2024-2025 La Nina

[40/70 Benchmark]

1 minute ago, snowman19 said:

The 1/18 - 1/22 period looks cutter-ish, inland runner-ish to me. Blocking is gone. Ridge completely off the west coast, +NAO/+AO and a WAR signature showing up

Yup.

[snowman19]

Just now, bluewave said:

The delayed start and continued EPAC warming makes this one of the most unusual La Niña events that we have seen.

 

Definitely. Late bloomer (NDJ) and a Modoki/CP La Niña at that 

[bluewave]

30 minutes ago, snowman19 said:

We are in an official La Niña @GaWx @40/70 Benchmark @bluewave @donsutherland1
 

The delayed start from such a warm global background state and continued 1+2 warming makes this one of the more unusual La Niña events that we have seen.

The equatorial Eastern Pacific off the South American coast has warmed in recent weeks *. The rains are felt in the entrance basins to #Poechos and #SanLorenzo where the 30% storage of the useful volume estimated by the operators has already been exceeded. It's raining again today, which will translate into higher income. *This does not mean that we are heading towards a #NiñoCostero just in case. But it helps tremendously to improve the contribution of humidity that is used, among other processes, for the formation of rain.

[MJO812]

15 minutes ago, 40/70 Benchmark said:

Yup.

Gradient event ?

[40/70 Benchmark]

14 minutes ago, bluewave said:

The delayed start from such a warm global background state and continued 1+2 warming makes this one of the more unusual La Niña events that we have seen.

The equatorial Eastern Pacific off the South American coast has warmed in recent weeks *. The rains are felt in the entrance basins to #Poechos and #SanLorenzo where the 30% storage of the useful volume estimated by the operators has already been exceeded. It's raining again today, which will translate into higher income. *This does not mean that we are heading towards a #NiñoCostero just in case. But it helps tremendously to improve the contribution of humidity that is used, among other processes, for the formation of rain.

2008 did essentially the same thing...late-blooming Modoki.

[michsnowfreak]

5 hours ago, PhiEaglesfan712 said:

I think a torch in the SE is possible for February, but I don't see it in the mid-Atlantic or Northeast. In fact, I think the first 10-15 days of the month will be favorable for snow in these areas. The February monthly temp departure will be close to normal in these areas, and maybe below in some areas of northern Vermont, NH, and Maine. I think it turns warmer for these areas during the 2nd half of February, leading into the inevitable torch during March/first part of April.

I have mostly great memories of Feb 2018 here. The first half of the month was deep, deep winter with only the last week seeing a torch/bare ground. The warmth that gets talked about in Feb 2018 was much more extreme to the south (not at all uncommon in a Nina). Wonder if something similar happens this Feb?

[bluewave]

34 minutes ago, 40/70 Benchmark said:

2008 did essentially the same thing...late-blooming Modoki.

The 07-08 La Niña developed during the summer of 07 after a much weaker El Niño and lingered into 08-09. 

https://www.climate.gov/news-features/blogs/enso/january-2025-update-la-nina-here

Why was La Niña so slow to develop?

The short answer to this is “we don’t yet know.” The emergence of La Niña-like atmospheric conditions before substantial tropical Pacific Ocean surface cooling was unusual, though. The global oceans have been running much, much warmer than average for more than a year, which might have had a hand in La Niña’s delay. When we calculate the Niño-3.4 index but account for the temperature of the tropical oceans (the “Relative Niño-3.4 index”) we get an index that’s been in La Niña territory for months. Only this past year or so has the difference between the traditional and relative Niño-3.4 indexes been so large, and we’re still researching this new measurement and all the implications for ENSO development and impacts in a warmer world.

[MJO812]

43 minutes ago, snowman19 said:

The 1/18 - 1/22 period looks cutter-ish, inland runner-ish to me. Blocking is gone. Ridge completely off the west coast, +NAO/+AO and a WAR signature showing up

- EPO favors the coastal plain 

[LibertyBell]

1 hour ago, 40/70 Benchmark said:

Yup.

and somehow cold again after 1/22 and to close out the month

[LakePaste25]

Ensembles are split post-MLK day. The GEFS continues with a full eastern trough, while the EPS and GEPS have more of an overrunning setup that favors the interior, potentially with snow/sleet/ice profiles. 

