2024-2025 La Nina

[Allsnow]

 

[FPizz]

2 hours ago, mitchnick said:

Can't we just guess? All in good faith, of course. 

Reconstructed data is pretty much that....

[GaWx]

 The bc MJO forecasts for early Jan from GEFS/EPS continue to be in the general vicinity of what has often during cold ENSO coincided with cold in much of the E US in Jan, that being just outside, near, or within the left half of the circle (7 out of the 8 cases that I found: 2022 2nd half, 2000 late, 1999 early, 1996 and 1994 (1st halves), 1982 late, and 1976 early). The only failure was the mild middle of Jan of 2023.

 

[snowman19]

As far as La Niña winters go, just in terms of cold, not snow so far obviously, maybe 10-11 wasn’t too horrible of an analog, 10-11 was night and day at this point with the record -NAO/-AO blocking. That winter was a classic front-loaded Niña too. If that’s the canonical Niña progression we are going to follow, the cold/blocking hangs around till mid-late January, then goes -PNA/Aleutian ridge with tropical forcing in the Maritime Continent 

[SnoSki14]

2 minutes ago, snowman19 said:

As far as La Niña winters go, just in terms of cold, not snow so far obviously, maybe 10-11 wasn’t too horrible of an analog, 10-11 was night and day at this point with the record -NAO/-AO blocking. That winter was a classic front-loaded Niña too. If that’s the canonical Niña progression we are going to follow, the cold/blocking hangs around till mid-late January, then goes -PNA/Aleutian ridge with tropical forcing in the Maritime Continent 

There were clear Nino influences this month especially the last third of December. 

It's not a canonical Nina due to multiple areas of forcing playing a role. There's no guarantee we go typical Nina after mid January. 

[snowman19]

2 minutes ago, SnoSki14 said:

There were clear Nino influences this month especially the last third of December. 

It's not a canonical Nina due to multiple areas of forcing playing a role. There's no guarantee we go typical Nina after mid January. 

Ok. I’m not saying the NPAC hasn’t resembled a Nino. I was speaking in terms of the cold and snow so far (albeit) nothing like 10-11 snow wise to this point. There are very clearly Niña influences in this pattern and the tropical PAC is and has been very strongly into a Niña state. There’s also no guarantee that the NPAC stays in a Nino like state either 

[GaWx]

19 minutes ago, snowman19 said:

As far as La Niña winters go, just in terms of cold, not snow so far obviously, maybe 10-11 wasn’t too horrible of an analog, 10-11 was night and day at this point with the record -NAO/-AO blocking. That winter was a classic front-loaded Niña too. If that’s the canonical Niña progression we are going to follow, the cold/blocking hangs around till mid-late January, then goes -PNA/Aleutian ridge with tropical forcing in the Maritime Continent 

 If the cold domination hangs on through Jan 15 and possibly as late as Jan 20, we’d be looking at the high likelihood that both Dec and Jan would end up averaging NN to BN in much of the E US, something you didn’t expect in advance per your posts. I certainly didn’t expect this then. So, even if Feb is mild (still quite possible as often is the case in La Niña…I favor it as of now), this winter is likely going to end up significantly colder than we had expected.

[snowman19]

2 minutes ago, GaWx said:

 If the cold domination hangs on through Jan 15 and possibly as late as Jan 20, we’d be looking at the high likelihood that both Dec and Jan would end up averaging NN to BN in much of the E US, something you didn’t expect in advance per your posts. I certainly didn’t expect this then. So, even if Feb is mild (still quite possible as often is the case in La Niña…I favor it as of now), this winter is likely going to end up significantly colder than we had expected.

