Indian Summer Monsoon Rainfall Characteristics During Contrasting Monsoon Years
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Nature Hits the 'Pause' Button On El Nino Development
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In this Feb. 4, 2014 file photo, a warning buoy sits on the dry, cracked bed of Lake Mendocino near Ukiah, California. A potential El Nino event could offer beneficial rains to California during the 2014-15 winter.
Image: Rich Pedroncelli/Associated Press
By Andrew Freedman2014-07-10 16:52:04 UTC
The much-trumpeted development of an El Niño event in the tropical Pacific Ocean has become more muted in recent weeks, yet most signs still point to El Niño's eventual arrival, the National Oceanic and Atmospheric Administration (NOAA) reported on Thursday.
For several months now, climate forecasters have advertised a high likelihood of an El Niño event beginning in the fall or winter of 2014-2015. In the newest forecast, issued Thursday, NOAA experts and scientists at Columbia University's International Research Institute for Climate and Society said there is a 68% chance of an El Niño event starting in the northern hemisphere summer, with a higher chance, about 78%, that one will commence during the fall and early winter.
See also: Why You Can't Blame El Niño for Extreme Weather (Yet)
El Niño events are characterized by unusually warm ocean waters in the central and eastern tropical Pacific Ocean, and a range of related shifts in air circulation across the Pacific. These events have ripple effects around the world, from favoring flooding rains in parts of California to raising the odds of drought in Australia and Indonesia. They can also give an upward nudge to global average temperatures, combining with manmade global warming to lead to record warm years.
Computer model forecasts for El Nino during the next several months.
Image: NOAA/IRI
For these reasons and more, forecasters pay close attention to their development, sifting through climate clues from subsurface ocean temperatures in the tropical Pacific to trends in the trade winds that typically blow from east to west near the equator.
Right now, most of these clues suggest that El Niño is still on its way, but it is taking its sweet time, like a family on a summer roadtrip that keeps pulling off the highway at each rest stop.
Ocean temperature departures from average during June through July 2014. This shows the milder than average waters in the eastern tropical Pacific.
Image: NOAA
For example, subsurface temperature departures from average, which tend to be quite high when an El Niño event is developing, have dropped off in the past few weeks, and the atmosphere is not yet behaving like an El Niño is underway either.
With El Niño events, it takes two to tango — the air and the sea — and neither seems entirely sure that they want to dance quite yet.
Michelle L'Heureux, a scientist at NOAA's Climate Prediction Center in Maryland, says the development of El Niño has paused for a bit, which is not uncommon at this time of year. For example, she says a similar evolution happened in 2009, when a moderate El Niño developed after a summer in which the ocean and atmosphere couldn't quite get their act together.
Right now, some of the ingredients of El Niño are missing, such as weaker or even reversed trade winds (blowing from west to east instead of east to west) in the eastern and central tropical Pacific, and persistent thunderstorms in the central Pacific. However, there is an abundance of warmer-than-average water in the eastern tropical Pacific, which is a hallmark of El Niño, L'Heureux said.
Sea and air circulation during "neutral" conditions (top panel) and El Nino conditions (bottom panel.)
Image: climate.gov
“El Niño is still likely here, yes we’re seeing a little bit of a structural slowdown but I also feel like this isn’t necessarily an unexpected thing,” she said. “For forecasters, these sort of peaks and valleys are sort of par for the course.”
El Niño is part of a larger cycle that involves the ocean and the atmosphere, and is known as the El Niño-Southern Oscillation, or ENSO. L'Heureux told Mashable that the ocean part is halfway to El Niño, while the atmospheric part, the Southern Oscillation, isn't.
As NOAA explains in a post on its El Niño blog, the Southern Oscillation is "a seesaw in surface pressure between a large area surrounding Indonesia and another in the central-to-eastern tropical Pacific; it’s the atmospheric half of El Niño."
At this point, L'Heureux says, “We’ve got the "EN," but we don’t have the "SO.""
While some El Nino researchers were speculating that a strong El Niño, comparable to a record event that occurred in 1997-98 and wreaked havoc on weather patterns worldwide, was on the way, NOAA and IRI said Thursday that this is most likely not the case. Instead, they are favoring a weak-to-moderate event.
L'Heureux told Mashable that while the computer models that forecasters use to help predict El Niño events are "clustering" around a weak-to-moderate event, a strong event cannot be completely ruled out.
Subsurface water temperature anomalies in the Pacific Ocean, showing a big spike a few months ago, followed by more average temperatures in July 2014.
Image: NOAA/CPC
She says the models that suggested a strong event would occur are “Clearly backing off from that, although there’s still possible solutions here where you could get that.”
In addition to the uncertainty regarding El Niño's strength, forecasters have relatively low confidence in exactly when El Niño conditions will kick in.
L'Heureux says the computer models are "awful" at pinpointing the moment of onset and the peak intensity of these events, but they show considerable skill at predicting events overall.
That, she says, is “So ironic, because those are the two pieces of info that people want to know.”
Topics: Climate, el nino, ENSO, U.S., US & World, World
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923
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What's This?
In this Feb. 4, 2014 file photo, a warning buoy sits on the dry, cracked bed of Lake Mendocino near Ukiah, California. A potential El Nino event could offer beneficial rains to California during the 2014-15 winter.
Image: Rich Pedroncelli/Associated Press
By Andrew Freedman2014-07-10 16:52:04 UTC
The much-trumpeted development of an El Niño event in the tropical Pacific Ocean has become more muted in recent weeks, yet most signs still point to El Niño's eventual arrival, the National Oceanic and Atmospheric Administration (NOAA) reported on Thursday.
For several months now, climate forecasters have advertised a high likelihood of an El Niño event beginning in the fall or winter of 2014-2015. In the newest forecast, issued Thursday, NOAA experts and scientists at Columbia University's International Research Institute for Climate and Society said there is a 68% chance of an El Niño event starting in the northern hemisphere summer, with a higher chance, about 78%, that one will commence during the fall and early winter.
See also: Why You Can't Blame El Niño for Extreme Weather (Yet)
El Niño events are characterized by unusually warm ocean waters in the central and eastern tropical Pacific Ocean, and a range of related shifts in air circulation across the Pacific. These events have ripple effects around the world, from favoring flooding rains in parts of California to raising the odds of drought in Australia and Indonesia. They can also give an upward nudge to global average temperatures, combining with manmade global warming to lead to record warm years.
Computer model forecasts for El Nino during the next several months.
Image: NOAA/IRI
For these reasons and more, forecasters pay close attention to their development, sifting through climate clues from subsurface ocean temperatures in the tropical Pacific to trends in the trade winds that typically blow from east to west near the equator.
Right now, most of these clues suggest that El Niño is still on its way, but it is taking its sweet time, like a family on a summer roadtrip that keeps pulling off the highway at each rest stop.
Ocean temperature departures from average during June through July 2014. This shows the milder than average waters in the eastern tropical Pacific.
Image: NOAA
For example, subsurface temperature departures from average, which tend to be quite high when an El Niño event is developing, have dropped off in the past few weeks, and the atmosphere is not yet behaving like an El Niño is underway either.
With El Niño events, it takes two to tango — the air and the sea — and neither seems entirely sure that they want to dance quite yet.
Michelle L'Heureux, a scientist at NOAA's Climate Prediction Center in Maryland, says the development of El Niño has paused for a bit, which is not uncommon at this time of year. For example, she says a similar evolution happened in 2009, when a moderate El Niño developed after a summer in which the ocean and atmosphere couldn't quite get their act together.
Right now, some of the ingredients of El Niño are missing, such as weaker or even reversed trade winds (blowing from west to east instead of east to west) in the eastern and central tropical Pacific, and persistent thunderstorms in the central Pacific. However, there is an abundance of warmer-than-average water in the eastern tropical Pacific, which is a hallmark of El Niño, L'Heureux said.
Sea and air circulation during "neutral" conditions (top panel) and El Nino conditions (bottom panel.)
