2024-2025 La Nina

[bluewave]

2 hours ago, 40/70 Benchmark said:

I ended up going +3 to +5 in Dec for the mid Atl and NE...hopefully I don't end up too cool....the potential translation of the MJO into phase 6 beyond mid month and towards the holiday is what kept me from really going bonkers. 

The next 3 weeks are going to be very telling. On one hand we had the split between the MJO and strength of the ENSO back in October that I went into detail about in an earlier post. So we’ll know one way or another by December 7th if there is to be some type of mismatch where the Niña and -PDO background gets nullified like we saw in 20-21 with the much better December which carried through the winter.  That was our only winter since 15-16 without at least one month with a +10. But if the warmer pattern the seasonal models have been advertising becomes evident during the first week of December, then the MJO will probably slow down in the warmer phases and the mid to late part of December will be the warmest part of the month. Then we wait and see what happens near the start of January. 

My post from late October

The MJO activity in MJO 5 is unusually strong for weaker La Niña this month. The latest RMM index is closer to 2020, 2017, and 2010 than 2022, 2021, 2016, and 2011. Whether we use the ONI or RONI this fall so far is closer to the weaker La Niña years like 2016. But for some reason we are still getting the stronger October MJO response which preceded the better La Niña winters. These Decembers like 2020, 2017, and 2010, had more of a mismatch pattern where the December patterns were snowier and in some cases colder like 2017 and 2010. Since we are getting this divergence between the strength of the La Niña and early MJO response not really sure what to make of it yet. Since our best La Niña winters were actually the stronger ones of the groupings and not the weaker ones. Plus there is no guarantee that this indicator will continue to work as it did in the past. As always, we may just have to wait until December actually gets underway in order to know for sure. Especially since there are other indicators signaling the potential for above to potentially well above normal temperatures and below average snowfall in NYC.

It’s based on the MJO RMM amplitude and VP anomalies in phase 5-6 during La Niña Octobers since 2010. The stronger October MJO responses had better winters in NYC relative to the other La Ninas in the multiyear event group. Those stronger MJO 5-6 Octobers also had the more robust peak La Niña ONIs from fall into winter of the multiyear groups.  All the La Niña winters around NYC since 11-12 have averaged warmer than normal. But even the warmer than average 17-18 and 20-21 winters had better snowfall than the other years in the multiyear group.

In addition, we haven’t had any cold neutral ENSOs in the -0.1 to -0.5 peak range with a strong -PDO since 2010. So not sure how the relationship would work for any year with the official CPC ONI not getting colder than -0.5. The other thing to consider is that we don’t know how long this relationship will continue to work it.

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

 

Multiyear La Niña groupings below with peak MJO 5-6 strength and the peak ONI from the fall into winter…….Strongest October MJO 5-6 and La Niña ONI leading to best NYC winters of the multiyear group bolded
 

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

October 2024….Phase 5 peak +2.762…ONI….latest weekly only -0.3

 

October 2022…Phase 6 peak +2.177…..ONI….-1.0

October 2021….Phase 5 peak +2.087….ONI….-1.0

October 2020…Phase 5 peak +2.818….ONI…..-1.3

 

October 2017….Phase 6 peak +3.353….ONI….-1.0

October 2016….Phase 5 peak +1.800….ONI….-0.7

 

October 2011….Phase 6 peak +1.674….ONI….-1.1

October 2010….Phase 5 peak +2.880…ONI…..-1.6 

[GaWx]

55 minutes ago, bluewave said:

The next 3 weeks are going to be very telling. On one hand we had the split between the MJO and strength of the ENSO back in October that I went into detail about in an earlier post. So we’ll know one way or another by December 7th if there is to be some type of mismatch where the Niña and -PDO background gets nullified like we saw in 20-21 with the much better December which carried through the winter.  That was our only winter since 15-16 without at least one month with a +10. But if the warmer pattern the seasonal models have been advertising becomes evident during the first week of December, then the MJO will probably slow down in the warmer phases and the mid to late part of December will be the warmest part of the month. Then we wait and see what happens near the start of January. 

 Even when the MJO isn’t technically in the warmer phases, doesn’t the W Pacific marine heatwave support the tendency toward E US warmth/stronger SE ridge often negating the cold tendencies of the colder MJO phases to an extent?

 Also, I’ll point out my detailed studies of large samples which have shown that lower amplitude MJO phases have tended to be colder than high amp. (not nearly always obviously but rather in the means). I’m talking with no lag. Perhaps it has something to do with less tropical forcing when the MJO phase is weaker. Then again though, the W Pac marine heatwave may tend to negate some of the cold tendencies of weak MJO, too, as these studies were based on data back to the mid 1970s.

[snowman19]

FWIW:

[40/70 Benchmark]

1 hour ago, bluewave said:

The next 3 weeks are going to be very telling. On one hand we had the split between the MJO and strength of the ENSO back in October that I went into detail about in an earlier post. So we’ll know one way or another by December 7th if there is to be some type of mismatch where the Niña and -PDO background gets nullified like we saw in 20-21 with the much better December which carried through the winter.  That was our only winter since 15-16 without at least one month with a +10. But if the warmer pattern the seasonal models have been advertising becomes evident during the first week of December, then the MJO will probably slow down in the warmer phases and the mid to late part of December will be the warmest part of the month. Then we wait and see what happens near the start of January. 

My post from late October

The MJO activity in MJO 5 is unusually strong for weaker La Niña this month. The latest RMM index is closer to 2020, 2017, and 2010 than 2022, 2021, 2016, and 2011. Whether we use the ONI or RONI this fall so far is closer to the weaker La Niña years like 2016. But for some reason we are still getting the stronger October MJO response which preceded the better La Niña winters. These Decembers like 2020, 2017, and 2010, had more of a mismatch pattern where the December patterns were snowier and in some cases colder like 2017 and 2010. Since we are getting this divergence between the strength of the La Niña and early MJO response not really sure what to make of it yet. Since our best La Niña winters were actually the stronger ones of the groupings and not the weaker ones. Plus there is no guarantee that this indicator will continue to work as it did in the past. As always, we may just have to wait until December actually gets underway in order to know for sure. Especially since there are other indicators signaling the potential for above to potentially well above normal temperatures and below average snowfall in NYC.

It’s based on the MJO RMM amplitude and VP anomalies in phase 5-6 during La Niña Octobers since 2010. The stronger October MJO responses had better winters in NYC relative to the other La Ninas in the multiyear event group. Those stronger MJO 5-6 Octobers also had the more robust peak La Niña ONIs from fall into winter of the multiyear groups.  All the La Niña winters around NYC since 11-12 have averaged warmer than normal. But even the warmer than average 17-18 and 20-21 winters had better snowfall than the other years in the multiyear group.

In addition, we haven’t had any cold neutral ENSOs in the -0.1 to -0.5 peak range with a strong -PDO since 2010. So not sure how the relationship would work for any year with the official CPC ONI not getting colder than -0.5. The other thing to consider is that we don’t know how long this relationship will continue to work it.

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php

 

Multiyear La Niña groupings below with peak MJO 5-6 strength and the peak ONI from the fall into winter…….Strongest October MJO 5-6 and La Niña ONI leading to best NYC winters of the multiyear group bolded
 

http://www.bom.gov.au/clim_data/IDCKGEM000/rmm.74toRealtime.txt

October 2024….Phase 5 peak +2.762…ONI….latest weekly only -0.3

 

October 2022…Phase 6 peak +2.177…..ONI….-1.0

October 2021….Phase 5 peak +2.087….ONI….-1.0

October 2020…Phase 5 peak +2.818….ONI…..-1.3

 

October 2017….Phase 6 peak +3.353….ONI….-1.0

October 2016….Phase 5 peak +1.800….ONI….-0.7

 

October 2011….Phase 6 peak +1.674….ONI….-1.1

October 2010….Phase 5 peak +2.880…ONI…..-1.6 

Yup....do we kick the can with respect to the MJO signal in December, like last year, or does it come to fruition...

Def. interested in hearing your thoughts on my outlook this year, whenever you get aorund to it.

