2025-2026 ENSO

[GaWx]

1 hour ago, Stormchaserchuck1 said:

Big time ridge NE of Japan in the +4-7 Day. In the last few years we've been seeing these Summer H5 anomalies, touching 6000dm, in areas that already had very anomalous +SSTs. 

Thanks, Chuck. I see that the Euro op has 6000+ at peak. The 0Z GFS also barely has it. But I think most or all of the others are just shy of 6K. Is they what you see?

[snowman19]

It might actually warm up a bit in Nino 1+2 in the coming months:

Does a warmer late Summer eastern ENSO region (Nino 1+2) precede an El Nino the following year (26-27)?
no
Slight opposite correlation actually

pretty strong +anomaly correlation over Indonesia and the Philippines 

All seasonal models seem to have a strong -PNA despite Neutral ENSO.. for the 2nd year in a row. Last year they were pretty far off though (for DJF). 

2nd year -ENSOs very strongly support predominantly -PNA winters. There’s multiple studies showing that.

As far as ENSO 1+2, it basically has been in an El Niño state for months and still is. It appears a Modoki/central-based cold-neutral or weak La Niña event is developing

[snowman19]

This is the strongest -PMM signature we’ve seen in many years. The odds of a weak La Niña are definitely increasing….

[bluewave]

The subsurface of the WPAC near Japan is also at all-time record warm levels. So even after the trough there last winter, the SSTs rapidly rebounded once the record 500mb ridge returned. The record SSTs driving the  -PDO along with the strong 500mb ridging seem to have entered a feedback loop which will be very difficult to interrupt.
 

https://link.springer.com/epdf/10.1007/s10872-025-00764-w?sharing_token=J-9irySGxF9HZQFLbNJGDve4RwlQNchNByi7wbcMAY7wFuZ-ylVtGh1WkIZzeCeQ7fT_EW6c-yTyHjHGAbkHkCIuMkU2ciJtaEwncsfGWwMweI1zmVqAoQWL6L9qQ_p-2UuxUREesHtW412KA2GJ2gCcNnxXT5r3CdJOSYmJ8_4%3D

 

[40/70 Benchmark]

11 hours ago, Stormchaserchuck1 said:

The frequency of La Nina's 1998-2025 is actually an anomaly in the global warming. Earth patterns were suppose to relax, or stabilize, which is default El Nino state. 

Check it out.. all warm

cold

 

The La Nina Standard Deviation in the last 27 years is about negative 4-5 sigma. 

 

Yes, but most of the warming is in the West Pacific, which biases the hemisphere towards a cool ENSO regime.

[GaWx]

5 hours ago, snowman19 said:

 

 

2nd year -ENSOs very strongly support predominantly -PNA winters. There’s multiple studies showing that.

As far as ENSO 1+2, it basically has been in an El Niño state for months and still is. It appears a Modoki/central-based cold-neutral or weak La Niña event is developing

 

 

There are usually exceptions to any rule. These 2nd year -ENSO winters or portions of winters were cold in much of the E US:

-1898-9 (including great 2/1899 frigid period)(March was also cold with its own outbreak early)

-1909-10 (Dec/Feb)

-1962-3 (frigid)

-1967-8 (Jan-Feb)

-Jan of 1985 (though Dec of 1984 warm)

-2013-4 especially Midwest

[bluewave]

11 hours ago, Stormchaserchuck1 said:

The frequency of La Nina's 1998-2025 is actually an anomaly in the global warming. Earth patterns were suppose to relax, or stabilize, which is default El Nino state. 

Check it out.. all warm

cold

 

The La Nina Standard Deviation in the last 27 years is about negative 4-5 sigma. 

 

It’s only an anomaly if we use the CMIP5 models which incorrectly forecast the EPAC warming faster than the WPAC. The GFDL model has done much better capturing the faster WPAC warming. We have seen time and time again that weather and climate modeling isn’t an exact science.
 

https://journals.ametsoc.org/view/journals/clim/30/11/jcli-d-16-0441.1.xml

 