Image: climate.gov
“El Niño is still likely here, yes we’re seeing a little bit of a structural slowdown but I also feel like this isn’t necessarily an unexpected thing,” she said. “For forecasters, these sort of peaks and valleys are sort of par for the course.”
El Niño is part of a larger cycle that involves the ocean and the atmosphere, and is known as the El Niño-Southern Oscillation, or ENSO. L'Heureux told Mashable that the ocean part is halfway to El Niño, while the atmospheric part, the Southern Oscillation, isn't.
As NOAA explains in a post on its El Niño blog, the Southern Oscillation is "a seesaw in surface pressure between a large area surrounding Indonesia and another in the central-to-eastern tropical Pacific; it’s the atmospheric half of El Niño."
At this point, L'Heureux says, “We’ve got the "EN," but we don’t have the "SO.""
While some El Nino researchers were speculating that a strong El Niño, comparable to a record event that occurred in 1997-98 and wreaked havoc on weather patterns worldwide, was on the way, NOAA and IRI said Thursday that this is most likely not the case. Instead, they are favoring a weak-to-moderate event.
L'Heureux told Mashable that while the computer models that forecasters use to help predict El Niño events are "clustering" around a weak-to-moderate event, a strong event cannot be completely ruled out.
Subsurface water temperature anomalies in the Pacific Ocean, showing a big spike a few months ago, followed by more average temperatures in July 2014.
Image: NOAA/CPC
She says the models that suggested a strong event would occur are “Clearly backing off from that, although there’s still possible solutions here where you could get that.”
In addition to the uncertainty regarding El Niño's strength, forecasters have relatively low confidence in exactly when El Niño conditions will kick in.
L'Heureux says the computer models are "awful" at pinpointing the moment of onset and the peak intensity of these events, but they show considerable skill at predicting events overall.
That, she says, is “So ironic, because those are the two pieces of info that people want to know.”
Topics: Climate, el nino, ENSO, U.S., US & World, World
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Development of El Niño in 2014 continues to edge closer with sea surface temperature in the key indicator equatorial regionapproaching El Niño thresholds.
The discharge of ocean heat to the atmosphere associated with the build-up of the El Niño phenomenon has predictably seen a rise in global surface temperatures, resulting in May 2014 being the warmest May ever recorded.
Despite the strong initial build-up of a large warm water volume anomaly (WWV) in the equatorial subsurface ocean earlier in the year, the atmosphere has so far not provided sufficient reinforcement to maintain this large pool of warmer-than-average water and a substantial portion has been eroded.
The last half-century of observations, however, still favour the development of an extreme El Niño event, but the substantial reduction of the warm water volume anomaly (thankfully) diminishes the odds of a powerful event rivaling that of 1997-1998 from taking hold.
Figure 1 - global sea surface temperature (SST) anomalies (departures from the long-term average) as at 26th June 2014. Strong equatorial SST warming off the coast of South America (shown in red rectangle) is a tell-tale signature of El Nino conditions beginning to form. Image from NOAA Coral Reef Watch.
El Niño on the Wane?
The intensity of El Niño is determined by a number of factors but, as discussed in the previous 2014 El Niño post, the size of the equatorial warm water volume (WWV) anomaly is a crucial ingredient because the heat from this warm water volume is discharged to the atmosphere as El Niño matures.
Earlier this year we saw the largest March WWV anomaly ever recorded. This warm anomaly exceeded even that of the monster El Niño of 1997-1998, raising fears of a similarly devastating El Niño in 2014. Fortunately, the chances of a repeat of 1997-1998 appear to have greatly diminished. The atmosphere needs to provide reinforcement in order for El Niño to fully take hold, and although there have been brief episodes of westerly wind bursts, which allow near-surface warm ocean currents to flow back toward the east and shut off the upwelling of cold water there, these have not been of sufficient strength, or persistence, to shut off the upwelling entirely. As a result, the anomalous pool of warm water sitting beneath the eastern Pacific Ocean has been eaten away (moved out of the equatorial region and is now substantially smaller than before - see Figure 2.
Figure 2 - Global ocean temperature anomaly for the period 29th March-17th June 2014 (the Pacific Ocean is in the centre frame). Note that these are anomalies, not absolute temperatures, so the warmest water is still at the surface. The decline in the equatorial WWV anomaly is obvious as time progresses. Image adapted from CPC GODAS.
One striking aspect of Pacific sea surface temperature patterns in Figure 1 is the difference between the North and South. In the North Pacific, the subtropical gyre - the large rotating mass of surface water in the equatorial to mid latitudes - appears to have spun-down. Consequently, the poleward export of warm surface water northwards out of the tropics has been greatly reduced, and the Pacific Decadal Oscillation - an index of sea surface temperature north of 20° latitude - has switched to a positive (warm) phase in 2014.
This isn't the case for the South Pacific subtropical gyre. The persistent easterly trade winds have the gyre still exporting heat poleward out of the tropics. The two main indicators of this, aside from the ongoing trade winds themselves, are the anomalously warm sea surface temperatures, and anomalous sea surface height, west of New Zealand (the centre of the gyre), and the ongoing upwelling of cold water off the coast of South America.
Figure 3 - Global sea surface height (SSH) anomaly for May 2014. The black ellipses are a (very) rough sketch of the Pacific Ocean subtropical gyres, with the arrows denoting the direction of their rotation. Above-average SSH in the South Pacific gyre indicates warm water mass (exported from the tropics) piling up in the centre of the gyre, whereas below average SSH in the North Pacific indicates weaker-than-normal circulation. Units are in centimetres Image adapted from CPC GODAS.
Or Extreme, Irreversible, El Niño Already Set in Motion?
So, with the subsurface blob of warm water in the eastern equatorial Pacific having decreased substantially, does that mean that there's no risk of an extreme El Niño happening? Well, no, not if the last 50 years of ENSO observations are anything to to go by.
Kim & Cai (2014) looked at the various phases of ENSO since 1960 and found that a strong flow of warm water (Kelvin waves) toward the eastern Pacific during the early, developing, phase of El Niño, specifically the months of April and May, only occurred in the lead-up to events which later matured into extreme El Niño. Kim & Cai (2014) defined an extreme El Niño as those events where sea surface temperatures in the Niño 3 region reached a peak anomaly in excess of 1.2°C above long-term mean. 4 of 16 El Niño in the 50-year observational record fell into the extreme category, namely; 1972-73, 1982-83, 1997-98, and 2009/10.
Figure 4 - from Kim & Cai (2014). SST change in the Niño3 region for El Niño years between 1960-2011 with the solid lines indicating the mean. The evolution in Nino 3 SST anomalies for strong & moderate events through the year is shown in (a), and the bottom panel (b) shows the rate of SST change throughout El Niño. The bottom panel demonstrates the importance of the warming rate in the months of April & May in creating the stronger SST warming later in the year. Image from Kim & Cai (2014).
What the authors found is that whenever this strong horizontal transport of warm water from western to eastern Pacific occurs over the critical April-May period, it is inevitably the precursor to an extreme El Niño taking place later in the year (El Niño reaches a peak around December). If this relationship still holds true, then the strong Kelvin wave activity, corresponding anomalous eastward flow of warm water, and the change in sea surface temperatures in the Niño 3 region during April-May this year, portends an extreme El Niño making its presence felt later in 2014.
Reinforcements May be on the Way
Unlike some previous El Nino years, notably the monster 1997-1998 one, the trade winds have picked up strength again over the last 4 weeks, which has held back further El Niño development. This is seen in the Southern Oscillation Index (SOI), which has been positive over the past month - indicating a lower sea level pressure at Darwin than at Tahiti.
For El Niño to keep evolving the atmosphere needs to respond and provide encouragement. This is typically accomplished by convection (evaporation/clouds/rainfall) moving out from the western Pacific to the central Pacific and beyond. Doing so reduces or reverses the sea level pressure gradient between Tahiti and Darwin (and shifts the SOI into negative values), thus shutting down the trade winds temporarily.
