2024-2025 La Nina

[mitchnick]

1 hour ago, GaWx said:

 Every one of these 5 indicators is at the coldest of the season to date clearly indicative of a rapidly strengthening La Niña to near weak/moderate Niña border on the dailies and suggesting equivalent RONI dailies probably at least high end moderate to quite possibly bordering on strong. This means a Nov to Dec cooling likely one of the strongest back to 1950 though not near the 0.8 record shattering cooling suggested by many earlier CFS runs:

OISST: -0.98 C

 

CRW: -0.95 C

CDAS: -1.43 C

 

Buoys: coldest below -1.5 C near equator along entire Nino 3.4:

 

OHC: 0.6 C plunge just since late Nov to -1.1 C

Thanks Larry. I don't doubt there are readings below -1C in 3.4, but I  would be shocked if we get a trimonthly of -1C or lower. 

[snowman19]

2 hours ago, GaWx said:

 Every one of these 5 indicators is at the coldest of the season to date clearly indicative of a rapidly strengthening La Niña to near weak/moderate Niña border on the dailies and suggesting equivalent RONI dailies probably at least high end moderate to quite possibly bordering on strong. This means a Nov to Dec cooling likely one of the strongest back to 1950 though not near the 0.8 record shattering cooling suggested by many earlier CFS runs:

OISST: -0.98 C

 

CRW: -0.95 C

CDAS: -1.43 C

 

Buoys: coldest below -1.5 C near equator along entire Nino 3.4:

 

OHC: 0.6 C plunge just since late Nov to -1.1 C

This is definitely historic strengthening for this late in the season. I’m sure the MEI also dropped like a rock, probably high-end moderate, borderline strong like the RONI. We have way, way surpassed the 2008 late bloomer La Niña strengthening. It’s incredibly rare to see a Niña event just take off like this in the NDJ trimonthly period

@bluewave @donsutherland1 @40/70 Benchmark

[GaWx]

23 minutes ago, snowman19 said:

This is definitely historic strengthening for this late in the season. I’m sure the MEI also dropped like a rock, probably high-end moderate, borderline strong like the RONI. We have way, way surpassed the 2008 late bloomer La Niña strengthening. It’s incredibly rare to see a Niña event just take off like this in the NDJ trimonthly period

@bluewave @donsutherland1 @40/70 Benchmark

 OISST 3.4 ERSST/OISST anomalies dropped 0.40 C/0.47 C in 2008 from Nov to Dec. This could easily end up near a 0.5C drop for OISST which would be a new record Nov to Dec drop for La Niña back to 1950.

 

[GaWx]

 The 12Z EPS 360 hour has about as negative H5 anomalies as I can recall on any run at 360 centered in the E US. NYC is at 534 dm, which is a whopping 14-15 dm BN! Keep in mind that that is a 50 member ensemble mean out 15 days, a very difficult modeled anomaly to have:

 

[LibertyBell]

1 hour ago, snowman19 said:

This is definitely historic strengthening for this late in the season. I’m sure the MEI also dropped like a rock, probably high-end moderate, borderline strong like the RONI. We have way, way surpassed the 2008 late bloomer La Niña strengthening. It’s incredibly rare to see a Niña event just take off like this in the NDJ trimonthly period

@bluewave @donsutherland1 @40/70 Benchmark

Does this mean it will probably stick around to later in the season than normal too?

[LibertyBell]

57 minutes ago, GaWx said:

 OISST 3.4 ERSST/OISST anomalies dropped 0.40 C/0.47 C in 2008 from Nov to Dec. This could easily end up near a 0.5C drop for OISST which would be a new record Nov to Dec drop for La Niña back to 1950.

 

I wasn't aware that 2008-09 was a possible analog for this season.  We did have snowy bouts in in all four wintry months DJFM that season.  Nothing huge (except for that one MECS we had on March 1st, still my largest March snowstorm lol.)

[GaWx]

 How about this earlier in the 12Z EPS (at 270)?This has E NC at 20 dm BN and NYC at only 532 dm, which is 17 dm BN! I’d say that’s ~equally impressive to the further out but not quite as cold 360 hour map posted above:

[snowman19]

10 minutes ago, LibertyBell said:

Does this mean it will probably stick around to later in the season than normal too?

