Winter 2020-2021

[Hoth]

37 minutes ago, weathafella said:

That UKMET is like warm and wet.  That can be pretty snowy in New England.  See 2012-13.

Warm and wet usually means exactly that in these parts.

[PhineasC]

I can’t imagine a scenario where the UKMET would have any real skill whatsoever at that range. 

[raindancewx]

That UKMET run is almost identical to what I had in my forecast. Makes me a little nervous because I don't really buy the models having skill this far out. Warm/Wet is the idea for New England though. Most places seem to have little trouble getting to their seasonal snow numbers in the US if they get snow every year and are less than +2F v. their long-term average highs I find, with above average precipitation. For truly cold locations, it can be even warmer than +2F if the highs are still predominantly in the mid-30s or colder it seems like.

One thing I noticed locally - there is at least some notable difference in precipitation timing from some of the big hurricane (ACE) years already. The past month has had no rain here, but you had pretty major precipitation events 9/10-10/10 in 1995, 2005, 2017, before getting essentially nothing after for eight months. Dry periods in the past month do show up in my analogs though. Of the recent three La Nina super hurricane seasons, 1995 is closest here, so the dry period started later September than this year, but you had a big system around 9/9 like this year. The 2005 and 2017 9/10-10/10 periods both had huge rain events late September, completely missing this year, one of the reasons I dislike those years (~1.5-2.0" rain 9/28 or so in both). The 2010 La Nina also had a big late September rain event here, but it had much lower ACE than the other three, and far more precipitation too.

[OSUmetstud]

4 hours ago, ORH_wxman said:

‘07-‘08 was also warm and wet. Not a blowtorch...was around +1ish for the winter. 

Yeah that UKMET composite is a really close match to 2007-2008

 

[weathafella]

25 minutes ago, OSUmetstud said:

Yeah that UKMET composite is a really close match to 2007-2008

 

Hard to imagine looking at that and ending up snowy with a great December but we did.

[OSUmetstud]

1 hour ago, weathafella said:

Hard to imagine looking at that and ending up snowy with a great December but we did.

Got to keep enough confluence over Greenland...otherwise its congrats maine. 

[A Moonlit Sky]

This is gonna be an interesting winter since I'm splitting my time between Brookfield and Albany.

[weathafella]

35 minutes ago, OSUmetstud said:

Got to keep enough confluence over Greenland...otherwise its congrats maine. 

12/16/07

[RUNNAWAYICEBERG]

20 hours ago, Hoth said:

Warm and wet usually means exactly that in these parts.

We like it cold and wet. 

That UK h5 look isn’t warming my buns anytime soon.

[dendrite]

18 hours ago, weathafella said:

Hard to imagine looking at that and ending up snowy with a great December but we did.

Yeah glad we don't live at H5.

[snowman19]

On 10/11/2020 at 9:17 AM, ORH_wxman said:

I don’t think < -2C for a trimonthly is all that realistic. Maybe -1.7ish could happen. 

Yea, that would make it one of the strongest La Niñas in history. A < -2C trimonthly is crazy. I kind of doubt we are heading into a super La Niña.....

[Typhoon Tip]

Strongest easterly jet phenomenon in the lower to mid troposphere along and S of the 30th parallel ..due to the strongest HC in observational Meteorological history  ... augmenting the NINA state.

...mm possible.

I do get the feeling ..at least wonder, if the the "global La Nina" story is not as emphatic as the SST due to exaggerated low level easterly stressing giving the latter a PR goose. It may not be a La Nina in the integral nearly as strongly as those SST anomalies ...meaning considering the total hemispheric interstitial factors that in whole, drives the ENSO states along... 

Simply put, maybe it's a weak to moderate integrated La Nina on whole, but with a low level trade wind exaggerated SST distribution contained within ... 

Never be able to separate those two - or at least 'good luck.'  Chicken vs egg headache too -

I think we're having a northern stream dominated winter ... and that is super-imposing over the extended HC latitude, where the layover is a positive feedback. 

We we may at times even observe the 'faux' STJ from ...or just a split into Canada/west...when the PNA tries to lapse .. But in those scenarios we're merely splitting the N -stream; southern component ends up with an mixed/ ice storm deal as the main storm profile threat when it does. 