 

[LakePaste25]

1 hour ago, michsnowfreak said:

I have mostly great memories of Feb 2018 here. The first half of the month was deep, deep winter with only the last week seeing a torch/bare ground. The warmth that gets talked about in Feb 2018 was much more extreme to the south (not at all uncommon in a Nina). Wonder if something similar happens this Feb?

I still recorded 10”+ of snow here in february 2018, but the latter part of the month was a torch here. I had 2 days over 70, which is over a +30 departure. 

[MANDA]

26 minutes ago, LakePaste25 said:

Ensembles are split post-MLK day. The GEFS continues with a full eastern trough, while the EPS and GEPS have more of an overrunning setup that favors the interior, potentially with snow/sleet/ice profiles. 

 

At least all 3 of them show the trof axis finally west of us and not over or east of us.  Obviously don't want it too far west but better than the positioning we have gone through and are going through.  Will open the door to the possibility of more freezing or frozen events at least to start.  Final outcomes dependent on individual storm track / details.

[PhiEaglesfan712]

1 hour ago, michsnowfreak said:

I have mostly great memories of Feb 2018 here. The first half of the month was deep, deep winter with only the last week seeing a torch/bare ground. The warmth that gets talked about in Feb 2018 was much more extreme to the south (not at all uncommon in a Nina). Wonder if something similar happens this Feb?

I think a hybrid of Feb 2018/Feb 2019 is what we're probably going to get. Feb 2019 (though not a la nina year) was even more extreme with the heat being contained to the south. I think we get something like this temperaturewise (with a more active storm track like Feb 2018):

 

[MJO812]

Euro weeklies are cold in the east right through mid February .

[FPizz]

1 minute ago, MJO812 said:

Euro weeklies are cold in the east right through mid February .

Yup, just saw that

[mitchnick]

44 minutes ago, MJO812 said:

Euro weeklies are cold in the east right through mid February .

Latest Cfs forecast average at TT has gone from torch to average in the east. Lol

[michsnowfreak]

1 hour ago, LakePaste25 said:

I still recorded 10”+ of snow here in february 2018, but the latter part of the month was a torch here. I had 2 days over 70, which is over a +30 departure. 

The torch was certainly impressive. But it was essentially a 10 day warm spell in a 6 month stretch where below normal temperatures dominated, including some cold records. Easily the most recent extended cold period we've had. 

 

[michsnowfreak]

1 hour ago, PhiEaglesfan712 said:

I think a hybrid of Feb 2018/Feb 2019 is what we're probably going to get. Feb 2019 (though not a la nina year) was even more extreme with the heat being contained to the south. I think we get something like this temperaturewise (with a more active storm track like Feb 2018):

 

That would be an interesting and very doable hybrid lol

[40/70 Benchmark]

7 hours ago, bluewave said:

The 07-08 La Niña developed during the summer of 07 after a much weaker El Niño and lingered into 08-09. 

https://www.climate.gov/news-features/blogs/enso/january-2025-update-la-nina-here

 

Why was La Niña so slow to develop?

The short answer to this is “we don’t yet know.” The emergence of La Niña-like atmospheric conditions before substantial tropical Pacific Ocean surface cooling was unusual, though. The global oceans have been running much, much warmer than average for more than a year, which might have had a hand in La Niña’s delay. When we calculate the Niño-3.4 index but account for the temperature of the tropical oceans (the “Relative Niño-3.4 index”) we get an index that’s been in La Niña territory for months. Only this past year or so has the difference between the traditional and relative Niño-3.4 indexes been so large, and we’re still researching this new measurement and all the implications for ENSO development and impacts in a warmer world.

No, 2008-2009....not 2007-2008.

[40/70 Benchmark]

15 hours ago, MJO812 said:

- EPO favors the coastal plain 

No, not necessarily..all -EPO does is keep Canada cold, but has nothing to do with storm track. 2018-2019 is a great example of an unfavorable -EPO where the coast got screwed.

[MJO812]

11 minutes ago, 40/70 Benchmark said:

No, not necessarily..all -EPO does is keep Canada cold, but had nothing to do with storm track. 2018-2019 is a great example of an unfavorable -EPO where the coast got screwed.

The long wave boundary of a - EPO lays its Arctic Boundary along the East coast. We have seen this happen many times in the past.

 

 

 

[mitchnick]

https://x.com/ericfisher/status/1877523038628888685?ref_src=twsrc^tfw|twcamp^tweetembed|twterm^1877523038628888685|twgr^76bad1cd6dc8012c5106e057e944268d4942253e|twcon^s1_&ref_url=https%3A%2F%2Fwww.americanwx.com%2Fbb%2Findex.php%3Fapp%3Dcoremodule%3Dsystemcontroller%3Dembedurl%3Dhttps%3A%2F%2Ftwitter.com%2Fericfisher%2Fstatus%2F1877523038628888685

[George001]

1 hour ago, 40/70 Benchmark said:

No, not necessarily..all -EPO does is keep Canada cold, but had nothing to do with storm track. 2018-2019 is a great example of an unfavorable -EPO where the coast got screwed.

Yep, the snowy -EPO dominant patterns with little to no blocking like Feb 2015 had the western ridge axis centered near Montana. The pattern advertised on long range guidance near the Jan 20th period is different because the western ridge axis is off the west coast. My read on the advertised pattern is it’s a cold pattern, but not a snowy one for coastal areas since the pattern favors lows running inland and warm sectoring us. Definitely looks more like 18-19 than 14-15, classic cold warm up rain, then cold again pattern. Not going to get a classic east coast nor’easter with that look for sure, but hopefully we can score some swfe type systems.

[40/70 Benchmark]

7 hours ago, MJO812 said:

The long wave boundary of a - EPO lays its Arctic Boundary along the East coast. We have seen this happen many times in the past.

 

 

 

-EPO keepa Canada cold allows said cold to dump imto the US....in. -PNA/+NAO pattern, it dumps WEST.

[PhiEaglesfan712]

[40/70 Benchmark]

10 hours ago, George001 said:

Yep, the snowy -EPO dominant patterns with little to no blocking like Feb 2015 had the western ridge axis centered near Montana. The pattern advertised on long range guidance near the Jan 20th period is different because the western ridge axis is off the west coast. My read on the advertised pattern is it’s a cold pattern, but not a snowy one for coastal areas since the pattern favors lows running inland and warm sectoring us. Definitely looks more like 18-19 than 14-15, classic cold warm up rain, then cold again pattern. Not going to get a classic east coast nor’easter with that look for sure, but hopefully we can score some swfe type systems.

I think there will be front enders, which 2018-2019 had plenty of. If things are timed right, some bonafide SWFEs, too.

[MJO812]

4 hours ago, 40/70 Benchmark said:

-EPO keepa Canada cold allows said cold to dump imto the US....in. -PNA/+NAO pattern, it dumps WEST.

There's no trough in the west in a - EPO pattern .You end with a split flow because- EPO force highs east of the Rockies .Its why the modeling is cold coast to coast even w + NAO. Those troughs lean back but the EPO boundary gets to the east coast.

[LakePaste25]

7 minutes ago, MJO812 said:

There's no trough in the west in a - EPO pattern .You end with a split flow because- EPO force highs east of the Rockies .Its why the modeling is cold coast to coast even w + NAO. Those troughs lean back but the EPO boundary gets to the east coast.

Sure it will get cold, but storms can cut with a -EPO if there’s no +PNA. Remember that historic blizzard in Buffalo in December 2022? That started with a huge cutter and -EPO. For the coast, it was a cutter followed by cold and dry. 

[40/70 Benchmark]

Speaking of the 2008 ENSO analog I have be talking up all last fall and into the winter....here is the peak on Xmas for both.

24DEC2008     22.9-0.3     24.4-0.8     25.6-1.0     27.5-0.9

25DEC2024     23.1-0.2     24.7-0.5     25.5-1.1     27.6-0.7

 

[40/70 Benchmark]

43 minutes ago, MJO812 said:

There's no trough in the west in a - EPO pattern .You end with a split flow because- EPO force highs east of the Rockies .Its why the modeling is cold coast to coast even w + NAO. Those troughs lean back but the EPO boundary gets to the east coast.

Do these look the same to you...because these are BOTH -EPO....