Yes

[mitchnick]

Today's weeklies looked to have gotten colder for week 2. Plus, the AN for the last week that was there yesterday is gone as a reload from sw Canada appears imminent. Recall I mentioned a few days ago how it looked like a possible pattern repeat due to cold air building from sw Canada.

https://charts.ecmwf.int/products/extended-anomaly-2t?base_time=202412240000&projection=opencharts_north_america&valid_time=202501060000

[roardog]

I'm also still impressed with the continuation of the nose dive in global SST anomalies to levels not seen in years on all sources.

[GaWx]

 New Euro Weeklies:

For Jan 6-12: H5 has the strongest negative anomalies yet with a whopping 13-14 BN at NYC with 536 dm for a full week! The PV is centered near 70N, 80W over far N Hudson Bay. The W ridge is a bit further east vs yesterday along W coast meaning stronger +PNA, thus bringing the center of the cold back to the E US like was the case before yesterday. The Aleutian low is the strongest yet.

H5: 1/6-12

 

2m: 1/6-12 is as Mitch just said colder in the E US though it isn’t as cold W/NW of Chicago, where the center of the cold was yesterday. Today’s has the 3rd shade of cold covering most of the E US vs just a tiny area in the 3rd shade mainly in NC the last 4 days. The third shade is 3-6C BN or 5.4-10.8F BN averaged over a full week!

 The subsequent week, 1/12-18, is still cold/slightly colder SE vs yesterday though not as cold Midwest with like the prior week having the W ridge a bit further east along W coast. This run keeps a pretty stout +PNA much of Jan.

[mitchnick]

10 minutes ago, GaWx said:

 New Euro Weeklies:

For Jan 6-12: H5 has the strongest negative anomalies yet with a whopping 13-14 BN at NYC with 536 dm for a full week! The PV is centered near 70N, 80W over far N Hudson Bay. The W ridge is a bit further east vs yesterday along W coast meaning stronger +PNA, thus bringing the center of the cold back to the E US like was the case before yesterday. The Aleutian low is the strongest yet.

H5: 1/6-12

 

2m: 1/6-12 is as Mitch just said colder in the E US though it isn’t as cold W/NW of Chicago, where the center of the cold was yesterday. Today’s has the 3rd shade of cold covering most of the E US vs just a tiny area in the 3rd shade mainly in NC the last 4 days. The third shade is 3-6C BN or 5.4-10.8C BN averaged over a full week!

 The subsequent week, 1/12-18, is still cold/slightly colder SE vs yesterday though not as cold Midwest. 

Larry, have you ever seen such a huge area of BN off the Atlantic seaboard on the weeklies? I can't recall it.

[mitchnick]

5 minutes ago, mitchnick said:

Larry, have you ever seen such a huge area of BN off the Atlantic seaboard on the weeklies? I can't recall it.

Can't help but think with that kind of contrast between air and sea, it will help with developing low pressure. 

[PhiEaglesfan712]

1 hour ago, LibertyBell said:

Does this mean it will probably stick around to later in the season than normal too?

Not necessarily. The late season la ninas in 2006 and 2009 went straight to el nino the following year, with the latter (2009-10) being a strong el nino. Although, each case produced a strong la nina in the second year following (2007-08 and 2010-11).

On the flip side, the late season la nina in 2022 continued into 2022-23, but went strong el nino during the 2nd year following.

My guess is that the 2022 scenario is more likely, but history favors 2026-27 having the opposite ENSO (in extreme strength) of 2025-26.

[LibertyBell]

2 minutes ago, PhiEaglesfan712 said:

Not necessarily. The late season la ninas in 2006 and 2009 went straight to el nino the following year, with the latter (2009-10) being a strong el nino. Although, each case produced a strong la nina in the second year following (2007-08 and 2010-11).

On the flip side, the late season la nina in 2022 continued into 2022-23, but went strong el nino during the 2nd year following.

My guess is that the 2022 scenario is more likely, but history favors 2026-27 having the opposite ENSO (in extreme strength) of 2025-26.

and thats also when the peak influence of the solar max would be in the next 2 winters.