I was never expecting a blowtorch winter, that’s why I went with a +2F - +4F average for Dec-Mar. But yes, definitely colder than I had expected up to this point in time and more -EPO than I had expected. Now the real question everyone cares about….what does the rest of this winter do snow wise? In the end, no one cares about the cold….if this ends up being a below average snowfall winter, people will call it a fail and say it sucked even if we average -5F from Dec-Mar

[brooklynwx99]

27 minutes ago, snowman19 said:

As far as La Niña winters go, just in terms of cold, not snow so far obviously, maybe 10-11 wasn’t too horrible of an analog, 10-11 was night and day at this point with the record -NAO/-AO blocking. That winter was a classic front-loaded Niña too. If that’s the canonical Niña progression we are going to follow, the cold/blocking hangs around till mid-late January, then goes -PNA/Aleutian ridge with tropical forcing in the Maritime Continent 

personally i think 13-14 is a better analog than 10-11 but it’s clear that we’re breaking colder. i think we moderate in late Jan and then who knows what happens in Feb. with all of the lingering Nino influence i’m not totally resigned to a super warm Feb

[GaWx]

6 hours ago, snowman19 said:

I was never expecting a blowtorch winter, that’s why I went with a +2F - +4F average for Dec-Mar. But yes, definitely colder than I had expected up to this point in time and more -EPO than I had expected. Now the real question everyone cares about….what does the rest of this winter do snow wise? In the end, no one cares about the cold….if this ends up being a below average snowfall winter, people will call it a fail and say it sucked even if we average -5F from Dec-Mar

 I don’t include Mar as part of winter. I’m talking met winter (DJF) since Mar normal temps are significantly higher (early met spring).

 I agree that many (though not me) just focus on snowfall and thus I agree with what you’re saying that many would think fail if cold but not snowy. But again not all think this way.

[PhiEaglesfan712]

39 minutes ago, brooklynwx99 said:

personally i think 13-14 is a better analog than 10-11 but it’s clear that we’re breaking colder. i think we moderate in late Jan and then who knows what happens in Feb. with all of the lingering Nino influence i’m not totally resigned to a super warm Feb

The last week of December doesn't look like a torch after all. I don't think we're going to get the really cold Jan 4-17 the models are showing. It will probably be closer to normal.

No way are we getting anything close to a 13-14 type winter, which was wall-to-wall cold from Jan-March. I think we're going to get something closer to 20-21.

[mitchnick]

1 hour ago, brooklynwx99 said:

personally i think 13-14 is a better analog than 10-11 but it’s clear that we’re breaking colder. i think we moderate in late Jan and then who knows what happens in Feb. with all of the lingering Nino influence i’m not totally resigned to a super warm Feb

Regarding February, I  noticed something on the Euro weeklies.  If you go to the link below, which is Arctic 2M temps, and progress through the weeks, keep an eye on the sw coast of Canada. As you get to week 2, you can see warm temps being replaced with average and BN temps, then that colder area expands and slides SE into the Plains.  some BN and normal come week 3. Week 4, the normal temps weaken to a little warmer than normal, followed by week 5 and it is AN. But then at week 6, and here's my point, the AN temps are replaced with normal temps and the whole process from earlier in the run "appears thru these weenie eyes," to be getting ready to repeat. 

One difference I see is that instead of large areas of both BN and AN temps on the other side of the Pole at week 1, there's mainly normal temps. Effects if I'm "somehow " correct with the repeat pattern idea, I  don't know. But my weenie brain says normal temps across the Poles come the end of January are cold vs recent years, and that would maintain seasonal, if not BN, cold.

This could all change with today's or future runs as there's plenty of time for that, but that area in sw Canada grabbed my attention. Of course, if the cooling is simply from the ridge decaying, that would likely negate my thoughts.

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412210000&projection=opencharts_arctic&valid_time=202502030000

[jconsor]

2 hours ago, PhiEaglesfan712 said:

The last week of December doesn't look like a torch after all. I don't think we're going to get the really cold Jan 4-17 the models are showing. It will probably be closer to normal.

No way are we getting anything close to a 13-14 type winter, which was wall-to-wall cold from Jan-March. I think we're going to get something closer to 20-21.