And, ...lots of height lines and winds as a canvased look.

This may be a good year for NJ model lows ... '86 Novie types...

 

[RUNNAWAYICEBERG]

1 hour ago, Typhoon Tip said:

Strongest easterly jet phenomenon in the lower to mid troposphere along and S of the 30th parallel ..due to the strongest HC in observational Meteorological history  ... augmenting the NINA state.

...mm possible.

I do get the feeling ..at least wonder, if the the "global La Nina" story is not as emphatic as the SST due to exaggerated low level easterly stressing giving the latter a PR goose. It may not be a La Nina in the integral nearly as strongly as those SST anomalies ...meaning considering the total hemispheric interstitial factors that in whole, drives the ENSO states along... 

Simply put, maybe it's a weak to moderate integrated La Nina on whole, but with a low level trade wind exaggerated SST distribution contained within ... 

Never be able to separate those two - or at least 'good luck.'  Chicken vs egg headache too -

I think we're having a northern stream dominated winter ... and that is super-imposing over the extended HC latitude, where the layover is a positive feedback. 

We we may at times even observe the 'faux' STJ from ...or just a split into Canada/west...when the PNA tries to lapse .. But in those scenarios we're merely splitting the N -stream; southern component ends up with an mixed/ ice storm deal as the main storm profile threat when it does. 

And, ...lots of height lines and winds as a canvased look.

This may be a good year for NJ model lows ... '86 Novie types...

 

Could be good for interior areas of our east zones. Like Will to Ray to Jeff and points NW. The rest of us are going to struggle as we fight the SE ridge. 

[Hoth]

11 hours ago, RUNNAWAYICEBERG said:

We like it cold and wet. 

That UK h5 look isn’t warming my buns anytime soon.

Amen brutha!

[Ginx snewx]

4 hours ago, Typhoon Tip said:

Strongest easterly jet phenomenon in the lower to mid troposphere along and S of the 30th parallel ..due to the strongest HC in observational Meteorological history  ... augmenting the NINA state.

...mm possible.

I do get the feeling ..at least wonder, if the the "global La Nina" story is not as emphatic as the SST due to exaggerated low level easterly stressing giving the latter a PR goose. It may not be a La Nina in the integral nearly as strongly as those SST anomalies ...meaning considering the total hemispheric interstitial factors that in whole, drives the ENSO states along... 

Simply put, maybe it's a weak to moderate integrated La Nina on whole, but with a low level trade wind exaggerated SST distribution contained within ... 

Never be able to separate those two - or at least 'good luck.'  Chicken vs egg headache too -

I think we're having a northern stream dominated winter ... and that is super-imposing over the extended HC latitude, where the layover is a positive feedback. 

We we may at times even observe the 'faux' STJ from ...or just a split into Canada/west...when the PNA tries to lapse .. But in those scenarios we're merely splitting the N -stream; southern component ends up with an mixed/ ice storm deal as the main storm profile threat when it does. 

And, ...lots of height lines and winds as a canvased look.

This may be a good year for NJ model lows ... '86 Novie types...

 

 

[OSUmetstud]

Lol

[40/70 Benchmark]

On 10/9/2020 at 4:10 PM, snowman19 said:

@40/70 Benchmark If this La Niña were to actually peak at strong come December, how much would it change the forecast than if it were only to peak at moderate in December?   

EL NIÑO/SOUTHERN OSCILLATION (ENSO)

DIAGNOSTIC DISCUSSION

issued by CLIMATE PREDICTION CENTER/NCEP/NWS and the International Research Institute for Climate and Society

