December 2023

[Allsnow]

6 minutes ago, 40/70 Benchmark said:

Yea, same page.

Care to link that OLR model?

https://rollerwx.wordpress.com/teleconnections/

[donsutherland1]

7 minutes ago, 40/70 Benchmark said:

Yea, same page.

Care to link that OLR model?

The statistical models can be found here: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/forca.shtml

[bluewave]

This has to be one of the most extreme VP anomaly signatures in the general MJO 6-7 regions for this time of year. The Pacific Jet extension and record breaking ridge and warmth over the Northern Tier and Canada are a perfect match for forcing in that location. Unfortunately, the warmth following these jet extensions can last a few weeks which the models are showing. 

 

[40/70 Benchmark]

19 minutes ago, Allsnow said:

https://rollerwx.wordpress.com/teleconnections/

 

19 minutes ago, donsutherland1 said:

The statistical models can be found here: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/forca.shtml

Thanks, guys.

Good stuff.

[ForestHillWx]

Interesting temperature inversions out this way this morning; Heavy, heavy frost along the shrubs/trees on my drive on the backroads thru Pottersville along the Black/Lamington rivers. 

Serene setting; wish I had time to take a picture. 

[40/70 Benchmark]

10 minutes ago, bluewave said:

This has to be one of the most extreme VP anomaly signatures in the general MJO 6-7 regions for this time of year. The Pacific Jet extension and record breaking ridge and warmth over the Northern   Tier and Canada are a perfect match for forcing in that location. Unfortunately, the warmth following these jet extensions can last a few weeks which the models are showing. 

 

Yea, I tried to go out of my way to communicate that key difference between this season and the 2009 analog when I did my work last month....

 some periods of a stronger PV are likely, especially early on, as implied earlier. This placement is also quite similar to the mean seasonal forcing during the QBO/solar el Nino analog season of 2009-2010, albeit even slightly further to the west as to include more maritime phase 6 involvement:

 

Which is one of the reasons why the coming season is unlikely to rival that one in terms of consistent cold and record magnitude of blocking/mid Atlantic snows. 

 

 

 

 

 

 

However, the winter pattern would also be volatile with extensive thawing periods due to the influence of MJO phase 6, which would feature a stronger PV working in conjunction with western troughing, which resonates with continued cool ENSO atmospheric momentum. Thus while more snowfall and colder temperatures than last winter is quite likely throughout the east, winter '23-24' may not be remembered for its snowpack retention along much of the coastal plane.

 

[40/70 Benchmark]

I think what I did poorly with is identifying the Pacific jet as primary cause of the warmth...instead opting to articulate it as "western troughing" and "cool ENSO atmospheric momentum".

I could have done a better job conveying that. My understanding of the Pacific jet isn't great...I need work there.

[Allsnow]

Here is the January p7-p8for Nino…

[40/70 Benchmark]

Just now, Allsnow said:

Here is the January p7-p8 for Nino…

Yea, I certainly do not expect a very cold month of January...just cold enough to get "in the game", so to speak.

[brooklynwx99]

2 minutes ago, 40/70 Benchmark said:

Yea, I certainly do not expect a very cold month of January...just cold enough to get "in the game", so to speak.

pretty solidly -AO/-NAO/-EPO there, though. that would be more than serviceable

[40/70 Benchmark]

Just now, brooklynwx99 said:

pretty solidly -AO/-NAO/-EPO there, though. that would be more than serviceable

Yea, I expect a lag, though.....because the reservoir of cold across Canada needs to be replenished....which is why I think the period of +AO/NAO prior to the reshuffle of the Pacific may be a blessing in disguise. 

[Volcanic Winter]

How are the current odds for a SSW into Jan? I’m not doing the “welp better hope for a SSW” meme and would be fine with a continued, weakened PV rolling forward. But the prospect of a SSW somewhat early this season is definitely interesting and makes sense with the -QBO / solar (thanks @40/70 Benchmarkand others who have helped me learn more about these interactions). 

Just curious, and not suggesting it’s ultimately necessary or anything. 

[40/70 Benchmark]

Just now, Volcanic Winter said:

How are the current odds for a SSW into Jan? I’m not doing the “welp better hope for a SSW” meme and would be fine with a continued, weakened PV rolling forward. But the prospect of a SSW somewhat early this season is definitely interesting and makes sense with the -QBO / solar (thanks @40/70 Benchmarkand others who have helped me learn more about these interactions). 

