December 2016 Observations and Model Discussion for the Pacific Northwest

[SilverFallsAndrew]

PDX NWS fully believes the roads will be bad Monday from the packed snow from the 1-3 inches they think Portland/North valley could magically get.

 

"Temperatures will drop below freezing early Sunday evening, and stay

there through Monday for most areas. So, roads likely to stay slick

and icy/snowpacked during that time, making for hazardous driving

conditions."

 

 

Getting real hard to take these guys seriously. I'm not sure any model supports the outcome they are going with.

 

Is this for real. LOL

[Heavy Snow]

No...no no no no no no no.

Do you still think late January to February I'd another window?

[Deweydog]

Portland NWS really missed an opportunity here.

Sounds like winter weather to me. People should be advised.

[Front Ranger]

I am beyond puzzled why anyone thinks it will be warm tomorrow.  Fraser outflow behind an Arctic front with 25mph north winds in Seattle.  It might be a bit above freezing, but the air will be dry.  FWIW the WRF insists on low to mid 30s for highs.

 

I think 32-35 for highs north of Seattle is a good call.

 

South of Seattle, I could see 36-40 happening. But some depends on if there is still ongoing precip, cloud cover, etc.

[snow_wizard]

The east coast always wins. It's not our fault we live in the PNW. If we lived in the Midwest or East Coast we would look like geniuses.

 

We will be fine.  Look at the index forecasts.  Any ridge over the NW would be unable to last for more than a day or two with that.  The models show a quick hitting cold wave in the east and then above normal heights again.  The models are struggling right now.  Ensembles are the way to go.

[Front Ranger]

True, but with the broad Hadley Cells today, the entire interactive NPAC structure will often be shifted poleward. So, I wasn't surprised to see it there.

 

If the polar/NAM domain had been more favorable, this would have unfolded much differently IMO.

 

Well, it hasn't unfolded quite yet...

[Phil]

Do you still think late January to February I'd another window?

Yes, following the next pseudo jet extension during mid/late January, there will be another retraction and round of anticyclonic wavebreaking in February.

 

I was never high on early January due to the raging PV dampening waves, though I was/am bullish on the block itself..structural amplitude and orientation are the problems in this case. Sometimes models don't catch onto these couplings until very late in the game..but this was exceptionally late.

[FroYoBro]

An excerpt from Mark's latest blog post.

 

"The NWS is going for a Portland snowstorm tonight and Sunday morning, but I think it’s unlikely.  They are forecasting 1-3″ in the metro area (3″ on hills) and have a winter weather advisory up starting at 10pm.

I feel that’s way overdone for several reasons.  The biggest is that we’re in mild onshore flow through around sunrise Sunday.  In fact southwest wind picks up this evening and continues until almost day break.  Freezing levels are above 1,000′ through 7am tomorrow, when almost all of the moisture will be falling out of the sky.  I’ve seen this many times here in Portland.  We’ll be too warm down at the valley floor until sometime after 4am to even think about snow sticking down here.  There is excellent model agreement on this as well.  That southwesterly breeze is a real killer (for snow) UNLESS the atmosphere is colder than what we’re expecting now.   Take a look at model snow forecasts from the ECMWF, WRF-GFS, & RPM and they agree."

 

Once again calling the NWS out!

[luminen]

snowing moderately with big flakes now.

[snow_wizard]

True, but with the broad Hadley Cells today, the entire interactive NPAC structure will often be shifted poleward. So, I wasn't surprised to see it there.

 

If the polar/NAM domain had been more favorable, this would have unfolded much differently IMO.

 

We shall see, but a good outcome is still very possible for us.

[MR.SNOWMIZER]

I think 32-35 for highs north of Seattle is a good call.

 

South of Seattle, I could see 36-40 happening. But some depends on if there is still ongoing precip, cloud cover, etc.

Bremerton area had a few days with a high in the low 30's in early December with a warmer airmass.

[snow_wizard]

Yes, following the next pseudo jet extension during mid/late January, there will be another retraction and round of anticyclonic wavebreaking in February.

 

I was never high on early January due to the raging PV dampening waves, though I was/am bullish on the block itself. Sometimes models don't catch onto these couplings until very late in the game..but this was exceptionally late.

 

You were on board with early January.  I clearly remember it.

[HighlandExperience]

snowing moderately with big flakes now.

You live in Surrey?

[ShawniganLake]

I should have known this was going to happen. Joe Bastardi said it on WeatherBell and that ridging would go over the PNW. I will never dismiss what Joe Bastardi says for now on.

Ridging over the PNW is not what is causing ugliness in the medium range right now.

[TT-SEA]

That with dps in the 20s should preserve the snow pretty well I would think.

 

I think Tim takes a perverse pleasure in knowing he will have good snow cover no matter what and then making the case nobody else will.

