PNW December 2022, winter might be coming; but mostly canceled.

[TT-SEA]

Just now, Nov1985 said:

This is one of my favorite forecast model incidents of all time. I'm saving this GFS Christmas day snowfall fcst map! 

 

I was so hoping that run could get to 40 inches in Seattle.    It was so close.   

[SouthHillFrosty]

[BLI snowman]

3 minutes ago, Perturbed Member said:

Slightly different topic than cocaine. 

Since you are in SW WA. What do you think of the climate of Camas/Washougal up around 1k ft in the hills to the NE? Any thoughts on the typical snow per season? 

Seems like it would be a nice spot. Any obvious downsides from a climate perspective? Annoyingly high amounts of precip? Damaging east winds?

I think you definitely get pretty consistent and noticeable east wind if you're south of Washougal River Road on that little ridge. That particular area has seen some pretty extreme wind events. But the elevation makes a huge difference and you'll be high enough (and wet enough) to get an onshore flow boost and low enough to stay in the low level gorge cold pools with offshore flow. It does make significant ice a bigger concern, but the snowfall averages are likely in the 20"+ range up there at 700-900'.

I think somewhere like Yacolt at a similar elevation gets a fair amount more precip, but also warms up much more quickly so their snowcover days are fewer overall.

[TT-SEA]

00Z GEFS for next Monday... somehow its even worse than the GFS run tonight.  

[snow_wizard]

Nice to see the GEM deliver a solid punch on this run.

[Front Ranger]

5 minutes ago, TT-SEA said:

The GFS, GEM, and ICON all show warm 850mb temps later next week... as do the EPS and GEFS.   

Meanwhile the ECMWF is showing one of the greatest arctic blasts in history at the same time.    Pretty crazy.

Can't think of another time the Euro has been this much on its own at this range. Without the EPS at least.

[snow_wizard]

Just now, TT-SEA said:

00Z GEFS for next Monday... somehow its even worse than the GFS run tonight.  

At least the pieces are there for something to come together better.

[TT-SEA]

Just now, Front Ranger said:

Can't think of another time the Euro has been this much on its own at this range. Without the EPS at least.

Yeah... I can't think of anything remotely close to this situation.   

[snow_wizard]

Just now, Front Ranger said:

Can't think of another time the Euro has been this much on its own at this range. Without the EPS at least.

The GEM gets there on this run.

[Phishy Wx]

the way I see it the euro has the best resolution, so maybe it is/(was on the 12z and previous runs) seeing something the others aren't.  not saying it's correct but that can't be discounted, imo. yeah EPS support would be golden.

[SilverFallsAndrew]

We'll find out in about an hour and a half, but I can't imagine the EURO doesn't cave. 

[Front Ranger]

8 minutes ago, Meatyorologist said:

That forcing mechanism is brief, but it's there. I've seen Arctic air seep its way in with worse upper level support. Some models are less aggressive with breaking down that ridge than others, which alters potential beyond day 6.

Yeah, what I meant is you need it there longer to have any significant push south. Sure, it can seep in to northern areas without that.

[TT-SEA]

1 minute ago, snow_wizard said:

The GEM gets there on this run.

That is some crazy gymnastics on the GEM... but we get snow and then cold out of it. 

[Meatyorologist]

18 minutes ago, snow_wizard said:

GEM is trying to shove it south at day 6.

9 minutes ago, snow_wizard said:

The GEM made a big step toward the ECMWF tonight.  This is far from over.

3 minutes ago, snow_wizard said:

Nice to see the GEM deliver a solid punch on this run.

2 minutes ago, snow_wizard said:

The GEM gets there on this run.

Guys, did you know the GEM delivers the GOODS??!

[snow_wizard]

It's easy to see why we are getting such extremely varied solutions.  The difference between total success and total failure is very delicate.  Just one little change early in the progression can easily snowball into something huge.

[GHweatherChris]

So the Euro will basically keep hope alive or prove that all weather models are horrible with distinctly different personality traits and biases.  Or vices, they probably all drink together.

[TT-SEA]

1 minute ago, Meatyorologist said:

Guys, did you know the GEM delivers the GOODS??!

The 00Z GEM actually buries Seattle!  

[Meatyorologist]

1 minute ago, GHweatherChris said:

So the Euro will basically keep hope alive or prove that all weather models are horrible with distinctly different personality traits and biases.  Or vices, they probably all drink together.

Insider betting?

[LowerGarfield]

For the main euro model,ECMF, what is the difference between it and the EPS ensembles? ELI5 please.

[snow_wizard]

BTW...there were some members on the 18z EPS that indicated a colder outcome.

[GHweatherChris]

Just now, Meatyorologist said:

Insider betting?

Could be, which one is bluffing......

[Slushy Inch]

1 minute ago, LowerGarfield said:

For the main euro model,ECMF, what is the difference between it and the EPS ensembles? ELI5 please.

Ensembles change the initial conditions for each member. And maybe some other stuff idk.

[snow_wizard]

1 minute ago, LowerGarfield said:

For the main euro model,ECMF, what is the difference between it and the EPS ensembles? ELI5 please.

Each ensemble member has a slightly different line of code than the operational.

[Phishy Wx]

1 minute ago, LowerGarfield said:

For the main euro model,ECMF, what is the difference between it and the EPS ensembles? ELI5 please.

higher resolution than the EPS ensemble members I think

[Slushy Inch]

Never has the time between GFS and EURO runs felt longer.

