2024-2025 La Nina

[bluewave]

ACE hasn’t traditionally had much relationship with the winter pattern outside the really high La Niña ACE years over 180  like 95-96, 05-06, 17-18, and 20-21.

 

Accumulated Cyclone Energy - Atlantic ^[14] 

Season	ACE	TS	HU	MH	Classification
1933	258.57	20	11	6	Extremely active
2005	245.3	28	15	7	Extremely active
1893	231.1475	12	10	5	Extremely active
1926	229.5575	11	8	6	Extremely active
1995	227.1025	19	11	5	Extremely active
2004	226.88	15	9	6	Extremely active
2017	224.8775	17	10	6	Extremely active
1950	211.2825	16	11	6	Extremely active
1961	188.9	12	8	5	Extremely active
1998	181.7675	14	10	3	Extremely active
1887	181.26	19	11	2	Extremely active
1878	180.85	12	10	2	Extremely active
2020	180.3725	30	14	7	Extremely active

[40/70 Benchmark]

51 minutes ago, bluewave said:

ACE hasn’t traditionally had much relationship with the winter pattern outside the really high La Niña ACE years over 180  like 95-96, 05-06, 17-18, and 20-21.

 

Accumulated Cyclone Energy - Atlantic ^[14] 

Season	ACE	TS	HU	MH	Classification
1933	258.57	20	11	6	Extremely active
2005	245.3	28	15	7	Extremely active
1893	231.1475	12	10	5	Extremely active
1926	229.5575	11	8	6	Extremely active
1995	227.1025	19	11	5	Extremely active
2004	226.88	15	9	6	Extremely active
2017	224.8775	17	10	6	Extremely active
1950	211.2825	16	11	6	Extremely active
1961	188.9	12	8	5	Extremely active
1998	181.7675	14	10	3	Extremely active
1887	181.26	19	11	2	Extremely active
1878	180.85	12	10	2	Extremely active
2020	180.3725	30	14	7	Extremely active

Glad you mentioned that in case anyone interpreted George's ACE update as reason for optimism.

[jm1220]

23 minutes ago, 40/70 Benchmark said:

Glad you mentioned that in case anyone interpreted George's ACE update as reason for optimism.

Our ACE card up our sleeve turned out to be a Joker pointing to map with another mega cutter to the Lakes. 

[40/70 Benchmark]

1 minute ago, jm1220 said:

Our ACE card up our sleeve turned out to be a Joker pointing to map with another mega cutter to the Lakes. 

I still think I will be okay here on the NH border.

[mitchnick]

9 minutes ago, 40/70 Benchmark said:

I still think I will be okay here on the NH border.

In a Niña, I sure hope so or we're all probably screwed!

[George001]

Bluewave is in fact correct about ACE not having much of a relationship to the winter pattern. I dug through some of Raindances old posts, and the correlation coefficient is only around .1 in Boston for ACE and snow in La Nina’s. It is slightly higher for NYC and Philly (roughly .23 in NYC and .21 in Philly), but that is still considered weak. 

[George001]

40 minutes ago, jm1220 said:

Our ACE card up our sleeve turned out to be a Joker pointing to map with another mega cutter to the Lakes. 

Just my opinion but I wouldn’t be worried where you live. Long Island in particular does better in miller bs (common in Nina’s) than even NYC, and you do significantly better than say Philly, DC, etc. Hell, even the whole solar = +NAO thing isn’t a given. I read the papers, all the meteorology shit goes over my head but the one thing I did get out of it is the correlation coefficient is highest in Feb, and even then the correlation is moderate at best. I would lean +NAO, but I just don’t think the correlation is strong enough to justify ignoring certain analogs due to solar.
Also, the NAO itself has a weak correlation to temps above a certain latitude (I believe it was an r^2 value of .2 for me and .3 for you, I’ll have to go back and check though). 
 

The thing I care about the most is the fall pattern leading up to winter. It is a lot different than the past 2 years as we do not have a parade of storms crashing into the Pacific Northwest. That’s part of the reason I was so bearish last winter (forecasted 20-30 inches of snow in the Boston area, and this turned out to be way too optimistic). We aren’t seeing that this year, and frankly that’s the big concern with strong -PDO Nina patterns. I get the pessimism, I really do. I agree with the pessimism south of say NYC because the farther south you go, the more hostile +NAO patterns are (although far from a guarantee, a positive NAO should be favored over a negative one). Also, snow wise areas farther south are more likely to get screwed in bigger storms during La Nina’s. Those areas do better in a strong STJ El Niño pattern. There are plenty of reasons to be optimistic that have absolutely nothing to do with ACE.

[jm1220]

1 minute ago, George001 said:

Just my opinion but I wouldn’t be worried where you live. Long Island in particular does better in miller bs (common in Nina’s) than even NYC, and you do significantly better than say Philly, DC, etc. Hell, even the whole solar = +NAO thing isn’t a given. I read the papers, all the meteorology shit goes over my head but the one thing I did get out of it is the correlation coefficient is highest in Feb, and even then the correlation is moderate at best. I would lean +NAO, but I just don’t think the correlation is strong enough to justify ignoring certain analogs due to solar.
Also, the NAO itself has a weak correlation to temps above a certain latitude (I believe it was an r^2 value of .2 for me and .3 for you, I’ll have to go back and check though). 
 

The thing I care about the most is the fall pattern leading up to winter. It is a lot different than the past 2 years as we do not have a parade of storms crashing into the Pacific Northwest. That’s part of the reason I was so bearish last winter (forecasted 20-30 inches of snow in the Boston area, and this turned out to be way too optimistic). We aren’t seeing that this year, and frankly that’s the big concern with strong -PDO Nina patterns. I get the pessimism, I really do. I agree with the pessimism south of say NYC because the farther south you go, the more hostile +NAO patterns are (although far from a guarantee, a positive NAO should be favored over a negative one). Also, snow wise areas farther south are more likely to get screwed in bigger storms during La Nina’s. Those areas do better in a strong STJ El Niño pattern. 

The SE ridge has to be kept in check or the Miller Bs etc won’t matter, it’ll be rain here and probably well north too. There has to be some mechanism to get colder here and keep it here for a storm. We can definitely get blasted by Miller B’s and Nina by itself isn’t a kiss of death IMBY but the overall conditions the last couple of winters with the rampaging Pacific jet and SE ridge has to change. 

[mitchnick]

Got this l I nk from NE forum regarding the PV.

https://www.severe-weather.eu/global-weather/record-weak-polar-vortex-event-2024-winter-weather-pattern-united-states-canada-europe-fa/

[snowman19]

Just my opinion but I wouldn’t be worried where you live. Long Island in particular does better in miller bs (common in Nina’s) than even NYC, and you do significantly better than say Philly, DC, etc. Hell, even the whole solar = +NAO thing isn’t a given. I read the papers, all the meteorology shit goes over my head but the one thing I did get out of it is the correlation coefficient is highest in Feb, and even then the correlation is moderate at best. I would lean +NAO, but I just don’t think the correlation is strong enough to justify ignoring certain analogs due to solar.
Also, the NAO itself has a weak correlation to temps above a certain latitude (I believe it was an r^2 value of .2 for me and .3 for you, I’ll have to go back and check though). 
 
The thing I care about the most is the fall pattern leading up to winter. It is a lot different than the past 2 years as we do not have a parade of storms crashing into the Pacific Northwest. That’s part of the reason I was so bearish last winter (forecasted 20-30 inches of snow in the Boston area, and this turned out to be way too optimistic). We aren’t seeing that this year, and frankly that’s the big concern with strong -PDO Nina patterns. I get the pessimism, I really do. I agree with the pessimism south of say NYC because the farther south you go, the more hostile +NAO patterns are (although far from a guarantee, a positive NAO should be favored over a negative one). Also, snow wise areas farther south are more likely to get screwed in bigger storms during La Nina’s. Those areas do better in a strong STJ El Niño pattern. There are plenty of reasons to be optimistic that have absolutely nothing to do with ACE.

There actually is a strong solar connection to the NAO, @Gawx has shown this several times. HM and Isotherm also used to speak of it in detail. Sunspots and radio flux aside, there is and has been a constant geomag onslaught going on. High geomag alone very strongly favors +NAO

[mitchnick]

25 minutes ago, snowman19 said:

There actually is a strong solar connection to the NAO, @Gawx has shown this several times. HM and Isotherm also used to speak of it in detail. Sunspots and radio flux aside, there is and has been a constant geomag onslaught going on. High geomag alone very strongly favors +NAO

 

 

 

 

Yet, we've been in a pretty deep - NAO state for a while now and will be for at least another week. Though I  don't disagree with the connection, there's apparently more to a -NAO than just the sun, not that you are saying that.

[snowman19]

Got this l I nk from NE forum regarding the PV.
https://www.severe-weather.eu/global-weather/record-weak-polar-vortex-event-2024-winter-weather-pattern-united-states-canada-europe-fa/

Judah Cohen

[40/70 Benchmark]

Finally updated temp/precip composites yesterday...just in time for me to pivot to winter after Milton.

https://psl.noaa.gov/data/usclimdivs/

Outlook season....

[40/70 Benchmark]

7 minutes ago, snowman19 said:

Judah Cohen

 

 

 

 

I'm guessing this article doesn't have a happy ending for NE winer enthusiasts.

[Typhoon Tip]

1 minute ago, snowman19 said:

There actually is a strong solar connection to the NAO, @Gawx has shown this several times. HM and Isotherm also used to speak of it in detail. Sunspots and radio flux aside, there is and has been a constant geomag onslaught going on. High geomag alone very strongly favors +NAO

 

 

the correlation with high latitude is more arctic oscillation in general.   don't mean to lecture, just adding this ...

higher solar activity favors the +annular mode; subsequently, because the ao shares ( overlaps) its domain geography with the wpo-epo-nao ( to varying degrees.. ) therefore a positive correlation with all these indices.  there is a partial disconnect, so yeah ... not 1::1 but 60 .. 70%

that fact that heightened summer and autumn solar activity correlates to a +nao is really just a quadrature of that bigger picture above, which ... frankly is a bit more important.  particularly because in determining long lead pattern tendencies, the nao is not the primary loading pattern for either cold or storm frequency across n/a.  the idea of that being the case became fallacy when the index was popularized in the 1990s and media went crazy with it...  but no.   cold and and/or increased storm amplitude come from the aa vs ab phase of the pacific's overall governing circulation type.  

aa is +wpo/+epo ( pna oscillations lag negative )

ab is -wpo/-epo ( pna oscillations lag positive )     hint, when the pna surges positive, trough digs in the east and there is a down stream ridge response over the nao =    -nao.   it is in total, a non-linear wave production as part of the larger dispersion signal arriving from the pacific - most don't get that.  not saying that is you or anyone per se ... but i hate it when reading some rock star's extended range outlook forecasts a joyous storm based a nao index outlook that could go negative whether there is storm or not..  

the winning forecast is always the one that can foresee ( correctly ...) the state of the aa vs ab pacific winter, and in either case, whether the ballast of that signal is biased west or east.  preferably for winter enthusiasts in the east, eastern limb ab pacific mode is what correlates very highly with winter complexion across the continent.

[40/70 Benchmark]

31 minutes ago, mitchnick said:

Got this l I nk from NE forum regarding the PV.

https://www.severe-weather.eu/global-weather/record-weak-polar-vortex-event-2024-winter-weather-pattern-united-states-canada-europe-fa/

I'm wating for @bluewaveto snip that author's balls off by illustrating how the NAO has given the SE ridge a lapse dance since 2015.

[40/70 Benchmark]

21 minutes ago, snowman19 said:

There actually is a strong solar connection to the NAO, @Gawx has shown this several times. HM and Isotherm also used to speak of it in detail. Sunspots and radio flux aside, there is and has been a constant geomag onslaught going on. High geomag alone very strongly favors +NAO

 

 

 

 

Agreed.

[George001]

48 minutes ago, snowman19 said:

There actually is a strong solar connection to the NAO, @Gawx has shown this several times. HM and Isotherm also used to speak of it in detail. Sunspots and radio flux aside, there is and has been a constant geomag onslaught going on. High geomag alone very strongly favors +NAO

 

 

 

 

I have seen some evidence for a weak to moderate positive correlation between solar and the NAO (both on this board and outside). However, I haven’t seen anything indicating the r^2 value for the correlation between sunspots and NAO is greater than 0.7, though I am open to being proven wrong on that. Regardless, you are correct that sunspots and solar activity aren’t the only +NAO indicators this year. I wasn’t aware of how strong the correlation between geomag and NAO was so I dug into it some. Apparently the correlation between high geomag and +NAO is 0.76 between 1962-1994, which is strong. Thats a good 32 years of data too. That is a great point you brought up about the strong correlation between high geomag activity and +NAO.

[bluewave]

2 hours ago, George001 said:

Bluewave is in fact correct about ACE not having much of a relationship to the winter pattern. I dug through some of Raindances old posts, and the correlation coefficient is only around .1 in Boston for ACE and snow in La Nina’s. It is slightly higher for NYC and Philly (roughly .23 in NYC and .21 in Philly), but that is still considered weak. 

The relationship exists only when the ACE is at extremely high levels like the La Niña years 95-96, 05-06, 17-18, and 20-21. I would say it’s more a marker than necessarily a cause and effect. In that there was a greater underlying pattern at play those years in which the ACE and other factors were part of. Other significantly lower La Niña ACE years from those very high peak years weren’t indicative of a positive or negative winter outcome just that they weren’t necessarily top tier La Ninas for snow and cold.

[George001]

10 minutes ago, bluewave said:

The relationship exists only when the ACE is at extremely high levels like the La Niña years 95-96, 05-06, 17-18, and 20-21. I would say it’s more a marker than necessarily a cause and effect. In that there was a greater underlying pattern at play those years in which the ACE and other factors were part of. Other lower La Niña ACE years from those very high peak years weren’t indicative of a positive or negative just that they weren’t necessarily top tier La Ninas. 

That makes sense. It’s not about the ACE index in itself, it’s about how you get there and the pattern in place that facilitated those high ACE totals. This is where my approach falls short, relying heavily on statistics to try to make sense of things is helpful, but just knowing a correlation exists and how strong it isn’t everything. The WHY is just as if not more important. That’s why I’m glad we have this board, there is so much useful information here that helps amateurs like myself fill those gaps. That has me thinking, although there is nothing out of the ordinary about the raw ACE numbers this year, how we got there is somewhat unusual. The hurricane season peak this year has been quite a bit later than usual, it may or may not mean anything, not too sure but it’s definitely an interesting observation.

[GaWx]

1 hour ago, mitchnick said:

Yet, we've been in a pretty deep - NAO state for a while now and will be for at least another week. Though I  don't disagree with the connection, there's apparently more to a -NAO than just the sun, not that you are saying that.

The analysis I did looking at -NAOs and sunspots was for winter, only, and for the last 35 winters, only. All 6 winters of the last 35 with a sub -0.25 NAO (1984-5, 86-7, 95-6, 2009-10, 10-11, 20-1) had a winter SSN under 35 and was within ~2 years of a solar minimum. -NAOs during the last winters have been much less frequent than they were during the prior 25. OTOH, -NAOs have become much more frequent during summer over the last 17 or so.

 Im not saying there isn’t one, but I’m not aware of any proven connection of solar and NAO outside of winter. NAO tendencies have been very seasonal as per the above.

[bluewave]

1 hour ago, George001 said:

That makes sense. It’s not about the ACE index in itself, it’s about how you get there and the pattern in place that facilitated those high ACE totals. This is where my approach falls short, relying heavily on statistics to try to make sense of things is helpful, but just knowing a correlation exists and how strong it isn’t everything. The WHY is just as if not more important. That’s why I’m glad we have this board, there is so much useful information here that helps amateurs like myself fill those gaps. That has me thinking, although there is nothing out of the ordinary about the raw ACE numbers this year, how we got there is somewhat unusual. The hurricane season peak this year has been quite a bit later than usual, it may or may not mean anything, not too sure but it’s definitely an interesting observation.

We went into this season recognizing that the Atlantic SSTs were at all time highs and it was a developing La Niña summer. So the model forecasts such as the Euro were indicating that there could be closer to 25 named storms and 225+ ACE. As of the time when Beryl went Cat 5 so early those very high numbers seemed plausible. But as the summer went on the dry air, increased stability, warmer 250 mb temperatures , and ITCZ shift into the Sahara were holding the ACE down into September.

My guess is that the burst of activity the last few weeks was helped by the SSTs increasing enough to overcome the initial warmer upper levels so the lapse rates and instability were able to improve. It’s also possible the upper levels began to cool in the last few weeks. The favorable MJO was part of it. But the previous favorable MJO in early August underperformed vs past periods that time of year with higher SSTs.

Its interesting that the Euro did show the drier air issues but it wasn’t reflected in its tropical storm and hurricane forecasts. Even if the total ACE came in under forecast, it doesn’t in any way take away from the recent weeks which picked up where Beryl left off although there was a large gap in the middle. So I would say the Euro seasonal added great value since it correctly implied what could happen if all the ducks lined up like we have seen last few weeks. But it may be that the models need to be upgraded to incorporate the influence to the pattern of all these competing marine heatwaves and interactions with the upper levels around 250mb. Absent that activity gap during midseason, we would most likely be over 200 ACE and 25 named storms if the rate of development last few weeks was uninterrupted going back to July. But the most important major hurricane forecast numbers were pretty close to the forecast centers issuances back in the spring. So the real world impacts of the last few weeks were well telegraphed ahead of time.

[Stormchaserchuck1]

October 10mb warming actually correlates with a -NAO in December

When the Southern Hemisphere had a -4 to -5 AAO in late July/early August, that also had about a 0.3 correlation to -NAO in December. 

Maybe the potential energy will give us a more favorable Pacific in Dec (my theory). 

[so_whats_happening]

9 hours ago, bluewave said:

We went into this season recognizing that the Atlantic SSTs were at all time highs and it was a developing La Niña summer. So the model forecasts such as the Euro were indicating that there could be closer to 25 named storms and 225+ ACE. As of the time when Beryl went Cat 5 so early those very high numbers seemed plausible. But as the summer went on the dry air, increased stability, warmer 250 mb temperatures , and ITCZ shift into the Sahara were holding the ACE down into September.

My guess is that the burst of activity the last few weeks was helped by the SSTs increasing enough to overcome the initial warmer upper levels so the lapse rates and instability were able to improve. It’s also possible the upper levels began to cool in the last few weeks. The favorable MJO was part of it. But the previous favorable MJO in early August underperformed vs past periods that time of year with higher SSTs.

Its interesting that the Euro did show the drier air issues but it wasn’t reflected in its tropical storm and hurricane forecasts. Even if the total ACE came in under forecast, it doesn’t in any way take away from the recent weeks which picked up where Beryl left off although there was a large gap in the middle. So I would say the Euro seasonal added great value since it correctly implied what could happen if all the ducks lined up like we have seen last few weeks. But it may be that the models need to be upgraded to incorporate the influence to the pattern of all these competing marine heatwaves and interactions with the upper levels around 250mb. Absent that activity gap during midseason, we would most likely be over 200 ACE and 25 named storms if the rate of development last few weeks was uninterrupted going back to July. But the most important major hurricane forecast numbers were pretty close to the forecast centers issuances back in the spring. So the real world impacts of the last few weeks were well telegraphed ahead of time.

The bolded was probably the biggest factor this year maybe they go hand in hand? When we finally relaxed the VP pattern where it was globally showing more uplift versus being concentrated around Maritime Continent things went wild. You can see the brief breaks in VP that allowed the small portion of time where storms were able to form. I get where you are coming from with ITCZ shift but to me that just signals a storm that would have formed but have a better recurve potential versus one in lower latitudes of around 7-10N. I do ask is there evidence of this via wind anomalies now that we have passed that time frame that we did indeed shift the ITCZ further north? I would assume we would need to look at maybe 850mb for this observation but Tropical is not my forte.

