November 2016 Observations and Model Discussion for the Pacific Northwest

[Kayla]

Model data is mostly 67-71 on today's 12z runs.

 

Yeah...underachieving today. I think even 70 is going to be a stretch.

 

With the trend today, I'm lowering my forecast for tomorrow at PDX to 66º.

[GobBluth]

the 8-14 day trend seems to be towards a W-NW jet rather than a cold blast.

[catnip]

Perhaps we need to get Andy in Woodinville back posting again for good luck!

 

:lol:

 

http://theweatherforums.com/archive/index.php?/topic/24085-christmas-eve-day-snow-event-on-the-horizon/

[Front Ranger]

That Hillsboro number is definitely bunk. 74 is their warmest reliable number from November.

 

Also quite warm, probably warmer than they'll be tomorrow.

[Front Ranger]

Rich Marriot posted this graph for snowfall at SeaTac. Pretty depressing if you ask me. He thinks this winter will be Good for snowfall though.

 

Couple of huge outliers there. One huge outlier this winter would make a world of difference.

[Deweydog]

Down to 62 at 2pm. 90 looking less likely.

[Jesse]

Good trends on the 12z Euro and its ensemble mean.

[Phil]

Good trends on the 12z Euro and its ensemble mean.

You looking at the same ensemble run I am? The Aleutian ridge has trended flatter in four consecutive runs. That's all that's going to matter in the long run, assuming it verifies.

[Jesse]

You looking at the same ensemble run I am? The Aleutian ridge has trended flatter in four consecutive runs. That's all that's going to matter in the long run, assuming it verifies.

Yeah I figured you'd disagree.

 

All I know is that the position of the main players look to be much better than the mega-torch pattern we're in right now, with a general trend of the GOA low going away and offshore heights rising. Obviously details like amplitude will be fuzzy at this range.

[SilverFallsAndrew]

18z is a small step in the right direction...At least toward Climo...

[James Jones]

Yeah...underachieving today. I think even 70 is going is a stretch.

 

With the trend today, I'm lowering my forecast for tomorrow at PDX to 66º.

Agreed that 70 is a stretch. The only time PDX has hit 70 this late was 11/13/99, and we had a south wind surfacing. I'll go with 67.

[Tundra]

Maybe. I would more like to see a quick hitting warning shot. Those can happen in November and be followed by cold Januaries. At any rate there is little doubt it will get cold to some extent.

 

One thing that may delay the onset of the colder weather is an extremely deep trough the GEM and ECMWF depict digging into the SE next week. Ensembles from both of those models overcome it though and lift it out after day 10. The GFS could be rushing things, but then again it hasn't been a terrible model lately.

 

We might need to rely on a front loaded Winter now, the last half of November to the end of December for our best chance to get an Arctic Blast down here to the PNW. I just took a look at the newest edition of the NCAR_CESM models and they don't look good. At least for December it looks decent with positive anomalies in Western Alaska and what looks like a SE ridge with Western Canada having lots of Arctic air bottled up. We just need it to drop down before the massive Ridge comes back starting in January and settles again in the Southern Canadian/Northern US Plains.

 

http://i.imgur.com/xS9gTAd.png

http://www.cpc.ncep.noaa.gov/products/NMME/current/images/NCAR_CESM_ensemble_tmax_us_lead2.png

http://i.imgur.com/qVr4UDA.png

http://i.imgur.com/3IWi9gd.png

[Bryant]

We might need to rely on a front loaded Winter now, the last half of November to the end of December for our best chance to get an Arctic Blast down here to the PNW. I just took a look at the newest edition of the NCAR_CESM models and they don't look good. At least for December it looks decent with positive anomalies in Western Alaska and what looks like a SE ridge with Western Canada having lots of Arctic air bottled up. We just need it to drop down before the massive Ridge comes back starting in January and settles again in the Southern Canadian/Northern US Plains.

 

You're basing our whole winter off of this model?

[Front Ranger]

You looking at the same ensemble run I am? The Aleutian ridge has trended flatter in four consecutive runs. That's all that's going to matter in the long run, assuming it verifies.

 

I think you have a slightly unhealthy fear of flat Aleutian ridges.

 

FWIW, while the ridge has trended flatter, the overall global pattern continues to show a significant shift.

[Tundra]

You're basing our whole winter off of this model?

Nope, it's just one part of it.