It kind of seems like the PV may kick to the other side of the globe again, but I expect a major disruption in early January.

[brooklynwx99]

1 minute ago, Volcanic Winter said:

How are the current odds for a SSW into Jan? I’m not doing the “welp better hope for a SSW” meme and would be fine with a continued, weakened PV rolling forward. But the prospect of a SSW somewhat early this season is definitely interesting and makes sense with the -QBO / solar (thanks @40/70 Benchmarkand others who have helped me learn more about these interactions). 

Just curious, and not suggesting it’s ultimately necessary or anything. 

they are definitely better than climo. not a guarantee by any means, but still a better than normal shot for this early. and you're correct, a weak SPV is still a good thing to have. however, a SSW can give you those truly anomalous retrograding -NAO blocks. I am personally rooting for one

[40/70 Benchmark]

4 minutes ago, brooklynwx99 said:

they are definitely better than climo. not a guarantee by any means, but still a better than normal shot for this early. and you're correct, a weak SPV is still a good thing to have. however, a SSW can give you those truly anomalous retrograding -NAO blocks. I am personally rooting for one

The stakes are higher with a true SSW.....a generally weak PV gives you a nice, safe floor with a lower ceiling, but a SSW can either give you February 2010, or February 2019.

[donsutherland1]

There's a mixture of good, bad, and ugly news as one looks ahead into the extended forecasting range.

The ugly: The last 7-10 days of December are looking decidedly on the warm side of normal. The probability that New York City could wind up with a monthly mean temperature of 42° or above has increased markedly with Atlantic blocking having broken down. Such warmth would approach the top 10 figure for the month (10th warmest: 42.6°, 1990).

The bad:  The largest pool of very cold air is located on the other side of the Hemisphere. It won't be available to be tapped through at least the next 10 days or longer. A jet streak will also flood the North American continent with mild Pacific air.

The good: Toward the end of the forecasting range, a trough could be developing over the southern United States  beneath a Hudson Bay block. The subtropical jet looks to remain active.

What all this means is that a transition toward a colder pattern that could present opportunities for snowfall still appears on track for the first week of January. At least through that time, genuine Arctic blasts appear unlikely.

Aside from the inherent uncertainty associated with the timeframe involved (more than two weeks), one has seen a lack of run-to-run continuity on the weekly ECMWF guidance. There has been better consistency in the idea that the first week of January should be colder than the last week of December. Both the ECMWF weekly guidance and CFSv2 are in reasonable agreement concerning the first week of January about a colder pattern than the last week of December. But abnormal warmth could still be lurking not too far away in North America.

What could go wrong?

Given the lack of a large pool of cold air, it is worth examining this possibility. Winter 1994-95 provides an example. On December 25-26, 1994, the MJO moved through Phase 8. A colder pattern took hold shortly thereafter and continued toward mid-January. December 30-January 12 saw a mean temperature of 32.4° in NYC with 3 highs of 32° or below and 3 lows in the teens. Despite 1.87" of precipitation during that colder period, just 0.2" of snow was measured. Boston saw 4.4"; Philadelphia had only a trace; and, Washington, DC picked up 3.9".

It then turned noticeably warmer toward mid-month with the temperature peaking at 64° on January 14th in NYC. Boston had two 66° highs. Philadelphia and Washington, DC reached 70°.

1994-95 argues for a measure of caution when it comes to the duration and impact of what appears to be a more favorable pattern in early January. Until one gets closer to that period, claims about high-impact snowstorms or high-impact cold are highly speculative.

For now, a more promising, but not necessarily very cold, pattern looks reasonably likely to develop during the first week of January. Details about the magnitude of cold, amount of snowfall, persistence of the pattern should it develop, etc., remain to be determined.

Most winter season snowfall during El Niño winters occurs in January and February with the largest share of 6" or more daily snowfall occurring in February for NYC.

[psv88]

2 hours ago, lee59 said:

I guess it was overcast over night. My temperature has gone from 33.3 an hour ago to 28.3 now.

Wow. Only dropped to 34 here. Must have stayed cloudy here 

[40/70 Benchmark]

13 minutes ago, donsutherland1 said:

There's a mixture of good, bad, and ugly news as one looks ahead into the extended forecasting range.

