November 2017 PNW Discussion Thread

[Front Ranger]

The PNA/NAO synchronicity continues..no surprise.

 

Will have to dig up the results, but based on a monthly-scale statistical analysis I did a little while back, the PNA and NAO share signs in over 80% of months since 1950.

 

Interesting.

 

Seems like the NAO is based further north, though (which is partly why it shares some relationships to the AO), so I wonder what the relationship to the further north indexes on the Pacific-side like the WPO/EPO?

 

I'd also to be curious how strong the correlation exists for months that are strongly -PNA or strongly -NAO, or vice versa. Like, if one index is strongly in one state, does that make it more likely for the other to be in the same state?

[Front Ranger]

MLK Day. He had a dream about sub-520dm thicknesses and lee side surface lows developing off VISL.

 

Given your prediction of frozen turkeys, sounds like we an expect record warmth to return on MLK day!

[SilverFallsAndrew]

44 with light rain now. 

[Deweydog]

Given your prediction of frozen turkeys, sounds like we an expect record warmth to return on MLK day!

2005 keeps resurfacing!!!?

[Gradient Keeper]

MLK Day. He had a dream about sub-520dm thicknesses and lee side surface lows developing off VISL.

Nah, he had bigger aspirations than that more around 505dm.

 

18z GFS in 36 minutes!

[SilverFallsAndrew]

Who knows what will happen. That is my take. 

[TigerWoodsLibido]

MLK Day. He had a dream about sub-520dm thicknesses and lee side surface lows developing off VISL.

He actually dreamed the lows move south along the coast before coming inland at about Coos Bay.

[Geos]

Sitting at 50 right now. Nice to have it dry so far today - gives me a chance to put up Christmas Lights. 

[Deweydog]

He actually dreamed the lows move south along the coast before coming inland at about Coos Bay.

Sorry. Tiger is not nearly black enough for Marty to have given two shits about central valley snow needs. You're screwed.

[snow_wizard]

Pretty much everything agrees on a ridge setting up along the West Coast with the highest anoms to the north of us.  The bottom line on that will be an inversion with weak offshore gradients while the jet is diverted well away from us.  Even the ECMWF ensemble control model agrees with this.  Before the ridge is directly over us it will begin well off the coast which will introduce colder air to be locked in by the ridge.  One interesting caveat with the ECMWF control model is it shows a classic retrogression around day 13.

[snow_wizard]

Who knows what will happen. That is my take. 

 

Bank on a major cold period this winter.

[Phil]

Interesting.

 

Seems like the NAO is based further north, though (which is partly why it shares some relationships to the AO), so I wonder what the relationship to the further north indexes on the Pacific-side like the WPO/EPO?

Yeah, it's complicated since each teleconnection represents different/unique boundary conditions. The PNA has a stronger statistical relationship to the NAO than the AO/NAM, which makes sense since the PNA and NAO are both technically measures of the meridional extratropical pressure gradients poleward of the subtropical highs, which tend to co-vary given longitudinal spacing/geography and forcings behind said variance.

 

The EPO/WPO don't correlate as strongly to either the NAO or AO/NAM. In fact, the PNA has a stronger statistical correlation with the NAO than it does the EPO/WPO, which is fascinating to me.

 

I'd also to be curious how strong the correlation exists for months that are strongly -PNA or strongly -NAO, or vice versa. Like, if one index is strongly in one state, does that make it more likely for the other to be in the same state?

This is an interesting one. From a decadal/multi-year standpoint, the PNA/NAO are indeed synchronized in amplitude. However, from a monthly standpoint, the opppsite is true, where one will typically enter a "dominant" state, and the other will be in a "submissive" state, even while sharing the same sign (+/-).

[SilverFallsAndrew]

Bank on a major cold period this winter.

 

Looking at what 1961-62 was like up here I am ruined now. No one even talks about that winter and a modern winter could never measure up. d**n.

[snow_wizard]

Sure is nice not living in a maritime climate and worrying about whether or not I’ll have an actual winter. More of a matter of when vs if.....

 

Tell us something we don't already know.  That having been said we do get good winters here on occasion.  

[snow_wizard]

Looking at what 1961-62 was like up here I am ruined now. No one even talks about that winter and a modern winter could never measure up. d**n.

 

 

It was really THAT good?

 

Interestingly October 1961 was the second highest on my NPS index.  This one was a bit higher.

[snow_wizard]

Yeah, it's complicated since each teleconnection represents different/unique boundary conditions. The PNA has a stronger statistical relationship to the NAO than the AO/NAM, which makes sense since the PNA and NAO are both technically measures of the meridional extratropical pressure gradients poleward of the subtropical highs, which tend to co-vary given longitudinal spacing/geography and forcings behind said variance.

 

The EPO/WPO don't correlate as strongly to either the NAO or AO/NAM. In fact, the PNA has a stronger statistical correlation with the NAO than it does the EPO/WPO, which is fascinating to me.

 

 

This is an interesting one. From a decadal/multi-year standpoint, the PNA/NAO are indeed synchronized in amplitude. However, from a monthly standpoint, the opppsite is true, where one will typically enter a "dominant" state, and the other will be in a "submissive" state, even while sharing the same sign (+/-).

 

I think a lot of people have a very mistaken idea about the relationship of the PNA and NAO.  I was one of them for quite a time.