Some models predicted that the Madden-Julian Oscillation (MJO), a tropical pulse of cloud and rainfall (i.e. strong convection) that moves eastward along the equator with a cycle of 1-2 months, was due to move eastward out over the equatorial Pacific at the time of writing. If so, we should expect to see westerly wind bursts (WWB) in the western Pacific develop, and early indications are that they have.
Figure 5 - Tropical SST and wind five-day means (top panel) and anomalies (bottom panel) from 22nd May-26th June 2014. Westerly wind bursts (arrows pointing to the right in bottom panel) die out on May 22, followed by a lull before strengthening again in late June. White areas of the animation are missing data. Note the pool of warmer-than-normal surface water moving westward in the last few frames. Images from the TAO Project.
This means that further Kelvin waves will makes their way across the Pacific Ocean, thus transporting more ocean heat from west to east, and giving the system a further nudge toward El Niño when it reaches the eastern Pacific in about two months time. But for El Niño to take a firm hold, the atmosphere is going to have to play ball by persistently shifting convection out toward the central and eastern Pacific, thereby relaxing the trade winds. Once the trade winds weaken sufficiently, so too will the upwelling of cold water in the east, and the poleward transport of warm surface water out of the tropics.
Let's Not Party Like it's 1997-1998
Earth's weather continues to slowly inch toward El Niño, but the failure of the trade winds to persistently weaken has seen El Niño's development in 2014 delayed. If, as some indicators suggest, the system does develop into a full-blown El Niño we can expect tropical sea surface temperatures to continue to increase right up to the end of the year (see Figure 4) before gradually diminishing in 2015.
Fortunately there has been a marked reduction in the equatorial warm water volume anomaly in the last month, so an El Niño rivaling that of 1997-1998 - the most powerful El Niño of the 20th Century - seems unlikely. But even so, Pacific Ocean trends of the last 50 years demonstrate that the strong equatorial flow of ocean currents toward the eastern Pacific in the critical April-May period, have always preceded extreme El Niño events later the same year. Should this trend continue, and based on observations earlier this year, we could still experience an extreme El Niño in 2014. Only time will tell.
The discharge of ocean heat to the atmosphere associated with the build-up of the El Niño phenomenon has predictably seen a rise in global surface temperatures, resulting in May 2014 being the warmest May ever recorded.
Despite the strong initial build-up of a large warm water volume anomaly (WWV) in the equatorial subsurface ocean earlier in the year, the atmosphere has so far not provided sufficient reinforcement to maintain this large pool of warmer-than-average water and a substantial portion has been eroded.
The last half-century of observations, however, still favour the development of an extreme El Niño event, but the substantial reduction of the warm water volume anomaly (thankfully) diminishes the odds of a powerful event rivaling that of 1997-1998 from taking hold.
Figure 1 - global sea surface temperature (SST) anomalies (departures from the long-term average) as at 26th June 2014. Strong equatorial SST warming off the coast of South America (shown in red rectangle) is a tell-tale signature of El Nino conditions beginning to form. Image from NOAA Coral Reef Watch.
El Niño on the Wane?
The intensity of El Niño is determined by a number of factors but, as discussed in the previous 2014 El Niño post, the size of the equatorial warm water volume (WWV) anomaly is a crucial ingredient because the heat from this warm water volume is discharged to the atmosphere as El Niño matures.
Earlier this year we saw the largest March WWV anomaly ever recorded. This warm anomaly exceeded even that of the monster El Niño of 1997-1998, raising fears of a similarly devastating El Niño in 2014. Fortunately, the chances of a repeat of 1997-1998 appear to have greatly diminished. The atmosphere needs to provide reinforcement in order for El Niño to fully take hold, and although there have been brief episodes of westerly wind bursts, which allow near-surface warm ocean currents to flow back toward the east and shut off the upwelling of cold water there, these have not been of sufficient strength, or persistence, to shut off the upwelling entirely. As a result, the anomalous pool of warm water sitting beneath the eastern Pacific Ocean has been eaten away (moved out of the equatorial region and is now substantially smaller than before - see Figure 2.
Figure 2 - Global ocean temperature anomaly for the period 29th March-17th June 2014 (the Pacific Ocean is in the centre frame). Note that these are anomalies, not absolute temperatures, so the warmest water is still at the surface. The decline in the equatorial WWV anomaly is obvious as time progresses. Image adapted from CPC GODAS.
One striking aspect of Pacific sea surface temperature patterns in Figure 1 is the difference between the North and South. In the North Pacific, the subtropical gyre - the large rotating mass of surface water in the equatorial to mid latitudes - appears to have spun-down. Consequently, the poleward export of warm surface water northwards out of the tropics has been greatly reduced, and the Pacific Decadal Oscillation - an index of sea surface temperature north of 20° latitude - has switched to a positive (warm) phase in 2014.
This isn't the case for the South Pacific subtropical gyre. The persistent easterly trade winds have the gyre still exporting heat poleward out of the tropics. The two main indicators of this, aside from the ongoing trade winds themselves, are the anomalously warm sea surface temperatures, and anomalous sea surface height, west of New Zealand (the centre of the gyre), and the ongoing upwelling of cold water off the coast of South America.
Figure 3 - Global sea surface height (SSH) anomaly for May 2014. The black ellipses are a (very) rough sketch of the Pacific Ocean subtropical gyres, with the arrows denoting the direction of their rotation. Above-average SSH in the South Pacific gyre indicates warm water mass (exported from the tropics) piling up in the centre of the gyre, whereas below average SSH in the North Pacific indicates weaker-than-normal circulation. Units are in centimetres Image adapted from CPC GODAS.
Or Extreme, Irreversible, El Niño Already Set in Motion?
So, with the subsurface blob of warm water in the eastern equatorial Pacific having decreased substantially, does that mean that there's no risk of an extreme El Niño happening? Well, no, not if the last 50 years of ENSO observations are anything to to go by.
Kim & Cai (2014) looked at the various phases of ENSO since 1960 and found that a strong flow of warm water (Kelvin waves) toward the eastern Pacific during the early, developing, phase of El Niño, specifically the months of April and May, only occurred in the lead-up to events which later matured into extreme El Niño. Kim & Cai (2014) defined an extreme El Niño as those events where sea surface temperatures in the Niño 3 region reached a peak anomaly in excess of 1.2°C above long-term mean. 4 of 16 El Niño in the 50-year observational record fell into the extreme category, namely; 1972-73, 1982-83, 1997-98, and 2009/10.
Figure 4 - from Kim & Cai (2014). SST change in the Niño3 region for El Niño years between 1960-2011 with the solid lines indicating the mean. The evolution in Nino 3 SST anomalies for strong & moderate events through the year is shown in (a), and the bottom panel (b) shows the rate of SST change throughout El Niño. The bottom panel demonstrates the importance of the warming rate in the months of April & May in creating the stronger SST warming later in the year. Image from Kim & Cai (2014).
What the authors found is that whenever this strong horizontal transport of warm water from western to eastern Pacific occurs over the critical April-May period, it is inevitably the precursor to an extreme El Niño taking place later in the year (El Niño reaches a peak around December). If this relationship still holds true, then the strong Kelvin wave activity, corresponding anomalous eastward flow of warm water, and the change in sea surface temperatures in the Niño 3 region during April-May this year, portends an extreme El Niño making its presence felt later in 2014.
Reinforcements May be on the Way
Unlike some previous El Nino years, notably the monster 1997-1998 one, the trade winds have picked up strength again over the last 4 weeks, which has held back further El Niño development. This is seen in the Southern Oscillation Index (SOI), which has been positive over the past month - indicating a lower sea level pressure at Darwin than at Tahiti.
For El Niño to keep evolving the atmosphere needs to respond and provide encouragement. This is typically accomplished by convection (evaporation/clouds/rainfall) moving out from the western Pacific to the central Pacific and beyond. Doing so reduces or reverses the sea level pressure gradient between Tahiti and Darwin (and shifts the SOI into negative values), thus shutting down the trade winds temporarily.
Some models predicted that the Madden-Julian Oscillation (MJO), a tropical pulse of cloud and rainfall (i.e. strong convection) that moves eastward along the equator with a cycle of 1-2 months, was due to move eastward out over the equatorial Pacific at the time of writing. If so, we should expect to see westerly wind bursts (WWB) in the western Pacific develop, and early indications are that they have.
