El Nino is Dead. Long Live La Nina.

[TT-SEA]

That is possible.  I think a progression like 1983-84 and 1984-85 may be in the cards.  Marginal Nina the first winter stronger the next. The big trade wind burst coming up may get the Nina really going.

I would not count on repeating those years.

[Bryant]

The sign of the PDO/OPDO (SST reflection in NPAC) does not help predict pattern tendencies going forward.

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00057.1

 

 

Some people just don't understand this simple connection

[Bryant]

i think the biggest concern for the PNW right now, regardless of the ENSO state:

 

 

 

The return of the blob.

 

The only way to offset the effects of the blob would be to have a strong ENSO state either way.. and given we're looking at a neutral/weak ENSO state... the blob is going to take precedence.

 

My call right now: warm fall and early winter. I'd say expect a back loaded winter/cold spring.

The "blob" does not drive our weather, it's a reflection of the atmospheric circulations

[Deweydog]

Typically you'd see a blocking area of high pressure over that warm pool, and it would be warm because of the warm waters--it would kill the chance of any modified Arctic air coming from the north. We'd need a retrograding ridge come from the east and pool in cold from central Canada.

Ridges are warm because of sinking air, not because they form over warm waters. This makes no sense.

[westcoastexpat]

Ridges are warm because of sinking air, not because they form over warm waters. This makes no sense.

 

You'd have onshore flow with that high placement, with the flow sourcing over anomalously warmer SSTs.

 

I think you are confusing surface high pressures systems (which I was talking about) and jet stream ridges... you can have surface high pressure in a trough... happens over central/eastern NA all the time. They are not one in the same.

[Front Ranger]

i think the biggest concern for the PNW right now, regardless of the ENSO state:

 

 

 

The return of the blob.

 

The only way to offset the effects of the blob would be to have a strong ENSO state either way.. and given we're looking at a neutral/weak ENSO state... the blob is going to take precedence.

 

My call right now: warm fall and early winter. I'd say expect a back loaded winter/cold spring.

 

That's not where the "blob" was in 2015.

[Front Ranger]

The sign of the PDO/OPDO (SST reflection in NPAC) does not help predict pattern tendencies going forward.

 

http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00057.1

 

 

Disagree. It's not a forcing, but it does have predictive pattern tendencies. The patterns tend to run in cycles.

 

We've gone over this many times. It's been demonstrated many times.

[Front Ranger]

I don't think it's "bad or "good". I don't think it means much of anything..cool, higher latitude SSTs are extremely overrated as a forcing, in my opinion. They're an excellent measure of dominant low frequency pattern tendencies that have already occurred, however, so by that measure they might or might not have extrapolative value.

 

I'd argue the PDO might be the most overrated "variable" in the entirety of seasonal forecasting, when considered to be a "forcing".

 

It's a huge indicator, for the PNW in particular, as to large scale pattern tendencies. See the past couple years.

[Front Ranger]

That is possible.  I think a progression like 1983-84 and 1984-85 may be in the cards.  Marginal Nina the first winter stronger the next. The big trade wind burst coming up may get the Nina really going.

 

It's interesting that the MEI is much lower than it was in 1983 at this time.

[ShawniganLake]

Typically you'd see a blocking area of high pressure over that warm pool, and it would be warm because of the warm waters--it would kill the chance of any modified Arctic air coming from the north. We'd need a retrograding ridge come from the east and pool in cold from central Canada.

 

 

You'd have onshore flow with that high placement, with the flow sourcing over anomalously warmer SSTs.

 

I think you are confusing surface high pressures systems (which I was talking about) and jet stream ridges... you can have surface high pressure in a trough... happens over central/eastern NA all the time. They are not one in the same.

Are surface highs and Blocking highs not 2 different things?

[Deweydog]

You'd have onshore flow with that high placement, with the flow sourcing over anomalously warmer SSTs.

 

I think you are confusing surface high pressures systems (which I was talking about) and jet stream ridges... you can have surface high pressure in a trough... happens over central/eastern NA all the time. They are not one in the same.

