El Nino 2023-2024

[bluewave]

21 hours ago, raindancewx said:

I've always found it a bit silly to look for a 500 mb profile in ENSO that is typical, and to complain that anything that doesn't match that profile is atypical. It's much more common for ENSO events to go to a temperature profile that matches the typical / atypical idea in comparison to the 500 mb profile.

You essentially had the normal warm North / cool South look from this El Nino, regardless of how you got to it, plus maybe a bit more coolness for the Northwest with the -PDO. 

I'd be more willing to agree with your assessment if the subtropical jet had failed to be strong. But that actually is a direct physical response to ENSO, and it was there. The mid-lattitude stuff that people look for is essentially over fitting trend lines and history in a lot of ways.

I removed the original post since you completely missed the points that I was trying to make. I will try to break it down piece by piece in this new post.

While the geographic locations of the temperature anomalies this winter we’re correlated to the El Niño, the magnitude of departures could not simply be reduced to saying it was a result of the El Niño. Sections to the north and the CONUS had their warmest winter on record with departures in spots above +10 against the warmest 30 year climate normals over the 91-20 period. The intensity of this El Niño wasn’t nearly as strong as the past winters which were previous the warmest record holders. So there was much more than just the El Niño going on this winter. 

My reference to the difference in the 500 mb anomalies this winter from past El Niño instances goes to the issue of why the deeper trough which was modeled by the Euro seasonal didn’t occur in the South. 

First, we saw record warmth for the WPAC basin during an El Niño. This is what I was pointing out in this thread last fall. My concern was that the risks to the winter forecasts would be much warmer than the computer models from various centers were indicating. It’s also why one dimensional model forecasts based mostly on El Niño were biased so cold. The more westward forcing even at times back to the eastern IO combined with the El Niño to produce warmth well beyond any seasonal forecast this winter. So these marine heatwaves in the warm forcing areas for North America realized through unusually active MJO 4-7 action for an El Niño contributed to the much warmer departures than a one dimensional El Niño model would suggest. So the more westward forcing for an El Niño would tend to weaken this trough and cold potential  in the south. This forcing combined with the El Niño through the El Niño set of MJO composites also created the stronger 500 mb and ridge and warmth to the north.

A second reason I showed 500 mb charts was to illustrate how different a response we got from the Aleutian low this winter than has typically been the case with stronger El Niños.This was the weakest Aleutian low response we have seen from a stronger El Nino. My guess is this is related to the more westward forcing lean which actually produced a ridge south of the Aleutians and to the NW of Hawaii instead of the trough being forecast by the models. Now you can say this is related to the -PDO and to an extent this is the case. But the -PDO this winter was more defined by the warm waters near Japan and west of the Dateline  rather than the usual cold ring In the east. So we have seen a shift in the way the PDO has be manifesting in recent years. Plus there have been recent studies that the PDO is more of an effect than a cause of the pattern across the North Pacific. This SST pattern may just be an effect of the predominant forcing at any given time.

I would agree with you that the enhanced STJ was one of the more typical El Niño responses this winter which did work out. But the extreme flooding and record rainfall in places like California was stronger in spots than even the 97-98 El Niño which was much stronger could muster. So another example of the overlapping influences this winter.

 

 

[GaWx]

54 minutes ago, bluewave said:

I removed the original post since you completely missed the points that I was trying to make. I will try to break it down piece by piece in this new post.

While the geographic locations of the temperature anomalies this winter we’re correlated to the El Niño, the magnitude of departures could not simply be reduced to saying it was a result of the El Niño. Sections to the north and the CONUS had their warmest winter on record with departures in spots above +10 against the warmest 30 year climate normals over the 91-20 period. The intensity of this El Niño wasn’t nearly as strong as the past winters which were previous the warmest record holders. So there was much more than just the El Niño going on this winter. 

My reference to the difference in the 500 mb anomalies this winter from past El Niño instances goes to the issue of why the deeper trough which was modeled by the Euro seasonal didn’t occur in the South. 