The majority of the models that participated in phase 5 of the Coupled Model Intercomparison Project global warming experiments warm faster in the eastern equatorial Pacific Ocean than in the west. GFDL-ESM2M is an exception among the state-of-the-art global climate models in that the equatorial Pacific sea surface temperature (SST) in the west warms faster than in the east, and the Walker circulation strengthens in response to warming. This study shows that this “La Niña–like” trend simulated by GFDL-ESM2M could be a physically consistent response to warming, and that the forced response could have been detectable since the late twentieth century. Two additional models are examined: GFDL-ESM2G, which differs from GFDL-ESM2M only in the oceanic components, warms without a clear zonal SST gradient; and HadGEM2-CC exhibits a warming pattern that resembles the multimodel mean. A fundamental observed constraint between the amplitude of El Niño–Southern Oscillation (ENSO) and the mean-state zonal SST gradient is reproduced well by GFDL-ESM2M but not by the other two models, which display substantially weaker ENSO nonlinearity than is observed. Under this constraint, the weakening nonlinear ENSO amplitude in GFDL-ESM2M rectifies the mean state to be La Niña–like. GFDL-ESM2M exhibits more realistic equatorial thermal stratification than GFDL-ESM2G, which appears to be the most important difference for the ENSO nonlinearity. On longer time scales, the weaker polar amplification in GFDL-ESM2M may also explain the origin of the colder equatorial upwelling water, which could in turn weaken the ENSO amplitude.

[40/70 Benchmark]

6 minutes ago, bluewave said:

It’s only an anomaly if we use the CMIP5 models which incorrectly forecast the EPAC warming faster than the WPAC. The GFDL model has done much better capturing the faster WPAC warming. We have seen time and time again that weather and climate modeling isn’t an exact science.
 

https://journals.ametsoc.org/view/journals/clim/30/11/jcli-d-16-0441.1.xml

 

The majority of the models that participated in phase 5 of the Coupled Model Intercomparison Project global warming experiments warm faster in the eastern equatorial Pacific Ocean than in the west. GFDL-ESM2M is an exception among the state-of-the-art global climate models in that the equatorial Pacific sea surface temperature (SST) in the west warms faster than in the east, and the Walker circulation strengthens in response to warming. This study shows that this “La Niña–like” trend simulated by GFDL-ESM2M could be a physically consistent response to warming, and that the forced response could have been detectable since the late twentieth century. Two additional models are examined: GFDL-ESM2G, which differs from GFDL-ESM2M only in the oceanic components, warms without a clear zonal SST gradient; and HadGEM2-CC exhibits a warming pattern that resembles the multimodel mean. A fundamental observed constraint between the amplitude of El Niño–Southern Oscillation (ENSO) and the mean-state zonal SST gradient is reproduced well by GFDL-ESM2M but not by the other two models, which display substantially weaker ENSO nonlinearity than is observed. Under this constraint, the weakening nonlinear ENSO amplitude in GFDL-ESM2M rectifies the mean state to be La Niña–like. GFDL-ESM2M exhibits more realistic equatorial thermal stratification than GFDL-ESM2G, which appears to be the most important difference for the ENSO nonlinearity. On longer time scales, the weaker polar amplification in GFDL-ESM2M may also explain the origin of the colder equatorial upwelling water, which could in turn weaken the ENSO amplitude.

Completely agree here.

[Stormchaserchuck1]

10 hours ago, GaWx said:

Thanks, Chuck. I see that the Euro op has 6000+ at peak. The 0Z GFS also barely has it. But I think most or all of the others are just shy of 6K. Is they what you see?

Yes.. there is also a 5900dm ridge in northern Sweden in 2 days. Both this one and the ridge NE of Japan trended on models in the last few days.. they weren't there this strong in the longer range. 

[GaWx]

Snowman,

 Further to my post above, three of the greatest (and arguably the two greatest are in this) E US Arctic outbreaks on record occurred during 2nd year -ENSO:

-Feb of 1899

-Jan of 1985

-Jan of 2014

Mere coincidence especially with sample size tiny?

@snowman19

[Yanksfan]

Looking pretty apparent at this early juncture we’re going to need a predominate -EPO to have any hopes of a decent winter snow wise around these parts.

[snowman19]

Snowman,
 Further to my post above, three of the greatest (and arguably the two greatest are in this) E US Arctic outbreaks on record occurred during 2nd year -ENSO:
-Feb of 1899
-Jan of 1985
-Jan of 2014
Mere coincidence especially with sample size tiny?
[mention=13098]snowman19[/mention]

Were those winters +PNA winters or -EPO/-PNA winters. -PNA/-EPO can still certainly be cold. Just because there may be a dominant -PNA doesn’t automatically mean warm

[snowman19]

Yes, but most of the warming is in the West Pacific, which biases the hemisphere towards a cool ENSO regime.