 

[PhiEaglesfan712]

Top 10 active hurricane seasons (through 2016)

Rank	Year	Wunderground ACE Index	NOAA ACE Index	Average
1	2005	250	245.3	247.65
2	1933	213	258.57	235.785
3	1893	231	231.1475	231.0738
4	1995	228	227.1025	227.5513
5	1950	243	211.2825	227.1413
6	2004	227	226.88	226.94
7	1926	222	229.5575	225.7788
8	1961	205	188.9	196.95
9	1998	182	181.7675	181.8838
10	1955	199	158.17	178.585

2004 is the only one that led into an el nino. 1926 and 1961 were ENSO neutral. The rest led to la ninas. (This holds true even if 2017 and 2020 replace 1955 and 1998.)

[GaWx]

11 hours ago, bluewave said:

We went into this season recognizing that the Atlantic SSTs were at all time highs and it was a developing La Niña summer. So the model forecasts such as the Euro were indicating that there could be closer to 25 named storms and 225+ ACE. As of the time when Beryl went Cat 5 so early those very high numbers seemed plausible. But as the summer went on the dry air, increased stability, warmer 250 mb temperatures , and ITCZ shift into the Sahara were holding the ACE down into September.

My guess is that the burst of activity the last few weeks was helped by the SSTs increasing enough to overcome the initial warmer upper levels so the lapse rates and instability were able to improve. It’s also possible the upper levels began to cool in the last few weeks. The favorable MJO was part of it. But the previous favorable MJO in early August underperformed vs past periods that time of year with higher SSTs.

Its interesting that the Euro did show the drier air issues but it wasn’t reflected in its tropical storm and hurricane forecasts. Even if the total ACE came in under forecast, it doesn’t in any way take away from the recent weeks which picked up where Beryl left off although there was a large gap in the middle. So I would say the Euro seasonal added great value since it correctly implied what could happen if all the ducks lined up like we have seen last few weeks. But it may be that the models need to be upgraded to incorporate the influence to the pattern of all these competing marine heatwaves and interactions with the upper levels around 250mb. Absent that activity gap during midseason, we would most likely be over 200 ACE and 25 named storms if the rate of development last few weeks was uninterrupted going back to July. But the most important major hurricane forecast numbers were pretty close to the forecast centers issuances back in the spring. So the real world impacts of the last few weeks were well telegraphed ahead of time.

Whereas the Euro preseason forecasts for ACE missed way too high, the shorter term Euro Weeklies did very well. They forecasted the very active early season, the inactive peak season, and the very active last couple of weeks.

[snowman19]

Latest SSTs: 

Radio flux is off the charts…over 310 now. Sunspots well over 200. Solar/geomag states:

[bluewave]

11 hours ago, Stormchaserchuck1 said:

October 10mb warming actually correlates with a -NAO in December

When the Southern Hemisphere had a -4 to -5 AAO in late July/early August, that also had about a 0.3 correlation to -NAO in December. 

Maybe the potential energy will give us a more favorable Pacific in Dec (my theory). 

Volatility continues to be the big NAO story as we are going to see a near record NAO reversal heading into mid-October.

 

 

 

[SnoSki14]

8 minutes ago, bluewave said:

Volatility continues to be the big NAO story as we are going to see a near record NAO reversal heading into mid-October.

 

 

 

Volatility is good if it continues into winter. It might gives us a chance of at least some wintry weather vs a 22/23 type winter. 

[PhiEaglesfan712]

4 minutes ago, SnoSki14 said:

Volatility is good if it continues into winter. It might gives us a chance of at least some wintry weather vs a 22/23 type winter. 

I highly doubt that we get a 22/23 type winter. If we do, then we've pretty reached a point of no return. In fact, I'm confident we get something closer to 20/21. The absolute worst case here (from NYC to the mid-Atlantic) is 07/08 [though, this was a very good winter in the midwest]. I think February will create the best chance for snow, and possibly a below average month. Also, don't count out a snow event in the first half of December.