Advertisements

Monster El Nino Hurls Record Barrage of Hurricanes at Hot Blob, Sets Sights on Drought-Ravaged California

The Hot Blob in the Northeastern Pacific held its own for quite some time. But it now faces the assault of a barrage of tropical cyclones spat from the maw of a monster El Nino that is now tracking its way toward the strongest such event on record. If this keeps up, the Ridiculously Resilient Ridge warding storms off the US West Coast will be besieged by increasingly powerful cyclonic systems. The Ekman pumping from such storms will cool the ocean surface at its periphery and expanding toward its heart, eventually crushing the ocean impetus for ridge formation. The continuation of such a pattern could then kick Bjerknes feedback into higher gear — opening wide the door for powerful storms striking the US West Coast this Fall and Winter.

*   *   *   *   *

A Record-Shattering Barrage of Pacific Cyclones

Late during the evening of August 29th of 2015 something odd happened. For the first time in the history of modern meteorological record keeping, three category four typhoons simultaneously churned their way northward through the Pacific Ocean. These massive and powerful storms, just one category shy of the strongest typhoons we have a measure for, were hurled out of a region of extremely hot sea surface temperatures near the Equator. A zone, that for late August was also hitting record hot levels amidst a building Monster El Nino. And never before in modern memory had so many storms of such high intensity filled Pacific Ocean waters.

image

(Signs that powerful Fall and Winter storms are coming for the US West Coast? From north to south, strong cyclones are starting to put the squeeze on the Ridiculously Resilient Ridge. The Central and Eastern Pacific between 10 and 30 North, in particular, shows an eye-widening number of tropical cyclones. As of Tuesday, September 1, a whopping four tropical systems were churning northward out of an extremely hot El Nino zone. Image source: Earth Nullschool.)

By today, the furthest northward cyclones had vented their fury and dropped in intensity. Meanwhile, a fourth storm — tropical depression 14-E — was in the process of exploding over the very hot waters of the Eastern Pacific. It’s an unprecedented number of storms flowing out of what may become the strongest El Nino on record as part of a powerful ocean-atmospheric feedback.

Strong Bjerknes Feedback to Crush RRR?

Now, this strong storm pulse is starting to put the squeeze on the famed Ridiculously Resilient Ridge (RRR). It’s a persistent ridge that for the better part of three years has turned storms away from the US West Coast — deepening already prevalent drought conditions over California and threatening water security across the US West.

But now the RRR is surrounded by storms. A strong frontal trough runs from 30 North across the Central Pacific and on up into the Bering Sea. Another significant late summer low churns off the Pacific Northwest — running south and east toward Seattle and British Columbia. And four tropical cyclones push northward into the ridge’s southern boundary. It’s a full court atmospheric press. One that, through the mechanism of Ekman pumping, will push for the generation of upwelling and related cooling of the Northeastern Pacific waters beneath the RRR.

Bjerknes Feedback

(Sea surface temperature and atmospheric conditions are beginning to fall more in line with an El Nino related pattern called Bjerknes Feedback. Image source: NOAA.)

If this happens, a good portion of the RRR’s atmospheric inertia will fail — opening wide the door for a powerful west to east storm track development fed by heat rising off a Monster El Nino sprawling over the Equatorial zones. It’s a pattern that’s starting to look like a rather significant Bjerknes-type feedback to a record or near record El Nino. One that may well continue to develop and grow ever-stormier as Fall progresses.

