November 2017 PNW Discussion Thread

[Phil]

Fascinating stuff Phil.

Thank you, and definitely agreed re: fascinating. So many questions, yet very few answers so far. Many of the climate changes appear to be either unforced threshold crossings, or nonlinear responses to long period orbital forcing, which only manifest after thresholds are crossed. Both scenarios are head scratchers.

 

Plus, the questions we do answer seem to open up a Pandora's box of new questions. So..shrug?

[TigerWoodsLibido]

Looks like the radar shows snow up on Mary's Peak. I'll try to drive up there later today and confirm.

[Phil]

Also, it strikes me as remarkable that the LIA didn't continue onward as glacial inception, because the sea/land ice extents were much more expansive during the LIA, when compared to the Eemian glacial inception 118kyrs ago (which triggered the Wisconsin Ice Age). In fact, sea levels were almost 2 meters higher than today's when glacial inception occurred during the late Eemian/LEAP. Baffling.

 

One thing you don't often hear (but it's true) is that, when our best climate models are initialized at the beginning of the LIA and run forward w/ the observed changes for hindcast purposes, they all trigger glacial inception. Very few exceptions.

 

One important difference between the two periods is that Obliquity was actually very reduced during the late Eemian, and said insolation signal was more amplified during boreal summer by an eccentricity-enhanced precession-insolation sign at aphelion.

 

If this is the case, then what actually matters might be the long period forcing, playing on the "thermodynamic inertia" of the system. In essence, it's as if climate system changes are analogous to a truck on a highway, where *rapid* system state changes tend to sustain better against opposing high frequency forcing, much like a tanker truck speeding down the freeway at 120mph will be harder to stop than a smart car traveling 20mph down a small residential street.

 

So, with the orbital forcing inching towards Eemian-esque boundary conditions over the next several thousand years, and given the profound (and structurally unsustainable) climate changes observed since ~ 1700, we should be wary that of the fact that the external forcings we've come to know and love are changing sign alongside an internal system state that is analogous to said tanker truck approaching a giant wall of concrete.

[Phil]

That said, there's another theory that's gaining traction in the paleoclimate community. There was an anomalous warming, lasting about 500 years, that occurred just before glacial inception terminated the Eemian between 119-117kyrs ago. Sea levels rose by 20-30 inches over that span.

 

So this theory is that polar insolation loss coupled with very warm tropical/subtropical SSTs provided the essential poleward moisture transport for glacial inception once that warming reversed to cooling, and the annular modes reversed.

 

If so, then the Eemian could be structurally homogenous to the Holocene in its late stages, even though it was much warmer during the Eemian compared to today, in the context of the ice core isotope proxies.

 

The new NEEM core (second image) picks up this warming better than the old GRIP/NGRIP cores, despite its reduced resolution, relatively speaking. The EPICA/Volstok cores are somewhat dampened, as expected, given the reduced magnitude of climate changes over the expansive Antarctic ice sheet and the increased weight of the ice sheet compressing the deeper layers.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/3AF6BDFA-41E1-452A-8789-53088B31AB31_zpsnow3q841.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/CB3EB9EB-2906-469F-A9F2-AA76CF164B69_zpsvwiqn8xq.jpg

[Phil]

Anyway, enough OT rants from me. Carry on.

[BLI snowman]

Over an inch of rain here today. Looks like most of the region is likely going to be around average this month precip-wise.

[Jesse]

Still a ton of spread on the 18z ensembles.

[Jesse]

Over an inch of rain here today. Looks like most of the region is likely going to be around average this month precip-wise.

Warmer and wetter than average month looking likely. The good news is all warm and wet Novembers were followed by Decembers and Januarys and sometimes even Februarys.

[Deweydog]

Still a ton of spread on the 18z ensembles.

Burgerville still does the same thing to their burgers.