 

Of course you can have surface high pressure with a trough, and it doesn't happen just over the central/eastern.  But over the offshore waters, surface high pressure is almost exclusively going to be associated with upper level ridging.  Stronger upper level ridge, stronger surface high pressure.  And the stronger the upper level ridge, the better the chances downstream troughing will be stronger.  There's a reason we want to see northern GOA heights crack 570dm when analyzing the broad aspects of a PNW cold pattern.  

[Phil]

Disagree. It's not a forcing, but it does have predictive pattern tendencies. The patterns tend to run in cycles.

 

We've gone over this many times. It's been demonstrated many times.

Wrong. It doesn't have any predictive value after factoring for the ENSO sign.

 

Yeah, we've been over this many times, but you're always denying the data.

[Phil]

It's a huge indicator, for the PNW in particular, as to large scale pattern tendencies. See the past couple years.

The last couple of years featured +ENSO signs, both in forcing and SSTs/MEIs, as well as powerful PVs.

[Front Ranger]

Wrong. It doesn't have any predictive value after factoring for the ENSO sign.

 

Yeah, we've been over this many times, but you're always denying the data.

 

No, I have provided the data many times. It is not completely dependent on ENSO.

[Front Ranger]

The last couple of years featured +ENSO signs, both in forcing and SSTs/MEIs, as well as powerful PVs.

 

From mid 2014 to mid 2015, we had weak +ENSO, but very strong +PDO. The PDO actually flipped positive (in early 2014), before ENSO went positive. Never a good sign.

[Phil]

No, I have provided the data many times. It is not completely dependent on ENSO.

It's completely depend on the nature of the tropical forcing(s) and the strength of the polar vortex. The ENSO sign (+/-) can explain away ~70% of the correlation between the PDO and the longwave pattern over NW North America, the rest can be explained via the QBO/stratosphere.

[Phil]

From mid 2014 to mid 2015, we had weak +ENSO, but very strong +PDO. The PDO actually flipped positive (in early 2014), before ENSO went positive. Never a good sign.

The +ENSO (Pacific) forcing (convection) was very strong in 2014-15, just located very far west. Hence, no coherent ENSO until it propagated eastward in early 2015, where it set off a super niño the following winter. It was still clearly a Niño forcing regime, for all intents and purposes.

[Phil]

Let's look at satellite era winters, separated into two groups.

 

First group: Niña cell winters that delivered continental Arctic air into the PNW.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/72DDACBE-21FB-4927-911E-EF79EECB8B05_zpslabfhxb5.png

 

Second group: Niña cell winters that failed to deliver continental Arctic air into the PNW:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/FB38E551-87D4-478E-9A3E-4DF3DBBA9496_zpsxjy6x1n0.png

 

Seems to me that, if there's any correlation here, it's to the latitude of the NPAC warm pool, which can probably be explained by the latitude of the NPAC anticyclone (mostly governed by the QBO during Niña winters). Certainly no correlation to the PDO here.

[snow_wizard]

You'd have onshore flow with that high placement, with the flow sourcing over anomalously warmer SSTs.

 

I think you are confusing surface high pressures systems (which I was talking about) and jet stream ridges... you can have surface high pressure in a trough... happens over central/eastern NA all the time. They are not one in the same.

 

Strong surface high pressure over the GOA is often associated with our coldest winters.  There is normally a lobe that extends off of the complex into the interior of BC that forces the Fraser outflow.

[snow_wizard]

Of course you can have surface high pressure with a trough, and it doesn't happen just over the central/eastern.  But over the offshore waters, surface high pressure is almost exclusively going to be associated with upper level ridging.  Stronger upper level ridge, stronger surface high pressure.  And the stronger the upper level ridge, the better the chances downstream troughing will be stronger.  There's a reason we want to see northern GOA heights crack 570dm when analyzing the broad aspects of a PNW cold pattern.  

 

So eloquently put!

[snow_wizard]

Let's look at satellite era winters, separated into two groups.

 

First group: Niña cell winters that delivered continental Arctic air into the PNW.

 

 

Second group: Niña cell winters that failed to deliver continental Arctic air into the PNW:

 

 

Seems to me that, if there's any correlation here, it's to the latitude of the NPAC warm pool, which can probably be explained by the latitude of the NPAC anticyclone (mostly governed by the QBO during Niña winters). Certainly no correlation to the PDO here.