Figure 5 - Tropical SST and wind five-day means (top panel) and anomalies (bottom panel) from 22nd May-26th June 2014. Westerly wind bursts (arrows pointing to the right in bottom panel) die out on May 22, followed by a lull before strengthening again in late June. White areas of the animation are missing data. Note the pool of warmer-than-normal surface water moving westward in the last few frames. Images from the TAO Project.
This means that further Kelvin waves will makes their way across the Pacific Ocean, thus transporting more ocean heat from west to east, and giving the system a further nudge toward El Niño when it reaches the eastern Pacific in about two months time. But for El Niño to take a firm hold, the atmosphere is going to have to play ball by persistently shifting convection out toward the central and eastern Pacific, thereby relaxing the trade winds. Once the trade winds weaken sufficiently, so too will the upwelling of cold water in the east, and the poleward transport of warm surface water out of the tropics.
Let's Not Party Like it's 1997-1998
Earth's weather continues to slowly inch toward El Niño, but the failure of the trade winds to persistently weaken has seen El Niño's development in 2014 delayed. If, as some indicators suggest, the system does develop into a full-blown El Niño we can expect tropical sea surface temperatures to continue to increase right up to the end of the year (see Figure 4) before gradually diminishing in 2015.
Fortunately there has been a marked reduction in the equatorial warm water volume anomaly in the last month, so an El Niño rivaling that of 1997-1998 - the most powerful El Niño of the 20th Century - seems unlikely. But even so, Pacific Ocean trends of the last 50 years demonstrate that the strong equatorial flow of ocean currents toward the eastern Pacific in the critical April-May period, have always preceded extreme El Niño events later the same year. Should this trend continue, and based on observations earlier this year, we could still experience an extreme El Niño in 2014. Only time will tell.
محمد پور رجبی a
Banned
جالب بود سپاس:گل:
El Niño plays coy with forecasters in 2014
BY ANGELA FRITZ
July 11 at 12:02 pm
Global sea surface temperature anomaly. (NOAA/ESRL)
Earlier this year, forecasts were hot and heavy on the development of El Niño. Conditions seemed favorable, and California is praying for a wet winter given the continued drought conditions. However, the trends shifted in the spring, thus leaving us wondering – is this El Niño really going to come to fruition? Forecasters (and the atmosphere) are waffling somewhat.
In an update on Thursday, scientists at the Climate Prediction Center continued to issue favorable odds of an El Niño developing this year (70 percent chance this summer, 80 percent by early next winter), and an El Niño watch remains in effect. However, they suspect this El Niño’s intensity to only reach weak-to-moderate strength, which is a far cry from the “super El Niño” that some forecasters once thought was possible.
At its core, El Niño is the warm phase of a sea surface temperature pattern near the equator in the Pacific Ocean. Right now, water temperatures are above normal in all the right regions, however, they’re not warm enough yet for scientists to officially declare it an El Niño event.
Time series of ocean heat content anomaly over the past year. After a spike in temperature in early 2014, the ocean heat content in the Pacific has been steadily declining. (Climate Prediction Center)
Paul Roundy, a professor of atmospheric science at the University at Albany, hypothesizes that the current “neutral” state is actually a warm phase (El Niño) with a cooler anomaly layered on top. He suspects that as this cool anomaly begins to wane, El Niño will pop through:
Think of [this] as a few weeks of colder conditions superimposed on a background of warm conditions. The combination of these two signals yields an impression of a condition near normal, but the cool conditions do not last as long, and after they move out of the equatorial region or dissipate, the warm state is left behind.
Weather Underground’s Jeff Masters suggests that the atmosphere is presenting El Niño signs. He writes on Wednesday:
Heavy thunderstorm activity over Indonesia and near the International Date Line is typically enhanced during an El Niño event, and has been picking up over the past month, but must increase more before we can say the atmosphere is responding in an El Niño-like fashion.
Early in 2014, a burst of favorable wind activity in the Pacific led some forecasters to believe that a strong El Niño was just around the corner. Winds typically flow east to west in the tropics, but sometimes bursts of wind in the opposite direction will grease the wheels for El Niño. This wind pushes warm water toward South America, and aids in the development of an El Niño event.
However, that pattern reversed in the spring. Winds began to flow strong from east to west, which causes upwelling of cooler water along South America. This dampened El Niño forecasts, which have steadily declined in intensity.
Model forecasts for El Niño and La Nino. Most models are forecasting El Niño conditions to begin this summer/fall, and a few are forecasting neutral conditions. (Climate Prediction Center/International Research Institute for Climate and Society)
While he agrees with the Climate Prediction Center that El Niño is likely this year, Roundy cautions that El Niño forecasts continue to be tricky business with all the moving pieces that need to be considered. “The ocean state is constantly changing as it interacts with forcing from winds associated with weather events,” Roundy says. “Since weather events influence El Niño, and since such events are not completely controlled by the developing El Niño, we cannot know for certain how a given El Niño event will evolve.”
El Niño has a wide range of impacts on global weather. It can alter precipitation patterns over the U.S., and it can decrease the likelihood that hurricanes will develop in the Atlantic. California remains in one of its most intense droughts in recent history – 79% of the state is in extreme drought, and nearly 40% is in exceptional drought, according to the U.S. Drought Monitor. So it’s no wondering that Californians are waiting with bated breath for a strong El Niño event, which has had some historical success at producing heavy winter rain and snowfall along the West Coast. In particular, the 1997-1998 El Niño was a record-breaker for the state.
Unfortunately, Weather Underground’s Christopher C. Burt cautions against getting our hopes up for a stellar California rainy season:
These hopes have little basis in reality since only very strong El Niño’s, like the last one of 1997-1998, actually impact seasonal precipitation across the entire state. Current models indicate the coming El Niño will be of only ‘moderate’ strength. This may have an impact on the southern third of the state but, historically, moderate El Niño’s have not influenced rainfall patterns one way or the other for the northern two-thirds of California.
Angela Fritz is the Deputy Weather Editor for the Washington Post. She holds a B.S. degree in meteorology from Valparaiso University and an M.S. in Earth and Atmospheric Science from the Georgia Institute of Technology.
BY ANGELA FRITZ
July 11 at 12:02 pm
Global sea surface temperature anomaly. (NOAA/ESRL)
Earlier this year, forecasts were hot and heavy on the development of El Niño. Conditions seemed favorable, and California is praying for a wet winter given the continued drought conditions. However, the trends shifted in the spring, thus leaving us wondering – is this El Niño really going to come to fruition? Forecasters (and the atmosphere) are waffling somewhat.
In an update on Thursday, scientists at the Climate Prediction Center continued to issue favorable odds of an El Niño developing this year (70 percent chance this summer, 80 percent by early next winter), and an El Niño watch remains in effect. However, they suspect this El Niño’s intensity to only reach weak-to-moderate strength, which is a far cry from the “super El Niño” that some forecasters once thought was possible.
At its core, El Niño is the warm phase of a sea surface temperature pattern near the equator in the Pacific Ocean. Right now, water temperatures are above normal in all the right regions, however, they’re not warm enough yet for scientists to officially declare it an El Niño event.
Time series of ocean heat content anomaly over the past year. After a spike in temperature in early 2014, the ocean heat content in the Pacific has been steadily declining. (Climate Prediction Center)
Paul Roundy, a professor of atmospheric science at the University at Albany, hypothesizes that the current “neutral” state is actually a warm phase (El Niño) with a cooler anomaly layered on top. He suspects that as this cool anomaly begins to wane, El Niño will pop through:
Think of [this] as a few weeks of colder conditions superimposed on a background of warm conditions. The combination of these two signals yields an impression of a condition near normal, but the cool conditions do not last as long, and after they move out of the equatorial region or dissipate, the warm state is left behind.
