La Niña/Winter 2016-17 Discussion

[Dsnowx53]

I don't see a -NAO winter as a whole, but I do think there is evidence that we'll see a -AO AND a -NAO in December. This may last through the first half of January. This is why I'm optimistic about December, even if we don't get the true Pacific overhaul with Arctic air. I do think the Pacific will eventually become a bit more conducive for colder weather though since I do expect some more poleward Aleutian ridging sometime in December as well.

[Isotherm]

A few general points for consideration. The stratospheric behavior both currently and progged, particularly as it pertains to the modelled sudden warming event in circa 10 days, doesn't guarantee an excellent or even semi-favorable pattern for our area. The relationship isn't 1:1, it's a chain of events which could progress in a variety of ways. The first "checkpoint" question to answer is: are stratospheric/tropospheric conditions conducive for effective propagation? Secondly; will downward propagation destructively interfere with a current tropospheric blocking pattern, thereby inducing a less blocky result? This has happened numerous times throughout the record (that is, a tropospheric blocking regime culminates in a SSW event, with a stronger polar night jet following, rather than the SSW preceding a block pattern). Thirdly, if the upper stratospheric warming propagates effectively, will the resultant stratospheric geopotential height configuration be conducive for our part of the world? After all of those aforementioned questions have been answered - and even if they're yes. Let's say the SSW event propagates effectively, will enhance the tropospheric pattern, and become conducive for our part of the globe: will the Pacific either amplify or reduce its effects?

 

Below is the z200 anomaly map for Oct 20-Nov 15; the Pacific jet is very intense, driven in part by the latitudinal thermal gradient, as noted in my outlook. The atmospheric pattern will continue to preclude the development of poleward Aleutian ridging. Will we evolve more favorably in the Pacific? It's possible (but not likely) down the road, for transient periods. The current progged stratospheric evolution is more favorable for Europe and Asia as well. I do think December could be interesting if there are some contemporaneous periods of favorable Pac/Atl, but the possibility of a poor outcome should be on the table in everyone's mind (and this is partially why I erred toward neutral for temps in Dec).

 

 

[PB GFI]

WE ALL REMEMBER LAST DEC . EN FUEGO .

HERE WAS IT`S 500 ... LOOK AT ALL THE LOW HEIGHTS OVER THE POLE .

 

THIS IS WHERE THE GUIDANCE TAKES US INTO DEC 

 

 

SIMILAR 500s

 

 

WHEN YOU BUILD THE HIGHER HEIGHTS OVER THE TOP YOU WILL RUN THE TROUGH UNDERNEATH .

WE DON`T NEED TEENS AND DO NOT NEED TO CHALLENGE 0 .

BUILD A FAVORABLE 500 DURING THE MONTH OF DECEMBER AND IT SHOULD PRODUCE . 

 

[Isotherm]

I'm now beginning to wonder whether we'll even officially achieve a zonal wind reversal at 10hpa/65N. The ECMWF gets us close at D 4-6, then strengthens the vortex, and now for two consecutive days, the GFS depicts the reversal but w/ rapid intensification thereafter. As expressed yesterday and throughout this season, there are factors destructively interfering with weak vortex maintenance, and other concerns regarding strat progression which favor Europe/Asia. We will be -NAM/-NAO over the next couple weeks but it probably won't translate into anything for the coast, in light of the Pacific and relatively ineffective orientation. The question becomes - what happens as December continues with respect to the blocking? If the zonal wind reversal fails, and vortex intensification is rapid, the blocking episode may not be as protracted as we think. A lot to consider, and certainly far from ready to be too optimistic at least from my perspective.

 

[qg_omega]

15 minutes ago, Isotherm said:

I'm now beginning to wonder whether we'll even officially achieve a zonal wind reversal at 10hpa/65N. The ECMWF gets us close at D 4-6, then strengthens the vortex, and now for two consecutive days, the GFS depicts the reversal but w/ rapid intensification thereafter. As expressed yesterday and throughout this season, there are factors destructively interfering with weak vortex maintenance, and other concerns regarding strat progression which favor Europe/Asia. We will be -NAM/-NAO over the next couple weeks but it probably won't translate into anything for the coast, in light of the Pacific and relatively ineffective orientation. The question becomes - what happens as December continues with respect to the blocking? If the zonal wind reversal fails, and vortex intensification is rapid, the blocking episode may not be as protracted as we think. A lot to consider, and certainly far from ready to be too optimistic at least from my perspective.

 

disturbing, GFS continues to over forecasting blocking, really busting in the day 8 - 14 day range.