The ugly: The last 7-10 days of December are looking decidedly on the warm side of normal. The probability that New York City could wind up with a monthly mean temperature of 42° or above has increased markedly with Atlantic blocking having broken down. Such warmth would approach the top 10 figure for the month (10th warmest: 42.6°, 1990).

The bad:  The largest pool of very cold air is located on the other side of the Hemisphere. It won't be available to be tapped through at least the next 10 days or longer. A jet streak will also flood the North American continent with mild Pacific air.

The good: Toward the end of the forecasting range, a trough could be developing over the southern United States  beneath a Hudson Bay block. The subtropical jet looks to remain active.
What all this means is that a transition toward a colder pattern that could present opportunities for snowfall still appears on track for the first week of January. At least through that time, genuine Arctic blasts appear unlikely.

Aside from the inherent uncertainty associated with the timeframe involved (more than two weeks), one has seen a lack of run-to-run continuity on the weekly ECMWF guidance. There has been better consistency in the idea that the first week of January should be colder than the last week of December. Both the ECMWF weekly guidance and CFSv2 are in reasonable agreement concerning the first week of January about a colder pattern than the last week of December. But abnormal warmth could still be lurking not too far away in North America.

What could go wrong?

Given the lack of a large pool of cold air, it is worth examining this possibility. Winter 1994-95 provides an example. On December 25-26, 1994, the MJO moved through Phase 8. A colder pattern took hold shortly thereafter and continued toward mid-January. December 30-January 12 saw a mean temperature of 32.4° in NYC with 3 highs of 32° or below and 3 lows in the teens. Despite 1.87" of precipitation during that colder period, just 0.2" of snow was measured. Boston saw 4.4"; Philadelphia had only a trace; and, Washington, DC picked up 3.9".

It then turned noticeably warmer toward mid-month with the temperature peaking at 64° on January 14th in NYC. Boston had two 66° highs. Philadelphia and Washington, DC reached 70°.

1994-95 argues for a measure of caution when it comes to the duration and impact of what appears to be a more favorable pattern in early January. Until one gets closer to that period, claims about high-impact snowstorms or high-impact cold are highly speculative.

For now, a more promising, but not necessarily very cold, pattern looks reasonably likely to develop during the first week of January. Details about the magnitude of cold, amount of snowfall, persistence of the pattern should it develop, etc., remain to be determined.

Most winter season snowfall during El Niño winters occurs in January and February with the largest share of 6" or more daily snowfall occurring in February for NYC.

Great post.......agreed. If the polar fields crap the bed, then we 1994-1995. But I still trust in the key solar differences to ensure that does not happen...I am sure snowman is more skeptical, so we will just have to see. I do foresee somewhat of a thaw in mid to late January before the real show in February, so I guess whether or not we capitalize on the better days in the first half of January will be a crucial point of inflection for this season.

[Dark Star]

37 minutes ago, 40/70 Benchmark said:

I think what I did poorly with is identifying the Pacific jet as primary cause of the warmth...instead opting to articulate it as "western troughing" and "cool ENSO atmospheric momentum".

I could have done a better job conveying that. My understanding of the Pacific jet isn't great...I need work there.

I would tend to agree that the Pacific Jet IS the cause of our warmer weather here in the Northeast.  As long as that is persistent, it will result in warmth in our area, and probably lack of cold air into Canada.  I guess we could argue the ancient Chicken and Egg controversy?  We will continue to see "colder signals" constantly postponed, until it is March, with perhaps an occasional ebb where some cold air will reach the NYC area.  

[the_other_guy]

Belleayre today. No snow guns on as they told me there was a Temp Inversion last night as others have posted

[40/70 Benchmark]

57 minutes ago, Dark Star said:

I would tend to agree that the Pacific Jet IS the cause of our warmer weather here in the Northeast.  As long as that is persistent, it will result in warmth in our area, and probably lack of cold air into Canada.  I guess we could argue the ancient Chicken and Egg controversy?  We will continue to see "colder signals" constantly postponed, until it is March, with perhaps an occasional ebb where some cold air will reach the NYC area.  

I don't agree with that.

[MJO812]

Cmc is a deluge with the storm for next week. It then pulls down cold air . Pattern change ?

[Stormlover74]

7 minutes ago, MJO812 said:

Cmc is a deluge with the storm for next week. It then pulls down cold air . Pattern change ?