Weather Underground’s Jeff Masters suggests that the atmosphere is presenting El Niño signs. He writes on Wednesday:
Heavy thunderstorm activity over Indonesia and near the International Date Line is typically enhanced during an El Niño event, and has been picking up over the past month, but must increase more before we can say the atmosphere is responding in an El Niño-like fashion.
Early in 2014, a burst of favorable wind activity in the Pacific led some forecasters to believe that a strong El Niño was just around the corner. Winds typically flow east to west in the tropics, but sometimes bursts of wind in the opposite direction will grease the wheels for El Niño. This wind pushes warm water toward South America, and aids in the development of an El Niño event.
However, that pattern reversed in the spring. Winds began to flow strong from east to west, which causes upwelling of cooler water along South America. This dampened El Niño forecasts, which have steadily declined in intensity.
Model forecasts for El Niño and La Nino. Most models are forecasting El Niño conditions to begin this summer/fall, and a few are forecasting neutral conditions. (Climate Prediction Center/International Research Institute for Climate and Society)
While he agrees with the Climate Prediction Center that El Niño is likely this year, Roundy cautions that El Niño forecasts continue to be tricky business with all the moving pieces that need to be considered. “The ocean state is constantly changing as it interacts with forcing from winds associated with weather events,” Roundy says. “Since weather events influence El Niño, and since such events are not completely controlled by the developing El Niño, we cannot know for certain how a given El Niño event will evolve.”
El Niño has a wide range of impacts on global weather. It can alter precipitation patterns over the U.S., and it can decrease the likelihood that hurricanes will develop in the Atlantic. California remains in one of its most intense droughts in recent history – 79% of the state is in extreme drought, and nearly 40% is in exceptional drought, according to the U.S. Drought Monitor. So it’s no wondering that Californians are waiting with bated breath for a strong El Niño event, which has had some historical success at producing heavy winter rain and snowfall along the West Coast. In particular, the 1997-1998 El Niño was a record-breaker for the state.
Unfortunately, Weather Underground’s Christopher C. Burt cautions against getting our hopes up for a stellar California rainy season:
These hopes have little basis in reality since only very strong El Niño’s, like the last one of 1997-1998, actually impact seasonal precipitation across the entire state. Current models indicate the coming El Niño will be of only ‘moderate’ strength. This may have an impact on the southern third of the state but, historically, moderate El Niño’s have not influenced rainfall patterns one way or the other for the northern two-thirds of California.
Angela Fritz is the Deputy Weather Editor for the Washington Post. She holds a B.S. degree in meteorology from Valparaiso University and an M.S. in Earth and Atmospheric Science from the Georgia Institute of Technology.
Michigan's upcoming winter may not be saved by El Nino; Polar vortex could dominate again
This graphic shows the water temperature anomalies in the Pacific Ocean between South America and Australia. Most of this part of the Pacific is warmer than normal, signaling the development of an El Nino. (Climate Prediction Center)
By Mark Torregrossa | For MLive.com
Follow on Twitter
on July 11, 2014 at 6:00 AM, updated July 11, 2014 at 1:58 PM
El Nino has been developing, but new data shows it may not become strong enough to influence our upcoming winter here in Michigan. And if El Nino can't shove the jet stream northward, the polar vortex could again be a dominant feature in our winter weather this year.
The top graphic shows a large area of the Pacific Ocean between South America and Australia now has surface water temperatures warmer than normal. El Nino is when this area warms up more than normal. Officially it has not been declared an El Nino by the Climate Prediction Center just yet. It is expected to be warm enough in the next month to be officially called an El Nino.
When El Nino becomes strong, with temperatures in the Pacific averaging more than three degrees Fahrenheit above normal, Michigan has about a 70 percent chance of a warmer and drier than normal winter.
But the newest data in yesterday shows El Nino may not become strong enough to bring us it's warming effect.
View full size
These graphs show four different regions in the Pacific, and their sea surface temperature anomalies. Notice region 4, which is the biggest region, has cooled off in the past month.
Climate Prediction Center
Water temperatures have cooled in past month
The next graphic shows four different regions of the El Nino. Regions 1 and 2 are small regions off the coast of western South America. Regions 3 and 4 are much bigger regions in the eastern Pacific. All four regions have cooled some in the past month. This could be a sign that further warming of the El Nino region may be small. So the signs are now that El Nino won't become a strong El Nino.
View full size
This graphic shows how much heat is stored up in the water just below the ocean's surface. There was a large amount of heat a few months ago, but now the sub-surface heat has waned.
Climate Prediction Center
Heat below the surface has tapered off
The final graphic shows the heat stored up in the layer just below the ocean's surface. If there is a lot of heat just below the surface, ocean temperatures usually continue to warm. Now it looks like the heat just below the surface has tapered off dramatically. So this could signal a slower development of El Nino, and a weaker El Nino in the end.
If El Nino remains weak into winter, there will be no warming in Michigan due to El Nino. And since the polar vortex and cold pocket of air are still alive and well, we have to wonder if the polar vortex will again bring us a wicked winter.
We should have a good feel for what will happen this winter by the end of September. By then, we will know how strong El Nino should be, and we will be able to see if the cold pocket around the polar vortex is expanding.
Before yesterday's new information, I was thinking that El Nino would help cancel out some of the cold brought by the polar vortex. With the new data in, I think we could be in for another nasty winter.
It is still a long ways off, but will be fun to watch as we get into late summer and fall. As soon as I see a strong sign one way or the other, I'll let you know. For now, I'd start to mentally prepare yourself for a cold winter, or start booking a trip to the tropics.
Any questions or comments? Post them below.
MLive Meteorologist Mark Torregrossa has been forecasting Michigan weather for more than 20 years. He's been chief meteorologist at three television news stations in Michigan, and he's an avid gardener and hunter. Email him at mark@farmerweather.com and find him on Facebook at facebook.com/mark.torregrossa and Twitter @weathermanmark
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This graphic shows the water temperature anomalies in the Pacific Ocean between South America and Australia. Most of this part of the Pacific is warmer than normal, signaling the development of an El Nino. (Climate Prediction Center)
By Mark Torregrossa | For MLive.com
Follow on Twitter
on July 11, 2014 at 6:00 AM, updated July 11, 2014 at 1:58 PM
El Nino has been developing, but new data shows it may not become strong enough to influence our upcoming winter here in Michigan. And if El Nino can't shove the jet stream northward, the polar vortex could again be a dominant feature in our winter weather this year.
The top graphic shows a large area of the Pacific Ocean between South America and Australia now has surface water temperatures warmer than normal. El Nino is when this area warms up more than normal. Officially it has not been declared an El Nino by the Climate Prediction Center just yet. It is expected to be warm enough in the next month to be officially called an El Nino.
When El Nino becomes strong, with temperatures in the Pacific averaging more than three degrees Fahrenheit above normal, Michigan has about a 70 percent chance of a warmer and drier than normal winter.
But the newest data in yesterday shows El Nino may not become strong enough to bring us it's warming effect.
View full size
These graphs show four different regions in the Pacific, and their sea surface temperature anomalies. Notice region 4, which is the biggest region, has cooled off in the past month.
Climate Prediction Center
Water temperatures have cooled in past month
The next graphic shows four different regions of the El Nino. Regions 1 and 2 are small regions off the coast of western South America. Regions 3 and 4 are much bigger regions in the eastern Pacific. All four regions have cooled some in the past month. This could be a sign that further warming of the El Nino region may be small. So the signs are now that El Nino won't become a strong El Nino.
View full size
This graphic shows how much heat is stored up in the water just below the ocean's surface. There was a large amount of heat a few months ago, but now the sub-surface heat has waned.
Climate Prediction Center
Heat below the surface has tapered off
The final graphic shows the heat stored up in the layer just below the ocean's surface. If there is a lot of heat just below the surface, ocean temperatures usually continue to warm. Now it looks like the heat just below the surface has tapered off dramatically. So this could signal a slower development of El Nino, and a weaker El Nino in the end.
If El Nino remains weak into winter, there will be no warming in Michigan due to El Nino. And since the polar vortex and cold pocket of air are still alive and well, we have to wonder if the polar vortex will again bring us a wicked winter.
We should have a good feel for what will happen this winter by the end of September. By then, we will know how strong El Nino should be, and we will be able to see if the cold pocket around the polar vortex is expanding.
Before yesterday's new information, I was thinking that El Nino would help cancel out some of the cold brought by the polar vortex. With the new data in, I think we could be in for another nasty winter.
It is still a long ways off, but will be fun to watch as we get into late summer and fall. As soon as I see a strong sign one way or the other, I'll let you know. For now, I'd start to mentally prepare yourself for a cold winter, or start booking a trip to the tropics.
Any questions or comments? Post them below.
MLive Meteorologist Mark Torregrossa has been forecasting Michigan weather for more than 20 years. He's been chief meteorologist at three television news stations in Michigan, and he's an avid gardener and hunter. Email him at mark@farmerweather.com and find him on Facebook at facebook.com/mark.torregrossa and Twitter @weathermanmark
Related Stories
Bizarre weather pattern on tap for Michigan early next week 'Juvenile lifer' ruling praised by victim advocate; GOP lawmaker denounces ruling
Strong El Nino Seen Unlikely by Australia as Pacific Cools
By Phoebe Sedgman Jul 15, 2014 2:31 PM GMT+0430 7 Comments Email Print
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The odds of a strong El Nino, which brings drought to the Asia-Pacific region and heavy rains to South America, are increasingly unlikely after the tropical Pacific Ocean cooled, according to Australia’s weather bureau.
A general lack of atmospheric response over the last month resulted in some cooling, the Bureau of Meteorology said on its website today. Warming of the ocean over the past several months had primed the conditions for the event, it said.
El Ninos can roil world agricultural markets as farmers contend with drought or too much rain. Palm oil, cocoa, coffee and sugar are most at risk, Goldman Sachs Group Inc. estimates. Rabobank International has warned the size of a global sugar deficit next season will depend on how El Nino develops, while the event may spur a 22 percent rally in palm oil prices, according to Dorab Mistry, director at Godrej International Ltd.
“While the majority of climate models suggest El Nino remains likely for the spring of 2014, most have eased their predicted strength,” the Melbourne-based bureau said today, referring to the season in the Southern Hemisphere. It maintained an alert for the event.
Five of eight international models signal El Nino will probably develop by the end of spring, with about half indicating the event will be established by September, the bureau said. The odds of an El Nino during the Northern Hemisphere summer are about 70 percent, the U.S. Climate Prediction Center estimates.
Monsoon Rains
The degree of tightening in the sugar market depends on El Nino, Rabobank said in a report e-mailed yesterday. The bank predicted a 900,000-ton deficit for 2014-2015 from a 1.4 million ton surplus in 2013-2014. Poor monsoon development and the prospect of the event may hurt yields in India, the world’s second biggest producer, it said.
The chances of a drought in the country increased to 60 percent from 25 percent in April amid forecasts for El Nino, Skymet Weather Services, a New Delhi-based private forecaster, said July 4. Showers in June were the lowest since 2009. The monsoon accounts for more than 70 percent of annual rainfall.
Most parts of the country will get widespread rains in the week through July 22, according to the India Meteorological Department. Rainfall was 4 percent above average yesterday, trimming the seasonal shortage in showers to 41 percent from 43 percent a week earlier, department data showed.
Surface Temperatures
Palm oil may climb to 2,800 ringgit a metric ton by December if the weather event occurs from mid-August, Mistry said June 26, cutting his March forecast for a rally to 3,500 ringgit. A rise may be capped if an El Nino starts later than expected, he said. Prices, which entered a bear market yesterday, last traded at 2,298 ringgit in Kuala Lumpur.
Australia’s weather bureau said July 1 that while surface temperatures in the tropical Pacific were at levels typically associated with a weak El Nino, sub-surface temperatures had cooled and there wasn’t the corresponding atmosphere change to support a declaration.
El Ninos, caused by periodic warmings of the tropical Pacific, occur every two to seven years and are associated with warmer-than-average years. The last El Nino was from 2009 to 2010, and the Pacific has either been in its cooler state, called La Nina, or neutral since then.
By Phoebe Sedgman Jul 15, 2014 2:31 PM GMT+0430 7 Comments Email Print
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The odds of a strong El Nino, which brings drought to the Asia-Pacific region and heavy rains to South America, are increasingly unlikely after the tropical Pacific Ocean cooled, according to Australia’s weather bureau.
A general lack of atmospheric response over the last month resulted in some cooling, the Bureau of Meteorology said on its website today. Warming of the ocean over the past several months had primed the conditions for the event, it said.
El Ninos can roil world agricultural markets as farmers contend with drought or too much rain. Palm oil, cocoa, coffee and sugar are most at risk, Goldman Sachs Group Inc. estimates. Rabobank International has warned the size of a global sugar deficit next season will depend on how El Nino develops, while the event may spur a 22 percent rally in palm oil prices, according to Dorab Mistry, director at Godrej International Ltd.
“While the majority of climate models suggest El Nino remains likely for the spring of 2014, most have eased their predicted strength,” the Melbourne-based bureau said today, referring to the season in the Southern Hemisphere. It maintained an alert for the event.
Five of eight international models signal El Nino will probably develop by the end of spring, with about half indicating the event will be established by September, the bureau said. The odds of an El Nino during the Northern Hemisphere summer are about 70 percent, the U.S. Climate Prediction Center estimates.
Monsoon Rains
The degree of tightening in the sugar market depends on El Nino, Rabobank said in a report e-mailed yesterday. The bank predicted a 900,000-ton deficit for 2014-2015 from a 1.4 million ton surplus in 2013-2014. Poor monsoon development and the prospect of the event may hurt yields in India, the world’s second biggest producer, it said.
The chances of a drought in the country increased to 60 percent from 25 percent in April amid forecasts for El Nino, Skymet Weather Services, a New Delhi-based private forecaster, said July 4. Showers in June were the lowest since 2009. The monsoon accounts for more than 70 percent of annual rainfall.
Most parts of the country will get widespread rains in the week through July 22, according to the India Meteorological Department. Rainfall was 4 percent above average yesterday, trimming the seasonal shortage in showers to 41 percent from 43 percent a week earlier, department data showed.
Surface Temperatures
Palm oil may climb to 2,800 ringgit a metric ton by December if the weather event occurs from mid-August, Mistry said June 26, cutting his March forecast for a rally to 3,500 ringgit. A rise may be capped if an El Nino starts later than expected, he said. Prices, which entered a bear market yesterday, last traded at 2,298 ringgit in Kuala Lumpur.
Australia’s weather bureau said July 1 that while surface temperatures in the tropical Pacific were at levels typically associated with a weak El Nino, sub-surface temperatures had cooled and there wasn’t the corresponding atmosphere change to support a declaration.
El Ninos, caused by periodic warmings of the tropical Pacific, occur every two to seven years and are associated with warmer-than-average years. The last El Nino was from 2009 to 2010, and the Pacific has either been in its cooler state, called La Nina, or neutral since then.
Stirred up: Satellite image of Typhoon Rammasun approaches the Philippines. Photo: NOAA
Expectations of a strong El Nino weather event in the Pacific are being pared back but warmer-than-usual conditions are expected to persist, meteorologists say.
The latest prediction by the Bureau of Meteorology retains the 70 per cent or more likelihood that an El Nino will form this year with sea-surface temperatures in the equatorial central and eastern Pacific remaining well above average.
So far, though, there are few signs that the atmosphere is responding to the oceanic priming, suggesting that if an El Nino forms it is less likely to be as strong as some models were indicating earlier this year.
Warm in the eastern - but also the western - Pacific. Photo: NOAA
With typical El Ninos, the eastern Pacific is warm relative to the west, reversing or stalling the easterly trade winds. During such events, much of Asia and Australia have relatively dry and warm years, while the Americas often have wet years.
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One aspect that is intriguing scientists is the fact that much of the Pacific – not just the east – is unusually warm. In fact, June may have experienced the largest departure in sea-surface temperatures of any month on record, climatologists say.