Yes it does bias towards a -ENSO, which is why I’m starting to agree with your musing that we may actually see a weak La Niña instead of just cold-neutral, which has been my guess up to this point

[yoda]

Thoughts?

https://x.com/BenNollWeather/status/1943673129965949186

 

[GaWx]

13 minutes ago, snowman19 said:

Were those winters +PNA winters or -EPO/-PNA winters. -PNA/-EPO can still certainly be cold. Just because there may be a dominant -PNA doesn’t automatically mean warm

I have EPO and PNA back only to 1950:

-1962-3, 1967-8, Jan of 1985, and 2013-14 were all -EPO dominated

-All of the above were +PNA dominated except just Jan of the 2013-4 winter

[GaWx]

7 minutes ago, yoda said:

Thoughts?

https://x.com/BenNollWeather/status/1943673129965949186

 

RONI could dip as low as moderate La Niña but I currently am forecasting ~-0.4 cold neutral ONI low point and -0.6 to -0.9 RONI low point (weak La Niña).

[donsutherland1]

1 hour ago, bluewave said:

It’s only an anomaly if we use the CMIP5 models which incorrectly forecast the EPAC warming faster than the WPAC. The GFDL model has done much better capturing the faster WPAC warming. We have seen time and time again that weather and climate modeling isn’t an exact science.
 

https://journals.ametsoc.org/view/journals/clim/30/11/jcli-d-16-0441.1.xml

 

The majority of the models that participated in phase 5 of the Coupled Model Intercomparison Project global warming experiments warm faster in the eastern equatorial Pacific Ocean than in the west. GFDL-ESM2M is an exception among the state-of-the-art global climate models in that the equatorial Pacific sea surface temperature (SST) in the west warms faster than in the east, and the Walker circulation strengthens in response to warming. This study shows that this “La Niña–like” trend simulated by GFDL-ESM2M could be a physically consistent response to warming, and that the forced response could have been detectable since the late twentieth century. Two additional models are examined: GFDL-ESM2G, which differs from GFDL-ESM2M only in the oceanic components, warms without a clear zonal SST gradient; and HadGEM2-CC exhibits a warming pattern that resembles the multimodel mean. A fundamental observed constraint between the amplitude of El Niño–Southern Oscillation (ENSO) and the mean-state zonal SST gradient is reproduced well by GFDL-ESM2M but not by the other two models, which display substantially weaker ENSO nonlinearity than is observed. Under this constraint, the weakening nonlinear ENSO amplitude in GFDL-ESM2M rectifies the mean state to be La Niña–like. GFDL-ESM2M exhibits more realistic equatorial thermal stratification than GFDL-ESM2G, which appears to be the most important difference for the ENSO nonlinearity. On longer time scales, the weaker polar amplification in GFDL-ESM2M may also explain the origin of the colder equatorial upwelling water, which could in turn weaken the ENSO amplitude.

A new paper that just came out reaffirms the Western Pacific warming from climate change and notes how the atmosphere-ocean forcing is similar to that for a PDO-

Excerpts concerning West Pacific Ocean Warming:

The simulations with prescribed vegetation show that mid-Holocene reductions in winter precipitation result from a coupled ocean–atmosphere response centred in the Pacific Ocean excited by hemispheric warming. This is evident in a distinct pattern of SST changes over the North Pacific, with intense surface warming extending across the mid- to high-latitude western Pacific surrounded by a ‘horseshoe’ pattern of minimal surface warming or cooling to the east and a weak La Niña-like pattern in the tropical Pacific... This ocean temperature pattern is accompanied by a region of increased sea-level pressure over the North Pacific, indicating a weakened Aleutian Low. The North Pacific surface temperature and pressure patterns are reminiscent of the negative phase of the Pacific Decadal Oscillation..., which has been implicated in the length and severity of historical wintertime precipitation deficits over the Southwest United States. However, unlike the observed PDO, which is a decadal-scale mode of variability presumed to be internally generated, in the mid-Holocene this pattern emerges as a sustained state in the North Pacific that dominates the climate over several millennia.  

The paper linked the pattern to decreased winter precipitation in the Southwest. So, as warming continues and the pattern becomes predominant, winter precipitation is expected to decline in an already dry region.

The paper did not discuss implications for winters in eastern North America. 

[snowman19]

Thoughts?
https://x.com/BenNollWeather/status/1943673129965949186
 

I agree. I really think I may have been wrong with my cold-neutral call and we actually see an official La Niña

[jm1220]

3 hours ago, Yanksfan said:

Looking pretty apparent at this early juncture we’re going to need a predominate -EPO to have any hopes of a decent winter snow wise around these parts.

My hopes are near zero for anything decent around my area until the Pacific meaningfully changes. Boiling warm water east of Japan and the general Perma-Nina/hyper Pacific jet pattern driven by the awful W PAC ruins 99% of the setups in this area. Even worse if it’s possible is that the Nina seems to be basing in the central not east Pacific. 

[bluewave]

2 hours ago, donsutherland1 said:

A new paper that just came out reaffirms the Western Pacific warming from climate change and notes how the atmosphere-ocean forcing is similar to that for a PDO-

Excerpts concerning West Pacific Ocean Warming:

The simulations with prescribed vegetation show that mid-Holocene reductions in winter precipitation result from a coupled ocean–atmosphere response centred in the Pacific Ocean excited by hemispheric warming. This is evident in a distinct pattern of SST changes over the North Pacific, with intense surface warming extending across the mid- to high-latitude western Pacific surrounded by a ‘horseshoe’ pattern of minimal surface warming or cooling to the east and a weak La Niña-like pattern in the tropical Pacific... This ocean temperature pattern is accompanied by a region of increased sea-level pressure over the North Pacific, indicating a weakened Aleutian Low. The North Pacific surface temperature and pressure patterns are reminiscent of the negative phase of the Pacific Decadal Oscillation..., which has been implicated in the length and severity of historical wintertime precipitation deficits over the Southwest United States. However, unlike the observed PDO, which is a decadal-scale mode of variability presumed to be internally generated, in the mid-Holocene this pattern emerges as a sustained state in the North Pacific that dominates the climate over several millennia.  

The paper linked the pattern to decreased winter precipitation in the Southwest. So, as warming continues and the pattern becomes predominant, winter precipitation is expected to decline in an already dry region.

The paper did not discuss implications for winters in eastern North America. 

Thanks for posting that paper which really confirms how significant a shift has occurred in the North Pacific. There was another article recently published on this paper which expands on the one that you posted. While this wasn’t what many of us on the forum wanted to hear, at least the team of researchers were clever enough to tie together paleoclimate reconstructions together with advanced climate modeling for a more coherent picture of what has been going on.

https://scienmag.com/north-pacific-climate-shifts-drive-southwest-us-drought/

In recent years, the American Southwest has been gripped by one of the most prolonged and severe droughts in recorded history. While variations in precipitation and temperature have long challenged water resource management in this already arid region, the ongoing drought has raised alarm bells for scientists, policymakers, and residents alike. Understanding what drives these shifts in water availability is critical to anticipating future risks and developing adaptive strategies. A groundbreaking new study published in Nature Geoscience now provides compelling evidence that warming in the Northern Hemisphere, particularly in the North Pacific, plays a pivotal role in shaping drought patterns over the Southwest United States through complex ocean-atmosphere interactions.

This research combines innovative paleoclimate reconstructions with advanced climate modeling to unravel how moderate warming episodes in Earth’s past—specifically during the mid-Holocene, around 6,000 years ago—triggered oceanic and atmospheric responses that closely mirror modern drought conditions. By studying leaf-wax stable isotopes preserved in sediment cores, the authors reconstructed ancient rainfall patterns with unprecedented precision. These reconstructions revealed that subtle changes in ocean temperatures off the North Pacific coast led to atmospheric circulation shifts that suppressed precipitation across the Southwest, a mechanism remarkably similar to currently observed drought drivers.

What makes this work especially illuminating is its identification of the Pacific Decadal Oscillation (PDO) as a critical mediator in this process. The PDO is a naturally occurring climate phenomenon characterized by long-term fluctuations in sea surface temperatures and atmospheric pressure in the North Pacific Ocean that profoundly influence weather and climate patterns across North America. The study’s findings indicate that moderate hemispheric warming can excite a PDO-like state—specifically its negative phase—resulting in sustained drying conditions in the Southwest. This conclusion challenges prior assumptions that natural oscillations would eventually reverse and alleviate drought conditions, instead implying that external forcings such as global warming may stabilize drought-inducing patterns.

The implications for future climate projections are sobering. Simulations of twenty-first century climate pathways, driven by anthropogenic greenhouse gas emissions, demonstrate that similar ocean-atmosphere dynamics are likely to emerge and endure. These simulations forecast persistent reductions in winter precipitation over the Southwest through at least the mid-century, exacerbating the region’s already critical water scarcity issues. Given that winter rains supply a substantial portion of the region’s annual precipitation and recharge vital aquifers, prolonged deficits pose significant threats to agriculture, urban water supplies, and natural ecosystems.