2015 El Nino Still Heating Up, Expected to Heat Up More

Feeding the powerful pulse of storms is a still-heating Equatorial Pacific. As of Monday, NOAA’s Weekly El Nino Report found that the critical Nino 3.4 zone had warmed 2.2 degrees Celsius above average. This warming follows an inexorable three month rise that began in June and has mostly continued unabated. Furthermore, seasonal trends together with the already powerful observed atmospheric feedbacks would tend to continue to push surface warming through October and November. So it’s likely that an El Nino that has already ventured well into monster event range will warm further over the coming 4-10 weeks — setting the stage for a possible excession of 1997’s record setting intensity.

image

(The 2015 El Nino is starting to look like one of the very intense events some climate models predicted as an upshot of human-forced global warming. It’s only early September and Nino 3.4 is already 2.2 C hotter than average. This Equatorial Pacific region is still heating up as storm-forced up-welling begins to develop cool regions in the RRR supporting zones of the Northeastern Pacific Hot Blob. It will take a boatload of strong storms to crush the RRR, but the still strengthening monster El Nino to the south keeps firing them northward. Image source: Earth Nullschool.)

Model runs still point toward this possibility with CPC/IRI convergent and dynamic 3 month average predictions in the range of 2.3 to 2.5 C above average (which would beat out 1997’s 2.2 C departure). Meanwhile, uncorrected CFSv2 model runs continue to put the October, November, December 3 month average prediction in the range of 2.75 C above baseline. A level that would basically blow the 1997 El Nino out of the water. To this point it’s worth re-iterating that weekly sea surface temperature departures for the Equatorial Pacific are now entering record setting ranges. Many analysts, like Weather Underground’s Steve Gregory, expecting these waters to continue to warm over the coming weeks.

Conditions in Context: Look Out For Rough Weather Coming to US West Coast

Though it’s too early to lock in the death of the RRR, conditions are lining up that will continue to put the squeeze on this persistent weather pattern. As a result, chances for some very intense storms beginning to slam into the US West Coast starting during October, November and December are on the rise. For those looking to a possible end to the droughts, wildfires and water shortages in the Western US, this potential change in conditions may be seen as a relief.

However, such an extreme switch brings with it the distinct possibility that storms associated with a potential strongest El Nino on record will be very disruptive. The droughts and numerous wildfires throughout the West have established soil conditions that will only enhance flood related impacts. Powerful rains associated with El Nino will likely increase erosion and further damage soils in regions already impacted by the severe droughts, mass tree deaths, and wildfires related to human forced climate change and fossil fuel burning.

California missing two years of rain

(As of August 13, 2015, some parts of California were facing a rainfall deficit of 2 years or more. In order to break the drought, 2015’s monster El Nino would have to set off severe flood conditions during Fall and Winter. With the RRR under threat, is California staring down the barrel of a switch to an equally ridiculous barrage of storms? Image source: National Weather Service, Phoenix.)

To this final point, parts of California are now entering a 2 year rainfall deficit. A deficit that, in some places, equals 30-40 inches or more. A monster El Nino crushing the RRR and massively amplifying the Pacific Ocean storm track and pumping immense volumes of moisture into the mid-latitudes raises the risk that this much water or more could be dumped upon parts of California and the US West Coast in little more than a season. A switch from persistent, crushing drought to flash flood that could be extraordinarily disruptive.

Links:

Earth Observatory: Trio of Hurricanes in the Central and Eastern Pacific

Earth Nullschool

National Hurricane Center

The Ridiculously Resilient Ridge

NOAA: Bjerknes Feedback

NOAA’s Weekly El Nino Report

CFSv2 Model SST Predicted Departures in Nino 3.4

Steve Gregory: El Nino Stronger!

Climate Change Could Double the Likelihood of Super El Ninos

National Weather Service, Phoenix

Hat Tip to Ray Duray

(Please support public, non-special interest based science like the fantastic El Nino reports provided by NOAA and without which this analysis would not be possible.)

Advertisements

Third Warm Kelvin Wave to Raise Extreme El Nino by Fall?

