2024-2025 La Nina

[donsutherland1]

Just so it's clear, my reference to a possible Arctic blast during the second week of January does not necessarily mean that it would be a historic shot of cold. It could still be the strongest shot of cold in parts of the Great Lakes region and Northeast, but that is not assured from this far out.

Indeed, the 12/28 0z ECMWF backed off from the magnitude of cold shown on the 12/28 0z run.

12/28 0z ECMWF at 312 hours (850 mb anomalies °C):

12/28 12z ECMWF at 300 hours (850 mb anomalies °C):

In terms of snowfall, a significant number of ensemble members show varying amounts of snowfall during January 6-12. If there will be a significant event, one would expect to see the ensemble members begin to converge on their timing for such an event. A large spread over dates typically favors lighter events in the short-range. In the medium- and long-range a large spread typically exists due to timing uncertainty.

[mitchnick]

Eps weeklies even colder than yesterday with some areas in the -6C to -10C level for the first time. All weeks are colder than yesterday and AN for MA and NE  in week 6 is gone now too!

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412280000&projection=opencharts_north_america&valid_time=202501060000

 

[GaWx]

2 hours ago, mitchnick said:

Eps weeklies even colder than yesterday with some areas in the -6C to -10C level for the first time. All weeks are colder than yesterday and AN for MA and NE  in week 6 is gone now too!

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412280000&projection=opencharts_north_america&valid_time=202501060000

 

 I keep saying this but it’s because they keep getting colder. This image below for 1/6-12 with the bulk of the E 1/3 of the US 8-13F BN (4th shade went from just tiny bit over W VA to much larger area several hundred miles either side of line from near Chicago to ATL as well as Richmond to Savannah and nearby areas) is easily the coldest Euro W map I can recall for the E US still over a week out and probably ever:

 

Also, 1/13-18 is the coldest by far for it with most of the E US in the 3rd shade. This run suggests a 5 to 7 BN Jan would be quite possible in a decent portion of the NE and SE US similar to 2018, 2011, 1985, 1904, and 1887 Niñas. 1996/1984 Nina’s were not as cold and 1918/1893 were even colder.

[George001]

28 minutes ago, mitchnick said:

Eps weeklies even colder than yesterday with some areas in the -6C to -10C level for the first time. All weeks are colder than yesterday and AN for MA and NE  in week 6 is gone now too!

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412280000&projection=opencharts_north_america&valid_time=202501060000

 

No AN temps through Feb 9th. Late Jan-early Feb is warmer than the early-mid Jan period but it’s still plenty cold enough for snow with a Nina gradient pattern look developing towards the end.

[PhiEaglesfan712]

26 minutes ago, GaWx said:

 I keep saying this but it’s because they keep getting colder. This image below for 1/6-12 with the bulk of the E 1/3 of the US 8-13F BN (4th shade went from just tiny bit over W VA to much larger area several hundred miles either side of line from near Chicago to ATL as well as Richmond to Savannah and nearby areas) is easily the coldest Euro W map I can recall for the E US still over a week out and probably ever:

 

Also, 1/13-18 is the coldest by far for it with most of the E US in the 3rd shade. This run suggests a -5 to -6 BN Jan would be quite possible in a decent portion of the NE and SE US similar to 2018 and 2011 and?….checking… Niñas.

2018 wasn't even that cold. The first week was, but the last few were warmer than normal. 2009 was colder than 2018. Cold la nina Januarys since 1980:

1984	26.2	-6.1
1985	27.3	-5.0

1996

30.2

-2.1

2009

29.0

-3.3

2011

29.3

-3.6

2018 and 2022 were near normal:

2018

32.8

-0.1

2022

32.4

-0.5

[snowman19]

1 hour ago, mitchnick said:

Eps weeklies even colder than yesterday with some areas in the -6C to -10C level for the first time. All weeks are colder than yesterday and AN for MA and NE  in week 6 is gone now too!

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412280000&projection=opencharts_north_america&valid_time=202501060000

 

If the level of unmodified arctic being predicted in Canada and the CONUS for early-mid January is close to reality, even if the pattern completely flips in late January, it’s going to take some time to scour it all out. Just like if we were flooded with mild PAC air, it would take some time to get it all out before it would truly turn colder. It would not just be an instant light switch flip either way to warmer or colder

[GaWx]

1 hour ago, PhiEaglesfan712 said:

2018 wasn't even that cold. The first week was, but the last few were warmer than normal. 2009 was colder than 2018. Cold la nina Januarys since 1980:

1984	26.2	-6.1
1985	27.3	-5.0

1996

30.2

-2.1

2009

29.0

-3.3

2011

29.3

-3.6

2018 and 2022 were near normal:

2018

32.8

-0.1

2022

32.4

-0.5

You’re looking at Phil only though. 1/2018 was significantly colder S and W of you.