[packbacker]

Not sure we are going to see a central pac nina...going to be close whether it's even officially a weak nina this winter.

I didn't expect the destruction of the strat PV to occur in Nov, though I do hope we can get a period of blocking in early Dec with the month as a whole BN.

Will be interesting to see how things unfold...with the overwhelming majority of winter forecasts for a AN temps and BN snow, outside of the MW.

 

[PB GFI]

On 11/14/2016 at 10:09 PM, PB GFI said:

 

I am buying a cold December because I like the 83 analog. 

I think the speed of the PAC slows down because the jet could buckle as the wave lengths shorten.

I think the AO will be firmly NEG and the guidance is starting to block up the Atlantic.

The mid latitudes should respond colder .

I tnought  this would change around November 15 to a colder regime that would not erase the front anomalies. 

It will change around the 20 , but it's a 5 day miss from 15 days ago .

 

 

Starting today, the 20th ... The next 15 days look to be below normal on all of the ensembles. 

So the idea of increasing heights in the upper latitudes which in turn allowed the low heights ti develop underneath in the mid latitudes was a good idea .

You can see that Canada being AN in terms of anomalies doesn't always translate to an AN regime here when cold air is able to sink to base of the trough fast enough over snowcover its moderation us muted .

What is + 3 SD at 50 N is BN at 40 N with a favorable 500.

 

You can see the 2 M departures for the last 10 days of Nov on the 6z GFS ensembles and those higher heights stay put over HB thru day 15.

This is a full scale pattern change that's here's for  at least 2 weeks , going to have to wait to see if it sticks around through all of December like I believe. 

 

Does it translate to snow , yes  I think we will eventually be able to bring the snowcover south .

[snowman19]

2 hours ago, qg_omega said:

disturbing, GFS continues to over forecasting blocking, really busting in the day 8 - 14 day range.

The GFS op and GEFS has been beyond horrible in the long range. It keeps overamplifying the blocking big time only to break it down as we get closer. Now like you said it is reversing its stratospheric PV forecast and it actually looks like it's going to gain strength and tighten up a lot. The Pacific pattern still looks really bad

[PB GFI]

31 minutes ago, snowman19 said:

The GFS op and GEFS has been beyond horrible in the long range. It keeps overamplifying the blocking big time only to break it down as we get closer. Now like you said it is reversing its stratospheric PV forecast and it actually looks like it's going to gain strength and tighten up a lot. The Pacific pattern still looks really bad

The next 15 days are BN on the GEFS and EPS  All the ensembles are in agreement with the higher heights over HB.

I wouldn't worry about NA blocking. The - AO is allowing the colder anomalies to show up underneath. 

 

Pull up last November Decembers 500 

 

Then check starting today the next 15 days at 500 , it will show why the torch at least thru this period is over .

 

After that we will see , but just like I believed in this change  I believe  it could extend through Dec.

 

[snowman19]

9 minutes ago, PB GFI said:

The next 15 days are BN on the GEFS and EPS  All the ensembles are in agreement with the higher heights over HB.

I wouldn't worry about NA blocking. The - AO is allowing the colder anomalies to show up underneath. 

 

Pull up last November Decembers 500 

 

Then check starting today the next 15 days at 500 , it will show why the torch at least thru this period is over .

 

After that we will see , but just like I believed this change in think it could extend through Dec.

 

I'm not disagreeing with you. I just urge extreme caution with the GFS suites op and ensembles. They keep grossly overplaying high latitude  blocking and have been for months. They also have been grossly overplaying their stratospheric polar vortex splits, breakdowns and SSW forecasts. Unreliable in the long range as far as I'm concerned 

[PB GFI]

3 hours ago, snowman19 said:

I'm not disagreeing with you. I just urge extreme caution with the GFS suites op and ensembles. They keep grossly overplaying high latitude  blocking and have been for months. They also have been grossly overplaying their stratospheric polar vortex splits, breakdowns and SSW forecasts. Unreliable in the long range as far as I'm concerned 

 

I think I have posted on this before, this is not a pattern for extreme cold 

I do like the higher latitude look . What that ultimately turns into I believe is BN on balance over the next 15 days .

 

Snow? Frigid ? We will see.