However, the study also reveals that current climate models may underestimate the severity of these precipitation deficits. The authors suggest that the ocean-atmosphere coupling—how strongly and accurately models simulate the interaction between ocean warmth and atmospheric circulation—is likely too weak in existing frameworks. This underestimation means that official drought risk assessments and water management strategies may not be adequately prepared for the intensity or duration of future dry spells dictated by North Pacific variability under a warming climate.

This advances a growing body of evidence underscoring the Pacific Ocean’s outsized influence on terrestrial climate variability in the western United States. The North Pacific’s role is multifaceted, involving the modulation of storm tracks, alterations in jet stream position and strength, and changes in moisture transport pathways. By illuminating the mechanisms through which relatively moderate warming perturbs this system, the research offers a nuanced understanding of regional climate dynamics that transcends simplistic attributions to long-term warming or random variability alone.

Perhaps most compellingly, the paleoclimate perspective grants the study an unparalleled vantage point. Utilizing ancient environmental archives to calibrate and validate model simulations bridges the gap between historical climate fluctuations and future projection scenarios. This approach ensures that the conclusions are firmly rooted in empirical evidence, helping to surmount some of the uncertainties that plague climate prediction in complex transitional zones like the Southwest. The mid-Holocene period serves as a natural analog for how the contemporary Earth climate system might respond to ongoing warming trends.

The study’s methodology highlights the innovative use of leaf-wax isotopes, a biomarker that preserves signals of past hydrological conditions through changes in hydrogen isotope ratios. This technique captures past rainfall variability integrated over plant growing seasons and provides a proxy record that can be spatially and temporally correlated with model outputs. Such high-resolution paleoclimate data strengthen confidence in attributing Southwest drought episodes to ocean-driven atmospheric circulations rather than isolated terrestrial or stochastic factors.

In practical terms, these findings emphasize the need for water managers, urban planners, and policymakers to incorporate dynamic ocean-atmosphere feedbacks into drought risk models and resource allocation strategies. Static assessments based solely on historical precipitation trends could lead to dangerously optimistic assumptions. Instead, adaptive frameworks must account for the possibility that warming seas off the Pacific Northwest and Alaska may sustain drying influences for decades, intensifying competition for scarce water supplies across municipal, agricultural, and ecological sectors.

Scientists are also calling for an urgent refinement of climate models to better replicate the subtle but critical feedbacks identifying the ocean’s influence on atmospheric patterns that steer precipitation regimes. Such improvements are crucial, as underestimating these processes risks downplaying the Southwest’s vulnerability to exacerbated drought conditions and the cascading socioeconomic impacts that follow. Enhanced model sophistication will also improve the reliability of seasonal and decadal forecasts, crucial for water allocation decisions in drought-prone regions.

Furthermore, this research situates the Southwest drought within the broader context of anthropogenic climate change, illustrating that natural variability modes like the PDO can be amplified or modulated by human-driven warming. This intersection complicates predictions but also stresses the urgency of climate mitigation efforts. Without substantial reductions in greenhouse gas emissions, these drought-favoring ocean-atmosphere states may become increasingly entrenched, imperiling water security for millions of residents and straining fragile ecosystems.

The findings also contribute to the growing discourse on climate resilience and the need for sustainable water use practices. Recognizing that intensified drought risk is not merely cyclical but potentially a forced response to anthropogenic warming highlights the importance of diversified water portfolios, investments in conservation technologies, and reforms in water rights systems. Communities in the Southwest must prepare for a future where drought is not an anomaly but a persistent stressor shaped by global climate dynamics.

In summary, this landmark study integrating paleoclimate evidence and future climate modeling transforms our understanding of the Southwest United States drought by pinpointing the North Pacific ocean-atmosphere system as a central driver modulated by Northern Hemisphere warming. It challenges prevailing assumptions about the transitory nature of current drought conditions and suggests that external forcing is capable of sustaining drought-inducing oceanic patterns similar to the negative phase of the Pacific Decadal Oscillation. This new insight demands meaningful recalibrations in climate prediction frameworks and resource management policies to adequately prepare for a potentially drier future under continued global warming.

The message is unequivocal: the interplay between warming seas and atmospheric circulation cannot be overlooked if we aim to understand and combat the growing risks of drought in one of America’s most vulnerable regions. As the Southwest grapples with dwindling water supplies amidst cities and landscapes dependent on reliable precipitation, this research underscores the urgent need to enhance predictive capabilities and strengthen societal resilience in the face of a changing climate punctuated by powerful ocean-driven droughts.

 

[donsutherland1]

12 minutes ago, bluewave said:

Thanks for posting that paper which really confirms how significant a shift has occurred in the North Pacific. There was another article recently published on this paper which expands on the one that you posted. While this wasn’t what many of us on the forum wanted to hear, at least the team of researchers were clever enough to tie together paleoclimate reconstructions together with advanced climate modeling for a more coherent picture of what has been going on.

https://scienmag.com/north-pacific-climate-shifts-drive-southwest-us-drought/

In recent years, the American Southwest has been gripped by one of the most prolonged and severe droughts in recorded history. While variations in precipitation and temperature have long challenged water resource management in this already arid region, the ongoing drought has raised alarm bells for scientists, policymakers, and residents alike. Understanding what drives these shifts in water availability is critical to anticipating future risks and developing adaptive strategies. A groundbreaking new study published in Nature Geoscience now provides compelling evidence that warming in the Northern Hemisphere, particularly in the North Pacific, plays a pivotal role in shaping drought patterns over the Southwest United States through complex ocean-atmosphere interactions.

This research combines innovative paleoclimate reconstructions with advanced climate modeling to unravel how moderate warming episodes in Earth’s past—specifically during the mid-Holocene, around 6,000 years ago—triggered oceanic and atmospheric responses that closely mirror modern drought conditions. By studying leaf-wax stable isotopes preserved in sediment cores, the authors reconstructed ancient rainfall patterns with unprecedented precision. These reconstructions revealed that subtle changes in ocean temperatures off the North Pacific coast led to atmospheric circulation shifts that suppressed precipitation across the Southwest, a mechanism remarkably similar to currently observed drought drivers.

What makes this work especially illuminating is its identification of the Pacific Decadal Oscillation (PDO) as a critical mediator in this process. The PDO is a naturally occurring climate phenomenon characterized by long-term fluctuations in sea surface temperatures and atmospheric pressure in the North Pacific Ocean that profoundly influence weather and climate patterns across North America. The study’s findings indicate that moderate hemispheric warming can excite a PDO-like state—specifically its negative phase—resulting in sustained drying conditions in the Southwest. This conclusion challenges prior assumptions that natural oscillations would eventually reverse and alleviate drought conditions, instead implying that external forcings such as global warming may stabilize drought-inducing patterns.

 

The implications for future climate projections are sobering. Simulations of twenty-first century climate pathways, driven by anthropogenic greenhouse gas emissions, demonstrate that similar ocean-atmosphere dynamics are likely to emerge and endure. These simulations forecast persistent reductions in winter precipitation over the Southwest through at least the mid-century, exacerbating the region’s already critical water scarcity issues. Given that winter rains supply a substantial portion of the region’s annual precipitation and recharge vital aquifers, prolonged deficits pose significant threats to agriculture, urban water supplies, and natural ecosystems.

However, the study also reveals that current climate models may underestimate the severity of these precipitation deficits. The authors suggest that the ocean-atmosphere coupling—how strongly and accurately models simulate the interaction between ocean warmth and atmospheric circulation—is likely too weak in existing frameworks. This underestimation means that official drought risk assessments and water management strategies may not be adequately prepared for the intensity or duration of future dry spells dictated by North Pacific variability under a warming climate.

This advances a growing body of evidence underscoring the Pacific Ocean’s outsized influence on terrestrial climate variability in the western United States. The North Pacific’s role is multifaceted, involving the modulation of storm tracks, alterations in jet stream position and strength, and changes in moisture transport pathways. By illuminating the mechanisms through which relatively moderate warming perturbs this system, the research offers a nuanced understanding of regional climate dynamics that transcends simplistic attributions to long-term warming or random variability alone.

Perhaps most compellingly, the paleoclimate perspective grants the study an unparalleled vantage point. Utilizing ancient environmental archives to calibrate and validate model simulations bridges the gap between historical climate fluctuations and future projection scenarios. This approach ensures that the conclusions are firmly rooted in empirical evidence, helping to surmount some of the uncertainties that plague climate prediction in complex transitional zones like the Southwest. The mid-Holocene period serves as a natural analog for how the contemporary Earth climate system might respond to ongoing warming trends.