More fuel for El Nino’s fire and a record hot 2015 on the way…

Last week, a set of climate models predicted the emergence of a large and moderately strong westerly wind burst running against the trades associated with an eastward propagating cloudy and rainy phase of the Madden-Julian Oscillation (MJO). And, over the past few days a moderate strength, but very wide-ranging, westerly wind pattern appeared.

image

(A strengthening westerly wind burst over the Western Equatorial Pacific could produce a third warm Kelvin Wave and further heighten an El Nino that already has a potential to be very intense come Fall. Image source: Earth Nullschool.)

Today, 20 to 35 mile per hour westerly winds are prevalent along a 2,500 mile stretch of ocean running from just east of the Philippines, across an equatorial zone just north of New Guinea, and on eastward for hundreds more miles in the direction of the Date Line. The winds are associated with numerous low pressure systems developing both north and south of the Equator — their cyclonic wind patterns joining in a daisy chain like feature to drive a large synoptic westerly wind back-burst (WWB).

Over the next few days, winds within the zone are predicted to strengthen to near gale force intensity. But it’s the size of the zone that may have the greatest impact.

Strong, long-fetch westerlies in this region of the world have a tendency to push warm surface waters, now topping off at 31 degrees Celsius (and 1-2 C above the already hotter than normal 1979 to 2000 average), downward and eastward. This heat pump action generates what, in meteorological parlance, are known as warm Kelvin Waves. And warm Kelvin Waves are high energy fuel for strengthening El Ninos.

Two Warm Kelvin Waves

(Warm water propagation through the upper 300 meters of the central and eastern Equatorial Pacific serves as oceanic fuel for El Nino events. In the above graph by NOAA, not one but two warm Kelvin Waves are indicated — one peaking during April and May, and a second ongoing now. Will a significant westerly wind burst, now lighting off in the Western Pacific, generate a third warm Kelvin Wave by August? Image source: NOAA’s Climate Prediction Center.)

During mid-March, the Strongest Madden Julian Oscillation on record drove an extreme westerly wind burst (WWB) and produced a very strong Kelvin Wave. This Kelvin Wave ensured the progression to El Nino during 2015, an El Nino event that would have probably reached moderate strength by summer on the force of this single Kelvin Wave’s heating alone. An El Nino ensuring, when combined with the greenhouse gas heat forcing produced by humans, that 2015 would march into the record books as yet one more hottest year in the global climate record.

By early May, a second, albeit somewhat weaker, WWB generated another warm Kelvin Wave, heightening the potential for strong El Nino yet again. This time El Nino model forecasts picked up the doubled Kelvin Wave signal and began to produce some rather extreme predictions for El Nino come Fall. Late spring is an uncertain time for El Nino models due to an ocean tendency to cool down by September. So the impact of strong Kelvin Waves during spring can be somewhat muted. However, as June arrived, the model consensus for a strong El Nino emerging by Fall had solidified, if not along a range quite so extreme as some of the May numbers indicated.

Meanwhile, in the Central Pacific, anomalous warm sea surface temperatures were continuing to build. By mid-May, Central Pacific sea surface temperatures exceeded the moderate El Nino threshold of 1 C above average. By Monday, June 22, NOAA’s weekly El Nino statement had indicated that the Central Pacific region had warmed to a 1.4 degree Celsius positive anomaly. A level just 0.1 C short of strong El Nino intensity.

Adding a third significant Westerly Wind Burst on top of an already warming Equatorial Pacific throws yet one more variable into the dynamic El Nino forecast. A variable that could heighten the already strong potential for a major El Nino event late this Summer through to Fall. And one that could further heighten extreme global record hot temperatures during 2015. For the late June WWB is likely to produce an extraordinary third Warm Kelvin Wave, giving the currently strengthening El Nino yet one more shove toward increasingly extreme conditions.

Links:

NOAA’s Climate Prediction Center (Please support public, non-special interest based, science like the quality research and data provided to us daily by NOAA.)

NOAA’s weekly El Nino statement

Strongest Madden Julian Oscillation On Record

Madden-Julian Oscillation

Earth Nullschool

 

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

Advertisements
%d bloggers like this: