2024-2025 La Nina

[40/70 Benchmark]

15 hours ago, Stormchaserchuck1 said:

If you remember, we had record warm SSTs across the Atlantic early last Hurricane season. I made that chart in February 2024 I think, and it was smoothed out, so the cutoff had to be 2023. But if you include last year, it would look like this:

Ok, gotcha. In that case, I agree that we haven't began to see the transition, but it should be fairly imminent.

[Stormchaserchuck1]

-NAO on models from the Stratosphere warming.. +15 days is about perfect time lag for this time of year

[GaWx]

2 hours ago, Stormchaserchuck1 said:

-NAO on models from the Stratosphere warming.. +15 days is about perfect time lag for this time of year

As a result of this strengthening -NAO, today’s Euro Weeklies have cooled a lot just since yesterday’s run for 4/7-13 (Masters Week):

Yesterday’s run for 4/7-13

 

Today run for 4/7-13

[Stormchaserchuck1]

2 minutes ago, GaWx said:

As a result of this strengthening -NAO, today’s Euro Weeklies have cooled a lot just since yesterday’s run for 4/7-13 (Masters Week):

Yesterday’s run for 4/7-13

Today run for 4/7-13

Thanks.. it's fitting the average time lag about perfectly this time (+15 days in April vs +45-60 days in Oct/Nov!) I wonder if models have a bias at all regarding SSW's and following -NAO's.. 

[Stormchaserchuck1]

CPC is actually going really aggressive on -NAO based cold from/after Stratosphere warming. 

[40/70 Benchmark]

Yea...I figured the late SSW would manifest in April, which is why I wasn't opptimistic about March....too little too late. Same thing happened in 2000.

[Stormchaserchuck1]

I found this interesting, a +NAO in March has a slightly cooler temp correlation in April (usually they all go in the same direction). 

[PhiEaglesfan712]

I'd say that with the exception of January, the 2020-21 analog worked almost in line with this year, especially with temperature. December and February were cool to near average, while November and March absolutely torched in the East.

[40/70 Benchmark]

1 hour ago, PhiEaglesfan712 said:

I'd say that with the exception of January, the 2020-21 analog worked almost in line with this year, especially with temperature. December and February were cool to near average, while November and March absolutely torched in the East.

Snowfall wasn't comparable most of NE.

[Stormchaserchuck1]

13 hours ago, 40/70 Benchmark said:

Snowfall wasn't comparable most of NE.

Cold will sometimes produce. Snowfall can be too localized for grand general analogs. Did you have any snow in March?

Does Boston still have its <4" streak going? 

[40/70 Benchmark]

9 hours ago, Stormchaserchuck1 said:

Cold will sometimes produce. Snowfall can be too localized for grand general analogs. Did you have any snow in March?

Does Boston still have its <4" streak going? 

Oh Yea, I know....ideally the snowfall will workout for an analog generally speaking, but its so variable.

2020-2021 was one of my polar analogs, so I def. agree that there was value to be had using it. It was an exceptional QBO analog.

I had a Trace in March...same as Boston.

[michsnowfreak]

On 4/1/2025 at 6:39 AM, PhiEaglesfan712 said:

I'd say that with the exception of January, the 2020-21 analog worked almost in line with this year, especially with temperature. December and February were cool to near average, while November and March absolutely torched in the East.

It was fairly similar here temp wise, but as always snow is always a wild card. Biggest difference here was January was mild in 2021 and cold in 2025

2020-21 vs 2024-25 at Detroit
Nov: +4.5 +5.3  **  3.5”   1.8”
Dec: +1.6 +2.2  **  9.6”   3.6”
Jan: +3.5 -2.8  **  6.4”   8.9”
Feb: -4.7 -1.9  ** 21.8”  12.2”
Mar: +5.7 +6.0  **    T    0.4”
Apr: +1.7    ?  **  3.6”     ?

 

[40/70 Benchmark]

1 hour ago, michsnowfreak said:

It was fairly similar here temp wise, but as always snow is always a wild card. Biggest difference here was January was mild in 2021 and cold in 2025

2020-21 vs 2024-25 at Detroit
Nov: +4.5 +5.3  **  3.5”   1.8”
Dec: +1.6 +2.2  **  9.6”   3.6”
Jan: +3.5 -2.8  **  6.4”   8.9”
Feb: -4.7 -1.9  ** 21.8”  12.2”
Mar: +5.7 +6.0  **    T    0.4”
Apr: +1.7    ?  **  3.6”     ?

 

I remember that in my area it ended up being mild largely due to unimpressive daily mins.....there were no real warm spells.

[LibertyBell]

On 3/25/2025 at 3:32 PM, Stormchaserchuck1 said:

If you remember, we had record warm SSTs across the Atlantic early last Hurricane season. I made that chart in February 2024 I think, and it was smoothed out, so the cutoff had to be 2023. But if you include last year, it would look like this:

It's definitely coming down now, the drier weather starting last fall and the weird hurricane season are sure signs of it, so are the cold but dry winter.

