2024-2025 La Nina

[LibertyBell]

15 minutes ago, 40/70 Benchmark said:

Colder relative to what many susepect.

Early winter might be cold (it's already turning cooler and feels like Fall), but it will also probably end after Mid January.  Most of our snow will likely be in December and part of January

Looks like the tropical season won't live up to expectations-- I never thought this was going to be some historic 2005/2020 repeat.

 

[bluewave]

4 hours ago, 40/70 Benchmark said:

I thought last summer was rather cool around here....

2023 and 2017 were the only summers a little cooler than average since the super El Niño in 2015. So we have had 9 out of 9 warmer to record warmer winters and 8 out of 10 warmer than average to record warm summers.

[40/70 Benchmark]

3 minutes ago, LibertyBell said:

Early winter might be cold (it's already turning cooler and feels like Fall), but it will also probably end after Mid January.  Most of our snow will likely be in December and part of January

Looks like the tropical season won't live up to expectations-- I never thought this was going to be some historic 2005/2020 repeat.

 

I think the early season will be more Pacfic driven..ie Aleutian ridging and -EPO/WPO, though the PV shouldn't be too stout....then mid season it goes very warm with less of an RNA before perhaps blocking/big RNA late season.

[LibertyBell]

7 minutes ago, 40/70 Benchmark said:

I think the early season will be more Pacfic driven..ie Aleutian ridging and -EPO/WPO, though the PV shouldn't be too stout....then mid season it goes very warm with less of an RNA before perhaps blocking/big RNA late season.

bookend winter perhaps Ray?

[40/70 Benchmark]

Just now, LibertyBell said:

bookend winter perhaps Ray?

I think the only wild card for mid season is Bluewave's October MJO rule...if the MJO isn't amplifed in October, then we roast mid winter.

[LibertyBell]

6 minutes ago, 40/70 Benchmark said:

I think the only wild card for mid season is Bluewave's October MJO rule...if the MJO isn't amplifed in October, then we roast mid winter.

hmm I wonder if that means that if we see a lot of tropical activity in October that's a good sign for winter?

[40/70 Benchmark]

2 minutes ago, LibertyBell said:

hmm I wonder if that means that if we see a lot of tropical activity in October that's a good sign for winter?

I think a big ACE value correlated to more poleward Aleutian ridging.

[40/70 Benchmark]

BTW, its still very active per ACE...bit of a misconception in relation to that.

2024 Accumulated Cyclone Energy [ACE]

Basin	Current YTD	Normal YTD	% of Normal YTD	Yearly Climo*	2023**
Northern Hemisphere	136.2100	210	64%	575	648
Western N Pacific	50.625	114	44%	298	266
Eastern + Cent N Pac	26.9875	66	40%	132	165
North Atlantic	56.31	21	268%	122	146
North Indian	2.2875	7	32%	23	60
Southern Hemisphere	169.958	209	81%	205	244
Global	269.3030	382	70%	780	881

 

*Yearly climatology from historical 1991-2020 Tropical cyclone best track datasets

[LibertyBell]

Just now, 40/70 Benchmark said:

BTW, its still very active per ACE...bit of a misconception in relation to that.

2024 Accumulated Cyclone Energy [ACE]

Basin	Current YTD	Normal YTD	% of Normal YTD	Yearly Climo*	2023**
Northern Hemisphere	136.2100	210	64%	575	648
Western N Pacific	50.625	114	44%	298	266
Eastern + Cent N Pac	26.9875	66	40%	132	165
North Atlantic	56.31	21	268%	122	146
North Indian	2.2875	7	32%	23	60
Southern Hemisphere	169.958	209	81%	205	244
Global	269.3030	382	70%	780	881

 

*Yearly climatology from historical 1991-2020 Tropical cyclone best track datasets

Yep, just not historic.  Getting a Cat 5 so early in the season helped boost the ACE.

[40/70 Benchmark]

27 minutes ago, 40/70 Benchmark said:

BTW, its still very active per ACE...bit of a misconception in relation to that.

2024 Accumulated Cyclone Energy [ACE]

Basin	Current YTD	Normal YTD	% of Normal YTD	Yearly Climo*	2023**
Northern Hemisphere	136.2100	210	64%	575	648
Western N Pacific	50.625	114	44%	298	266
Eastern + Cent N Pac	26.9875	66	40%	132	165
North Atlantic	56.31	21	268%	122	146
North Indian	2.2875	7	32%	23	60
Southern Hemisphere	169.958	209	81%	205	244
Global	269.3030	382	70%	780	881

 

*Yearly climatology from historical 1991-2020 Tropical cyclone best track datasets

There are all of the "extremely active" (ACE) La Nina seasons since 1950...can see the bouts of poleward Aleutian ridging and -NAO that I alluded to in my write up:

[40/70 Benchmark]

I wonder if the ACE may also tie into that October MJO amplitude, as liberty suggested. That composite looks pretty -WPO to me, but also mainly -QBO.

[snowman19]

13 minutes ago, 40/70 Benchmark said:

There are all of the "extremely active" (ACE) La Nina seasons since 1950...can see the bouts of poleward Aleutian ridging and -NAO that I alluded to in my write up:

Which ones of the high ACE Nina’s were also high solar and geomag, +QBO, -PDO?

[40/70 Benchmark]

14 minutes ago, snowman19 said:

Which ones of the high ACE Nina’s were also high solar and geomag, +QBO, -PDO?

Just 2000?

Note sure about 1951 and 1962 in terms of QBO and solar...anyway, I don't expect a huge winter, regardless.

[snowman19]

13 minutes ago, 40/70 Benchmark said:

Just 2000?

Note sure about 1951 and 1962 in terms of QBO and solar...anyway, I don't expect a huge winter, regardless.

Besides the La Niña, solar/geomag, MJO and -PDO, I think another important factor to watch is the QBO. I remember years ago, DT found good evidence that strong positive QBO’s lead to a raging PAC jet. I forget what his actual ranges were for that though….

[GaWx]

58 minutes ago, 40/70 Benchmark said:

Just 2000?

Note sure about 1951 and 1962 in terms of QBO and solar...anyway, I don't expect a huge winter, regardless.

QBO/solar

1950-1 slight E/moderate solar ~3 yrs after prior peak

1961-2 slight W/moderate solar ~4 hrs after prior peak

 

 

 

[bluewave]

2 hours ago, 40/70 Benchmark said:

I wonder if the ACE may also tie into that October MJO amplitude, as liberty suggested. That composite looks pretty -WPO to me, but also mainly -QBO.

The better La Niña winters for snowfall were associated with very high ACE and storm totals. Not exactly sure whether it was a cause and effect relationship or they were both just part of the same pattern with another underlying cause. 
 

2005…second most active hurricane season for ACE at 245 with the 2nd highest named storms at 28.

1995…227 ACE which was 5th highest with 19 named storms 

2017…224 ACE which was 6th highest

2020..180 ACE….With the highest named storm count at 30

2010…165 ACE…with 19 named storms 

[roardog]

1 hour ago, snowman19 said:

Besides the La Niña, solar/geomag, MJO and -PDO, I think another important factor to watch is the QBO. I remember years ago, DT found good evidence that strong positive QBO’s lead to a raging PAC jet. I forget what his actual ranges were for that though….

I thought DT used to say it was a strong negative QBO that he believed resulted in a strong pacific jet. This was like 20 or 25 years ago that I’m talking about so my memory might be wrong. 

[snowman19]

3 minutes ago, roardog said:

I thought DT used to say it was a strong negative QBO that he believed resulted in a strong pacific jet. This was like 20 or 25 years ago that I’m talking about so my memory might be wrong. 

I remember distinctly that he said strong positive QBO leads to a raging PAC jet. I’m looking for it now. He had a specific range on numbers

[PhiEaglesfan712]

8 hours ago, 40/70 Benchmark said:

This is an absolutely lethal match to the MEI analogs....uncoincidentally.

If we go by the MEI, which has 2023-24 as a weak el nino, then 2007-08 is the closest match. Next best would be 2020-21.

I guess our best hope is the la nina goes east-based. Then maybe we could squeeze out a 2021-22 or even 2017-18 type winter.

[roardog]

2 hours ago, snowman19 said:

I remember distinctly that he said strong positive QBO leads to a raging PAC jet. I’m looking for it now. He had a specific range on numbers

For some reason I remember it being opposite and there being disagreement with it. But again, I’m talking early 00’s during the Wright Weather days. His stance could easily be different now 20+ years later. 

[PhiEaglesfan712]

6 hours ago, LibertyBell said:

Early winter might be cold (it's already turning cooler and feels like Fall), but it will also probably end after Mid January.  Most of our snow will likely be in December and part of January

Looks like the tropical season won't live up to expectations-- I never thought this was going to be some historic 2005/2020 repeat.

 

Maybe we could carve out a 1998-99 type season. That was a very warm first 3 weeks of December. We got most of our snow from Dec 23 to mid-January. We got no snow and it was warm until the 3rd week of March, which produced one more snow event.

[bluewave]

9 hours ago, 40/70 Benchmark said:

@bluewave or anyone....Do you have the piece on the new Pacific pattern designations...ie. Alaskan trough, etc...?

The Pacific Ridge pattern or Aleutian ridge as it’s also called was displaced a little further SW this June and July. So a bit of a hybrid pattern also allowing a ridge in the PNA region. The 500 MB anomaly just west of the Dateline was the highest on record for June and July. Another case of record breaking 500 mb height anomalies which have become so common. That’s roughly where the winter ridge axis has been since the 15 -16 super El Niño.

https://simonleewx.com/north-american-weather-regimes/

 

 

[LibertyBell]

3 hours ago, PhiEaglesfan712 said:

If we go by the MEI, which has 2023-24 as a weak el nino, then 2007-08 is the closest match. Next best would be 2020-21.

I guess our best hope is the la nina goes east-based. Then maybe we could squeeze out a 2021-22 or even 2017-18 type winter.

There's another similarity to 2007 which I'll throw out there, although it might mean nothing but it still sticks out.  It's the last time it got this cool in August..... it's the last time we saw temps of 57 or colder here in August.

 

[raindancewx]

I've found that hyperactive Atlantic hurricane seasons tend to occur in seasons with a big year/year warming in the tropical Atlantic. Do we have that this year? Not at all. Could it still change? Yes, but it is becoming less likely. The cold AMO has the blue backward c around the Greenland-Iceland-Azores zones with the warm tongue in between, like you see below on the y/y change map. You can see the 1994-1995 flip from cold AMO to warm AMO has the exact opposite signature flip by intensity and spatial composition.

Since 1950, the La Ninas following an El Nino with a colder tropical Atlantic are pretty rare. Your La Nina after El Nino years are 1954, 1964, 1966 (close enough to a Nina), 1970, 1973, 1980 (close enough), 1983, 1988, 1995, 1998, 2005, 2007, 2010, 2016 (close enough), 2020.

Of those years, 1954, 1964, 1970, 2007 are really the only ones in which the tropical Atlantic (blue stripe west of West Africa) is colder than the prior El Nino year in July. Atlantic ACE in those years is 104/153/40/74 or about 93. 2007 had two cat 5 hurricanes, despite the low ACE. 1964/1970 are both cold AMO years in a colder global period, so I'd expect ACE to be somewhat higher than the 93, but maybe pretty average in the modern context (105-145). A 125 ACE year is well below the recent La Nina mean of 155 or so.

[raindancewx]

Also, as a reminder from my 2022-23 winter outlook, La Ninas without high ACE values tend to see major cold waves in the Southwest.2022 Atlantic ACE = 95.1. X is ACE in the Atlantic, Y is cold days in Nov-Feb (at least 5F below daily averages)

Y = -0.1177x + 42.063

Y = (-0.1177 * 95.1) + 42.063

Y = 30.863 days that are 'cold' (5F or more below daily averages from Nov-Feb)

Nov: 14 cold days

2022-11-18	40	28	34.0	-10.6	31	0	0.00	0.0	0
2022-11-11	48	26	37.0	-10.5	28	0	0.00	0.0	0
2022-11-04	48	32	40.0	-10.4	25	0	0.03	T	0
2022-11-16	44	26	35.0	-10.4	30	0	0.00	0.0	0
2022-11-17	47	23	35.0	-10.0	30	0	0.00	0.0	0
2022-11-19	46	24	35.0	-9.2	30	0	0.00	0.0	0
2022-11-15	49	26	37.5	-8.3	27	0	0.00	0.0	0
2022-11-12	54	24	39.0	-8.1	26	0	0.00	0.0	0
2022-11-20	50	23	36.5	-7.3	28	0	0.00	0.0	0
2022-11-05	58	29	43.5	-6.5	21	0	0.00	0.0	0
2022-11-24	47	25	36.0	-6.2	29	0	0.00	0.0	0
2022-11-22	49	25	37.0	-6.0	28	0	0.00	0.0	0
2022-11-14	49	32	40.5	-5.7	24	0	0.01	0.0	0
2022-11-23	55	20	37.5	-5.1	27	0	0.00	0.0	0

December: 5 cold days

2022-12-17	37	16	26.5	-9.8	38	0	0.00	0.0	0
2022-12-18	36	21	28.5	-7.7	36	0	0.00	0.0	0
2022-12-16	37	22	29.5	-6.9	35	0	0.00	0.0	0
2022-12-23	41	19	30.0	-5.9	35	0	0.00	0.0	0
2022-12-13	39	24	31.5	-5.4	33	0	0.00	0.0	0

January: 5 cold days

2023-01-26	40	19	29.5	-9.0	35	0	0.00	0.0	0
2023-01-27	43	17	30.0	-8.7	35	0	0.00	0.0	0
2023-01-19	41	21	31.0	-6.7	34	0	0.00	0.0	0
2023-01-25	41	25	33.0	-5.4	32	0	0.00	0.0	0
2023-01-22	44	22	33.0	-5.0	32	0	0.00	0.0	0

February: 7 cold days

2023-02-16	34	19	26.5	-15.6	38	0	T	0.1	T
2023-02-17	44	17	30.5	-11.8	34	0	0.00	0.0	0
2023-02-10	43	21	32.0	-8.9	33	0	0.00	0.0	0
2023-02-15	41	25	33.0	-8.9	32	0	0.14	1.0	1
2023-02-09	40	27	33.5	-7.2	31	0	T	T	0
2023-02-27	55	21	38.0	-6.8	27	0	0.00	0.0	0
2023-02-11	49	21	35.0	-6.1	30	0	T	0.0	0

That's 31 cold days. Formula implies 30.8. Yay math. For a 'warm' favored pattern that's not bad, especially since 31 cold days represent 1/4 of the period (120 days). We're certainly well ahead of 2022 so far, but that year had 76 ACE in September and then not much else in the other months. Wouldn't shock me if we saw something similar. 

[snowman19]

13 hours ago, roardog said:

For some reason I remember it being opposite and there being disagreement with it. But again, I’m talking early 00’s during the Wright Weather days. His stance could easily be different now 20+ years later. 

Here is a post I found, (16-17 winter) he attributed the roaring PAC jet directly to the strong +QBO: https://www.facebook.com/share/m9tFjr63aZJ2aebL/?mibextid=WC7FNe

[PhiEaglesfan712]

I feel that an active season is more likely if after the 2nd year of a la nina, we get a neutral, rather than a 3rd year la nina. None of the 3rd year la nina seasons (1956, 1975, 2000, or 2022) were particularly active. Meanwhile, 2012 (a neutral season) was just as active as 2010 and 2011.

First year la ninas are either hit or miss. Years like 2005 and 2020 were hyperactive and 2010 active, but years like 1970, 1973, 1988, and 2007 were not really big seasons. Second year la ninas seem to be the sweet spot, like 1999, 2008, 2011, and 2021.

Next year, assuming the la nina continues (which is a high chance given the -PDO), is probably going to be the active season.

[snowman19]

11 hours ago, raindancewx said:

I've found that hyperactive Atlantic hurricane seasons tend to occur in seasons with a big year/year warming in the tropical Atlantic. Do we have that this year? Not at all. Could it still change? Yes, but it is becoming less likely. The cold AMO has the blue backward c around the Greenland-Iceland-Azores zones with the warm tongue in between, like you see below on the y/y change map. You can see the 1994-1995 flip from cold AMO to warm AMO has the exact opposite signature flip by intensity and spatial composition.

Since 1950, the La Ninas following an El Nino with a colder tropical Atlantic are pretty rare. Your La Nina after El Nino years are 1954, 1964, 1966 (close enough to a Nina), 1970, 1973, 1980 (close enough), 1983, 1988, 1995, 1998, 2005, 2007, 2010, 2016 (close enough), 2020.

Of those years, 1954, 1964, 1970, 2007 are really the only ones in which the tropical Atlantic (blue stripe west of West Africa) is colder than the prior El Nino year in July. Atlantic ACE in those years is 104/153/40/74 or about 93. 2007 had two cat 5 hurricanes, despite the low ACE. 1964/1970 are both cold AMO years in a colder global period, so I'd expect ACE to be somewhat higher than the 93, but maybe pretty average in the modern context (105-145). A 125 ACE year is well below the recent La Nina mean of 155 or so.

If you compare 1995 (classic tripole/New Foundland cold pool, warm SSTs north of there from Greenland and just south of Iceland to Northern Europe) to now, it’s night and day. We now have the New Foundland marine heatwave with the cold SSTs north of there, extending from Greenland and Iceland to Europe. That’s a very strong +NAO signature and supports a roided up Atlantic zonal jet running right along that cold/warm SST temperature differential 

[PhiEaglesfan712]

1 hour ago, snowman19 said:

If you compare 1995 (classic tripole/New Foundland cold pool, warm SSTs north of there from Greenland and just south of Iceland to Northern Europe) to now, it’s night and day. We now have the New Foundland marine heatwave with the cold SSTs north of there, extending from Greenland and Iceland to Europe. That’s a very strong +NAO signature and supports a roided up Atlantic zonal jet running right along that cold/warm SST temperature differential 

But why was 1995 a hyperactive season, while a similar year, 1983, which was also a developing la nina in +PDO, produced the least active season in the satellite era? And it's not like the following year, 1984 (another +PDO la nina), was that active either.

What's interesting is that outside of 1980 and maybe 1981, the rest of the 1980s were filled with a lot of inactive seasons. I get 1982, 1986, and 1987 because of strong el nino years, but even some of the la ninas produced some underwhelming seasons.

[snowman19]

3 minutes ago, PhiEaglesfan712 said:

But why was 1995 a hyperactive season, while a similar year, 1983, which was also a developing la nina in +PDO, produced the least active season in the satellite era? And it's not like the following year, 1984 (another +PDO la nina), was that active either.

What's interesting is that outside of 1980 and maybe 1981, the rest of the 1980s were filled with a lot of inactive seasons. I get 1982, 1986, and 1987 because of strong el nino years, but even some of the la ninas produced some underwhelming seasons.

Simple, the 1980’s were during the -AMO cycle. 1995 was the first year of the +AMO cycle