[GaWx]

44 minutes ago, mitchnick said:

Larry, have you ever seen such a huge area of BN off the Atlantic seaboard on the weeklies? I can't recall it.

 It’s as big as any I can recall. The size of the area in the 3rd shade of blue off the E coast is the most impressive I can recall. It isn’t easy to get that offshore as we know.

  Looking back in my saved maps, today’s EW map for 1/6-12, with it covering most of the E US in 3-6C/5.4-10.8F BN is THE coldest of any I have in the E US for the week still being 13 days out!  The only other one I have that is comparable (slightly colder NE/slightly warmer SE) with most of the E US in 5.4-10.8F BN is closer in at 9 days out (11/23/24) preceding Dec 2-8:

How well did this 9 days out map verify for 12/2-8/24?

NYC (map: ~-5.5F): actual was -5.3F (so, very close)

Wilmington, NC (map: ~-6F): actual was -10.9F (so, it wasn’t nearly cold enough)

Savannah (map ~-5.5F): actual was -9.7 (so, it wasn’t nearly cold enough)

 If this verification were to happen to be an indication of what’s to come Jan 6-12, the SE (at the very least) would verify colder then what today’s map shows. Also, if the strong cold signal maintains itself, look for a portion of this going into the 4th shade of blue on a run within a few days. The 4th shade starts at -10.8F.

[EasternLI]

The PDO should continue to climb too, with the progged pattern. Which is interesting. This is a 5 day mean from the 12z eps. 

[GaWx]

Way up will go the HDDs it appears as of now! 12Z EPS US pop weighted HDDs in purple on left is a bit colder than the 0Z (yellow). Green is normal. They’re progged to double between 12/29 and Jan 4th:

[bluewave]

5 hours ago, snowman19 said:

This is definitely historic strengthening for this late in the season. I’m sure the MEI also dropped like a rock, probably high-end moderate, borderline strong like the RONI. We have way, way surpassed the 2008 late bloomer La Niña strengthening. It’s incredibly rare to see a Niña event just take off like this in the NDJ trimonthly period

@bluewave @donsutherland1 @40/70 Benchmark

The cooling was probably delayed due to the record background SST warmth. While global SSTs have cooled some in the last several months, they are still as warm as December 2015 which was a super El Niño. So this La Niña is definitely a late bloomer. EQSOI was on par with stronger La Ninas back in November. Plus CP OLR was the strongest on record for any La Niña during the month of November.

 

[40/70 Benchmark]

9 hours ago, snowman19 said:

This is definitely historic strengthening for this late in the season. I’m sure the MEI also dropped like a rock, probably high-end moderate, borderline strong like the RONI. We have way, way surpassed the 2008 late bloomer La Niña strengthening. It’s incredibly rare to see a Niña event just take off like this in the NDJ trimonthly period

@bluewave @donsutherland1 @40/70 Benchmark

I think its a great analog.

[40/70 Benchmark]

11 hours ago, mitchnick said:

Thanks Larry. I don't doubt there are readings below -1C in 3.4, but I  would be shocked if we get a trimonthly of -1C or lower. 

Right.

[Terpeast]

4 hours ago, bluewave said:

The cooling was probably delayed due to the record background SST warmth. While global SSTs have cooled some in the last several months, they are still as warm as December 2015 which was a super El Niño. So this La Niña is definitely a late bloomer. EQSOI was on par with stronger La Ninas back in November. Plus CP OLR was the strongest on record for any La Niña during the month of November.

 

One positive takeaway from this is it might put a dent in the global temperatures. The overall spatial SST maps look a lot cooler with the ENSO region cooling off, as well as the Japan marine heat wave abating. 

[Stormchaserchuck1]

4 hours ago, bluewave said:

The cooling was probably delayed due to the record background SST warmth. While global SSTs have cooled some in the last several months, they are still as warm as December 2015 which was a super El Niño. So this La Niña is definitely a late bloomer. EQSOI was on par with stronger La Ninas back in November. Plus CP OLR was the strongest on record for any La Niña during the month of November.