Dewpoint will be in the low 30s tomorrow for us... WRF is garbage.

[Phil]

You were on board with early January. I clearly remember it.

I was on board with mid/late January. Still am somewhat on board for the second half of January.

[TT-SEA]

You were on board with early January.  I clearly remember it.

I was one of the first to call for a cold January last spring.

[Perturbed Member]

An excerpt from Mark's latest blog post.

 

"The NWS is going for a Portland snowstorm tonight and Sunday morning, but I think it’s unlikely.  They are forecasting 1-3″ in the metro area (3″ on hills) and have a winter weather advisory up starting at 10pm.

I feel that’s way overdone for several reasons.  The biggest is that we’re in mild onshore flow through around sunrise Sunday.  In fact southwest wind picks up this evening and continues until almost day break.  Freezing levels are above 1,000′ through 7am tomorrow, when almost all of the moisture will be falling out of the sky.  I’ve seen this many times here in Portland.  We’ll be too warm down at the valley floor until sometime after 4am to even think about snow sticking down here.  There is excellent model agreement on this as well.  That southwesterly breeze is a real killer (for snow) UNLESS the atmosphere is colder than what we’re expecting now.   Take a look at model snow forecasts from the ECMWF, WRF-GFS, & RPM and they agree."

 

Once again calling the NWS out!

 

Was just about to post the same.

 

Mark Nelsen with a quick dose of reality to balance out the absurd NWS wishcast.

[Front Ranger]

An excerpt from Mark's latest blog post.

 

"The NWS is going for a Portland snowstorm tonight and Sunday morning, but I think it’s unlikely.  They are forecasting 1-3″ in the metro area (3″ on hills) and have a winter weather advisory up starting at 10pm.

I feel that’s way overdone for several reasons.  The biggest is that we’re in mild onshore flow through around sunrise Sunday.  In fact southwest wind picks up this evening and continues until almost day break.  Freezing levels are above 1,000′ through 7am tomorrow, when almost all of the moisture will be falling out of the sky.  I’ve seen this many times here in Portland.  We’ll be too warm down at the valley floor until sometime after 4am to even think about snow sticking down here.  There is excellent model agreement on this as well.  That southwesterly breeze is a real killer (for snow) UNLESS the atmosphere is colder than what we’re expecting now.   Take a look at model snow forecasts from the ECMWF, WRF-GFS, & RPM and they agree."

 

Once again calling the NWS out!

 

He's no dummy.

 

I'm curious who the "local met" Andrew was having a laugh with (at this forum's expense) the other night was? Was it someone working at the NWS? If so, guess what buddy...we're all laughing at you right now!

[Phil]

I made a post on December 16th outlining my thoughts, if I'm recalling correctly. In this thread I believe.

[Front Ranger]

I was one of the first to call for a cold January last spring.

 

You gotta post one of these or it's not official: http://theweatherforums.com/index.php/topic/1442-2016-17-winter-outlook/

[HighlandExperience]

I made a post on December 16th outlining my thoughts, if I'm recalling correctly. In this thread I believe.

I thought you called for an ice age starting in 2017

[luminen]

You live in Surrey?

 

Nope. 

[snow_wizard]

I was on board with mid/late January. Still am somewhat on board for the second half of January.

If this is all still just the appetizer I'm good with that. Some winters have behaved like this in the past. The ultimate payoff is almost always very good.

[Heavy Snow]

We will be fine. Look at the index forecasts. Any ridge over the NW would be unable to last for more than a day or two with that. The models show a quick hitting cold wave in the east and then above normal heights again. The models are struggling right now. Ensembles are the way to go.

I hope so. Every time I lose hope and say it's over the models suddenly come around again.

[FroYoBro]

If this is all still just the appetizer I'm good with that. Some winters have behaved like this in the past. The ultimate payoff is almost always very good.

 

This is the third warning shot of the winter. 3 warning shots = HUGE BLAST COMING 

[snow_wizard]

I thought you called for an ice age starting in 2017

In all fairness things have really starting falling into place for us now. Just had a cold December and January is going to be cold also. The patterns have an old time feel to them all of a sudden. The solar aspect may be kicking in after one very low cycle under our belts and then the recent very quiet conditions.

[Heavy Snow]

Yes, following the next pseudo jet extension during mid/late January, there will be another retraction and round of anticyclonic wavebreaking in February.

 

I was never high on early January due to the raging PV dampening waves, though I was/am bullish on the block itself..structural amplitude and orientation are the problems in this case. Sometimes models don't catch onto these couplings until very late in the game..but this was exceptionally late.

That's encouraging, we should have all listened to you in the first place. At this point I'm hoping for a similar event to what happened in our last snowstorm here but with more snow. Then wait for another bigger chance later in the month like you mentioned.