Japan Meteorological Agency noted this week that monthly sea-surface temperatures were ''remarkably'' above average in regions ranging from near Japan to the coast of North America, and from Mexico to the Philippines.
Global average surface temperatures – including land and near-surface readings – were 0.32 degrees above the long-term average, making last month the hottest June in records going back to 1891, JMA said, citing preliminary figures.
If June is the hottest month, it would add to the warmest May and the equal warmest April, increasing the likelihood that 2014 will top 2005 and 2010 as the warmest year on record.
The fact the El Nino-like conditions in the ocean are waiting for the atmosphere to respond is one reason for the recent warmth.
The release of ''stored heat is helping to warm up the global atmosphere'', Andrew Watkins, manager of Climate Prediction Services at the Bureau of Meteorology, said. "It's not unexpected that these months have been so warm given the amount of heat that must have come out of the Pacific."
Meteorologists are also watching the Indian Ocean, where warmer-than-usual conditions in the east are helping to stall the development of an El Nino. One benefit of unusual warmth in this region is that moisture is streaming over the Australian continent, bringing much needed rain to south-eastern parts.
Central western and south-western NSW had their best rains this week in three months and more is on the way, according to Weatherzone.
Sydney, though, will probably see another week of above-average maximum temperatures and little rain – continuing a trend of the past month and longer.
Friday will be the coolest day, with a maximum of 17 degrees, but other days should have tops of 18-21 out to next Wednesday, the bureau said.
'On its way'
Max Gonzalez, a senior meteorologist at Weatherzone said that while some Pacific waters had cooled off lately, sub-surface temperatures were as much as 3 degrees warmer than normal in parts of the centre and east.
“The strength of the event may not be as strong as we are thinking a couple of months ago but an El Nino is still on its way," Mr Gonzalez said.
The bureau's Dr Watkins said computer modelling suggested an El Nino effect is still likely, although not until later in the year than earlier thought.
A bout of westerly winds a fortnight ago hinted at the atmosphere coupling with the ocean to reverse the trade winds and reinforce El Nino conditions, but things then settled back to normal.
"It's starting to pick up a little bit again," Dr Watkins said, with meteorologists studying the persistence of weakening of the trade winds. "We're still in that waiting phase" to see whether the event is a short one or more prolonged.
Weatherzone is owned by Fairfax Media, publisher of this website.
Read more: http://www.smh.com.au/environment/w...ing-el-nino-20140716-ztoz4.html#ixzz37cScyAhl
Though there are no strict physical arguments that could explain in detail how solar activity causes ENSO events, it is quite possible to develop working hypotheses that suggest potential connections. Figure 2 shows that energetic solar eruptions coincide with the Golden section phase 0.382 in the subcycles of the sunspot cycle which are closely correlated with ENSO events, as shown in Figure 4. Strong solar eruptions cause the highest velocities in the solar wind and create shockwaves that compress and intensify magnetic fields in the sun’s plasma moving outward to the boundary of the solar system. The solar wind strenghtened by solar eruptions weakens cosmic rays. The ensuing Svensmark-effect is regionally strongest where cloudiness is highest. It is very high around Indonesia [40] where el Niños seem to develop. So one would think that shrinking cloud cover, stronger irradiance, intensified Hadley circulation and changing trade winds, caused by the modulating effect of solar eruptions on cosmic rays, improve the conditions for the birth of El Niños. This all the more so as M. Pudvokin and S. Veretenenko [42] as well as Svensmark and Friis-Christensen [53] have shown that Forbush decreases - dips in cosmic rays by several percent within 2 days after a strong solar eruption - are associated with immediate decreases in cloudiness by 2 - 3 percent that last a week or longer. Such short-term effects, especially when they trigger tropical cyclones [44], may release and sustain El Niños.
A blast of cold air that blew in from the Gulf of Alaska and swept across the Great Lakes is now making its way south. Headlines warn that the cold front could herald a return of the "polar vortex," but experts are saying otherwise.
Polar vortexes typically develop around the North Pole during most winters. They form in a pattern similar to that of tropical hurricanes, except the winds spinning around the calm center of a polar vortex are freezing cold.
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In January, a polar vortex blasted the northern United States with frigid air and caused bitterly cold temperatures farther south than normal. This week's cold front is following a similar pattern, where cold air from the Arctic is sweeping down south. [Weirdo Weather: 7 Rare Weather Events]
Typhoon Neoguri, which battered southern Japan with strong wind and rains last week, likely set off the wacky weather pattern that is interfering with the jet stream over the Midwest. TheMidwestern jet stream is a strip of air that forms when cool air masses from the north meet warm air masses from the south. An unusual amount of cold air can drive the jet stream further south and trigger thunderstorms.
By this Wednesday (July 16), the unusual weather could turn what is normally one of the hottest weeks of the summer into a pleasant autumnlike week in parts of the western United States and Northern Plains, where highs may be about 65 to 70 degrees Fahrenheit. The cold front will likely deal the Northeast only a glancing blow, and temperatures in this region may dip about 10 degrees below average.
Strictly speaking, the cold front is not a polar vortex, according to experts. The impending cold front is called a "high meridional event," but there are some similarities.
"It's the same general circulation pattern, but the effects are extremely different," Bob Oravec, a senior forecaster at the National Oceanic and Atmosphere Administration (NOAA) Weather Prediction Center, told Live Science. "In the summer, if you go outside in 20 degrees (Fahrenheit) below normal weather, you won't really care, but in the winter, the effects were significantly different because it was already so cold."
NOAA is predicting below-normal temperatures for a huge swath of the East Coast this week. The cool air is expected to roll through July 15, and should keep temperatures between 70 and 80 degrees Fahrenheit on the East Coast.
The unusual summer chill could also trigger some extreme and dangerous weather in the United States, experts say. The cold temperatures will likely send thunderstorms sweeping across much of the country this week. Hail and tornadoes are possible in southern New England down to the mid-Atlantic. In the West, severe lightning, flash floods and dust storms are possible, according to the Weather Channel.
Despite the wild weather in store for this week, Oravec said the cold front could bring some significant benefits. The predicted downpour may finally quench the severe drought in the western United States. While parts of the country may welcome a change from the sweltering July heat, temperatures are expected to climb back up soon.
"No weather pattern lasts forever, and we'll likely see temperatures return to normal by the weekend," Oravec said.
After a record year in the Midwest & the East Coast, El Nino will have a huge impact going into the 2014-2015 winter season. Here in late June we see a 76% chance of El Nino at this point and we feel this is GAME ON in a month or so!
The biggest influence will be in the South as the southern jet and El Nino produce a few big time winter storms with snow and ice. The key to the entire winter will be the intensity of the now trending El Nino. The trend would be to a moderate to perhaps strong El Nino and depending on where you live this will have an small or large impact on your winter forecast.
ALL EL NINO WINTERS SNOW/RAINFALL AVERAGE
The biggest influence will be in the South as the southern jet and El Nino produce a few big time winter storms with snow and ice. The key to the entire winter will be the intensity of the now trending El Nino. The trend would be to a moderate to perhaps strong El Nino and depending on where you live this will have an small or large impact on your winter forecast.
ALL EL NINO WINTERS SNOW/RAINFALL AVERAGE
JULY 16, 2014 UPDATE NEW INFO JUST IN...DELAYED EL NINO?
A developing El Niño in the equatorial Pacific has generated the usual predictions of drastic weather changes—some devastating, some beneficial—throughout the world.
There’s a 90 percent probability that an El Niño will form, according to some experts. That’s up considerably from previous predictions, but the main question at this point is whether this will be moderate El Niño or, more likely, a powerful warm-water event such as those in the early 1980s and late ’90s.
(El Niño is characterized by unusually warm sea-surface temperatures in the equatorial Pacific, whereas a La Niña is characterized by unusually cold temperatures. Strong El Niños typically alter weather patterns and can cause severe flooding in some areas, and droughts in others.)
The extent of El Niño’s strength won’t be known until late summer or fall. But based on several interesting signals, in the form of mammals, birds, and fish showing up where they don’t typically belong, it’s looking as though this El Niño is going to be a very powerful event.