[bluewave]

1 hour ago, GaWx said:

Even when the MJO isn’t technically in the warmer phases, doesn’t the W Pacific marine heatwave support the tendency toward E US warmth/stronger SE ridge often negating the cold tendencies of the colder MJO phases to an extent?

This may be why October was the 2nd warmest on record for the CONUS well beyond what would have been suggested by just looking at the MJO. 

[GaWx]

25 minutes ago, bluewave said:

This may be why October was the 2nd warmest on record for the CONUS well beyond what would have been suggested by just looking at the MJO. 

 That’s why I’m implying more than the normal amount of caution is recommended to any folks who might be tempted to put large weight on the MJO phases while the W Pacific marine heatwave persists. All things being equal, I’d think that a colder phase would still be preferred, however.

[snowman19]

Sustained EWBs confined in region 3.4! Yep, this is definitely a textbook east-based event!!
 

[bluewave]

1 minute ago, GaWx said:

 That’s why I’m implying more than the normal amount of caution is recommended to any folks who might be tempted to put large weight on the MJO phases while the W Pacific marine heatwave persists. All things being equal, I’d still think that a colder phase would still be preferred, however.

I mentioned this the other day. The warmer MJO phases since October have been responding much warmer than past events. The cooler phases this month have been much warmer than past occasions.

[mitchnick]

PDO still rising

[GaWx]

3 minutes ago, mitchnick said:

PDO still rising

Indeed, that’s a rise of ~1.3 from Oct 10th’s ~~-4 to -4.1 on a NOAA basis. So, now it is likely ~~-2.7 to -2.8 on a NOAA basis.

[mitchnick]

30 minutes ago, GaWx said:

 That’s why I’m implying more than the normal amount of caution is recommended to any folks who might be tempted to put large weight on the MJO phases while the W Pacific marine heatwave persists. All things being equal, I’d still think that a colder phase would still be preferred, however.

Fwiw, lots of cooling in worldwide ocean SSTA's including a few places where it counts too.

[roardog]

31 minutes ago, mitchnick said:

Fwiw, lots of cooling in worldwide ocean SSTA's including a few places where it counts too.

Yeah. The global SST anomalies are actually the lowest we’ve seen in quite sometime at least as of a couple of days ago when I last looked. 

[GaWx]

Is OISST on crack? This shows it already barely into the positive!

 

while the cool biased CDAS is still down near -0.7 (huge discrepancy):

and the slightly warm biased CRW is still down at -0.3:

 

-Of course the equivalent RONI is still likely sub -0.5.

- This all gives me hope that the last 3 CANSIPS depictions of Modoki El Niño by next summer aren’t on crack.

[Eskimo Joe]

1 hour ago, mitchnick said:

PDO still rising

Where can I find this graphic?

[GaWx]

2 minutes ago, Eskimo Joe said:

Where can I find this graphic?

https://s2s.worldclimateservice.com/climatepanel/
 

Then click on PDO, which is 2nd graph down on right.

[Daniel Boone]

4 hours ago, GaWx said:

 That’s why I’m implying more than the normal amount of caution is recommended to any folks who might be tempted to put large weight on the MJO phases while the W Pacific marine heatwave persists. All things being equal, I’d think that a colder phase would still be preferred, however.

Yeah, looking like some changes may be in store with the recent changes in the SST'S out there. 

[michsnowfreak]

Euro weeklies continue to cool.

[PhiEaglesfan712]

10 hours ago, michsnowfreak said:

 

If I'm understanding the question from @mitchnick, I think he's asking if you forecast a DJF departure of +10, not just if any one location somewhere had a +10 month. 

I'm no forecaster but I personally think for most (especially my area/Great Lakes) there will be one month that's a real dud and one month that's a lot of fun. 

