2024-2025 La Nina

[GaWx]

6 minutes ago, so_whats_happening said:

I get what you are saying but im personally not a fan of picking and choosing years for different metrics how we can go from last year using ONI and saying that was the true metric, to this year and saying RONI is the true metric is not befitting. There needs to be consistency.

 If he’s actually saying that last year’s true metric was ONI and this year RONI is the true metric, I’d agree with you as I believe in being consistent first and foremost since otherwise it would make me suspicious of a bias. But is snowman actually saying that? @snowman19, what say you?

[so_whats_happening]

2 minutes ago, snowman19 said:

I was skeptical of the RONI last year, but once I researched it more and looked at the atmospheric response to last winter’s Nino, I’m a believer. Something obviously changed big time (AGW/warm oceans) and we need to change our metrics with it. @40/70 Benchmark ended up being correct about that part of it

Im not saying it is the wrong metric if RONI was to be the metric last year it very much should have ended up like a moderate El Nino and it just didn't.

1 minute ago, GaWx said:

 If he’s actually saying that last year’s true metric was ONI and this year RONI is the true metric, I’d agree with you as I believe in being consistent first and foremost since otherwise it would make me suspicious of a bias. But is snowman actually saying that? @snowman19, what say you?

The consistency of overstating that this was going to be a super Nino last year per ONI was a lot and yes the RONI was mentioned over time for sure. Was RONI the true metric if so this should have very much acted like a moderate Nino which it actually didn't now we go do down this path so far this year where RONI is still well below the ONI values and now we want to use this as the metric? Im all for consistency but one needs to be used. 

I personally just see RONI as taking out the background noise of Oceanic warming but water temps are water temps regardless of the surrounding oceanic warmth. I know we had a major discussion on this last year.

If the waters are still consistently +2 above normal even with a warmer state the atmosphere should still respond in the same way even at a higher point.

[George001]

6 hours ago, snowman19 said:

It’s a miracle that we haven’t had a major, full fledged mid-Atlantic to northeast drought since 2002. The fact that it’s been over 22 years since the last one is pretty astounding in itself. I guess you can say “we’re due”

I suspect AGW is playing a major role in this

[GaWx]

51 minutes ago, so_whats_happening said:

Im not saying it is the wrong metric if RONI was to be the metric last year it very much should have ended up like a moderate El Nino and it just didn't.

The consistency of overstating that this was going to be a super Nino last year per ONI was a lot and yes the RONI was mentioned over time for sure. Was RONI the true metric if so this should have very much acted like a moderate Nino which it actually didn't now we go do down this path so far this year where RONI is still well below the ONI values and now we want to use this as the metric? Im all for consistency but one needs to be used. 

I personally just see RONI as taking out the background noise of Oceanic warming but water temps are water temps regardless of the surrounding oceanic warmth. I know we had a major discussion on this last year.

If the waters are still consistently +2 above normal even with a warmer state the atmosphere should still respond in the same way even at a higher point.

 I’m a RONIer more than an ONIer. If Nino regions are, say, +2, but surrounding tropical regions are, say, +1, I feel that that’s probably going to act more like an El Niño with Nino regions at +1 and surrounding near 0 rather than acting more like a Nino with +2 and surrounding at 0. To a bigger hypothetical extreme, let’s say all tropical waters are +2. If Nino regions are also at +2, how is that going to act like El Niño with no contrast to surrounding waters?
 
 I used it starting last year when I learned about it and I’m using it again this year. Last year was a borderline moderate/strong El Nino peak per RONI. We’ll see where RONI dips to this year. I earlier thought that moderate to strong La Niña RONI dip was a high probability. Now I think that the chances for a dip to strong La Niña per RONI have diminished due to the sluggishness of the last few weeks.

 You said last year’s El Nino didn’t act like a moderate. But did it act like a borderline strong/super? I know it was mild in the NE US but was that mainly due to the effects of a strong/super El Nino or to something else like the very warm WPAC taking over like it has in recent years?