The study’s methodology highlights the innovative use of leaf-wax isotopes, a biomarker that preserves signals of past hydrological conditions through changes in hydrogen isotope ratios. This technique captures past rainfall variability integrated over plant growing seasons and provides a proxy record that can be spatially and temporally correlated with model outputs. Such high-resolution paleoclimate data strengthen confidence in attributing Southwest drought episodes to ocean-driven atmospheric circulations rather than isolated terrestrial or stochastic factors.

In practical terms, these findings emphasize the need for water managers, urban planners, and policymakers to incorporate dynamic ocean-atmosphere feedbacks into drought risk models and resource allocation strategies. Static assessments based solely on historical precipitation trends could lead to dangerously optimistic assumptions. Instead, adaptive frameworks must account for the possibility that warming seas off the Pacific Northwest and Alaska may sustain drying influences for decades, intensifying competition for scarce water supplies across municipal, agricultural, and ecological sectors.

Scientists are also calling for an urgent refinement of climate models to better replicate the subtle but critical feedbacks identifying the ocean’s influence on atmospheric patterns that steer precipitation regimes. Such improvements are crucial, as underestimating these processes risks downplaying the Southwest’s vulnerability to exacerbated drought conditions and the cascading socioeconomic impacts that follow. Enhanced model sophistication will also improve the reliability of seasonal and decadal forecasts, crucial for water allocation decisions in drought-prone regions.

Furthermore, this research situates the Southwest drought within the broader context of anthropogenic climate change, illustrating that natural variability modes like the PDO can be amplified or modulated by human-driven warming. This intersection complicates predictions but also stresses the urgency of climate mitigation efforts. Without substantial reductions in greenhouse gas emissions, these drought-favoring ocean-atmosphere states may become increasingly entrenched, imperiling water security for millions of residents and straining fragile ecosystems.

The findings also contribute to the growing discourse on climate resilience and the need for sustainable water use practices. Recognizing that intensified drought risk is not merely cyclical but potentially a forced response to anthropogenic warming highlights the importance of diversified water portfolios, investments in conservation technologies, and reforms in water rights systems. Communities in the Southwest must prepare for a future where drought is not an anomaly but a persistent stressor shaped by global climate dynamics.

In summary, this landmark study integrating paleoclimate evidence and future climate modeling transforms our understanding of the Southwest United States drought by pinpointing the North Pacific ocean-atmosphere system as a central driver modulated by Northern Hemisphere warming. It challenges prevailing assumptions about the transitory nature of current drought conditions and suggests that external forcing is capable of sustaining drought-inducing oceanic patterns similar to the negative phase of the Pacific Decadal Oscillation. This new insight demands meaningful recalibrations in climate prediction frameworks and resource management policies to adequately prepare for a potentially drier future under continued global warming.

The message is unequivocal: the interplay between warming seas and atmospheric circulation cannot be overlooked if we aim to understand and combat the growing risks of drought in one of America’s most vulnerable regions. As the Southwest grapples with dwindling water supplies amidst cities and landscapes dependent on reliable precipitation, this research underscores the urgent need to enhance predictive capabilities and strengthen societal resilience in the face of a changing climate punctuated by powerful ocean-driven droughts.

 

The article is actually based around on the same paper. 

[TheClimateChanger]

2 hours ago, donsutherland1 said:

A new paper that just came out reaffirms the Western Pacific warming from climate change and notes how the atmosphere-ocean forcing is similar to that for a PDO-

Excerpts concerning West Pacific Ocean Warming:

The simulations with prescribed vegetation show that mid-Holocene reductions in winter precipitation result from a coupled ocean–atmosphere response centred in the Pacific Ocean excited by hemispheric warming. This is evident in a distinct pattern of SST changes over the North Pacific, with intense surface warming extending across the mid- to high-latitude western Pacific surrounded by a ‘horseshoe’ pattern of minimal surface warming or cooling to the east and a weak La Niña-like pattern in the tropical Pacific... This ocean temperature pattern is accompanied by a region of increased sea-level pressure over the North Pacific, indicating a weakened Aleutian Low. The North Pacific surface temperature and pressure patterns are reminiscent of the negative phase of the Pacific Decadal Oscillation..., which has been implicated in the length and severity of historical wintertime precipitation deficits over the Southwest United States. However, unlike the observed PDO, which is a decadal-scale mode of variability presumed to be internally generated, in the mid-Holocene this pattern emerges as a sustained state in the North Pacific that dominates the climate over several millennia.  