 

No doubt the current SST's closely mirror scenario number 1.

[Front Ranger]

Let's look at satellite era winters, separated into two groups.

 

First group: Niña cell winters that delivered continental Arctic air into the PNW.

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/72DDACBE-21FB-4927-911E-EF79EECB8B05_zpslabfhxb5.png

 

Second group: Niña cell winters that failed to deliver continental Arctic air into the PNW:

 

http://i724.photobucket.com/albums/ww243/phillywillie/Mobile%20Uploads/FB38E551-87D4-478E-9A3E-4DF3DBBA9496_zpsxjy6x1n0.png

 

Seems to me that, if there's any correlation here, it's to the latitude of the NPAC warm pool, which can probably be explained by the latitude of the NPAC anticyclone (mostly governed by the QBO during Niña winters). Certainly no correlation to the PDO here.

Dec 1998 delivered a major Arctic blast to the PNW.

[Phil]

Dec 1998 delivered a major Arctic blast to the PNW.

Doesn't change the maps to any noticeable degree.

[Front Ranger]

Doesn't change the maps to any noticeable degree.

 

Jan 2012 also had a continental air intrusion into the PNW. Bellingham saw a 19/12 day. SEA saw two sub-freezing days and almost 10" of snowfall.

 

Dec 1980 also saw a Fraser Valley Arctic event, though it didn't penetrate very far south. Bellingham saw 4 straight days with highs below 25. SEA managed a 33/22 day.

 

Both of those years were similar to 1996-97 (part of your first map), in that they had Arctic seepage, but not a full-scale regional blast.

[Abbotsford_wx]

WxBell's preliminary winter forecast:

 

 

That's the spring forecast. Our winter is Nov-Dec.

[TT-SEA]

That's the spring forecast. Our winter is Nov-Dec.

 

That is the forecast for the first 3 months of our 6-month spring.

[Phil]

Jan 2012 also had a continental air intrusion into the PNW. Bellingham saw a 19/12 day. SEA saw two sub-freezing days and almost 10" of snowfall.

 

Dec 1980 also saw a Fraser Valley Arctic event, though it didn't penetrate very far south. Bellingham saw 4 straight days with highs below 25. SEA managed a 33/22 day.

 

Both of those years were similar to 1996-97 (part of your first map), in that they had Arctic seepage, but not a full-scale regional blast.

I wouldn't classify 2011-12 as an Arctic event, given no Arctic air made it south of the border..1980-81 wasn't an Arctic event either.

 

Anyways, 1980-81 was +PDO, 2011-12 was -PDO. Doesn't change the picture much.

[Front Ranger]

I wouldn't classify 2011-12 as an Arctic event, given no Arctic air made it south of the border..1980-81 wasn't an Arctic event either.

 

Anyways, 1980-81 was +PDO, 2011-12 was -PDO. Doesn't change the picture much.

You said continental air. BLI's numbers make it clear some very cold air made it south of the border in both cases.

 

And you classify Dec 1996 as arctic?

[westcoastexpat]

That's not where the "blob" was in 2015.

 

Agreed.

 

I've been talking about the blob in 2013-2014, though.

[Phil]

You said continental air. BLI's numbers make it clear some very cold air made it south of the border in both cases.

 

And you classify Dec 1996 as arctic?

Temperatures aloft were notable cooler relative to average region wide during 1996, according to ESRL, with larger dewpoint depressions. More Arctic than 2012 and 1980.

[snow_wizard]

Temperatures aloft were notable cooler relative to average region wide during 1996, according to ESRL, with larger dewpoint depressions. More Arctic than 2012 and 1980.

 

I think Front Ranger is being VERY obtuse trying to argue the winter of 1980-81 had any noteworthy Arctic air in the NW.

[BLI snowman]

I think Front Ranger is being VERY obtuse trying to argue the winter of 1980-81 had any noteworthy Arctic air in the NW.

 

It's obviously not accurate to say that it had any noteworthy arctic event for our region as a whole. 