[nzucker]

5 hours ago, Isotherm said:

I'm now beginning to wonder whether we'll even officially achieve a zonal wind reversal at 10hpa/65N. The ECMWF gets us close at D 4-6, then strengthens the vortex, and now for two consecutive days, the GFS depicts the reversal but w/ rapid intensification thereafter. As expressed yesterday and throughout this season, there are factors destructively interfering with weak vortex maintenance, and other concerns regarding strat progression which favor Europe/Asia. We will be -NAM/-NAO over the next couple weeks but it probably won't translate into anything for the coast, in light of the Pacific and relatively ineffective orientation. The question becomes - what happens as December continues with respect to the blocking? If the zonal wind reversal fails, and vortex intensification is rapid, the blocking episode may not be as protracted as we think. A lot to consider, and certainly far from ready to be too optimistic at least from my perspective.

It looks to me as if the favorable -NAM/-NAO pattern is occurring a little too early for the coast. Nov 20-Dec 10 is not really a good period for snow in NYC with average highs still around the 45-50F mark. If we saw this pattern a few weeks later, the Thanksgiving threat and the one following on the 28th would be more significant.

The big question is what happens after the period of Hudson Bay blocking and whether the stratospheric vortex rebuilds in time to keep the 2nd half of December milder. We had a weak West Coast trough in Dec 2010 but the -NAO overwhelmed it.

[Morris]

Latest values:

Nino 1.2: -0.1 (-0.5)

Nino 3: -0.3 (+0.1)

Nino 3.4: -0.4 (+0.3)

Nino 4: -0.3 (+0.2)

http://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for

[dmillz25]

Euro weeklies look great starting next week. -epo -nao trough in the east

[dmillz25]

What's up with the SSTs update?

[packbacker]

1 hour ago, dmillz25 said:

What's up with the SSTs update?

Per there weekly update it looks like it's cooler in region 1.2.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf

 

 

[snowman19]

Region 3.4 is cooling again as the trades strengthen. Down to -0.8C on tropical tidbits today. Region 1+2 is downwelling and warming again approaching +0.3C. So the classic modoki signature continues

[Morris]

Latest values VS THE PREVIOUS WEEK:

Nino 1.2: -0.3 (-0.2)

Nino 3: -0.3 (-)

Nino 3.4: -0.4 (-)

Nino 4: -0.3 (-)

http://www.cpc.ncep.noaa.gov/data/indices/wksst8110.for

[dmillz25]

Yup looks more like a la nada

[packbacker]

1 minute ago, dmillz25 said:

Yup looks more like a la nada

Going to be close whether it gets officially classified as a nina.  Just how much does it drop next two months...or maybe it doesn't.

[dmillz25]

1 minute ago, packbacker said:

Going to be close whether it gets officially classified as a nina.  Just how much does it drop next two months...or maybe it doesn't.

Well yeah definitely but I'm talking about current numbers. Honestly I hope it's classified a la nada

[snowman19]

1 hour ago, bluewave said:

This looks like one of those rare La Ninas that peaked early in October as the subsurface has warmed in November.

The -0.84 for October will probably be the coldest Nino 3.4 monthly reading of this event. Most La Ninas

typically put in there peak coldest SST month during November or December.

http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/detrend.nino34.ascii.txt

2016   7   26.99   27.37   -0.38
2016   8   26.39   27.02   -0.63
2016   9   26.22   26.94   -0.72
2016  10   26.06   26.91   -0.84

 

 

 

This may yet still peak in December. There is quite a substantial trade wind surge coming now that the MJO has progressed along. 3.4 should continue cooling 

[uncle W]

5 hours ago, bluewave said:

We could easily dip back into the weak La Nina territory from the latest weekly neutral with any trade wind surge. But it doesn't look strong enough right now

to surpass the October weekly 3.4 average.

 05OCT2016     -0.9     
 12OCT2016     -0.6     
 19OCT2016     -0.6     
 26OCT2016     -0.8     
 02NOV2016     -0.8     
 09NOV2016     -0.7     
 16NOV2016     -0.4     
 23NOV2016     -0.4     

I was thinking the la nina could be in trouble and in the end it will be a neutral negative winter...It could possibly get stronger later on in 2017 or reverse to el nino again...TWT...

[bluewave]

8 hours ago, uncle W said:

I was thinking the la nina could be in trouble and in the end it will be a neutral negative winter...It could possibly get stronger later on in 2017 or reverse to el nino again...TWT...

It has been a very unusual several years in the Pacific. We saw a record strong PMM at the beginning of the super El Nino event.