The paper linked the pattern to decreased winter precipitation in the Southwest. So, as warming continues and the pattern becomes predominant, winter precipitation is expected to decline in an already dry region.

The paper did not discuss implications for winters in eastern North America. 

Can you speculate as to implications for winter in eastern North America?

[Stormchaserchuck1]

The +AO coming up is so extreme, it had to even out with massive ridges in northern Europe/Greenland, and NE of Japan, a short time after. The actual H5 gets down to 5080dm just south of Alert, Canada later on today! 

[KakashiHatake2000]

i have a few to several questions with in regards to this topic so how come we apparently are experiencing more la ninas im guessing that is what yall are talking about also are they becoming shorter wouldnt el nino come in eventually i would think as well since apparently el nino happens more than la nina what about since climate change and global warming wouldnt that correlate to el nino since its warm and warm waters or is it just some sort of opposite effect type thing if yall could please explain all of this in simple terms 

[donsutherland1]

48 minutes ago, TheClimateChanger said:

Can you speculate as to implications for winter in eastern North America?

For eastern North America, the relationships are weak, especially for snowfall. Nevertheless, an increased tendency for the PDO to be negative would translate into some reduction in seasonal snowfall and also warmer winters. However as the relationships are weak, additional variables could, at times, more than compensate for the PDO's state.

[Stormchaserchuck1]

7 minutes ago, KakashiHatake2000 said:

i have a few to several questions with in regards to this topic so how come we apparently are experiencing more la ninas im guessing that is what yall are talking about also are they becoming shorter wouldnt el nino come in eventually i would think as well since apparently el nino happens more than la nina what about since climate change and global warming wouldnt that correlate to el nino since its warm and warm waters or is it just some sort of opposite effect type thing if yall could please explain all of this in simple terms 

Global warming is associated with a stabilization of the Earth climate.. less low pressures/wind, more high pressures. Since the Tropical Pacific is associated with strong winds as an "average", cooling the waters as much as 3-5c along the equator for "neutral" compared to areas north and south, then an El Nino, and actually strong El Nino, is a stabilization of that system. This is not what has happened since 1998... we have actually seen cold SSTs relative to the global warming on the order of 4-5 standard deviations below normal during that time.. the thought is that more El Nino's will happen in the coming time to even this system out, as a product of global warming. However, the last 27 years is a very interesting datapoint because something is causing an opposite pattern.  

[TheClimateChanger]

Just now, donsutherland1 said:

For eastern North America, the relationships are weak, especially for snowfall. Nevertheless, an increased tendency for the PDO to be negative would translate into some reduction in seasonal snowfall and also warmer winters. However as the relationships are weak, additional variables could, at times, more than compensate for the PDO's state.

That's what I thought. I was surprised AI suggested a tendency towards colder winters when I prompted the question, citing colder winters in the 1940s-70s coinciding with a predominantly negative PDO?

[KakashiHatake2000]

6 minutes ago, Stormchaserchuck1 said:

Global warming is associated with a stabilization of the Earth climate.. less low pressures/wind, more high pressures. Since the Tropical Pacific is associated with strong winds as an "average", cooling the waters as much as 3-5c along the equator for "neutral" compared to areas north and south, then an El Nino, and actually strong El Nino, is a stabilization of that system. This is not what has happened since 1998... we have actually seen cold SSTs relative to the global warming on the order of 4-5 standard deviations below normal during that time.. the thought is that more El Nino's will happen in the coming time to even this system out, as a product of global warming. However, the last 27 years is a very interesting datapoint because something is causing an opposite pattern.  

oh okay thank you so im guessing more enso? and el nino and less la nina long story short

[donsutherland1]

3 minutes ago, TheClimateChanger said:

That's what I thought. I was surprised AI suggested a tendency towards colder winters when I prompted the question, citing colder winters in the 1940s-70s coinciding with a predominantly negative PDO?

I suspect that the increase in aerosols that drove the general cooling into the 1970s more than overcame the modest warming effects of the PDO- during the winters.

[Stormchaserchuck1]

5 minutes ago, KakashiHatake2000 said:

oh okay thank you so more el nino and less la nina long story short

In the coming time, there will probably be 60% El Nino's, or +20% more than La Nina's.. it's just really interesting that after the 97-98 Super El Nino the opposite occurred. That's probably not a sustainable pattern though, and will probably switch in the coming time. That's why they have also developed the "RONI", which is relative average compared to the global warming (if global warming is +0.5, and Nino 3.4 is 0.0, that's a -0.5 RONI).