Good post. I've been noticing how much subsurface anomalies have been dropping the past few weeks, we are back almost in Moderate Nina range. And the 30-day SOI recently hit +15, after not going above +6 all year. There are not many analogs of the SOI behaving like that. Could increase La Nina chances going into next year, should be interesting to see how it evolves. Events don't usually "start" in December like this. 

[PhiEaglesfan712]

15 minutes ago, Stormchaserchuck1 said:

Good post. I've been noticing how much subsurface anomalies have been dropping the past few weeks, we are back almost in Moderate Nina range. And the 30-day SOI recently hit +15, after not going above +6 all year. There are not many analogs of the SOI behaving like that. Could increase La Nina chances going into next year, should be interesting to see how it evolves. Events don't usually "start" in December like this. 

The closest analogs are 05-06, 08-09, and 21-22. Two of these (2006 and 2009) flipped to el nino the following year (with one, 09-10, being a strong el nino), while the third (2022) stayed a la nina. Oddly enough, the two that flipped to el nino produced strong la ninas in year 2, while the one that stayed a la nina flipped to a strong el nino in year 2. So I guess whatever ENSO state we have in 2025-26, we'll have the reverse in 2026-27 (and likely a strong event).

[GaWx]

Merry Christmas and also Happy Hanukkah as it starts later today.

0Z ensembles:

1. Whereas EPS retains a very cold look at 500 mb at the end and is still cold overall especially at the end, the total HDDs of the run dropped some vs the 12Z. Thus, today’s Weekly for 1/6-12 may not be as cold.

2. Bigger news: Last 2 runs of GEFS have gone a long way toward the EPS. HDDs are up significantly. The end of the 0Z GEFS is even colder than the 0Z EPS or even the 12Z EPS. The end is the coldest GEFS run yet vs the extended portions, which go out further at 0Z, of prior 0Z runs. The very cold end has MB 850s covering almost all of the E 1/2 of the US:

[snowman19]

13 hours ago, bluewave said:

The cooling was probably delayed due to the record background SST warmth. While global SSTs have cooled some in the last several months, they are still as warm as December 2015 which was a super El Niño. So this La Niña is definitely a late bloomer. EQSOI was on par with stronger La Ninas back in November. Plus CP OLR was the strongest on record for any La Niña during the month of November.

 

The idea from some folks that the NPAC is just going to somehow magically stay in a default Nino look the rest of this winter with a massive, record La Niña response like this in the tropical PAC is about to go down in flames

Edit: @roardog Not disagreeing that the NPAC has resembled a Nino from late November to this point in time. However, the idea from some that this is just going to continue through March, no way. This winter would have to completely defy the laws of physics and reality for that to happen. This wasn’t just some week long Niña push, it’s been a strong, record breaking, sustained Niña push since November. The effects are going to be lagged, but there has to be an equal response to the tropical PAC in the NPAC. I don’t see it (Nino-like look) continuing much beyond mid-January and the models are starting to reflect this 

[mitchnick]

Merry Christmas and Happy Hanukkah!

[roardog]

27 minutes ago, snowman19 said:

The idea from some folks that the NPAC is just going to somehow magically stay in a default Nino look the rest of this winter with a massive, record La Niña response like this in the tropical PAC is about to go down in flames

If I was betting, I would certainly bet against the Nino look sticking around the entire winter. However, that being said, it’s looking like we are essentially going to have this Nino like pattern for at least half of this met winter. For the people who like cold and snow chances in the east, you can’t ask for more than that with what everyone expected going into this winter. 

[mitchnick]

Euro's last monthly forecast did a pretty good job with the drop. IF it maintains its forecast accuracy, it hascthe Niña peaking mid-January. Euro monthly updates in around 10 days or so, so maybe it changes. I do think the westerlies the Eps has sneaking in before restarting trades will at least stall further cooling and may, I  said may (lol), interrupt the cooling process despite resumption of the trades. That would coincidence with the Euro's monthly forecast it seems.

Obviously, this is 1 possible scenario. We'll see.

[GaWx]

MJO forecasts: pretty consistent with the often favorable for cold E US with still having weak left side