[snow_wizard]

Rich Marriot posted this graph for snowfall at SeaTac. Pretty depressing if you ask me. He thinks this winter will be Good for snowfall though.

Keep in mind the stretch that is flat lined is when they didn't record snowfall at SEA. Sadly 1996-97 falls into that category.

[snow_wizard]

The ECMWF ensemble actually moved up the timing of the height rises over the GOA / Aleutians.

[snow_wizard]

We might need to rely on a front loaded Winter now, the last half of November to the end of December for our best chance to get an Arctic Blast down here to the PNW. I just took a look at the newest edition of the NCAR_CESM models and they don't look good. At least for December it looks decent with positive anomalies in Western Alaska and what looks like a SE ridge with Western Canada having lots of Arctic air bottled up. We just need it to drop down before the massive Ridge comes back starting in January and settles again in the Southern Canadian/Northern US Plains.

 

Everyone is setting themselves up to get burned by that model. It did really well during the summer, but that means nothing for this winter. It reminds of when I first starting looking at models and the GFS just happened to nail the Dec 1998 cold wave two weeks ahead of time. The next time it showed a big cold wave I just took it for granted it would be right...

[snow_wizard]

I think you have a slightly unhealthy fear of flat Aleutian ridges.

 

FWIW, while the ridge has trended flatter, the overall global pattern continues to show a significant shift.

I agree. The table is set for extreme amplification this winter. I'm not worried about a flat ridge out there.

[Kayla]

Surprised no one has mentioned the Euro weeklies today. The November ~17th-24th period continues to be a timeframe to watch. Todays controlled run showed -10 to -15 850mb departures. Keeping in mind seasonal average 850mb temps in that same timeframe are right around zero.

 

Not sure if we'll have that much cold air on this side of the globe to tap into by then but definitely bears watching.

[Phil]

Yeah I figured you'd disagree.

 

All I know is that the position of the main players look to be much better than the mega-torch pattern we're in right now, with a general trend of the GOA low going away and offshore heights rising. Obviously details like amplitude will be fuzzy at this range.

Definitely a better look than what we have currently. I'm just terrified of flat NPAC ridging in general. It's the primary +EPO loading pattern, and it inhibits poleward propagating vertical wave activity fluxes, which are required to keep the PV/NAM in check.

 

Amplified, poleward biased NPAC ridging is another story.

[Front Ranger]

Definitely a better look than what we have currently. I'm just terrified of flat NPAC ridging in general. It's the primary +EPO loading pattern, and it inhibits poleward propagating vertical wave activity fluxes, which are required to keep the PV/NAM in check.

 

Amplified, poleward biased NPAC ridging is another story.

 

Most PNW Arctic outbreaks are preceded by a period of flat NPAC ridging.

[Phil]

I think you have a slightly unhealthy fear of flat Aleutian ridges.

 

FWIW, while the ridge has trended flatter, the overall global pattern continues to show a significant shift.

That's probably true, haha. I've just seen so many beautiful hemisphere-scale wavetrain progressions ruined by them.

 

It doesn't affect my winter climo or anything, but I'd much rather have an anomalous hemispheric wavetrain and perturbed PV than a mundane, flat process like we've seen over the last few winters.

[Gradient Keeper]

Most PNW Arctic outbreaks are preceded by a period of flat NPAC ridging.

Yep.

[Phil]

Most PNW Arctic outbreaks are preceded by a period of flat NPAC ridging.

Huge misconception here, IMO. Flat Aleutian ridging destructively interferes with the processes that lead to the necessary amplification. It's a huge negative. The amplification occurs when that boundary state is perturbed externally, often via changes in the E-HEM circulation which induce east-Asian mountain/gravity wave drag torques. This then leads to the changes in the NPAC.

[Bryant]

Nope, it's just one part of it.

Care to explain why else we should write off the 2nd half of winter?

[Phil]

Another conduit is actually achieved via the Aleutian low induced WAFz/PV perturbations (think DEC 2009, NOV 2014, etc). This is arguably easier to achieve in the modern Hadley Cell era, however this sort of event is often quick and/or can slide east of the Rockies more easily.

 

Events like 1955/56 w/ the modest Aleutian ridge amplification are nearly impossible under today's Hadley/Walker state(s).