[Timmy]

I hope so. Every time I lose hope and say it's over the models suddenly come around again.

Working some reverse psychology, good move!

[HighlandExperience]

In all fairness things have really starting falling into place for us now. Just had a cold December and January is going to be cold also. The patterns have an old time feel to them all of a sudden. The solar aspect may be kicking in after one very low cycle under our belts and then the recent very quiet conditions.

 

I'm happy with the recent pattern, but I just worry that at some point the other shoe has to drop and we wasted our cold/snow chances. 

[Front Ranger]

If this is all still just the appetizer I'm good with that. Some winters have behaved like this in the past. The ultimate payoff is almost always very good.

 

After 9 rounds of appetizers, then the main course, I would hope everyone's snow/cold appetite is fully sated.

[snow_wizard]

I hope so. Every time I lose hope and say it's over the models suddenly come around again.

At times like this look at the big picture and the ensembles. I just looked at the Canadian ensemble and it has a large number of excellent members for week 2. The analog composites and index forecasts are useful also. Things have mostly been breaking our way in the end lately.

[luvssnow_spokane]

SAME THING HAPPENED IN JAN 1950, a** HOLE.

 

 

[Heavy Snow]

Ridging over the PNW is not what is causing ugliness in the medium range right now.

I know but it's that ugliness that might eventually cause it.

[Deweydog]

I thought about it getting cold and snowy again after the February 2014 event at some point in the future.

 

I wasted all of you prognosticators.

[HighlandExperience]

After 9 rounds of appetizers, then the main course, I would hope everyone's snow/cold appetite is fully sated.

 

Still waiting for the main course. All we have had is a few nachos. 

[Front Ranger]

This is the third warning shot of the winter. 3 warning shots = HUGE BLAST COMING 

 

[Phil]

My thoughts from mid-December. The polar domain is fighting a bit harder than I thought it would, but it should give in eventually.

 

Yeah, this was probably just a warm-up. Surf zone amplifies around/just after New Years, blowing up the NPAC high again while the Scandinavian ridge attempts to nudge poleward. End result: More winter.

While the (initial) longitudinal location of the block may be somewhat challenging, eventually (through discontinuous retrogression), you will score an Arctic blast and some additional snowfall opportunities.

An update on my expectations for midwinter.

January is revealing its hand now. Looks like a much easier forecast than December, thankfully, given initial conditions. Here's the progression I'm seeing now, of which I'm reasonably confident this time..much more so than I was earlier.

1) The remainder of December should continue the -PNA/+AO circulation. However, the combination of that Eurasian ridge and pseudo +WPO will lead to a poleward WAFz regime that'll perturb the PV/strat towards New Years and amplify the various surf zones.

2) Moving through the first 7-10 days of January, the -PNA regime will continue, while the Eurasian conduit to NAM/PV destabilizes the upper level vortex further. This will gradually destabilize the +AO, hence destroy the constructive mode of interference sustaining the +EPO. So, expect the +AO/PV to degrade through the early portion of January, with NEPAC wavebreaking/EPO attempting to return.

3) This process amplifies further between January 10th and 20th, and possibly beyond, with the AO likely dropping into the most negative state since October. The strongest supplementary anticyclonic wavebreaking will be of NEPAC origin, so I'd expect more of an EPO/AO look versus an AO/NAO look. I think another Arctic shot over the US is likely during this time.

4) Late January and beyond will depend on how significant the NAM/PV perturbations alters the tropical convection and tropopausal temperatures. The more significant the perturbation, the more likely we see an MJO wave ignite and orbit the globe.

First 7-10 days of JAN: +AO/+EPO gradually weakens and collapses as waves amplify and upper PV is destabilized. More continental oppprtunties for PNW as surf zone sharpens upstream.

JAN 10-20: Polar blocking/-AO develops, possibly another Arctic shot into the US. More like to coincide with EPO/AK block than NAO/NATL block.

[snow_wizard]

That's encouraging, we should have all listened to you in the first place. At this point I'm hoping for a similar event to what happened in our last snowstorm here but with more snow. Then wait for another bigger chance later in the month like you mentioned.

A lot of us have been pretty good with this stuff lately. I'm the one who predicted lowland snow (and or snow on the ground) for New Years at least two weeks ago.

[luvssnow_spokane]

At times like this look at the big picture and the ensembles. I just looked at the Canadian ensemble and it has a large number of excellent members for week 2. The analog composites and index forecasts are useful also. Things have mostly been breaking our way in the end lately.

What has broken our way??  lol... I have seen nothing break our way up here yet. Was it in December? Because I missed it. Oh yeah I got a trace of snow when many models at time showed more. Or was it when this weekend showed 3 inches of snow here tonight through tomorrow. Maybe that's it. OH yeah it has not happened yet but I am sure it will ... that's it.