8 October 2020

Quote Synopsis:  La Niña is likely to continue through the Northern Hemisphere winter 2020-21 (~85% chance) and into spring 2021 (~60% chance during February-April). La Niña continued during September, as evidenced by below-average sea surface temperatures (SSTs) extending from the Date Line to the eastern Pacific Ocean [Fig. 1]. The SST indices in the two westernmost Nino regions, Nino-4 and Nino-3.4, cooled throughout the month, and the Nino-3.4 index was -1.1°C in the past week [Fig. 2]. The equatorial subsurface temperature anomalies (averaged from 180°-100°W) remained substantially unchanged [Fig. 3], and continued to reflect below-average temperatures from the surface to 200m depth in the eastern Pacific Ocean [Fig. 4]. The atmospheric circulation anomalies over the tropical Pacific Ocean remained consistent with La Niña. Low-level wind anomalies were easterly across most of the tropical Pacific, and upper-level wind anomalies were westerly over the east-central Pacific. Tropical convection continued to be suppressed from the western Pacific to the Date Line, and a slight enhancement of convection emerged over Indonesia [Fig. 5]. Also, both the Southern Oscillation and Equatorial Southern Oscillation indices remained positive. Overall, the coupled ocean-atmosphere system indicates the continuation of La Niña. A majority of the models in the IRI/CPC plume predict La Nina (Niño-3.4 index less than -0.5°C) to persist through the Northern Hemisphere winter 2020-21 and to weaken during the spring [Fig. 6]. The latest forecasts from several models, including the NCEP CFSv2, suggest the likelihood of a moderate or even strong La Nina (Niño-3.4 index values < -1.0°C) during the peak November-January season. The forecaster consensus supports that view in light of significant atmosphere-ocean coupling already in place. In summary, La Niña is likely to continue through the Northern Hemisphere winter 2020-21 (~85% chance)

I don't think it changes much. I think it just increases confidence that it will not be a very cold winter in the east...especially south of 40N. I think it also augments the importance of the polar fields this season. I am not sold on a strong la nina by a long shot,  though....frankly, I am surprised that it looks to make moderate considering where we were a month ago.

[40/70 Benchmark]

5 hours ago, OSUmetstud said:

Lol

He didn't event address that fact it is NEGATIVE, not positive...which is in conflict with his premise that October blocking positively correlates to a re occurrence during boreal winter. He deflected the dialogue towards strength of correlation.

My interpretation of him is that he engages in backwards forecasting.....he comes into each season with an agenda and looks for data to support it. The data should guide you to a position.

[OSUmetstud]

Just now, 40/70 Benchmark said:

He didn't event address that fact it is NEGATIVE, not positive...which is in conflict with his premise that October blocking positively correlates to a re occurrence during boreal winter. He deflected the dialogue towards the strength of correlation.

My interpretation of him is that he engages in backwards forecasting.....he comes into each season with an agenda and looks for data to support it. The data should guide you to a position.

Yeah, that's good work by you. It's just funny that this supposed expert didn't know that. He was making a huge deal about strong October blocking. 

[40/70 Benchmark]

On 10/10/2020 at 6:05 PM, raindancewx said:

https://www.scribd.com/document/479516526/Winter-2020-21-Outlook

That's my winter outlook. Finally finished updating and caught most-all of the typos.

It's a much colder winter than last year overall, but it's still not "cold" for many people. I have fairly limited areas wetter than average too. I think the PDO will fluctuate a lot, but should  be primarily pretty negative from Nov-Apr with how cold Nino 1.2 is. What we're seeing now is some cooling east of Japan (toward a +PDO), but also cooling by NW North America (toward a -PDO). You should at least see continue cooling by NW North America if the usual build up of cold in a La Nina happens in Western Canada.

Excellent work. I have come to respect you as one of the better posters on these forums. We don't always agree, but the quality of your work is top notch.

[40/70 Benchmark]

10 minutes ago, OSUmetstud said:

Yeah, that's good work by you. It's just funny that this supposed expert didn't know that. He was making a huge deal about strong October blocking. 

I actually feel as though he DID know that....if you read his blog, he uses subjective language such as "observational" to substantiate his positions....which I interpret as a tacit acknowledgement that its not empirically founded. Either that, or its an admission that he was lazy and didn't check.

The weak negative correlation between October NAO and winter NAO is pretty well known...I see it referenced in posts every season. I know raindance mentioned it in his outlook as support for a positive wintertime NAO, since October looks to finish with with a negative NAO in the mean.

[OSUmetstud]

3 minutes ago, 40/70 Benchmark said:

I actually feel as though he DID know that....if you read his blog, he uses subjective language such as "observational" to substantiate his positions....which I interpret as a tacit acknowledgement that its not empirically founded. Either that, or its an admission that he was lazy and didn't check.