[SilverFallsAndrew]

It was really THAT good?

 

Interestingly October 1961 was the second highest on my NPS index.  This one was a bit higher.

 

I am probably exaggerating. But it was really good. Silver Falls always has spotty snowfall data, but it is obvious there was plenty of snow. 

 

November - Heavy rain turns to snow, a couple inches, a 34/21 day.

 

December -  Looks like some arctic air the first half of the month, a 34/13 day. SLE had 32/15.

 

January - Major arctic outbreak and 2 weeks of snow cover at Silver Falls. A 24/9 and 30/1 day. Four straight single digit lows. 

 

SLE had a snow event and 5 straight sub-freezing highs, along with a low of 8. 

 

February - Major early month torch, the 1st was 69/30! At Silver Falls. Big time cold and snow at Silver Falls the end of the month, with two single digit lows. SLE had a low of 10 on the 26th and 8.5" of snow on the month.

 

March - 21.5" of snow the first 10 days of the month at Silver Falls. Salem even had about 3" of snow. 

 

Easily better than last winter for a combination of snow and cold outbreaks imo. The meaningful cold last winter was really in the Dec. 10-Jan 20 window, though there were some good snow events in some places outside of that.  

[Jesse]

Who knows what will happen. That is my take.

BARF

[umadbro]

BARF

Well said!

[Jesse]

Well said!

I learn from the best.

[umadbro]

I learn from the best.

Well yeah. 8 years in college would make anyone smart.

[Jesse]

Well yeah. 8 years in college would make anyone smart.

Only losers go to college.

[Deweydog]

Sounds like there's a stomach bug going around.

[Phil]

I think a lot of people have a very mistaken idea about the relationship of the PNA and NAO. I was one of them for quite a time.

I agree. The idea that -NAO = cold east and -PNA = cold west is really nothing more than wx-weenie mythology. In reality they're very much interlinked, and generally speaking, are expressive of large scale tropical/subtropical dynamics across the entire Western Hemisphere.

[Phil]

Mt. Agung popped off last night. Looks like a phreatic eruption so far, but there was a visible tower of hot rock last night, suggesting a magmatic eruption could be starting/about to start.

[weatherfan2012]

I agree. The idea that -NAO = cold east and -PNA = cold west is really nothing more than wx-weenie mythology. In reality they're very much interlinked, and generally speaking, are expressive of large scale tropical/subtropical dynamics across the entire Western Hemisphere.

unfortunately a lot of respected Mets do use this idea of the nao and the pna so while it's very much a weenie made up thing Mets tend to fall for the trap to which adds insult in injery.as the pubic is likely getting mislead what and how these indexes truly operate.

[weatherfan2012]

I think a lot of people have a very mistaken idea about the relationship of the PNA and NAO. I was one of them for quite a time.

I think it human nature really we want to believe we know how these things work when in truth it's more complex then we would like to amint.

[Phil]

Agung's ash cloud up to 20,000ft. Looks like the eruption is fluctuating in intensity, but gradually intensifying.

 

VONA status raised to "red".

[Front Ranger]

Has anyone NOT put up their Christmas lights yet? The only way to ensure God/Santa delivers snow this winter is if everyone is done by tomorrow.

[Phil]

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/C9F561D0-6BD9-4118-802C-2BFD635A2089_zpsdo7ydbch.jpg

[Jesse]

Agung's ash cloud up to 20,000ft. Looks like the eruption is fluctuating in intensity, but gradually intensifying.

 

VONA status raised to "red".

LIA II here we come?

[Phil]

LIA II here we come?

Lol.

 

Need to see how much ash penetrates the tropopause. Then the LIA V2.0 forecasts can start.

[Gradient Keeper]

Well said!

unauseousbro?

[Gradient Keeper]

18z GFS = The Motherlode of Greenland blocks. Jeez

 

00z GFS in 3 hours 29 minutes!

[Deweydog]

Has anyone NOT put up their Christmas lights yet? The only way to ensure God/Santa delivers snow this winter is if everyone is done by tomorrow.

Done. We did the lights EXACTLY how they were last year but we added lights to a couple trees which finally filled out enough to do so.

 

#2016-17reduxonlycolderandsnowier

[weatherfan2012]

Lol.

Need to see how much ash penetrates the tropopause. Then the LIA V2.0 forecasts can start.

agreed those you know Robert will still post it on his site.

[TT-SEA]

Well... my wife ordered a snowblower on sale on Black Friday.   Should be here in a couple weeks.   Sorry guys.   Just ruined winter.   I tried to warn her... I think she did it on purpose.  

[Deweydog]

Well... my wife ordered a snowblower on sale on Black Friday. Should be here in a couple weeks. Sorry guys. Just ruined winter. I tried to warn her... I think she did it on purpose.

F#ck you.

 

We adopted a secondary snow shovel while cleaning out my wife's grandparent's house a couple months ago.

[snow_wizard]

The GFS is slowly trending toward developing a bridge between the GOA block and NAO block in the crucial 4 to 6 day period.  Any amplification or slowing down of the progression of the block could make a huge difference for us.

[snow_wizard]

18z GFS = The Motherlode of Greenland blocks. Jeez

 

00z GFS in 3 hours 29 minutes!

 

You got that right.  Crazy arse blocking!