[GaWx]

 Per the model consensus, especially today’s GEFS, there’s a good chance for the following to verify when averaged out over Jan 1-11:

PNA > +0.5

AO < -2

NAO < -0.5

-EPO

 
 Since 1950 the only Jan 1-11 with this combo were 2010 and 1985 (the only La Niña). So, this would be a rare occurrence if it occurs. On top of that the MJO is forecasted to be favorable for a cold E US.

 

[snowman19]

8 hours ago, snowman19 said:

If the level of unmodified arctic being predicted in Canada and the CONUS for early-mid January is close to reality, even if the pattern completely flips in late January, it’s going to take some time to scour it all out. Just like if we were flooded with mild PAC air, it would take some time to get it all out before it would truly turn colder. It would not just be an instant light switch flip either way to warmer or colder

^As an example, here are the Euro weeklies for late January/early February upper level maps vs. the 2m surface temp maps @mitchnick shared:

 

 

 

 

[mitchnick]

43 minutes ago, snowman19 said:

^As an example, here are the Euro weeklies for late January/early February upper level maps vs. the 2m surface temp maps @mitchnick shared:

 

 

 

 

2 warmanistas stewing over their likely wrong forecast. Big time sour grapes there imho. 

Freebie maps do not show ridging as strong as the WxBell maps. JB maps overdoing it...whoda' thunk? And the Euro weeklies maps do not show the East cooking at all. Normal temps, which will work fine for those who like snow, unlike Gabe and Vlad, given the right track.

[40/70 Benchmark]

Just now, 40/70 Benchmark said:

Welcome to January 2025.

https://easternmassweather.blogspot.com/2024/12/much-colder-than-forecast-december.html

 

[roardog]

3 hours ago, mitchnick said:

2 warmanistas stewing over their likely wrong forecast. Big time sour grapes there imho. 

Freebie maps do not show ridging as strong as the WxBell maps. JB maps overdoing it...whoda' thunk? And the Euro weeklies maps do not show the East cooking at all. Normal temps, which will work fine for those who like snow, unlike Gabe and Vlad, given the right track.

Like I said the other day, it wouldn’t surprise at all if we eventually go to a typical Nina like pattern but I want to see signs of that on medium range guidance before I believe it. This feels so much like all of those times when it’s been warm and everyone is waiting for a cold pattern that never comes. This current “pacific puke” pattern is certainly the exception so far for this winter and not the rule. Right now we’re waffling between weak Nino and strong Nino patterns with no sign of Nina. lol

[EasternLI]

I'm kinda impressed with the way this MJO is progressing. Plus it's of the slow moving variety. Which is good in this case because those are the more likely versions to affect the circulation. Velocity potential tells a better story then the RMM charts. It's interesting too, that models continually have tried to kill this wave in extended ranges. Since November really. Yet it still continues on. 

These are both from the GEFS. Check out where we were and compare it to where we are headed. Effectively muting the MC region, while allowing the western hemisphere to be more dominant in the forecast period. Cold enso base state is also is also identifiable on these but not overpowering everything like our most recent La ninas have. 

Top image I have saved from the 12/12 00z GEFS. With a forecast ending at 00z today, the 29th. Bottom image is last nights 00z GEFS. 

[bluewave]

NAO and AO volatility continue to be the big story since the summer. Big swings both using 500mb anomalies and the raw teleconnection indices. Very challenging to do a long range forecast of these indices with such record swings. We have seen unprecedented volatility since 2009-2010.

 

New EPS run first week of January

 

Old run

 

 

 

[GaWx]

On 12/28/2024 at 3:42 PM, GaWx said:

 I keep saying this but it’s because they keep getting colder. This image below for 1/6-12 with the bulk of the E 1/3 of the US 8-13F BN (4th shade went from just tiny bit over W VA to much larger area several hundred miles either side of line from near Chicago to ATL as well as Richmond to Savannah and nearby areas) is easily the coldest Euro W map I can recall for the E US still over a week out and probably ever:

 

Also, 1/13-18 is the coldest by far for it with most of the E US in the 3rd shade. This run suggests a 5 to 7 BN Jan would be quite possible in a decent portion of the NE and SE US similar to 2018, 2011, 1985, 1904, and 1887 Niñas. 1996/1984 Nina’s were not as cold and 1918/1893 were even colder.

 Ditto to the above with today’s Euro Weeklies ens mean once again coldest by a decent margin for the E US so far for Jan 6-12 and coldest for the E US a week+ out I can recall for any week since I’ve been following this product (several years). The bulk of the E 1/3 of the US is 9-13F BN. The coldest is near Nashville with 15F BN! Note that the area covered by the 4th shade (-11F or colder) is even larger. We could easily not have another week like this in the E US for many years to come:
 

 

 Credit to the Euro Weeklies starting to see a cold signal for Jan 6-12 two weeks ago!

[michsnowfreak]

49 minutes ago, GaWx said:

 Ditto to the above with today’s Euro Weeklies ens mean once again coldest by a decent margin for the E US so far for Jan 6-12 and coldest for the E US a week+ out I can recall for any week since I’ve been following this product (several years). The bulk of the E 1/3 of the US is 9-13F BN. The coldest is near Nashville with 15F BN! Note that the area covered by the 4th shade (-11F or colder) is even larger. We could easily not have another week like this in the E US for many years to come:
 

 

 Credit to the Euro Weeklies starting to see a cold signal for Jan 6-12 two weeks ago!

To be fair we had a very cold week even last January. 

[40/70 Benchmark]

5 hours ago, bluewave said:

NAO and AO volatility continue to be the big story since the summer. Big swings both using 500mb anomalies and the raw teleconnection indices. Very challenging to do a long range forecast of these indices with such record swings. We have seen unprecedented volatility since 2009-2010.

 

New EPS run first week of January

 

Old run

 

 

 

Yea, the big NAO blocking is the wrinkle for me personally. Everything else about my January call from last fall looks great.

[40/70 Benchmark]

11 hours ago, EasternLI said:

I'm kinda impressed with the way this MJO is progressing. Plus it's of the slow moving variety. Which is good in this case because those are the more likely versions to affect the circulation. Velocity potential tells a better story then the RMM charts. It's interesting too, that models continually have tried to kill this wave in extended ranges. Since November really. Yet it still continues on. 

These are both from the GEFS. Check out where we were and compare it to where we are headed. Effectively muting the MC region, while allowing the western hemisphere to be more dominant in the forecast period. Cold enso base state is also is also identifiable on these but not overpowering everything like our most recent La ninas have. 

Top image I have saved from the 12/12 00z GEFS. With a forecast ending at 00z today, the 29th. Bottom image is last nights 00z GEFS. 

In my blog post about 3 weeks ago, I made mention of how the GEFS were progressing the MJO into phase 7 hear the new year, but other guidance was hanging it up in phase 6. I favored the GEFS, which has worked out.

https://easternmassweather.blogspot.com/2024/12/much-milder-balance-of-december-before.html

[GaWx]

6 hours ago, michsnowfreak said:

To be fair we had a very cold week even last January. 

 Indeed it was very cold. Detroit was 14BN 1/14-20/24. But I don’t recall the Euro Weeklies being anywhere near that cold over such a large area over a week out like today’s map is.

[Snowstorms]

On 12/28/2024 at 4:10 PM, PhiEaglesfan712 said:

2018 wasn't even that cold. The first week was, but the last few were warmer than normal. 2009 was colder than 2018. Cold la nina Januarys since 1980:

1984	26.2	-6.1
1985	27.3	-5.0

1996

30.2

-2.1

2009

29.0

-3.3

2011

29.3

-3.6

2018 and 2022 were near normal:

2018

32.8

-0.1

2022

32.4

-0.5

January 2000 was cold too with an intense cold outbreak that second half. I think central park was well below freezing for 7 days in a row. 

[snowman19]

After a brief lull the first few days of January, the models have another period of very strong trades/EWBs developing. This is definitely going to be record strengthening into January, even for a late bloomer La Niña event, it’s been extremely impressive since November

[bluewave]

On 12/29/2024 at 4:59 AM, roardog said:

Right now we’re waffling between weak Nino and strong Nino patterns with no sign of Nina

The one significant La Niña sign this December has been the much stronger than normal Northern Stream of the Pacific Jet. It lead to the ridge axis getting pushed further east than forecast with warmer temperatures than issued back on December 5th. Plus the dominant storm track through the Great Lakes was also classic La Niña. Very unusual to get such a strong Northern Stream with a +PNA. So even more of a La Niña mismatch December than we have seen on past occasions.

Euro monthly forecast

 

Verification

 

 

 

[snowman19]

The one significant La Niña sign this December has been the much stronger than normal Northern Stream of the Pacific Jet. It lead to the ridge axis getting pushed further east than forecast with warmer temperatures than issued back on December 5th. Plus the dominant storm track through the Great Lakes was also classic La Niña. Very unusual to get such a strong Northern Stream with a +PNA. So even more of a La Niña mismatch December than we have seen on past occasions.
Euro monthly forecast

 
Verification


 
 
 

Remember when we discussed how the strong trades/EWB’s (shear/subsidence) and colder waters from the La Niña would destructively interfere with the MJO just pushing into phase 8 without any resistance?

