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Polar Amplification vs a Godzilla El Nino — Is the Pacific Storm Track Being Shoved North by Arctic Warming?

It’s an El Nino year. One of the top three strongest El Ninos on record. The strongest by some NOAA measures. And we are certainly feeling its effects all over the world. From severe droughts in Southeast Asia, Africa, and South America, to Flooding in the Central and Eastern US, Southern Brazil, and India, these impacts, this year and last, have been extreme and wide-ranging. During recent days, Peru and Chile saw enormous ocean waves and high tides swamping coastlines. Record flooding and wave height events for some regions. All impacts related to both this powerful El Nino and the overall influence of human-forced warming by more than 1 C above 1880s temperatures on the whole of the hydrological cycle.

Amped up by a global warming related 7 percent increase in atmospheric water vapor (and a related increase in evaporation and precipitation over the Earth’s surface), many of these El Nino related impacts have followed a roughly expected pattern (you can learn more about typical El Nino patterns and links to climate change related forcings in this excellent video by Dr Kevin Trenberth here). However, so far, some of the predicted kinds of events you’d typically see during a strong El Nino have not yet emerged. A circumstance that may also be related to the ongoing human-forced warming of the globe.

Storm Track Not Making it Far Enough South

Particularly, there has been an absence of powerful storms running in over Southern California then surging on into Arizona, New Mexico and West Texas. During strong El Nino events, heat and moisture bleeding off the super-warmed Equator have typically fed powerful storms racing across the Pacific. These storms have tended to engulf the entire US Pacific Coast from San Diego through to Seattle. However, much of the storm energy is often directed further south toward Central and Southern California.

Ridiculously Resilient Ridge Returns

(A massive Pacific storm being warded off by high pressure systems over the US West Coast on Tuesday, January 26th. Image source: Earth Nullschool.)

These storms tend to run over regions that are typically much drier. So strong El Ninos of the past have often generated abnormal and memorable storms and rains. But this year there has been, mostly, an abscense of such events. Storms have slammed into Northern California, Oregon, been deflected back into the coasts of Canada and Alaska, or even been bottled up near the Aleutian Island Chain.

But today, a high pressure cell dominates the western US, warding off a powerful storm system. The storm, howling just south of Alaska and pushing out average 60 foot wave heights and hurricane force winds across the Pacific, is predicted to rebound toward Alaska where it will become bottled up in the Bering sea and push above freezing temperatures into the Arctic Beaufort Sea during Winter. The storms and rains will steer far away from Southern California and even much of California altogether.

Rainfall Patterns Have Tended Toward the North, Contrary to NOAA’s Seasonal Predictions

 

NOAA Precipitation

(NOAA precipitation quantities prediction for the coming week is indicative a continued northward shift of the Pacific Storm track. Image source: NOAA.)

It’s a pattern more reminiscent of some strange ridiculously resilient ridge (RRR) than that of a strong El Nino. And though storms later this week are again predicted to slam into the Northwest and weekly rainfall totals are expected to rise to near 1 inch for parts of Southern California, the path of these storms and related moisture flows are quite a bit further north than one would expect for a year in which strong El Nino was the dominant feature.

The moisture flow, instead, so far has tended northward across the upper and central tiers of the US even as the El Nino related moisture bleed toward the Gulf and East Coasts has remained quite intense. Such observed weather is both contrary to what we’ve tended to know about Strong El Nino and to NOAA’s seasonal forecasts which had predicted much more rain for the southwest than what we’ve seen so far.

Seasonal Outlook NOAA

(NOAA three month outlook is more in line with traditional strong El Nino forecasts bringing strong storms in through the southwestern US. We currently do not see a prevalence of that particular pattern. Image source: NOAA’s Climate Prediction Center.)

Polar Warming + Hot Blob Tugging the Storm Track Northward?

Since weather patterns related to El Nino are an aspect of global atmospheric dynamics — teleconnections between the influence of an excess of hot air and heavy rainfall at the Equator and of large scale atmospheric wave patterns downstream, you have to wonder if there isn’t some kind of influence competing with El Nino on a global scale. One with enough oomph to nudge the Pacific Storm Track northward.