Single digits the morning of the 23rd

[donsutherland1]

1 hour ago, 40/70 Benchmark said:

Great post.......agreed. If the polar fields crap the bed, then we 1994-1995. But I still trust in the key solar differences to ensure that does not happen...I am sure snowman is more skeptical, so we will just have to see. I do foresee somewhat of a thaw in mid to late January before the real show in February, so I guess whether or not we capitalize on the better days in the first half of January will be a crucial point of inflection for this season.

I agree. I think we'll see the blocking return. I suspect we'll get something in the first half of January, but most of the snowfall will likely occur late January or February (possibly with one storm accounting for most of it). I remain reasonably confident that this will not be a replay of the 2022-23 lack of snowfall or 1997-98 in terms of snowfall.

[40/70 Benchmark]

4 minutes ago, donsutherland1 said:

I agree. I think we'll see the blocking return. I suspect we'll get something in the first half of January, but most of the snowfall will likely occur late January or February (possibly with one storm accounting for most of it). I remain reasonably confident that this will not be a replay of the 2022-23 lack of snowfall or 1997-98 in terms of snowfall.

Its often one or two opportunities that define(s) a season...at least from about my latitude points south.

[the_other_guy]

19 minutes ago, MJO812 said:

Cmc is a deluge with the storm for next week. It then pulls down cold air . Pattern change ?

what you’re seeing is the guys that profess gospel two or three weeks out leave themselves open to being wrong. Nobody could predict the weather or the specific patterns three weeks out. It is a generalization.

 

What you’re looking at is a December with a marginal air mass interrupted by three or four days at a time of warmth. It isn’t a torch. it isn’t 2015.

You get a big storm, cold air gets pulled in, things happen. 

 

That’s why I’m not so quick to praise people for predicting things with certainty when no such certainty exists in this science

[snowman19]

1 hour ago, 40/70 Benchmark said:

Great post.......agreed. If the polar fields crap the bed, then we 1994-1995. But I still trust in the key solar differences to ensure that does not happen...I am sure snowman is more skeptical, so we will just have to see. I do foresee somewhat of a thaw in mid to late January before the real show in February, so I guess whether or not we capitalize on the better days in the first half of January will be a crucial point of inflection for this season.

I’m seeing Nino standing wave forcing. The thing is, once the MJO propagates east, it’s going to constructively interfere with the El Niño, promote tropical westerlies and strengthening. It may be unintended consequences. We are starting with a stagnated base of +2.0C in 3.4. So it warms how much from there? I do think we see the decaying process start around mid-January and any strengthening before then may cause more jet extension/raging jet into January. As Griteater showed yesterday with the equatorial SOI, this is a very robust event, you don’t want a roided up STJ blasting into the west coast or our good February idea is in trouble. A lot to watch

CPC MJO discussion: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

[40/70 Benchmark]

23 minutes ago, snowman19 said:

I’m seeing Nino standing wave forcing. The thing is, once the MJO propagates east, it’s going to constructively interfere with the El Niño, promote tropical westerlies and strengthening. It may be unintended consequences. We are starting with a stagnated base of +2.0C in 3.4. So it warms how much from there? I do think we see the decaying process start around mid-January and any strengthening before then may cause more jet extension/raging jet into January. As Griteater showed yesterday with the equatorial SOI, this is a very robust event, you don’t want a roided up STJ blasting into the west coast or our good February idea is in trouble. A lot to watch

CPC MJO discussion: https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf

I  know that would undoubtedly break your heart...

[snowman19]

4 minutes ago, 40/70 Benchmark said:

I  know that would undoubtedly break your heart...

Well if that happens then my February idea I discussed with you back in early November in the ENSO thread is dead wrong. As we showed with 97-98 MJO phase 8 even at the end of December and January could make no difference with a very strong El Niño in place ——-raging jet promotion 

[cleetussnow]

2 hours ago, Dark Star said:

I would tend to agree that the Pacific Jet IS the cause of our warmer weather here in the Northeast.  As long as that is persistent, it will result in warmth in our area, and probably lack of cold air into Canada.  I guess we could argue the ancient Chicken and Egg controversy?  We will continue to see "colder signals" constantly postponed, until it is March, with perhaps an occasional ebb where some cold air will reach the NYC area.  

We are already seeing can kicking.  It seems like once that starts, it persists.  We are already talking a month push back on any favorable pattern.  Yeah, then it's Spring, or supposed to be, when the PV splits.