[roardog]

The temp anomalies last winter across the US looked strikingly similar to ‘72-‘73. As we know, that winter featured an ONI very close to what this past winter had. It also had a -PDO as we all know. The individual months were different(December ‘72 had some Arctic air around while this past winter we had that in January) but December, January and February totaled up look very similar. So I think maybe we can say it acted like a very strong/borderline super Nino with a -PDO.

[40/70 Benchmark]

1 hour ago, snowman19 said:

I was skeptical of the RONI last year, but once I researched it more and looked at the atmospheric response to last winter’s Nino, I’m a believer. Something obviously changed big time (AGW/warm oceans) and we need to change our metrics with it. @40/70 Benchmark ended up being correct about that part of it

 

@GaWx

Yea, I got that right but was flat-wrong about the implication of it and how it would manifest.

[PhiEaglesfan712]

Most recent ENSO event by strength

Super El Nino: 2015-16

Strong El Nino: 2023-24

Moderate El Nino: 2002-03 [we're definitely due for one of these, right?]

Weak El Nino: 2018-19 (or 2019-20?)

ENSO Neutral: 2013-14 (or 2019-20?)

Weak La Nina: 2017-18

Moderate La Nina: 2022-23

Strong La Nina: 2010-11

[bluewave]

2 hours ago, George001 said:

I suspect AGW is playing a major role in this

 

 

[GaWx]

30 minutes ago, bluewave said:

 

 

 Good stuff! I see that the greatest increase is in the Midwest. I wonder what % of that heavy precip increase is due to increased crop sizes/transpiration/RH/dewpoints, which is itself partially related to AGW.

 Also, I bet that slightly increased rainfall rates from TCs along with slightly slower avg speed of movement (both related to AGW) have contributed a good bit to the TX/S Plains and E US increases.

[Terpeast]

2 hours ago, roardog said:

The temp anomalies last winter across the US looked strikingly similar to ‘72-‘73. As we know, that winter featured an ONI very close to what this past winter had. It also had a -PDO as we all know. The individual months were different(December ‘72 had some Arctic air around while this past winter we had that in January) but December, January and February totaled up look very similar. So I think maybe we can say it acted like a very strong/borderline super Nino with a -PDO.

Yeah, that's true. While last winter was the best chance for an east coast KU, it was also the best chance for a 72-73 repeat. It just so happened that the latter did happen, except with a different monthly flavor. 

I agree with you in that I wouldn't say that last year's nino was acting only like a moderate. It was strong, and it showed in the STJ. The only time the STJ weakened or shut off was that January -EPO period, and ironically, that got us snow in the MA. 

[George001]

22 minutes ago, Terpeast said:

Yeah, that's true. While last winter was the best chance for an east coast KU, it was also the best chance for a 72-73 repeat. It just so happened that the latter did happen, except with a different monthly flavor. 

I agree with you in that I wouldn't say that last year's nino was acting only like a moderate. It was strong, and it showed in the STJ. The only time the STJ weakened or shut off was that January -EPO period, and ironically, that got us snow in the MA. 

Yeah the temp + precip profile last year was consistent with previous strong and super Nino events. Warm and wet. Unfortunately, it was more like the really bad ones than the decent ones with a big KU event.

[PhiEaglesfan712]

PHL Winter Temp/snowfall in strong/super el nino years

1957-58: Temp 33.1 F, Snowfall 41.8 in

1965-66: Temp 32.5 F, Snowfall 27.4 in

1972-73: Temp 36.0 F, Snowfall 0 in

1982-83: Temp 36.5 F, Snowfall 35.9 in (blizzard in February, latest ever snow on April 19-20)

1987-88: Temp 33.7 F, Snowfall 15.0 in

1991-92: Temp 37.6 F, Snowfall 4.7 in

1997-98: Temp 40.4 F, Snowfall 0.8 in

2009-10: Temp 33.8 F, Snowfall 78.7 in

2015-16: Temp 41.3 F, Snowfall 27.5 in (blizzard in January skews the total)

2023-24: Temp 40.1 F, Snowfall 11.2 in

[bluewave]

72-23 was a much colder winter across the entire CONUS with a historic Southeast snowstorm.

 

https://www.weather.gov/ilm/Feb1973Snow

 

 

 

 

[GaWx]

39 minutes ago, bluewave said:

72-23 was a much colder winter across the entire CONUS with a historic Southeast snowstorm.

 

https://www.weather.gov/ilm/Feb1973Snow

 

 

 

 

Indeed. Even if you use 1961-90 normals for 72-3, it was still much colder in the NE US in 72-3. Also, 72-3 was much wetter than 23-4 in the SE. Furthermore, in addition to the historic Feb snowstorm, there was a historic Jan icestorm in some areas including Atlanta area in 73. Even way down here there was a very rare over 3” of snow! In sharp contrast, Atlanta and many areas of the SE had no wintry precip in 23-4. There hasn’t even been a flake here since Jan of 2018 during the longest wintry precip drought on record here.

[bluewave]

11 minutes ago, GaWx said:

Indeed. Even if you use 1961-90 normals for 72-3, it was still much colder in the NE US in 72-3. Also, 72-3 was much wetter than 23-4 in the SE. Furthermore, in addition to the historic Feb snowstorm, there was a historic Jan icestorm in some areas including Atlanta area.

Our last two strong to super El Niños in 15-16 and 23-24 had much weaker troughs along the Southern Tier than in the 97-98, 82-83, and 72-73 El Niños. My guess is it’s related to the record MJO 4-7 activity. It looks like the unusual ridge over Mexico for such a strong El Niño was a precursor to the record heat this spring into early summer there.

 

[raindancewx]

Presumably the entire plume will shift warmer with the Euro miss for June.

Subsurface heat content also weakened a lot (i.e. it warmed) in June from 100-180W.

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ocean/index/heat_content_index.txt

1999 and 2007 seem to have had similar June thinning of the subsurface. 1999 by itself is a good match - that's a fairly cold / wet Summer here, which is kind of the right feel for how things are trending with a late start to the heat and a lot of rain. Lot of Caribbean hurricanes in those years.

            Apr      May   June

1999   -0.91, -0.81, -0.52 (x3)

2007   -0.59, -0.58, -0.18 (x1)

--------------------------------

Blend  -0.83, -0.75, -0.44

2024   -0.81, -0.80, -0.46

[40/70 Benchmark]

7 hours ago, so_whats_happening said:

Im not saying it is the wrong metric if RONI was to be the metric last year it very much should have ended up like a moderate El Nino and it just didn't.

The consistency of overstating that this was going to be a super Nino last year per ONI was a lot and yes the RONI was mentioned over time for sure. Was RONI the true metric if so this should have very much acted like a moderate Nino which it actually didn't now we go do down this path so far this year where RONI is still well below the ONI values and now we want to use this as the metric? Im all for consistency but one needs to be used. 

I personally just see RONI as taking out the background noise of Oceanic warming but water temps are water temps regardless of the surrounding oceanic warmth. I know we had a major discussion on this last year.

If the waters are still consistently +2 above normal even with a warmer state the atmosphere should still respond in the same way even at a higher point.

Not according to the research....

[so_whats_happening]

6 hours ago, GaWx said:

 I’m a RONIer more than an ONIer. If Nino regions are, say, +2, but surrounding tropical regions are, say, +1, I feel that that’s probably going to act more like an El Niño with Nino regions at +1 and surrounding near 0 rather than acting more like a Nino with +2 and surrounding at 0. To a bigger hypothetical extreme, let’s say all tropical waters are +2. If Nino regions are also at +2, how is that going to act like El Niño with no contrast to surrounding waters?
 
 I used it starting last year when I learned about it and I’m using it again this year. Last year was a borderline moderate/strong El Nino peak per RONI. We’ll see where RONI dips to this year. I earlier thought that moderate to strong La Niña RONI dip was a high probability. Now I think that the chances for a dip to strong La Niña per RONI have diminished due to the sluggishness of the last few weeks.

 You said last year’s El Nino didn’t act like a moderate. But did it act like a borderline strong/super? I know it was mild in the NE US but was that mainly due to the effects of a strong/super El Nino or to something else like the very warm WPAC taking over like it has in recent years?

Im game for whichever metric you would like to use I have no issue with that but when comparing it to ambient weather I have yet to see RONI take the lead in that aspect, ONI still seems like a much more reasonable fit. The bold I would assume you are saying comparing tropics to subtropic or are you comparing one tropical region to a different basin?

If waters warm globally the same amount (of course this is not the case but averaging it out) the effects are still felt from an ENSO event but since mid latitudes to the poles are warming much faster than Equatorial regions there has to be some effect that this causes. I think this is what you were maybe trying to allude to? 

Im just not seeing RONI as the answer for this explanation is all. This year should have acted very similar to 1965-66 and 1972-73 both strong/super in a -PDO state (multi year -PDO surrounding) but it just didnt. It is possible to explain this year may have had extremely bad luck in that the +AMO (which was nearly triple the value we saw back in 1997/98) was to blame? Both 65-66 and 72-73 saw the PDO values go to neutral over the winter versus 82-83, 97-98, and 15-16 where they all were positive.

2015/16 I think was able to get a bit closer to the classic look of strong/super ENSO because it was on another level with SST anomalies.

[so_whats_happening]

1 minute ago, 40/70 Benchmark said:

Not according to the research....

please post would love to read

[40/70 Benchmark]

2 minutes ago, so_whats_happening said:

please post would love to read

 

Defining El Niño indices in a warming climate - IOPscience

[40/70 Benchmark]

3 hours ago, George001 said:

.Yeah the temp + precip profile last year was consistent with previous strong and super Nino eventsWarm and wet. Unfortunately, it was more like the really bad ones than the decent ones with a big KU event.

The North Pacific was pretty different.

[GaWx]

18 minutes ago, so_whats_happening said:

Im game for whichever metric you would like to use I have no issue with that but when comparing it to ambient weather I have yet to see RONI take the lead in that aspect, ONI still seems like a much more reasonable fit. The bold I would assume you are saying comparing tropics to subtropic or are you comparing one tropical region to a different basin?

If waters warm globally the same amount (of course this is not the case but averaging it out) the effects are still felt from an ENSO event but since mid latitudes to the poles are warming much faster than Equatorial regions there has to be some effect that this causes. I think this is what you were maybe trying to allude to? 

Im just not seeing RONI as the answer for this explanation is all. This year should have acted very similar to 1965-66 and 1972-73 both strong/super in a -PDO state (multi year -PDO surrounding) but it just didnt. It is possible to explain this year may have had extremely bad luck in that the +AMO (which was nearly triple the value we saw back in 1997/98) was to blame? Both 65-66 and 72-73 saw the PDO values go to neutral over the winter versus 82-83, 97-98, and 15-16 where they all were positive.

2015/16 I think was able to get a bit closer to the classic look of strong/super ENSO because it was on another level with SST anomalies.

I’m doing what RONI does, comparing Nino 3.4 anomaly to the concurrent avg worldwide tropical ocean anomaly (20N to 20S).

[so_whats_happening]

40 minutes ago, 40/70 Benchmark said:

 

Defining El Niño indices in a warming climate - IOPscience

Interesting read again Im not sure how this can be used in the most recent year. There is simply no way this was a moderate event using a RONI indicator which would have been on the order of .5-.6 cooler if we were using this. Meaning SST anomalies would have settled around ~1.4. Maybe this is a more useful tool in the ENSO neutral/weak states to help better understand the atmospheric mode for regions that are highly affected by the ENSO state.

It is different to sit there and say 2019/20 was essentially -.1 to-.2 via RONI though when the atmospheric pattern very much resembled that of an El Nino and the precip pattern was almost spot on to that mode. The only difference was the SST's didn't warm substantially in the central/east Pacific like lets say 1997/98 and 2015/16 did so VP was a bit off around South America versus those years, so locally those regions experienced something different due to the lack of overall warming of the Pacific.