Hot Blob Pacific Northwest

(The Hot Blob is still a dominant feature of ocean waters in the Pacific Northwest. Is its influence helping to pull the Pacific Storm Track northward during a strong El Nino year? Image source: Earth Nullschool.)

The first likely suspect is the pool of still much warmer than normal sea surface temperatures lurking off the US West Coast. Though somewhat diminished from their peak during 2014 and 2015, the waters in the hot blob off California, Oregon, Washington, Canada and Alaska are still in the range of 1 to 3 C above average. A very large region of significantly warmer than normal ocean surfaces that wasn’t present during the 1982-83 and 1997-1998 super El Ninos. And much of the warmest anomalies are now centered much further to the north along the coast of Alaska.

But the second potential player is likely even more significant. And that would be an ongoing and extreme warming of the northern polar region. Heating at the Pole generates less thermal gradient between the higher Latitudes and the Equator. And such a lessened gradient would tend to impact the strength of the circumpolar winds that drive weather systems and storm tracks. In particular, the overall warming of the globe would tend to pull these storm tracks northward even as the loss of thermal gradient would tend to enhance wave patterns in the Jet Stream.

 

Polar Amplification January 26

(Polar Amplification shown as very intense in the January 26 Climate Reanalyzer graphic. Is Polar Amplification helping to shove the Pacific Storm Track northward even during a record strong El Nino year? If so, it’s bad news for long term moisture levels in the US Southwest. Image source: Climate Reanalyzer.)

Perhaps also specifically related to this ongoing polar amplification, we find that two warm slots — one over the Barents and far North Atlantic east of Greenland and another over the Bering — have tended to develop during recent Winter years. These slots have often served as staging areas for warm air invasions of the Arctic. But what they also represent are regions of water that have been freshly liberated from their sea ice coverings. As such, these vast regions of water serve as heat transport and ventilation zones. And all this extra heat energy may be sucking the related North Atlantic and North Pacific Storm tracks into what may well be described as an oceanic and atmospheric trap.

If such a situation where the case, we’d tend to see a dipole of warm east, cold west in the storm trap regions. And that’s exactly what we’ve seen more and more of with Greenland and Siberia serving as the backdrops to reinforce this tendency. Thus setting up the stage for cold air slots cutting through Northeast Siberia and Northeast Canada and warm, wet air slots over Alaska and the UK.

The question to be asked is, then, are these new influences related to human-forced warming also now doing battle with El Nino for control over the Pacific Storm Track? And has that influence increased enough to dramatically nudge that track northward? We may find the answer to that question in what happens to the direction of powerful Pacific Storms over the next few months. But early indications seem to be that polar warming and the related hot blob may have thrown a wrench in the kinds of El Nino storms that we’ve been used to.

Links:

El Nino Related Waves, Floods Strike Chile

Dr Kevin Trenberth on El Nino and Climate Change

Earth Nullschool

Climate Reanalyzer

NOAA’s Climate Prediction Center

NOAA

The United States Drought Monitor

Hat Tip to Colorado Bob

Hat Tip to DT Lange

Hat Tip to Andy in San Diego

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Summer El Nino on The Way; Long Range Models Are Still Freaking Out

Well, it’s official. According to NOAA’s May 14 update, we are now looking at a 90 percent chance that El Nino conditions prevail through Northern Hemisphere Summer and a greater than 80 percent chance El Nino will last throughout all of 2015:

El Nino Potential through 2015

(Climate Prediction Center’s ENSO probability forecast shows 90 percent chance of El Nino through June, July and August and a greater than 80 percent chance that El Nino continues on through to the end of this year. Image source: CPC/IRI.)

What this means, especially when we add in likely record warm global atmospheric temperatures (due to an excessive burning of fossil fuels by human beings) throughout the El Nino event period, is some rather odd, and probably extreme summer weather.

For the US, it means an increasing likelihood of heavy precipitation events from the southern plains states through the desert southwest. Storm track intensification through the Pacific to North America means that extreme rainfall events are a distinct possibility for states like Texas, Oklahoma, Colorado, Arizona, Nevada, and New Mexico. California may even see some abnormal summer rainfall, taking a bit of the edge off the current drought.