[Phil]

Haha, wow.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/59EC24EB-9E0B-4737-A3F2-B06C967F348D_zpsalb3wx1c.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0AF09483-6DCD-413E-A31E-1011F5913C5A_zpsjs1hdzs0.png

[TigerWoodsLibido]

Burgerville still does the same thing to their burgers.

In N Out's is better

[Jesse]

[TigerWoodsLibido]

Haha, wow.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/59EC24EB-9E0B-4737-A3F2-B06C967F348D_zpsalb3wx1c.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0AF09483-6DCD-413E-A31E-1011F5913C5A_zpsjs1hdzs0.png

Light it up! Torchy thanksgiving leading to a big blast later.

[Jesse]

Haha, wow.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/59EC24EB-9E0B-4737-A3F2-B06C967F348D_zpsalb3wx1c.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0AF09483-6DCD-413E-A31E-1011F5913C5A_zpsjs1hdzs0.png

All that high latitude blocking and the Central/Western part of the country still finds a way to torch.

[umadbro]

Today has been my highest rainfall day this season. 0.93"

[Guest El nina]

Warmer and wetter than average month looking likely. The good news is all warm and wet Novembers were followed by Decembers and Januarys and sometimes even Februarys.

November is always followed by December, January and February.

[Front Ranger]

Over an inch of rain here today. Looks like most of the region is likely going to be around average this month precip-wise.

 

If so, that would be different than such analogs as 1950/1962/1973/1984/1990/1995/1996 (wet), 1967/2000/2007/2013 (dry).

 

1954, 1970, 1971, 1981, and 1989 were all near normal for the region overall. 1954, 1970, and 1989 have been three of my top analogs for a few weeks, and 1981 was second tier. All four Novembers also ended up warm across most of the West.

[Phil]

All that high latitude blocking and the Central/Western part of the country still finds a way to torch.

So, we have the long period homogeneity between NPAC and NATL, which has been integral to the climate system for (at least) the last century or so.

 

The PNA and NAO synchronize in the long run, however on a seasonal and/or subseasonal scale, one is usually dominant (in a more amplified state) and the other is submissive (in a less amplified state). For the time being, the NATL is in the dominant state, while the NPAC is in the submissive state.

 

However, this should reverse, as we'll soon be completing the poleward transfer of the AAM sink, which will open the conduit for the -QBO/easterly belt to downwell and affect the z-cells and alter wave activity/surf zone emanating from Eurasia, which will start juicing the PNA/NPAC more, and put the NAO/NATL into a more submissive state towards the Holidays and beyond, into January.

[Front Ranger]

1981 shows up a couple times on the long range CPC analogs as well.

 

[stuffradio]

Warmer and wetter than average month looking likely. The good news is all warm and wet Novembers were followed by Decembers and Januarys and sometimes even Februarys.

One might even say, March occurs following those Februarys!

[stuffradio]

Haha, wow.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/59EC24EB-9E0B-4737-A3F2-B06C967F348D_zpsalb3wx1c.png

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/0AF09483-6DCD-413E-A31E-1011F5913C5A_zpsjs1hdzs0.png

Yewg -NAO

[Phil]

1981 shows up a couple times on the long range CPC analogs as well.

 

814analog.off.gif

Interesting that 1981 was also one of the best summer pattern analogs for the Western Hemisphere. Great QBO analog too.

 

That said, the solar/AMO signal in 1981 bothers me. I could easily see 2017 veering off in a different direction starting in late December or early January. Or not, lol.

[crf450ish]

[Phil]

All that high latitude blocking and the Central/Western part of the country still finds a way to torch.

Oh, and those warm off-equator EPAC SSTs are part of the reason for the expanded EPAC Hadley Cell/SW ridge right now.

 

[Front Ranger]

Interesting that 1981 was also one of the best summer pattern analogs for the Western Hemisphere. Great QBO analog too.

 

That said, the solar/AMO signal in 1981 bothers me. I could easily see 2017 veering off in a different direction starting in late December or early January. Or not, lol.