Many of those months had widespread warmth. In fact, with the exception of February 2019, PHL had a +5 temperature departure (1981-2010 normals) 

Dec…2015….51.2….+13.8

JAN…2017….38.5…..+5.6

FEB….2017….44.2….+8.5

FEB…..2018…41.9….+6.2

JAN….2020…38.9….+6.0

DEC….2021….45.3….+7.9

JAN….2023….43.3….+10.4

FEB….2023…..42.7…..+7.0

DEC….2023….43.5…..+6.1

Feb 2019 was just barely above average for us, and was in fact the snowiest month of that winter. Come to think of it, 2018-19 was probably the most consistent winter post-2015 here at PHL. 2017-18 and 2020-21 may have had more snow, but 18-19 didn't have the prolonged warmth that Feb 2018 had or the snow shut-off that mid-Dec to Jan 2020-21 had. Plus, Nov 18 and Mar 19 were well below average temperaturewise, making 18-19 the coldest Nov-Mar post-2015.

[michsnowfreak]

1 hour ago, PhiEaglesfan712 said:

Many of those months had widespread warmth. In fact, with the exception of February 2019, PHL had a +5 temperature departure (1981-2010 normals) 

Dec…2015….51.2….+13.8

JAN…2017….38.5…..+5.6

FEB….2017….44.2….+8.5

FEB…..2018…41.9….+6.2

JAN….2020…38.9….+6.0

DEC….2021….45.3….+7.9

JAN….2023….43.3….+10.4

FEB….2023…..42.7…..+7.0

DEC….2023….43.5…..+6.1

Feb 2019 was just barely above average for us, and was in fact the snowiest month of that winter. Come to think of it, 2018-19 was probably the most consistent winter post-2015 here at PHL. 2017-18 and 2020-21 may have had more snow, but 18-19 didn't have the prolonged warmth that Feb 2018 had or the snow shut-off that mid-Dec to Jan 2020-21 had. Plus, Nov 18 and Mar 19 were well below average temperaturewise, making 18-19 the coldest Nov-Mar post-2015.

Yeah its definitely been a mild stretch of winters, especially for the east coast. But forecasting a +10 DJF anomaly would be a huge stretch for anywhere. My favorite post 2015 winter is 2017-18. Very snowy and wall to wall cold Nov-Apr except the last 10 days of Feb. 

[BuffaloWeather]

It's coming, who's ready?

[DarkSharkWX]

7 hours ago, GaWx said:

Is OISST on crack? This shows it already barely into the positive!

 

while the cool biased CDAS is still down near -0.7 (huge discrepancy):

and the slightly warm biased CRW is still down at -0.3:

 

-Of course the equivalent RONI is still likely sub -0.5.

- This all gives me hope that the last 3 CANSIPS depictions of Modoki El Niño by next summer aren’t on crack.

oisst is the newest sst method and uses buoys/obs in addition to satellite, while CDAS/CRW dont

CDAS was showing a moderate nino last year while we were well in strong-super territory, oldest out of the 3 which is why alex's website doesnt use it 

[DarkSharkWX]

[40/70 Benchmark]

46 minutes ago, michsnowfreak said:

Yeah its definitely been a mild stretch of winters, especially for the east coast. But forecasting a +10 DJF anomaly would be a huge stretch for anywhere. My favorite post 2015 winter is 2017-18. Very snowy and wall to wall cold Nov-Apr except the last 10 days of Feb. 

Same..my only above average snowfall season since 2014-2015. It was still warm here, but March made it worth it.

[GaWx]

1 hour ago, michsnowfreak said:

Yeah it’s definitely been a mild stretch of winters, especially for the east coast. But forecasting a +10 DJF anomaly would be a huge stretch for anywhere. My favorite post 2015 winter is 2017-18. Very snowy and wall to wall cold Nov-Apr except the last 10 days of Feb. 

 Mine too. I got ~1,000% of my climo mean liquid equivalent of wintry precip (all from one storm in early 1/2018), which is the largest since 1921-2! The one in late 1/1922 was the predecessor to the NE US’ Knickerbocker Storm. The snow/sleet combo portion of 1/2018 was the heaviest since the great 12/1989 coastal pre-Christmas near blizzard.