Moving southward, we find drier conditions for equatorial South America and warmer than normal conditions for much of Brazil and Chile. Northern Hemisphere Summer El Nino also enhances the risk of drought throughout Australia, Southeast Asia, and India. In particular, India is vulnerable to monsoonal disruption due to emergence of El Nino during summer time. Enhanced precipitation near the date line also can spur increased cyclone development for the Western Pacific.

Northern Hemisphere teleconnections

(A geographic representation of major prevailing summer El Nino teleconnections. Image source: Berkley.)

These sets of atmospheric changes are what we could generally expect from a typical El Nino emerging throughout Northern Hemisphere summer. But we’re not really dealing with normal conditions. We’re dealing with global temperatures in the range of +0.8 degrees C above 20th Century averages and + 1 C above 1880s averages. As such, we should probably look to the margins for potential added impact.

Two areas in particular come to mind when considering such outliers. The first region is a zone from Ukraine through to Western Russia. Under added human heat forcing and conditions prevalent during summer El Ninos, this region shows an increased likelihood of drought and heatwave. A vulnerability that became particularly apparent during the El Nino of 2009-2010. Drought conditions are somewhat widespread for that region already this year. In addition, atmospheric high pressure development in this vulnerable area would now, with the enhanced surface warming due to human heat forcing, telegraph into the Arctic through a vulnerable zone near Yamal and the Kara and Laptev Seas. This would particularly enhance snow melt, permafrost thaw, and sea ice melt throughout this region. So with El Nino now a summertime certainty, this broader area certainly bears watching.

El Nino Teleconnection

(El Nino teleconnection to warming in Northwestern North America through to the Arctic Ocean and in regions of Central, Western and Northern Asia are possible this summer. Above is a GFS model  forecast temperature anomaly summary provided by The University of Maine’s Climate Reanalyzer.)

The second region to look out for is the zone ranging from Northwest Canada through Alaska and on into the Chukchi and Beaufort Seas. Summer El Ninos tend to enhance warming for this region. When adding in an already persistent heating throughout 2015 winter and spring, the area will fall under greatly heightened risk of severe wildfires and extreme and early snow and sea ice melt. Early extreme wildfires in British Columbia combined with rapid sea ice recession already ongoing through the Beaufort and Chukchi may well be indications that such a trend has already asserted.

Some Long Range Models Are Still Freaking Out Over a Potential Monster El Nino Later This Year

Moving beyond summer, we find a wide range of model consensus estimates showing strong El Nino by fall and winter of this year. NINO 3.4 departures from an average of global model ensembles compiled by Weather Underground hit a value of +1.7 C by September. A level just below the so-called Super El Nino Threshold of +1.8 C.

NOAA CFSv2 ensembles have continued to ramp higher. Weighted seasonal means have now spiked to +2.75 C for the key NINO 3.4 region with unweighted ensembles hitting +3 C for October, November and December. Weighted monthly means have spiked to +3 C anomaly for November while unweighted anomaly values for the same month have proceeded off the charts to an implied +3.5 C:

Nino 3.4 Monthly Anomalies May 15

(Some El Nino forecast models, like the one above, are really freaking out about the potential for a monster event by the end of this year. This NOAA model is basically off the charts. Image source: NOAA’s Climate Prediction Center.)

Should these predicted values emerge, they will literally blow the 1998-1999 Super El Nino out of the water. A monster event to shatter all records.

It’s likely that the currently extreme subsurface temperatures due to a very strong warm Kelvin Wave as well as continued powerful west wind back-bursts have kicked these models into freak out mode. And it’s certainly an issue worth keeping an eye on.

But it’s also worthwhile to consider that global deep ocean and atmospheric dynamics will push to cool equatorial Pacific waters during September, which would tend to tamp down warming extremes. A factor that many models, which measure the shallow water zone primarily, tend to miss.

Dr. Kevin Treberth, a top expert on El Nino and Ocean Temperature dynamics, notes to Weather Underground in a recent interview that:

“What happens after this Kelvin wave response is all over the place. This El Niño is being fought by the annual cycle, which tries to make SSTs cold by Sept-Oct.  That tendency keeps the warmest waters back near the International Date Line and cuts off the Bjerknes feedback.  If the SSTs develop to be big enough to overcome the annual cycle tendencies, then the Bjerknes feedback can kick in.”

For reference, Bjerknes feedback involves storm formation and subsequent west wind backbursts east of the Date Line and on toward South America. A feedback that tends to trap and channel ocean surface heat into the relevant El Nino zones and generally enhance warm sea surface temperature anomalies:

Bjerknes Feedback

(Graphic illustration of Bjerknes feedback showing sea surface temperature anomalies in the color measure and direction of wind flow indicated by black lines. It’s feature influenced by a general shoving of the Walker Cell eastward [implied but not shown]. Image source: ENSO as an Integrating Concept of Earth Science.)

So, at this point, we have a lock on a weak to moderate El Nino event continuing through this summer. After that time, an unprecedentedly warm Kelvin Wave will do battle with a seasonal tendency for cooling in the Eastern Equatorial Pacific. And if it wins out, we may see something never before recorded in the whole of the Earth Sciences — which would be very bad news for rates of global surface temperature increase this year, along with a huge number of other issues.

If not, we likely have a mid ocean El Nino through Fall and Autumn. And that may be bad news for a California desperately in need of drought relief.

Links:

NOAA’s May 14 El Nino Update

CPC/IRI

Berkley

Climate Reanalyzer

Weather Underground

ENSO as an Integrating Concept of Earth Science

Climate Change Ratcheting Up: El Nino Strengthens in Equatorial Pacific Increasing Likelihood for Record Warm 2015

A powerful Kelvin Wave continued to ripple through the near-surface waters of the Equatorial Pacific this week — heightening sea surface temperatures, strengthening an ongoing El Nino, and pushing a wave of oceanic heat back into a human-warmed atmosphere that is hotter now than at any time in modern human reckoning.

High temperature anomalies in the Kelvin Wave plug have spread out across the ocean surface. Readings in the range of +1 to +2 C above average stretch along surface waters all the way from the Date Line through 120 West Longitude. East of the 120 line, surface waters have now hit readings of 2 to 4 degrees Celsius above average. And lurking just below the surface along thousands of miles of ocean is a dense zone of 5-6 degree above average water. A zone of extreme heat at the heart of the current intense Kelvin Wave:

NOAA Kelvin Wave April 23

(A strong Kelvin Wave shuts down atmospheric heat transfer into the Equatorial Pacific setting up conditions for an extended El Nino and possible new record heat for 2015. Image Source: NOAA’s Climate Prediction Center.)

Heat that could well make 2015 yet another worsening of the human warming and extreme weather twilight zone we now find ourselves in.

Pushing into Moderate El Nino Range

According to NOAA’s weekly El Nino report, sea surface temperatures in the critical Nino 3.4 region hit a range of 1 degree C above average last week. A jump from the previous week’s measure of +0.7 C and a new push toward moderately strong El Nino levels off the back of the current warm Kelvin Wave. Atmospheric teleconnections that are signatures of a moderate El Nino also began to emerge over past weeks — with a strengthening of the subtropical Jet and related storm track setting off powerful tornadoes, thunderstorms and heavy rain events in states bordering the Gulf of Mexico over the past ten days.

Heat content from the current Kelvin Wave is enough to continue to keep Equatorial Pacific sea surface temperatures in present ranges or to push for further warming over at least the next 1-2 months. A set of factors that will almost certainly lock near moderate El Nino conditions in through Summer and general El Nino conditions through early Autumn. The result is that the extra heat bleed off the Pacific Ocean will combine with the impressive human forcing to generate a high risk that 2015 atmospheric temperatures will beat out all-time record highs set in 2014.

Model Runs Still Showing Potential for Super El Nino

Nino 3.4 Monthly Anomalies

(Unweighted model ensemble runs show the current El Nino peaking out at extreme intensity. Long range model runs can be quite uncertain, but these are very high values. Image source: NOAA Seasonal and Monthly SST Anomalies.)

NOAA model runs also show a potential for El Nino strengthening through the end of 2015. Probability weighted CFS model ensembles (PDF) point toward a seasonal anomaly for Nino 3.4 in the range of 1998 Super El Nino values at 2.1 degrees Celsius above average by the end of 2015. Mean model runs (non-weighted) push the long range forecast heat values even higher at 2.6 C above seasonal averages or 2.75 C above monthly averages.