First, we saw record warmth for the WPAC basin during an El Niño. This is what I was pointing out in this thread last fall. My concern was that the risks to the winter forecasts would be much warmer than the computer models from various centers were indicating. It’s also why one dimensional model forecasts based mostly on El Niño were biased so cold. The more westward forcing even at times back to the eastern IO combined with the El Niño to produce warmth well beyond any seasonal forecast this winter. So these marine heatwaves in the warm forcing areas for North America realized through unusually active MJO 4-7 action for an El Niño contributed to the much warmer departures than a one dimensional El Niño model would suggest. So the more westward forcing for an El Niño would tend to weaken this trough and cold potential  in the south. This forcing combined with the El Niño through the El Niño set of MJO composites also created the stronger 500 mb and ridge and warmth to the north.

A second reason I showed 500 mb charts was to illustrate how different a response we got from the Aleutian low this winter than has typically been the case with stronger El Niños.This was the weakest Aleutian low response we have seen from a stronger El Nino. My guess is this is related to the more westward forcing lean which actually produced a ridge south of the Aleutians and to the NW of Hawaii instead of the trough being forecast by the models. Now you can say this is related to the -PDO and to an extent this is the case. But the -PDO this winter was more defined by the warm waters near Japan and west of the Dateline  rather than the usual cold ring In the east. So we have seen a shift in the way the PDO has be manifesting in recent years. Plus there have been recent studies that the PDO is more of an effect than a cause of the pattern across the North Pacific. This SST pattern may just be an effect of the predominant forcing at any given time.

I would agree with you that the enhanced STJ was one of the more typical El Niño responses this winter which did work out. But the extreme flooding and record rainfall in places like California was stronger in spots than even the 97-98 El Niño which was much stronger could muster. So another example of the overlapping influences this winter.

 

 

Keep in mind that if one were to go by RONI or MEI peaks, 2023-4 was a moderate rather than a strong El Niño.

[michsnowfreak]

When it comes to weather analysis, especially locally, I would give myself 10/10 in past climatology and probably 4/10 in all the other factors that make it happen (ENSO, NAO, PDO, etc etc). I understand what atmospheric factors are good/bad for a good/bad winter, but I am really novice when it comes to how they work together and definitely at how to forecast them (I dont ever forecast though lol).

 

I always look at ENSO as one piece of the puzzle. It may be the biggest piece, but there are lots of other pieces that will have somewhat of an effect. The mean of a strong El Nino here is a guaranteed mild winter, and snowfall/precip will very likely finish below normal. But what else happens and how extreme will be dictated by other factors, as sometimes late winter can get cold, and nearly unanimously December will be mild.

 

If i chop this winter into 3rd, by calendar month at Detroit, this is what I get:

DECEMBER 2023- 3rd warmest on record (40.1F), and tho precip was near normal, it was the 2nd least snowy on record (0.1"). Literally as bad as it gets (we did have snow on the ground last 4 days of November tho), but a warm December in a strong El Nino here is basically a 100% surefire bet. Just didnt expect it this warm.

JANUARY 2024- Temps only slightly above avg (27.5F) and this was due to excessive cloudiness causing higher mins. The avg high was actually -0.2F. It was the wettest Jan on record (5.25") and snowfall was above avg at 17.0". It was a good month overall, and the parade of nonstop snow, rain, and ice was quite a surprise for what is supposed to be a dry winter.

FEBRUARY 2024- 3rd warmest on record (37.1F) and 4th driest (0.24"). What a crazy switch from Januarys storminess, as El Ninos "dry" showed up in full force. Despite the warmth, nearly all of the minimal precip we did have was snow (3.1").

DJF 2023-24- 4th warmest on record (34.8F). Precip finished a little above avg (thanks to Jan), which goes against typical Strong Nino climo, although it was nowhere near the top 20 wettest. Snowfall finished below avg, but thanks to Jan, it too was nowhere near the top 20 least snowy DJF's.