[brooklynwx99]

the pattern that closes out November might be crucial for determining the flavor of the overall winter. given that we're seeing a pretty favorable winter pattern showing itself on medium to long range guidance, i wanted to see if it would have any predictive power for the winter

i did some digging on the analogs which i find viable: 1983-84, 1998-99, 1999-00, 2001-02, 2007-08, 2008-09, 2010-11, 2011-12, 2012-13, 2013-14, 2020-21, 2021-22, and 2022-23. better analogs are bolded

i plotted the pattern from Nov 19-29 (basically just a 10 day stretch in late Nov) and the resulting winter pattern. the results were interesting... most years had a decent to strong correlation between the late Nov pattern and the overall winter, mainly in the Pacific

there are years like 1998-99, 1999-00, 2010-11, 2011-12, and 2013-14 that had late Nov periods that strongly correlated to the following winter. years like 2011-12 and 1998-99 were near dead ringers... years that went into Dec with a potent AK trough often had it linger for the winter. years like 2010-11 aren't as airtight, but the Pacific patterns were very similar

years like 2001-02, 2008-09, 2020-21, and 2021-22 had a decent correlation, mainly in the Pacific. for example, although there was no early -NAO blocking in 2020-21, the Pacific patterns are nearly identical. the patterns for 2021-22 aren't perfectly matched, but late Nov picked up on the +PNA tendency that would lead to a cold Jan (2008-09 is similar). 2001-02 had a EC ridge that never really went away with -PNA rearing its head early

the other four years had little to no correlation, like 2012-13: 

overall, 9/13 years had at least a decent correlation, and 5 of those 9 were strongly correlated IMO. this isn't a perfect science by any means, though it does provide some numbers to the age-old "when does winter start showing itself" question

[brooklynwx99]

now, it's another can of worms as to whether modeling will be correct. we'll find out in the coming weeks, though the +PNA/-EPO pattern is moving forward in time

if late Nov does indeed feature a +PNA/-EPO pattern, it will make me more optimistic for the +TNH pattern that people like Webb are hinting at

[so_whats_happening]

Impressive changes going on across the warm pool. I expect a monthly down to -2 to -2.5 area for November and if activity continues then maybe just maybe above -2 for the first time in awhile. 

https://psl.noaa.gov/map/clim/sst.anom.anim.week.html

[so_whats_happening]

1 hour ago, brooklynwx99 said:

now, it's another can of worms as to whether modeling will be correct. we'll find out in the coming weeks, though the +PNA/-EPO pattern is moving forward in time

if late Nov does indeed feature a +PNA/-EPO pattern, it will make me more optimistic for the +TNH pattern that people like Webb are hinting at

Myself and others have noticed things seem to be off by about a month right now. Not to say this continues going forward but I can't help but think that maybe just maybe this still has a really solid possibility this winter. If we actually really start to reduce the -PDO within the next 2 weeks or so it only helps the idea. If we really start to amplify this -EPO pattern it could be interesting going forward.

[brooklynwx99]

can't say these don't match up pretty well either

[michsnowfreak]

12 hours ago, GaWx said:

 Mine too. I got ~1,000% of my climo mean liquid equivalent of wintry precip (all from one storm in early 1/2018), which is the largest since 1921-2! The one in late 1/1922 was the predecessor to the NE US’ Knickerbocker Storm. The snow/sleet combo portion of 1/2018 was the heaviest since the great 12/1989 coastal pre-Christmas near blizzard.

2017-18 was a fantastic winter, we set a few cold records, had a snowy December including a perfect Christmas Eve snowstorm, had the longest stretch on record with temps of 19F or colder, spent much of the late Feb torch with snowpack as it was deep early in the month and had to melt, and had a crazy mid-April ice storm. NO complaints at all about 2017-18, and it probably would have seemed even more harsh had the record 2007-15 stretch not been so fresh in the mind.

Its been the only winter that has really stood out in the post-2015 era, but outside of last winter its really not been too bad for snow here either. Its been far more the fact that 5 of the 9 winters were very mild. Ironically, the other low-snow year was 2018-19, a winter with near avg temps and 3 ice storms. 

% of avg snowfall in the post-2015 era:

2015-16: 78%
2016-17: 83%
2017-18: 134%
2018-19: 69%
2019-20: 96%
2020-21: 99%
2021-22: 104%
2022-23: 82%
2023-24: 52%
9-winter avg: 88%

It should also be noted this is using the 1991-2020 avg snowfall, the highest on record. If we use the long-term avg which is a few inches less, all those % would be higher.