These unweighted long range forecasts are well outside the strength of even the monster event of nearly two decades ago. A new super El Nino that would have very serious consequences for global temperatures and result in far-reaching climate impacts should it emerge. Atmospheric temperatures that are now in the range of +0.7 C above 20th Century averages and +0.9 C above 1880s values could well push into a new range at +0.8 C and +1 C, or higher, respectively.

Super El Nino Late 2015

(Long range models show Equatorial Pacific has potential to hit near Super El Nino status by late 2015. At this time, such model runs are low certainty. Image source: NOAA Seasonal and Monthly SST Anomalies.)

Cranking up the Human Hothouse

Entering the range of 1-2 C above 1880s values is a zone of heat anomaly that will amplify already apparent ice sheet melt, sea level rise, droughts, wildfires, water stress, and ocean health impacts. At temperatures around +1.5 C we begin to enter a period of strong glacial outflows, weather instability, geophysical changes, and record related storm events in a ‘Storms of My Grandchildren‘ type scenario. At +2 C these very dangerous impacts will likely be in full swing.

It is worth noting that it took 10,000 years to warm the world 4 degrees Celsius at the end of the last ice age. Under current human fossil fuel burning scenarios, it is likely that we reach half that threshold in just 150 to 170 years — from 1880 to 2030-2050. A rapid reduction in fossil fuel emissions along a progression to a net carbon negative human society over the next few decades is absolutely necessary to prevent these outcomes. And while model forecasts indicating the potential for a Super El Nino type event for late 2015 may be somewhat uncertain, there is a much higher certainty that very dangerous climate impacts starting at the current level of human warming will ramp up here on out — with the 1.5 C threshold looking very bad and the 2.0 C threshold looking terrible.

As such, we should do all we can to prevent hitting those marks.

Links:

NOAA’s Climate Prediction Center

NOAA’s Weekly El Nino Report

NOAA Seasonal and Monthly SST Anomalies

The Storms of My Grandchildren

Far Worse than Being Beaten With a Hockey Stick

Onrush of Second Monster Kelvin Wave Raises Specter of 2015 Super El Nino

And so it appears we are living in a time of Monster Kelvin Waves — powerful confluences of Pacific Ocean heat running just beneath the surface — bringing with them the potential for both record global temperature spikes and strong, climate-wracking El Nino events.

*   *   *   *   *

Last year, a powerful pulse of sub-surface heat called a Kelvin Wave rippled across the Equatorial Pacific. It shoved sub-surface temperature anomalies into an extreme range of 6 degrees Celsius above average at a depth of 90-130 meters over an equatorial zone stretching out for hundreds of miles. Overall, this heat surge pushed anomalies below the rippling waves of the vast Equatorial Pacific from New Guinea to the Central American Coastline above 1.8 degrees C hotter than average.

image

(Building heat in Pacific Equatorial Surface waters on April 9 of 2015 — a sign of a massive pulse of hotter than normal water running at about 100 meters depth. A heat pulse that may be setting in place conditions for a powerful El Nino later this year. Image source: Earth Nullschool. Data Source: Global Forecast System Model.)

This immense heat pulse was enough to shove the equatorial region inexorably toward El Nino status. By September, mid-ocean values were hot enough to have reached the critical threshold of 0.5 C above surface value average. Perhaps more importantly, the Winter/Spring 2014 Kelvin Wave also contributed to record positive PDO values for the Pacific by December of 2014. A surface heat departure that was unprecedented to modern climates. Block-busting ocean warmth that almost certainly spurred 2014 global atmospheric temperatures to new all-time record highs in the current age of human warming.

Monster Kelvin Wave Redux

Now, a second, and equally strong monster Kelvin Wave is again rippling across the Pacific Ocean subsurface zone. A powerful pulse of heat that will reinforce the current weak, mid-ocean El Nino, lend energy to ridiculously warm Pacific Ocean sea surface states, and pave the way for a long-duration equatorial heat spike.

monster kelvin wave redux

(Monster Kelvin Wave Redux. A second powerful Kelvin Wave is surging across the Pacific Equatorial Subsurface zones, strengthing prospects for both a continued El Nino and for a record hot year in 2015. Image source: NOAA/CPC.)