The weak negative correlation between October NAO and winter NAO is pretty well known...I see it referenced in posts every season. I know raindance mentioned it in his outlook as support for a positive NAO, since October looks to finish with with a negative NAO in the mean.

I'd be interested to see if the strength matters. Like if it's really strong blocking now, is it more favorable for winter blocking or less? 

 

[CoastalWx]

He also has some sizzle to sell if you know what I mean. Gotta get that money. 

[ORH_wxman]

11 minutes ago, OSUmetstud said:

I'd be interested to see if the strength matters. Like if it's really strong blocking now, is it more favorable for winter blocking or less? 

 

I remember doing a little study on this back on EasternUSwx and found that extremely negative NAOs in October actually tended to favor a -NAO winter. It wasn't a high correlation at all, but it reversed the classic negative correlation.

This was only through like 2009 though...not sure what the last decade had produced.

[OSUmetstud]

5 minutes ago, ORH_wxman said:

I remember doing a little study on this back on EasternUSwx and found that extremely negative NAOs in October actually tended to favor a -NAO winter. It wasn't a high correlation at all, but it reversed the classic negative correlation.

Cool, well it looks substantial the next few weeks. Maybe it will finally happen this winter...

 

[40/70 Benchmark]

11 minutes ago, OSUmetstud said:

Cool, well it looks substantial the next few weeks. Maybe it will finally happen this winter...

 

I don't have any issues with blocking during December or even into early January...I just wouldn't expect it mid season.

[40/70 Benchmark]

20 minutes ago, ORH_wxman said:

I remember doing a little study on this back on EasternUSwx and found that extremely negative NAOs in October actually tended to favor a -NAO winter. It wasn't a high correlation at all, but it reversed the classic negative correlation.

This was only through like 2009 though...not sure what the last decade had produced.

I remember my first season on the boards, I used the crazy blocking during 10/2006 to support my premise for a harsh winter in refute of Chuck back when he was a thing. Needless to say, I lost. lol That was his "This will be the warmest winter on record in the US" outlook year.

[ORH_wxman]

3 minutes ago, 40/70 Benchmark said:

I remember my first season on the boards, I used the crazy blocking during 10/2006 to support my premise for a harsh winter in refute of Chuck back when he was a thing. Needless to say, I lost. lol That was his "This will be the warmest winter on record in the US" outlook year.

2006 was one of the years where the excessive -NAO in October didn't foreshadow a -NAO winter. There's some others too because the "strong October -NAO = winter -NAO" correlation is somewhat weak. It's notable though because it reverses the overall inverse correlation we normally see.

I think off the top of my head, some years that had strongly -NAO Octobers that also produced -NAO winters are 1946-1947, 1968-1969, 2002-2003, 2004-2005, 2009-2010 and since the last time I ran the numbers, I think 2012-2013 also may have had an excessively strong October -NAO that foreshadowed winter blocking.

[40/70 Benchmark]

5 minutes ago, ORH_wxman said:

2006 was one of the years where the excessive -NAO in October didn't foreshadow a -NAO winter. There's some others too because the "strong October -NAO = winter -NAO" correlation is somewhat weak. It's notable though because it reverses the overall inverse correlation we normally see.

I think off the top of my head, some years that had strongly -NAO Octobers that also produced -NAO winters are 1946-1947, 1968-1969, 2002-2003, 2004-2005, 2009-2010 and since the last time I ran the numbers, I think 2012-2013 also may have had an excessively strong October -NAO that foreshadowed winter blocking.

2004-2005 was not a neg NAO winter going by CPC, nor have I ever known it to be one. March 2005 was very negative, but Feb was near neutral and Dec and Januaru were ++.

2002-2003 was pretty neutral...even a hair +.

2012 and 2009 def. work....not sure about '46. I'll take your word for it.

[40/70 Benchmark]

What I am willing to say is that a deeply negative NAO October favors at least one month from DM to average a neg NAO, which only increases confidence in what I am already going with. 

That may not sound like much, but if you consider the past several years, I think its pretty significant. Dating back to March 2013, the only DM month that has managed a neg NAO in the mean is March 2018...which I accurately predicted.

I'm pretty confident that I will also accurately predict the first neg NAO winter month since March 2018, this season.