Indeed, as we get closer in the guidance is correcting to a stronger high pressure and CAD wedge for the last week of Dec.

https://x.com/yconsor/status/1870772344031268877

[bluewave]

The biggest shift we have seen in recent days modeling is the much stronger 500 mb blocking forecast east of Hudson Bay. This feature wasn’t showing up on the older runs. You have to wonder if the record warmth that Hudson Bay absorbed during the summer leading to the current delayed free up is playing a role. A +500 meter anomaly would be one of the strongest on record for this time of year.  Even before the record warmth for next week, the Hudson Bay Area has been much warmer than normal this month.
 

https://nsidc.org/sea-ice-today/analyses/sluggish-freeze-warming-north

 

 

[donsutherland1]

The probability that a colder pattern could begin evolving during the first week of January has increased. That does not guarantee the rapid onset of severe cold. Below are the composite maps for multi-day periods of severe cold during the first half of January since 1980:

Below are the 12/21 6z and 12z runs of the GFS vs. the 12/22 6z and 12z runs:

Below are the temperature anomalies for the last six runs of the GFS:

Key Points:

• Even as the probability of an evolution toward a colder pattern during the first week of January has increased, that outcome does not mean that there would be a rapid outbreak of severe cold in the eastern half of the CONUS
• The timeframe involved is still subject to considerable change (as seen in the recent GFS runs)
• The GFS briefly showed a 500 mb pattern consistent with multi-day shots of severe cold in the eastern half of the CONUS, but has since backed away. Whether that means any such outbreaks would be delayed or that the cold would dump into the West only to reach the East in modified form remains to be seen (the 12z ECMWF still brings the severe cold early with a pattern that is somewhat similar to Cluster 2)
• The ECMWF weeklies suggest that there will be a multi-week pattern of below normal temperatures in the East, though the CFS is more muted on the outcome
• Separately, with January opening with a forecast AO-/PNA+ pattern, the potential of moderate (4" or more) or perhaps significant (6" or more) snowfall could increase in an area including Boston, Chicago, Detroit, New York City, Philadelphia, Toronto, and Washington, DC.  A persistent PNA+ pattern would be more important for New York City, Philadelphia, and Washington, DC. Needless to say, short waves that would be candidates for such storms would be needed. Those are details that cannot be forecast reliably on multi-week timeframes.

[Snowstorms]

8 minutes ago, bluewave said:

The biggest shift we have seen in recent days modeling is the much stronger 500 mb blocking forecast east of Hudson Bay. This feature wasn’t showing up on the older runs. You have to wonder if the record warmth that Hudson Bay absorbed during the summer leading to the current delayed free up is playing a role. A +500 meter anomaly would be one of the strongest on record for this time of year.  
 

https://nsidc.org/sea-ice-today/analyses/sluggish-freeze-warming-north

Canada is about to blowtorch this week. Some of these temperatures are almost unheard of at these latitudes at this time of the year. See below some select cities near Hudson Bay. If you scroll down a bit you'll see their daily normals (averages). Many places are expected to be nearly 30 degrees above average.  

https://weather.gc.ca/en/location/index.html?coords=55.295,-77.744 

https://weather.gc.ca/en/location/index.html?coords=51.282,-80.645

https://weather.gc.ca/en/location/index.html?coords=58.762,-94.132 

If the Bay doesn't freeze over before this blowtorch, were going to have some problems getting cold in January. 

[Snowstorms]

4 hours ago, SnoSki14 said:

There were clear Nino influences this month especially the last third of December. 

It's not a canonical Nina due to multiple areas of forcing playing a role. There's no guarantee we go typical Nina after mid January. 

The pattern advertised in January is almost like a hybrid Nina/Nino pattern. A big ridge builds from Alaska right into the Aleutians, typical Nina look combined with a 50/50 low thats typical for a Nino. As a result almost all of Canada and US are below normal. I'll take it. 

[bluewave]

59 minutes ago, Snowstorms said:

Canada is about to blowtorch this week. Some of these temperatures are almost unheard of at these latitudes at this time of the year. See below some select cities near Hudson Bay. If you scroll down a bit you'll see their daily normals (averages). Many places are expected to be nearly 30 degrees above average.  

https://weather.gc.ca/en/location/index.html?coords=55.295,-77.744 

https://weather.gc.ca/en/location/index.html?coords=51.282,-80.645

https://weather.gc.ca/en/location/index.html?coords=58.762,-94.132 

If the Bay doesn't freeze over before this blowtorch, were going to have some problems getting cold in January. 