 

This is why looking at seasonal averages doesnt always tell the tale. We are all guilty of analyzing final numbers, but if you would have showed me a crystal ball and said these are the final numbers of this strong Nino, I would sigh and probably say "Typical strong Nino. Im not surprised". But I didnt dream the winter would be as wacky as it ended up being. Basically a nightmare of warmth that was masked by a 2 week siege of deep winter in January. We had wind chill warnings and advisories for like 3-4 days straight, and we can EASILY go a good, enjoyable winter without seeing any. Had it been even a more modest stretch of cold, this couldve been the warmest winter on record. The pic below was taken Jan 15th with a temp of 5F and wind chill near -30F. Definitely not my most scenic pic, but its one where you can "feel" the cold. I should change it to B&W and caption "taken during one of the warmest winters on record". 

[raindancewx]

We seem to be entering the March 1973 part of the pattern now. After 10 feet of snow in California's high terrain in two days earlier this month, I suspect our mountains will get 1-3 feet in 1-2 days with this storm. I don't think it's the last one either. I would prefer to have a stout cold high in Wyoming trapping a flow of moisture from Puerto Penasco, but trapping a strong storm with a lot of moisture and some cold for a long duration under a high isn't half bad. If any of you still need your snow fix, our mountains will get pasted with this setup even though it's not as good as the Casper v. Penasco setup. I'm a little surprised this didn't happen in December or January, but these types of regimes tend to accompany the transition from East based to Modoki setups. If you look, the thunderstorm activity has kind of died in the East Pacific in recent days / weeks.

It makes sense that it looks fairly cold in the East now. I would bite on this being a Modoki El Nino from now until it completely collapses into an East based La Nina in six weeks. 

 

[GaWx]

On 2/3/2024 at 3:34 PM, GaWx said:

The unrounded ONI max came in at +1.97. RONI never made strong with another +1.49.

I just noticed that the unrounded ONI peak (NDJ) was revised down slightly from +1.97 to +1.95:

https://www.cpc.ncep.noaa.gov/data/indices/oni.ascii.txt
 

 The RONI peak remained at +1.49 (OND)(border of moderate and strong):

https://www.cpc.ncep.noaa.gov/data/indices/RONI.ascii.txt

 

[40/70 Benchmark]

On 3/4/2024 at 9:27 AM, GaWx said:

Keep in mind that if one were to go by RONI or MEI peaks, 2023-4 was a moderate rather than a strong El Niño.

Larry, this plays into what Chris is saying...the weaker RONI value was a reflction of the competing hemispheric forces that he just spoke of.

 

[40/70 Benchmark]

16 hours ago, raindancewx said:

We seem to be entering the March 1973 part of the pattern now. After 10 feet of snow in California's high terrain in two days earlier this month, I suspect our mountains will get 1-3 feet in 1-2 days with this storm. I don't think it's the last one either. I would prefer to have a stout cold high in Wyoming trapping a flow of moisture from Puerto Penasco, but trapping a strong storm with a lot of moisture and some cold for a long duration under a high isn't half bad. If any of you still need your snow fix, our mountains will get pasted with this setup even though it's not as good as the Casper v. Penasco setup. I'm a little surprised this didn't happen in December or January, but these types of regimes tend to accompany the transition from East based to Modoki setups. If you look, the thunderstorm activity has kind of died in the East Pacific in recent days / weeks.

It makes sense that it looks fairly cold in the East now. I would bite on this being a Modoki El Nino from now until it completely collapses into an East based La Nina in six weeks. 

 

Modioki El Nino shows up riiiiight as the climo window for east coast snowfall closes, then transitions to an east-based La Nina during the warm season and back to a Modoki La Nina for winter 2024-2025.....series of east coast butt-plugs marches on and on.

[so_whats_happening]

Just as a last look with monthly TAO data for the El Nino, may update for March in the near future.