SEA]

Looks like this will end up being a minor flood event for upper Snoqualmie Valley.    This type of event happens almost every year... usually multiple times.

[the_convergence_zone]

11 minutes ago, NorthBend RainEnthusiast said:

I don't see how that supports that the Stillaguamish River would "floods worse with lower snowpack situations". Maybe there is an argument to be made that deep snowpack would absorb some of the rainfall and lessen impacts? But is that the case in these warm AR events, where the wind, temps, and rainfall are all facilitating runoff? My guess would be if there had been more snow in the Stillaguamish watershed, there would be worse flooding.  

I'm not an hydrologist, but a quick literature search reveals that this is a hot topic in atmospheric river hydrology, the term for it is "Rain On Snow (ROS)" flooding. It can not be distilled down to a yes or no answer, the properties of the snowpack are important -- the "cold content" (i.e. temperature), the density, and the liquid water content. Not surprisingly, heavy rainfall on top of relatively "warm" snowpack produces the greatest runoff, up to a 50% greater streamflow:rainfall ratio than if there is no snow. 

Intuitively, I don't think deeper snowpack is going to make much of a difference because the rain can only accomplish so much heat transfer to warming and then melting the snowpack before it cools to 32 F. In an event like this one, there was still plenty of snow available to melt...the central Cascades had 93% of normal SWE on Monday morning. 

 

 

[the_convergence_zone]

4 minutes ago, TT-SEA said:

Looks like this will end up being a minor flood event for upper Snoqualmie Valley.    This type of event happens almost every year... usually multiple times.

You're lucky you missed this one given what's going on with the Stillaguamish. Up to the #2 all-time event and still rising.