[Front Ranger]

Another conduit is actually achieved via the Aleutian low induced WAFz/PV perturbations (think DEC 2009, NOV 2014, etc). This is arguably easier to achieve in the modern Hadley Cell era, however this sort of event is often quick and/or can slide east of the Rockies more easily.

 

Events like 1955/56 w/ the modest Aleutian ridge amplification are nearly impossible under today's Hadley/Walker state(s).

 

[Phil]

Poor wording. Meaning, an amplified aleutian ridge without a notably strong EPO component or deep anticyclonic wavebreak in the vicinity. That was almost solely a -PNA driven winter, something that probably cannot happen today, IMO.

[Gradient Keeper]

Quite dramatic cooling across the Pacific north of 40 N.

 

http://i.imgur.com/2y5sacR.png

[Gradient Keeper]

00z GFS in 4 minutes!

[Phil]

Saw this discussed on Twitter earlier and think it's pertinent to this discussion. Another artifact of the modern day climatological boundary state is the increasingly positive East Atlantic Pattern. We're currently observing record breaking positive values, and have been for the last several years.

 

Note how it abruptly switched modes in the late 1970s, in tandem with the great Hadley Cell shift and Pacific climate shift that occurred at the same time:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/8F585BD5-3D8D-4BF7-9E65-E525E6AA8934_zps2id2dbtd.jpg

[crf450ish]

Quite dramatic cooling across the Pacific north of 40 N.

 

http://i.imgur.com/2y5sacR.png

I like this post. Can't figure out how to like a post on smart phone. Not sure if the little check mark means like post or report post. Didn't wanna take the chance on the latter.

[crf450ish]

Saw this discussed on Twitter earlier and think it's pertinent to this discussion. Another artifact of the modern day climatological boundary state is the increasingly positive East Atlantic Pattern. We're currently observed record breaking positive values, and have been for the last several years.

 

Note how it abruptly switched modes in the late 1970s, in tandem with the great Hadley Cell shift and Pacific climate shift that occurred at the same time:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/8F585BD5-3D8D-4BF7-9E65-E525E6AA8934_zps2id2dbtd.jpg

Would be in line with the abrupt climate change theories that have been popping up recently. Recent as in last 10 years or so....

[Front Ranger]

Poor wording. Meaning, an amplified aleutian ridge without a notably strong EPO component or deep anticyclonic wavebreak in the vicinity. That was almost solely a -PNA driven winter, something that probably cannot happen today, IMO.

 

It was also a very -AO winter...lots of high latitude blocking in general in 1955-56. Much like 2010-11.

[Front Ranger]

Saw this discussed on Twitter earlier and think it's pertinent to this discussion. Another artifact of the modern day climatological boundary state is the increasingly positive East Atlantic Pattern. We're currently observing record breaking positive values, and have been for the last several years.

 

Note how it abruptly switched modes in the late 1970s, in tandem with the great Hadley Cell shift and Pacific climate shift that occurred at the same time:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/8F585BD5-3D8D-4BF7-9E65-E525E6AA8934_zps2id2dbtd.jpg

 

I could be wrong...but it looks to mirror very closely the pattern of global warming, with ups/downs tied closely to ENSO warming/cooling.

[Gradient Keeper]

I like this post. Can't figure out how to like a post on smart phone. Not sure if the little check mark means like post or report post. Didn't wanna take the chance on the latter.

No worries.

[snow_wizard]

SEA broke the record high today by 4 degrees. Old record was set in 2008...yesterday's was set in 1949. Good time for record highs to be set it would appear.

[Gradient Keeper]

*Crickets* ......

 

I happen to really like 00z GFS(Upstream) Persistent ridging/anomaly over the North Pacific nosing near the Aleutians which could be good if amplification takes place and exactly where it sets up. A good ways to go to be "good", but it's far better than the stubborn GOA vortex. Signs an Omega block might be setting up after day 10. So far out one can only speculate and only barely at that.

[Phil]

I could be wrong...but it looks to mirror very closely the pattern of global warming, with ups/downs tied closely to ENSO warming/cooling.

Well, the EA measures one of the dominant modes of atmospheric circulation within the NATL domain, like an Atlantic counterpart to the PNA in some respects. You'd expect some coherence w/ global temperatures given the Hadley Cell expansions are a conduit for significant extratropical warming regardless of the reason(s) for the expansion, and these circulatory changes are responsible for some of the "issues" we've been discussing here as of late.