[GaWx]

1 hour ago, snowman19 said:

Remember when we discussed how the strong trades/EWB’s (shear/subsidence) and colder waters from the La Niña would destructively interfere with the MJO just pushing into phase 8 without any resistance?

 

 

 

 

 

 

 

 

 

 

 

 

-This CFS is still going into phase 8 but with it under 1 in amplitude, which is what inside the circle means (~0.85-0.9 in this case).

-Whether it is just outside the circle, near or inside, it is a weak to borderline moderate left side of diagram path, which is the most favorable for a cold E US and has been on the models for many days. A cold E US obviously means higher chances for snow in general.

-Model consensus is favoring weak to possibly moderate phases 8, 1, 2, and probably 3 thereafter. These are the 4 coldest phases in Jan on average and have been colder in the means when not strong.

-Natural gas prices are up over a whopping 20% since just Friday bringing prices to their highest in nearly 2 years due to a potentially very cold Jan!

GEFS (bc):

 

EPS (bc):

[GaWx]

 The prospects during the 1st half of Jan for a weak to moderate left side of diagram MJO, along with mainly a +PNA, -AO/-NAO (both the strongest yet on GEFS), and -EPO remains intact on the models. That combo can’t be beat for cold E US potential.

 The GEFS mean now gets the AO/NAO down to ~-4/-1.5 ~Jan 7-8. The other Jans since 1950 with a lowest AO/NAO of sub -4/-1.5 have been these: 2010, 1979, 1970, 1966, 1963, 1959, and 1958. 5 of the 7 were during El Niño. None have occurred during La Niña. So, 2025 could be the first Niña Jan on record with this.

 Temperature anomalies for these 7 Jans: cold most favored Midwest, Plains, and South but overall quite a cold map for a 7 Jan composite:

[GaWx]

Coldest Euro weekly for 1/6-12 once again! Much of the area in the 4th shade of blue in the E US is 11-15F BN. The 5th shade is 18 BN!

 Also, the 2 weeks after this are easily the coldest for those weeks yet suggesting that some areas could see a 7 to 8 BN Jan!

[MANDA]

18 minutes ago, GaWx said:

Coldest Euro weekly for 1/6-12 once again! Much of the area in the 4th shade of blue in the E US is 11-15F BN. The 5th shade is 18 BN!

 Also, the 2 weeks after this are easily the coldest for those weeks yet suggesting that some areas could see a 7 to 8 BN Jan!

Seems many are not focusing on the potential for lasting and some record setting cold.  There is a growing and impressive signal for intense cold.  Cross polar flow and frigid high pressure building from the high Arctic into the U.S.  Could be quite a significant event down the plains and into the southern plains and southeast especially in terms of departures from normal.  Severe citrus freeze??  Texas as well with impactful and life adjusting cold for a time over the next 2 weeks or so.

[so_whats_happening]

8 hours ago, snowman19 said:

Remember when we discussed how the strong trades/EWB’s (shear/subsidence) and colder waters from the La Niña would destructively interfere with the MJO just pushing into phase 8 without any resistance?

 

 

 

 

 

 

 

 

 

 

 

 

Im sorry but the CFS has not been the most accurate for MJO forecasts not as bad as BOMM but not great. The model has consistently shown the MJO wave wayyy to strong in fact it had this period we are going through now above 2 and even to 3 through both 5/6 and into some of 7. Clearly this has not been the case. Whether you like them or not the more accurate has been the Euro and JMA. They are not perfect past 5-7 days but the amplitude has been way off on RMM plots for the CFS.

[so_whats_happening]

Quick update while im on vacation/ holiday but here is the TAO depiction of subsurface. Pretty strong moves to a La Nina state.

As expected 3.4 has stabilized and has since risen a bit via OISST numbers. I do not expect these to rise too much more and stabilize out again around -.6 ish area. There does seem to be some extended period coming up here of weakened trades through about the 20th that will help relax the Nina flex a bit. It does look like we are building a subsurface warm pool in the proper area for potentially a light Nino setup next year, remains to be seen of course.

[so_whats_happening]

Also models have backed off the SSW wave 2 response, such a bummer. They seem to be pointing toward a very strong wave 1 response similar to what we had last year as we go into mid month. With that type of response I do not see it breaking the SPV just significantly weakening it and maybe allowing for maybe a reversal (major warming) event to take place. Once the warming wanes the SPV should still be intact and probably some regaining of strength into February which could reverse the course of what we are seeing at 500mb currently but this is far to ahead of the game to know for sure, plus being close to the end of the season my mindset kind of says so what? Lol

Until then we are seeing a different response at 500mb last year to the current SSW setup so hopes are we don't go uber torch but honestly I feel I would be fine with one solid snow event (12"+) for the season and move on. Enjoy the snow and cold that comes over the next 2-3 weeks, fingers are crossed. Happy New Year everyone!