[Slushy Inch]

1 minute ago, snow_wizard said:

Each ensemble member has a slightly different line of code than the operational.

What?

[snow_wizard]

Just now, 12345WeatherNerd said:

Never has the time between GFS and EURO runs felt longer.

It seems to me we are due for a time where we get the opposite of a rug pull.  Jan 2005 and Jan 2011 need to be made up for.

[LowerGarfield]

Ah that makes perfect sense! Similiar to probabilities or scientific testing. Thank you. Last question. Is the main Euro the same thing as the control?

[Meatyorologist]

2 minutes ago, snow_wizard said:

Each ensemble member has a slightly different line of code than the operational.

Nope! Same architecture, terrain, resolution. Just slightly different starting conditions.

Different modeling between members would defeat the purpose of an "ensemble suite"

[snow_wizard]

1 minute ago, 12345WeatherNerd said:

What?

They change something in the code of each ensemble member.  In the case of the ECMWF the ensemble has 51 different members.  Each one is a slightly different model basically.

[snow_wizard]

Just now, LowerGarfield said:

Ah that makes perfect sense! Similiar to probabilities or scientific testing. Thank you. Last question. Is the main Euro the same thing as the control?

The control is slightly dumbed down, but they are very similar.

[Rubus Leucodermis]

50-burgers galore!

[Rubus Leucodermis]

1 minute ago, snow_wizard said:

They change something in the code of each ensemble member.  In the case of the ECMWF the ensemble has 51 different members.  Each one is a slightly different model basically.

I thought it was in the data they feed to the code, not the code itself.

[snow_wizard]

1 minute ago, Rubus Leucodermis said:

I thought it was in the data they feed to the code, not the code itself.

Possible.

[Front Ranger]

18 minutes ago, TT-SEA said:

But man... I never bet against a consistent ECMWF.    If its the same tonight its going to be hard to discount.  

Problem is that it really hasn't been that consistent with the evolution and timing of the pattern in the 4-6 day period. It's just consistently gotten very cold, eventually past that point.

[snow_wizard]

2 minutes ago, Rubus Leucodermis said:

50-burgers galore!

One wise man at the NWS always liked to say....when all else is equal go with persistence.  We haven't had anything like that in weeks.

[Kolk1604]

For the medium-range forecasts an ensemble of 52 individual ensemble members are created twice a day. One member is at a higher spatial resolution than the other members (called the HRES at ECMWF), its initial state is the most accurate estimate of the current conditions and it uses the currently best description of the model physics. 

The HRES provides a highly detailed description of future weather and averaged over many forecasts it is the most accurate forecast for a certain period, which is currently estimated as 10 days for large scale properties of the atmosphere. However for any particular forecast it may not be the most skilful member of the ensemble. Also when viewed in isolation it cannot provide an estimate of forecast uncertainty or confidence.

Another member of the ensemble (CNTL: Control forecast) is at a lower spatial resolution than the HRES but at that lower resolution it utilises the most accurate estimate of the current conditions and the currently best description of the model physics. Its significance for the ensemble is that it provides the unperturbed member to which the perturbations for the remainder of the ensemble members are applied.

The perturbed members (50 members) are similar to the CNTL but their initial states and model physics have been perturbed to explore the currently understood range of uncertainty in the observations and the model. They provide a range of possible future weather states. When averaged over many forecasts (although not necessarily for any particular forecast) these have lower skill than either the HRES or the CNTL.  However they do provide an estimate of the forecast uncertainty or confidence.

[Slushy Inch]

5 minutes ago, snow_wizard said:

They change something in the code of each ensemble member.  In the case of the ECMWF the ensemble has 51 different members.  Each one is a slightly different model basically.

It's not the code

[Kolk1604]

Just now, Kolk1604 said:

For the medium-range forecasts an ensemble of 52 individual ensemble members are created twice a day. One member is at a higher spatial resolution than the other members (called the HRES at ECMWF), its initial state is the most accurate estimate of the current conditions and it uses the currently best description of the model physics. 

The HRES provides a highly detailed description of future weather and averaged over many forecasts it is the most accurate forecast for a certain period, which is currently estimated as 10 days for large scale properties of the atmosphere. However for any particular forecast it may not be the most skilful member of the ensemble. Also when viewed in isolation it cannot provide an estimate of forecast uncertainty or confidence.

Another member of the ensemble (CNTL: Control forecast) is at a lower spatial resolution than the HRES but at that lower resolution it utilises the most accurate estimate of the current conditions and the currently best description of the model physics. Its significance for the ensemble is that it provides the unperturbed member to which the perturbations for the remainder of the ensemble members are applied.

The perturbed members (50 members) are similar to the CNTL but their initial states and model physics have been perturbed to explore the currently understood range of uncertainty in the observations and the model. They provide a range of possible future weather states. When averaged over many forecasts (although not necessarily for any particular forecast) these have lower skill than either the HRES or the CNTL.  However they do provide an estimate of the forecast uncertainty or confidence.

I think that best explains it 

https://www.ecmwf.int/en/forecasts/documentation-and-support/medium-range-forecasts

[snow_wizard]

1 minute ago, Front Ranger said:

Problem is that it really hasn't been that consistent with the evolution and timing of the pattern in the 4-6 day period. It's just consistently gotten very cold, eventually past that point.

In this case I think it's a toss up right now.