[LibertyBell]

30 minutes ago, 40/70 Benchmark said:

I remember that in my area it ended up being mild largely due to unimpressive daily mins.....there were no real warm spells.

higher winds kept the mins higher

[LibertyBell]

On 3/26/2025 at 6:42 AM, 40/70 Benchmark said:

Ok, gotcha. In that case, I agree that we haven't began to see the transition, but it should be fairly imminent.

it started last fall, Ray.

[michsnowfreak]

5 hours ago, 40/70 Benchmark said:

I remember that in my area it ended up being mild largely due to unimpressive daily mins.....there were no real warm spells.

Same here! A low monthly range (warmest 45, coldest 11) and warmer mins and very gray, even more gray than usual. The avg high was +1.9F but the avg low +5.3F, and being the coldest month of the year, it was still cold, just not the deep winter feel most of Jan 2025 was.

[Stormchaserchuck1]

This STJ aspect of this past Winter really looks like a La Nina

[40/70 Benchmark]

3 hours ago, Stormchaserchuck1 said:

This STJ aspect of this past Winter really looks like a La Nina

It clearly was a La Nina if you look at everything besides the 5 consecutive tri monthly ONI readings of -.5

[Stormchaserchuck1]

10 hours ago, 40/70 Benchmark said:

It clearly was a La Nina if you look at everything besides the 5 consecutive tri monthly ONI readings of -.5

We did have +NOI, which is a little High pressure off the West coast. That's what I look for, for ENSO effects. And the year before in Strong El Nino, although we had mostly -PNA, it was -NOI. The North Pacific High region has greatest ENSO correlation effects, not the PNA (very misunderstood).. although I guess you can say in west-based events it's more PNA-correlated. 

[PhiEaglesfan712]

JFM 2025 ONI (NOAA): -0.4

JFM 2025 RONI: -0.90

March 2025 PDO: -1.12

[Stormchaserchuck1]

13 minutes ago, PhiEaglesfan712 said:

JFM 2025 ONI (NOAA): -0.4

That means if you subtract 0.2 to account for global warming trend (which is about what it is: 0.2 to 0.3), this event did officially hit Weak Nina. 

[snowman19]

After all the SSWE hype the end of February and throughout March, the mid-March event failed to couple, as was the case with every other stratospheric wave reflection and stretching event that has occurred since November. The stratosphere and troposphere have remained totally uncoupled
 

[Stormchaserchuck1]

We are going to have a -NAO event in 4-5 days.. it's trended less cold in the US, but for like 5 days the NAO will be effected in the typical time lag period.  Edit: It is a 4 week major Stratosphere warming, and we aren't going to get 3-4 weeks of -NAO, you are right about that.. They couple with major -NAO +time historically about 2/3 times. 

This was also the 1st Stratosphere warming event since Nov.. it's been all cold Stratosphere Nov-Feb

[40/70 Benchmark]

14 hours ago, PhiEaglesfan712 said:

JFM 2025 ONI (NOAA): -0.4

JFM 2025 RONI: -0.90

March 2025 PDO: -1.12

Exactly the point.

[40/70 Benchmark]

14 hours ago, Stormchaserchuck1 said:

We did have +NOI, which is a little High pressure off the West coast. That's what I look for, for ENSO effects. And the year before in Strong El Nino, although we had mostly -PNA, it was -NOI. The North Pacific High region has greatest ENSO correlation effects, not the PNA (very misunderstood).. although I guess you can say in west-based events it's more PNA-correlated. 

What in the hell is NOI?

[40/70 Benchmark]

1 hour ago, snowman19 said:

After all the SSWE hype the end of February and throughout March, the mid-March event failed to couple, as was the case with every other stratospheric wave reflection and stretching event that has occurred since November. The stratosphere and troposphere have remained totally uncoupled
 

Who hyped this? I think maybe JB....but I didn't see anyone else. Judah never did...I though it would be useless daying back to last fall.

[40/70 Benchmark]

40 minutes ago, Stormchaserchuck1 said:

We are going to have a -NAO event in 4-5 days.. it's trended less cold in the US, but for like 5 days the NAO will be effected in the typical time lag period.  Edit: It is a 4 week major Stratosphere warming, and we aren't going to get 3-4 weeks of -NAO, you are right about that.. They couple with major -NAO +time historically about 2/3 times. 

This was also the 1st Stratosphere warming event since Nov.. it's been all cold Stratosphere Nov-Feb

Yea, the Feb warming was odd in that it was triggered by lower level, tropospheric phenomena.

[Stormchaserchuck1]

10 minutes ago, 40/70 Benchmark said:

What in the hell is NOI?

Northern Hemisphere version of SOI. Pressure difference between the North Pacific High and Tahiti I think. 

[40/70 Benchmark]

Looks like I was a hair too robust with the RONI peak...I had -1.2 to -1.4 vs the actual peak of -1.12. MEI peak forecast range was -1 to -1.2 and the actual peak was on the high end of the range at -1. I had the La Nina ONI peak between -0.6 and -0.8. Peak was -0.6. 

I was pretty accurate in terms of the peak, albeit at the weaker end of my range. Pretty impressive consiering the headfake by guidance late last fall and even into the early winter in cancelling La Nina. The comparison to the 2008-2009 event in terms of the late come back and shift west into more of a weaker Modoki worked out well.