You can see the ripple effect it having on the modeling going forward. The extended EPS runs from a week ago had stronger Pacific blocking and weaker Atlantic blocking. Now the Atlantic blocking is forecast to be stronger January 6th to 13th and the Pacific a little weaker. Notice the narrower ridge over Western North America and stronger and more expansive from Eastern Canada through Iceland. 

New EPS weekly run for January 6th to 13th 

 Old run

[GaWx]

 Today’s forecasted GEFS AO is getting quite low, sub -2 mean and still falling at the end. It averages ~-2 for Jan 1-5:

 Here are the 13 1950+ cold ENSO Jans with Jan 1-5 averaging sub -1.5 AO together with the full Jan avg temps anomaly (based on each respective 30 year climo period) at Baltimore (proxy for E US):
 

2021 -2.9 +2

2014 -1.5 -7

2011 -2.9 -4

2009 -1.7 -5

2008 -1.6 +1

2001 -2.6 -1

1997 -1.8 -1

1996 -2.0 -2

1985 -2.3 -4

1965 -2.4 -2

1963 -3.6 -4

1955 -2.6 -2

1951 -2.4 +3

AVG -2; 1 MBN (2014); 7 BN; 3 NN; 2 AN (2021, 1951)

 So, this fwiw implies a notably better chance for BN than AN for Jan 2025 at Baltimore (as a proxy for the E US) assuming todays GEFS AO forecast for Jan 1-5 will verify pretty well.

[LibertyBell]

6 hours ago, snowman19 said:

I was never expecting a blowtorch winter, that’s why I went with a +2F - +4F average for Dec-Mar. But yes, definitely colder than I had expected up to this point in time and more -EPO than I had expected. Now the real question everyone cares about….what does the rest of this winter do snow wise? In the end, no one cares about the cold….if this ends up being a below average snowfall winter, people will call it a fail and say it sucked even if we average -5F from Dec-Mar

right you can have a colder winter with very little snow, this happened a lot during the 80s...another question is even if the pattern breaks towards the latter third of January and February ends up milder, could there be a return to colder/snowier weather in March as has been the case with quite a few la ninas?

 

[Daniel Boone]

49 minutes ago, GaWx said:

 Today’s forecasted GEFS AO is getting quite low, sub -2 mean and still falling at the end. It averages ~-2 for Jan 1-5:

 Here are the 13 1950+ cold ENSO Jans with Jan 1-5 averaging sub -1.5 AO together with the full Jan avg temps anomaly (based on each respective 30 year climo period) at Baltimore (proxy for E US):
 

2021 -2.9 +2

2014 -1.5 -7

2011 -2.9 -4

2009 -1.7 -5

2008 -1.6 +1

2001 -2.6 -1

1997 -1.8 -1

1996 -2.0 -2

1985 -2.3 -4

1965 -2.4 -2

1963 -3.6 -4

1955 -2.6 -2

1951 -2.4 +3

AVG -2; 1 MBN (2014); 7 BN; 3 NN; 2 AN (2021, 1951)

 So, this fwiw implies a notably better chance for BN than AN for Jan 2025 at Baltimore (as a proxy for the E US) assuming todays GEFS AO forecast for Jan 1-5 will verify pretty well.

Good, unbiased work as usual Larry. Much appreciated!

[mitchnick]

47 minutes ago, GaWx said:

 Today’s forecasted GEFS AO is getting quite low, sub -2 mean and still falling at the end. It averages ~-2 for Jan 1-5:

 Here are the 13 1950+ cold ENSO Jans with Jan 1-5 averaging sub -1.5 AO together with the full Jan avg temps anomaly (based on each respective 30 year climo period) at Baltimore (proxy for E US):
 

2021 -2.9 +2

2014 -1.5 -7

2011 -2.9 -4

2009 -1.7 -5

2008 -1.6 +1

2001 -2.6 -1

1997 -1.8 -1

1996 -2.0 -2

1985 -2.3 -4

1965 -2.4 -2

1963 -3.6 -4

1955 -2.6 -2

1951 -2.4 +3

AVG -2; 1 MBN (2014); 7 BN; 3 NN; 2 AN (2021, 1951)

 So, this fwiw implies a notably better chance for BN than AN for Jan 2025 at Baltimore (as a proxy for the E US) assuming todays GEFS AO forecast for Jan 1-5 will verify pretty well.