The PMM turned strongly negative following the last two supers in 82-83 and 97-98. But for some unknown reason

stayed in positive mode after the recent one while the La Nina struggled to develop.

https://www.climate.gov/news-features/blogs/enso/your-eight-minute-speed-date-pacific-meridional-mode

The following 2015-16 El Niño event was unique among strong El Niños in that the PMM was exceptionally strong and positive (i.e. warm anomalies in the subtropics) prior to the event and has persisted more or less throughout and following the event. During the previous two extreme El Niño events (1982-83 and 1997-98), the meridional mode flipped into a strong negative phase as the event reached peak intensity (see time series above). This was especially true of the 1997-1998 El Niño, which was followed by persistent cold conditions and extreme negative PMM values for a few years afterwards.

But, mysteriously, the PMM has not really shifted into a negative phase after the 2015-16 El Niño, and in fact has been moderate to strongly positive over the last few months. While we can’t perfectly quantify the PMM’s role in the evolution of the 2015-16 El Niño, its extreme positive values are consistent with the subsequent strong El Niño. Their persistence through the peak of the event, however, is not.

What’s next for us?

What does this positive PMM mean for the currently borderline, weak La Niña? It’s tough to know. While research shows a relationship between the PMM and ENSO, there’s a lot of competitors for ENSO’s attention in the Pacific, and the 2015-16 ENSO event has been a strange one for a lot of reasons, the ongoing positive PMM values included. Positive PMM values tend to precede El Niño events, so the current PMM conditions would be consistent with a weakening La Niña forecast. BUT, I’ll caution that there is a lot of other competitors for ENSO’s attention in the Pacific, so at this point it’s tough to attribute such a forecast to the PMM.

[uncle W]

2 hours ago, bluewave said:

It has been a very unusual several years in the Pacific. We saw a record strong PMM at the beginning of the super El Nino event.

The PMM turned strongly negative following the last two supers in 82-83 and 97-98. But for some unknown reason

stayed in positive mode after the recent one while the La Nina struggled to develop.

https://www.climate.gov/news-features/blogs/enso/your-eight-minute-speed-date-pacific-meridional-mode

The following 2015-16 El Niño event was unique among strong El Niños in that the PMM was exceptionally strong and positive (i.e. warm anomalies in the subtropics) prior to the event and has persisted more or less throughout and following the event. During the previous two extreme El Niño events (1982-83 and 1997-98), the meridional mode flipped into a strong negative phase as the event reached peak intensity (see time series above). This was especially true of the 1997-1998 El Niño, which was followed by persistent cold conditions and extreme negative PMM values for a few years afterwards.

But, mysteriously, the PMM has not really shifted into a negative phase after the 2015-16 El Niño, and in fact has been moderate to strongly positive over the last few months. While we can’t perfectly quantify the PMM’s role in the evolution of the 2015-16 El Niño, its extreme positive values are consistent with the subsequent strong El Niño. Their persistence through the peak of the event, however, is not.

What’s next for us?

What does this positive PMM mean for the currently borderline, weak La Niña? It’s tough to know. While research shows a relationship between the PMM and ENSO, there’s a lot of competitors for ENSO’s attention in the Pacific, and the 2015-16 ENSO event has been a strange one for a lot of reasons, the ongoing positive PMM values included. Positive PMM values tend to precede El Niño events, so the current PMM conditions would be consistent with a weakening La Niña forecast. BUT, I’ll caution that there is a lot of other competitors for ENSO’s attention in the Pacific, so at this point it’s tough to attribute such a forecast to the PMM.

interesting...thanks...

[packbacker]

30 day change looks like a CP Nino.  Not sure if this is typically how these things fade but interesting.  That's if it continues to fade...

[packbacker]

Update daily..enso 3.4.  More warm then cold at the moment....

[Dsnowx53]

This Nina is definitely very much dying, and with each upwelling/downwelling cycle, the cold anomalies have weakened and shifted east. It's definitely not a CP Weak Nina anymore, and it might not be a Nina at all. Nino 3.4 is positive, Nino 3 is positive, Nino 4 is rapidly rising towards neutral, and Nino 1+2 is slightly negative. Nino 1+2 being negative is always a good thing. The coldest subsurface anomalies are now just below Nino 1+2, while they are dramatically weakening elsewhere. Future trade wind projections also don't support a Nina. Perhaps the SOI finally caught up to everything.

http://www.atmos.albany.edu/student/ventrice/real_time/timeLon/u.anom.30.5S-5N.gif

 

[thunderbolt]

http://www.bom.gov.au/climate/enso/   see don't want to be ya Nina 

[uncle W]

if this becomes a failed la nina attempt it will be like 1978-79 and 1959-60 with the peak coming before the winter months...other failed years did have negative numbers peak during or after the winter...1966-67 and 2005-06 was like that...if we could only get a storm as big as the ones during these years I'd be happy...