 

Yeah, 1981 is riding quite the hot streak. What gives me some confidence in it continuing to be a solid analog, though, is that it is not alone. And FWIW, I think temperature patterns are much more telling than precip.

 

Posted some updated thoughts in the predictions thread: http://theweatherforums.com/index.php/topic/1654-winter-predictions/page-3?p=272097

[Front Ranger]

So, we have the long period homogeneity between NPAC and NATL, which has been integral to the climate system for (at least) the last century or so.

 

The PNA and NAO synchronize in the long run, however on a seasonal and/or subseasonal scale, one is usually dominant (in a more amplified state) and the other is submissive (in a less amplified state). For the time being, the NATL is in the dominant state, while the NPAC is in the submissive state.

 

And let's face it, this turns you on.

[snow_wizard]

The 12z GFS was certainly an interesting hiccup.  The solution isn't even all that far fethched when you look at the progression.  The brief GOA low simply rotated under the block aroud 170.  Right now I would say that still has a 30 or 40% chance of happening.  It's just a matter of balance.

[Phil]

And let's face it, this turns you on.

Lol, we all have our guilty pleasures.

[snow_wizard]

Yewg -NAO

 

West based at that.

[snow_wizard]

Yeah, 1981 is riding quite the hot streak. What gives me some confidence in it continuing to be a solid analog, though, is that it is not alone. And FWIW, I think temperature patterns are much more telling than precip.

 

Posted some updated thoughts in the predictions thread: http://theweatherforums.com/index.php/topic/1654-winter-predictions/page-3?p=272097

 

I still think there's a reasonable chance you will be wrong about this month ending up above normal for temps.  50/50 at this point IMO.

[Front Ranger]

I still think there's a reasonable chance you will be wrong about this month ending up above normal for temps.  50/50 at this point IMO.

 

It's certainly possible. You're discounting a lot of guidance to say 50/50, though. Any particular reason you think the pattern may not turn as warm as modeled?

[Deweydog]

It's certainly possible. You're discounting a lot of guidance to say 50/50, though. Any particular reason you think the pattern may not turn as warm as modeled?

Inversion excursion!!!

[Gradient Keeper]

00z GFS in 7 minutes!

[snow_wizard]

It's certainly possible. You're discounting a lot of guidance to say 50/50, though. Any particular reason you think the pattern may not turn as warm as modeled?

 

Just a hunch.  The models have already added the little chilly blip early next week...then of course you had the very cold 12z run.  Pretty much all model runs have indicated high GOA heights / pressure returning late in the month.

[High Desert Mat!]

[Front Ranger]

Inversion excursion!!!

 

That would be pretty localized to the PNW lowlands mainly. I'm talking about the overall, big picture pattern.

 

Doesn't sound like Snow Wiz is counting on an inversion, anyhow.

[Front Ranger]

Just a hunch.  The models have already added the little chilly blip early next week...then of course you had the very cold 12z run.  Pretty much all model runs have indicated high GOA heights / pressure returning late in the month.

 

At this point, though, looks too far west and not amplified enough to deliver cold to your neck of the woods. But we still have a long way to go...

 

My main reasoning for the pattern progression has simply been what happened with similar analogs. Since the late October/early November -EPO pattern emerged, the primary analog progression pointed to a warmer pattern likely becoming dominant later this month. Much more unusual to have significant -EPO continue through November.

[Deweydog]

That would be pretty localized to the PNW lowlands mainly. I'm talking about the overall, big picture pattern.

 

Doesn't sound like Snow Wiz is counting on an inversion, anyhow.

It's usually the fallback for rising heights during the cold season.

[luvssnow_spokane]

It's certainly possible. You're discounting a lot of guidance to say 50/50, though. Any particular reason you think the pattern may not turn as warm as modeled?

YAh... I think it is more like 40/70

[MR.SNOWMIZER]

I guess whats important is Tims roses.