Usetobe, a retired NWS Met out of LWX (DC) who now only posts when storms are imminent, did a study some years ago and found a -AO was a far more reliable predictor of mod and major snowstorms at DCA/BWI/Mid-Atlantic than a -NAO. So that's music to my ears Larry. Thank you!

[Daniel Boone]

Just now, mitchnick said:

Usetobe, a retired NWS Met out of LWX (DC) who now only posts when storms are imminent, did a study some years ago and found a -AO was a far more reliable predictor of mod and major snowstorms at DCA/BWI/Mid-Atlantic than a -NAO. So that's music to my ears Larry. Thank you!

Yep. I remember that Study by Wes. Miss him posting regularly. He's one of the best.

[bluewave]

8 hours ago, SnoSki14 said:

There were clear Nino influences this month especially the last third of December. 

It's not a canonical Nina due to multiple areas of forcing playing a role. There's no guarantee we go typical Nina after mid January. 

All we can say is that the temperature departures are following a frontloaded La Niña seasonal progression with December 1st through January 15th probably averaging colder than normal around NYC.This would be the first time for NYC since the 17-18 La Niña.The big question is if January 16th to February 28th second half will follow the warmer shift we saw in 17-18 which tilted the whole winter warmer than average. But if we can maintain some Nino influences in February such as we saw with the +AAM rise, then we could have our first colder winter since 14-15. We probably won’t know for sure which way it will go until we get further into January.

[EasternLI]

Impressive poleward ridging from the 18z GEFS heading into the heart of January. 

 

It's interesting also, to see the eps weeklies now weakening the SPV pretty substantially by mid January. Which would be consistent with an mjo 7 response. 

[LibertyBell]

3 hours ago, bluewave said:

All we can say is that the temperature departures are following a frontloaded La Niña seasonal progression with December 1st through January 15th probably averaging colder than normal around NYC.This would be the first time for NYC since the 17-18 La Niña.The big question is if January 16th to February 28th second half will follow the warmer shift we saw in 17-18 which tilted the whole winter warmer than average. But if we can maintain some Nino influences in February such as we saw with the +AAM rise, then we could have our first colder winter since 14-15. We probably won’t know for sure which way it will go until we get further into January.

But we did swing back to colder and snowier again in March and even early April in 2018, and that often happens in a la nina too.  And even during that milder February (it got close to 70!) we had a nice moderate snow event around Valentine's Day.

 

[40/70 Benchmark]

5 hours ago, bluewave said:

All we can say is that the temperature departures are following a frontloaded La Niña seasonal progression with December 1st through January 15th probably averaging colder than normal around NYC.This would be the first time for NYC since the 17-18 La Niña.The big question is if January 16th to February 28th second half will follow the warmer shift we saw in 17-18 which tilted the whole winter warmer than average. But if we can maintain some Nino influences in February such as we saw with the +AAM rise, then we could have our first colder winter since 14-15. We probably won’t know for sure which way it will go until we get further into January.

I don't think February is going to be excessively warm like 2018.

[snowman19]

I figured with the huge push into a Niña over the last few weeks, it was just a matter of time before the modeling caught on and started dumping -PNA into the west. They are probably rushing it though, don’t think it actually starts until mid-January or more likely just after that point, which would be climo for a front-loaded Nina winter

[bluewave]

7 hours ago, 40/70 Benchmark said:

I don't think February is going to be excessively warm like 2018.

So far this winter isn’t as cold or snowy as 2017 was during the first half. So we wouldn’t need that type of warmth for the winter to still finish above average. All we know so far is that we are starting with a typical frontloaded La Niña cold scenario. 

[40/70 Benchmark]

18 minutes ago, bluewave said:

So far this winter isn’t as cold or snowy as 2017 was during the first half. So we wouldn’t need that type of warmth for the winter to still finish above average. All we know so far is that we are starting with a typical frontloaded La Niña cold scenario. 

Correct, nor do I think that we will.