 

But if you want to play the semantics game then it's also not accurate to say that it had no continental airmasses, either. In particular, February 1981 and January 1997 both produced more regional glancing blow type cold airmasses that would certainly qualify as continental

 

http://mp1.met.psu.edu/~fxg1/NARR/1981/us0210.php

 

http://mp1.met.psu.edu/~fxg1/NARR/1997/us0112.php

 

2011-12 was obviously more lacking in that regard. Deep, cold offshore flow never really took hold at any point for Portland or Seattle.

[snow_wizard]

It's obviously not accurate to say that it had any noteworthy arctic event for our region as a whole. 

 

But if you want to play the semantics game then it's also not accurate to say that it had no continental airmasses, either. In particular, February 1981 and January 1997 both produced more regional glancing blow type cold airmasses that would certainly qualify as continental

 

http://mp1.met.psu.edu/~fxg1/NARR/1981/us0210.php

 

http://mp1.met.psu.edu/~fxg1/NARR/1997/us0112.php

 

2011-12 was obviously more lacking in that regard. Deep, cold offshore flow never really took hold at any point for Portland or Seattle.

 

A low level Arctic front did make it to the Seattle area in January 2012.  I remember when that came through here we switched from freezing rain to snow.

[Front Ranger]

I think Front Ranger is being VERY obtuse trying to argue the winter of 1980-81 had any noteworthy Arctic air in the NW.

 

Huh? That's not what I was arguing. It was a similar situation to Jan 2012 and Dec 1996. Not a true Arctic outbreak, which I said.

 

You must have read something wrong.

[Phil]

New round of ENSO cooling underway with the trade burst. That heavy -IOD is still going strong, too, which historically favors deeper western troughing during -ENSO winters by keeping a lid on the W-IO/WHEM forcing relative to the E-IO/MT..WPAC is a wildcard though.

 

http://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta_global_1.png

[Jesse]

New round of ENSO cooling underway with the trade burst. That heavy -IOD is still going strong, too, which historically favors deeper western troughing during -ENSO winters by keeping a lid on the W-IO/WHEM forcing relative to the E-IO/MT..WPAC is a wildcard though.

 

http://www.tropicaltidbits.com/analysis/ocean/cdas-sflux_ssta_global_1.png

That is one hell of a warm pool in the GOA.

[Phil]

That is one hell of a warm pool in the GOA.

Yeah, the NPAC SST gradient is very weak this autumn..if there's any effect it'd be to weaken the NPAC jet/zonal winds over that domain (basic thermal wind laws), which is actually something you guys want (as opposed to a raging jet).

 

The +QBO alone favors a strong/poleward anticyclone and weaker zonal wind component, so I think a more blocky, meridional component might be more likely over the NPAC this winter.

[Jesse]

Yeah, the NPAC SST gradient is very weak this autumn..if there's any effect it'd be to weaken the NPAC jet/zonal winds over that domain (basic thermal wind laws), which is actually something you guys want (as opposed to a raging jet).

 

The +QBO alone favors a strong/poleward anticyclone and weaker zonal wind component, so I think a more blocky, meridional component might be more likely over the NPAC this winter.

Will its placement continue to favor the development of an offshore ridge? It seems models have been trending toward more offshore troughing in recent days. It would be nice to see that trend reverse again, and the GOA ridge reassert itself.

[Phil]

Will its placement continue to favor the development of an offshore ridge? It seems models have been trending toward more offshore troughing in recent days. It would be nice to see that trend reverse again, and the GOA ridge reassert itself.

Oh, I'm confident the GOA ridge will return, especially given what looks to be a fully entrenched +QBO @ 50mb. I mentioned in the September thread that I suspect a heavy anticyclonic wavebreaking (blocking high) event will manifest in the NPAC during November.

 

The ongoing NPAC jet extension and subsequent cyclonic wavebreaking is a result of intraseasonal Pacific forcing (again), so it's temporary. In a +QBO, stronger/poleward biased NPAC blocking is usually a safe bet during a Niña.

[westcoastexpat]

http://komonews.com/weather/scotts-weather-blog/cliff-mass-the-warm-blob-is-back-in-the-pacific-ocean

 

Interesting article...