[40/70 Benchmark]

17 minutes ago, so_whats_happening said:

Interesting read again Im not sure how this can be used in the most recent year. There is simply no way this was a moderate event using a RONI indicator which would have been on the order of .5-.6 cooler if we were using this. Meaning SST anomalies would have settled around ~1.4. Maybe this is a more useful tool in the ENSO neutral/weak states to help better understand the atmospheric mode for regions that are highly affected by the ENSO state.

It is different to sit there and say 2019/20 was essentially -.1 to-.2 via RONI though when the atmospheric pattern very much resembled that of an El Nino and the precip pattern was almost spot on to that mode. The only difference was the SST's didn't warm substantially in the central/east Pacific like lets say 1997/98 and 2015/16 did so VP was a bit off around South America versus those years, so locally those regions experienced something different due to the lack of overall warming of the Pacific.

We can agree to disagree on this. The cooler RONI was a reflection of how the West PAC warm pool acted to partially negate the warm ENSO influence, as evidenced by the high residence time of the MJO in phases 4-6 and the Aleutian ridging. That is not typical super El Niño, regardless of the fact that it was also a warm result.

Not complicated....+ SST anomalies don't have the same capacity to alter forcing schemes when surrounded by a sea of warmth. ....same reason a 980mb low is much stronger when there is a 1050mb high upstream as opposed to a 1020mb high. its all about the gradient. CC is making this a more prevalent issue that it had been in the past.

[40/70 Benchmark]

Look at all of the other super El Niños......you had the strong west-east dipole across the Pacific in terms of SSTs and pressure, which produced much stronger WWBs. That whole system was much less pronounced last year, which is reflective of a more moderate event.

[so_whats_happening]

8 minutes ago, 40/70 Benchmark said:

We can agree to disagree on this. The cooler RONI was a reflection of how the West PAC warm pool acted to partially negate the warm ENS influence, as evidenced by the high residence time of the MJO in phases 4-6 and the Aleutian ridging. That is not typical super El Niño, regardless of the fact that it was also a warm result.

It is a damn shame we can't see back to 1972-73 and 1965-66 for RMM plots. These years had similar patterns of SST anomaly and PDO state (although these years managed to get the PDO to near neutral in winter but were surrounded by a largely negative state). This was the last time we experienced such events coinciding.

I would post these 500mb patterns but I cant seem to do more than 98kb, gotta figure this one out.

 

[raindancewx]

You were never going to have a big Aleutian low last year with the PDO near -3 to -1 the whole time. The north pacific stuff is tied much more to the PDO than ENSO. The ENSO stuff has direct control over the subtropical jet which was very strong last year.

[40/70 Benchmark]

1 minute ago, so_whats_happening said:

It is a damn shame we can't see back to 1972-73 and 1965-66 for RMM plots. These years had similar patterns of SST anomaly and PDO state (although these years managed to get the PDO to near neutral in winter but were surrounded by a largely negative state). This was the last time we experienced such events coinciding.

I would post these 500mb patterns but I cant seem to do more than 98kb, gotta figure this one out.

 

Yep....1994 and 2006 weren't too dissimilar, either.

[40/70 Benchmark]

1972 probably got the PDO near neutral because the RONI wasn't as cool that year, most likely due to the cooler west PAC relative to last year. I was slow to catch on, but Bluewave nailed it with that marine heat wave.

[40/70 Benchmark]

3 minutes ago, raindancewx said:

You were never going to have a big Aleutian low last year with the PDO near -3 to -1 the whole time. The north pacific stuff is tied much more to the PDO than ENSO. The ENSO stuff has direct control over the subtropical jet which was very strong last year.

I think the PDO being so negative was at least partially a reflection of a poorly coupled El Niño.....intuitively speaking, it makes sense that the one element of a poorly coupled super El Niño that would be relatively unmitigated is the potent STJ given all of the warmth around the globe right now.