As we can see in the NOAA CPC rendering above, the current Kelvin Wave is a massive and extraordinarily warm beast of a thing. It encompasses most of the thousands-miles broad Equatorial Pacific with its hottest zone peaking at 5-6 degrees Celsius above average temperatures — a region that stretches from near the Date Line all the way to just west of Central America. At +1.75 C for the entire below-surface equatorial region, the current Kelvin Wave is already approaching last year’s peak values. Values it may well exceed in the coming days.

Overall, the current Kelvin Wave seems to have more connection to the surface environment than last year’s powerful surge. A massive plug of Pacific Ocean heat readying to belch back into the atmosphere.

Some Models Show Potential For Super El Nino

Already, NOAA is upping its forecast chances for El Nino to continue through summer to 70 percent and is placing a greater than 60 percent chance that El Nino will stretch on through late autumn. An upshot from earlier predictions made just a little more than a month ago that El Nino formation for 2015 remained uncertain. Now, we have a rather high certainty that El Nino will continue throughout at least the next 4-6 months.

But perhaps more concerning is the fact that a strong El Nino is again starting to show up in some of the long range models. NOAA’s CFS ensemble shows El Nino continuing to steadily strengthen throughout 2015 reaching overall Nino 3.4 surface values above +2.1 C by October, November and December of this year:

nino34Sea

glbSSTSeaInd6

(Top frame shows predicted sea surface temperature anomalies in the critical Nino 3.4 zone exceeding 2.2 C by late 2015. Such an event would be a monster to rival or possibly exceed 1998. The lower frame shows sea surface temperature departures for the entire globe. Note the seasonal spike of 2-3+ C above average for the Eastern Equatorial Pacific. Image Source: NOAA’s Seasonal Climate Forecast.)

The departures we see in this long range forecast are extraordinary — rivaling or possibly exceeding the intensity of the 1998 Super El Nino. An event of this kind would result in powerful ocean and atmospheric surface temperature spikes, catapulting us well beyond the climate range previously established by the 1998 event. Globally, we would be entering new, record hot territory, possibly approaching 1 C above 1880s values for the 2015-2016 period.

Troubling Situation With High Uncertainty

As such, we should consider this to be a troubling situation, in need of close, continued monitoring. To this point, it is worth noting that El Nino prediction during Spring is highly uncertain. Last year’s very strong Kelvin Wave also set off predictions for a moderate-to-strong El Nino event by summer-through-fall. Though El Nino did eventually emerge, it was weaker and later in coming than expected. Now, a new set of conditions is setting up similar, and perhaps, even more intense ocean and atmosphere heat potentials.

Though still uncertain, what we observe now are ocean conditions that raise potentials for both extreme El Nino and human-warming related weather. Powerful ocean heat pulses of the kind we observe now, when combined with an extraordinary human greenhouse gas heat forcing, also increases the likelihood of another record warm year. El Nino associated droughts and heatwaves — particularly for South America, India, Australia and Europe through Central Asia are at rising risk. In the event of mid-ocean El Nino, the risk increases that the 1200 year California drought will continue or even intensify. If the heat pulse shifts eastward, a switch to much heavier rainfall (potentially terribly heavy) could coincide with a breaking of the Ridiculously Resilient Ridge pattern that has warded moisture away from the US West Coast for nearly three years. Extra heat of this kind would also tend to enhance precipitation extremes — more rain when it does rain and far more intense drought in areas affected by heat and atmospheric ridging.

Given the patterns we have observed over the last year, we could expect worsening conditions for some regions (India, Australia, some sections of South America, Eastern Europe) and the potential for a shift from one extreme to the next for other regions (US West Coast). These potentials depend on the disposition and intensity of surface heat in the Pacific, which bears an even closer watch going forward.

Links:

NOAA’s Climate Prediction Center

NOAA’s April 9 El Nino Statement

NOAA’s Seasonal Climate Forecast

Earth Nullschool

Global Forecast System Model

Monster El Nino Emerging From the Depths?

Atmospheric Warming to Ramp up as PDO Swings Positive?

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