The birds, fish and mammels of the Pacific are already heading to the warmer waters and they know the ocean better than the models we use to predict El Nino's.
حتما اين لينك را بخون
http://www.liveweatherblogs.com/ind...-2014-2015-it-could-be-big-real-big?groupid=6
A developing El Niño in the equatorial Pacific has generated the usual predictions of drastic weather changes—some devastating, some beneficial—throughout the world.
There’s a 90 percent probability that an El Niño will form, according to some experts. That’s up considerably from previous predictions, but the main question at this point is whether this will be moderate El Niño or, more likely, a powerful warm-water event such as those in the early 1980s and late ’90s.
(El Niño is characterized by unusually warm sea-surface temperatures in the equatorial Pacific, whereas a La Niña is characterized by unusually cold temperatures. Strong El Niños typically alter weather patterns and can cause severe flooding in some areas, and droughts in others.)
The extent of El Niño’s strength won’t be known until late summer or fall. But based on several interesting signals, in the form of mammals, birds, and fish showing up where they don’t typically belong, it’s looking as though this El Niño is going to be a very powerful event.
The birds, fish and mammels of the Pacific are already heading to the warmer waters and they know the ocean better than the models we use to predict El Nino's.
حتما اين لينك را بخون
http://www.liveweatherblogs.com/ind...-2014-2015-it-could-be-big-real-big?groupid=6
A blast of cold air that blew in from the Gulf of Alaska and swept across the Great Lakes is now making its way south. Headlines warn that the cold front could herald a return of the "polar vortex," but experts are saying otherwise.
Polar vortexes typically develop around the North Pole during most winters. They form in a pattern similar to that of tropical hurricanes, except the winds spinning around the calm center of a polar vortex are freezing cold.
In January, a polar vortex blasted the northern United States with frigid air and caused bitterly cold temperatures farther south than normal. This week's cold front is following a similar pattern, where cold air from the Arctic is sweeping down south.
Typhoon Neoguri, which battered southern Japan with strong wind and rains last week, likely set off the wacky weather pattern that is interfering with the jet stream over the Midwest.
SEE WILD VIDEO OF A HUGE MUDSLIDE IN JAPAN
The Midwestern jet stream is a strip of air that forms when cool air masses from the north meet warm air masses from the south. An unusual amount of cold air can drive the jet stream further south and trigger thunderstorms.
By tomorrow (July 16), the unusual weather could turn what is normally one of the hottest weeks of the summer into a pleasant autumnlike week in parts of the western United States and Northern Plains, where highs may be about 65 to 70 degrees Fahrenheit. The cold front will likely deal the Northeast only a glancing blow, and temperatures in this region may dip about 10 degrees below average.
Strictly speaking, the cold front is not a polar vortex, according to experts. The impending cold front is called a "high meridional event," but there are some similarities.
It's the same general circulation pattern, but the effects are extremely different. "In the summer, if you go outside in 20 degrees (Fahrenheit) below normal weather, you won't really care, but in the winter, the effects were significantly different because it was already so cold."
SEE THE ARCTIC INDEX FOR TODAY
NOAA is predicting below-normal temperatures for a huge swath of the East Coast this week. The cool air is expected to roll through today, and should keep temperatures between 70 and 80 degrees Fahrenheit on the East Coast.
The unusual summer chill could also trigger some extreme and dangerous weather in the United States, experts say. The cold temperatures will likely send thunderstorms sweeping across much of the country this week. Hail and tornadoes are possible in southern New England down to the mid-Atlantic. In the West, severe lightning, flash floods and dust storms are possible.
Despite the wild weather in store for this week, the cold front could bring some significant benefits. The predicted downpour may finally quench the severe drought in the western United States. While parts of the country may welcome a change from the sweltering July heat, temperatures are expected to climb back up soon.
"No weather pattern lasts forever, and we'll likely see temperatures return to normal by the weekend," Hey it's just a break from the summer, so enjoy it. Oh yeah look at the outlook for July 21-25 looks like summer wants to come back again.
Polar vortexes typically develop around the North Pole during most winters. They form in a pattern similar to that of tropical hurricanes, except the winds spinning around the calm center of a polar vortex are freezing cold.
In January, a polar vortex blasted the northern United States with frigid air and caused bitterly cold temperatures farther south than normal. This week's cold front is following a similar pattern, where cold air from the Arctic is sweeping down south.
Typhoon Neoguri, which battered southern Japan with strong wind and rains last week, likely set off the wacky weather pattern that is interfering with the jet stream over the Midwest.
SEE WILD VIDEO OF A HUGE MUDSLIDE IN JAPAN
The Midwestern jet stream is a strip of air that forms when cool air masses from the north meet warm air masses from the south. An unusual amount of cold air can drive the jet stream further south and trigger thunderstorms.
By tomorrow (July 16), the unusual weather could turn what is normally one of the hottest weeks of the summer into a pleasant autumnlike week in parts of the western United States and Northern Plains, where highs may be about 65 to 70 degrees Fahrenheit. The cold front will likely deal the Northeast only a glancing blow, and temperatures in this region may dip about 10 degrees below average.
Strictly speaking, the cold front is not a polar vortex, according to experts. The impending cold front is called a "high meridional event," but there are some similarities.
It's the same general circulation pattern, but the effects are extremely different. "In the summer, if you go outside in 20 degrees (Fahrenheit) below normal weather, you won't really care, but in the winter, the effects were significantly different because it was already so cold."
SEE THE ARCTIC INDEX FOR TODAY
NOAA is predicting below-normal temperatures for a huge swath of the East Coast this week. The cool air is expected to roll through today, and should keep temperatures between 70 and 80 degrees Fahrenheit on the East Coast.
The unusual summer chill could also trigger some extreme and dangerous weather in the United States, experts say. The cold temperatures will likely send thunderstorms sweeping across much of the country this week. Hail and tornadoes are possible in southern New England down to the mid-Atlantic. In the West, severe lightning, flash floods and dust storms are possible.
Despite the wild weather in store for this week, the cold front could bring some significant benefits. The predicted downpour may finally quench the severe drought in the western United States. While parts of the country may welcome a change from the sweltering July heat, temperatures are expected to climb back up soon.
"No weather pattern lasts forever, and we'll likely see temperatures return to normal by the weekend," Hey it's just a break from the summer, so enjoy it. Oh yeah look at the outlook for July 21-25 looks like summer wants to come back again.
Record cold in Winnipeg – Coldest July 13th since 1884
by ROBERT on JULY 14, 2014 · 12 COMMENTS
“It’s not the kind of record you want to be hearing about in the middle of July,” says Matt Carty of AM680 CJOB.
Yesterday’s high of 15.7 degrees Celsius was the coldest July 13th in Winnipeg since 1884, according to David Phillips, senior Climatologist for Environment Canada.
He blames the polar vortex – that cold low now sitting over the heart of North America.
http://www.cjob.com/2014/07/14/record-low-temps-hit-winnipeg/
by ROBERT on JULY 14, 2014 · 12 COMMENTS
“It’s not the kind of record you want to be hearing about in the middle of July,” says Matt Carty of AM680 CJOB.
Yesterday’s high of 15.7 degrees Celsius was the coldest July 13th in Winnipeg since 1884, according to David Phillips, senior Climatologist for Environment Canada.
He blames the polar vortex – that cold low now sitting over the heart of North America.
http://www.cjob.com/2014/07/14/record-low-temps-hit-winnipeg/
Warmth across the Pacific stalls brewing El Nino
Date
July 16, 2014 - 5:17PM
Read later
Peter Hannam
Environment Editor, The Sydney Morning Herald
View more articles from Peter Hannam
Follow Peter on Twitter Follow Peter on Google+ Email Peter
Twitter
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Stirred up: Satellite image of Typhoon Rammasun approaches the Philippines. Photo: NOAA
Expectations of a strong El Nino weather event in the Pacific are being pared back but warmer-than-usual conditions are expected to persist, meteorologists say.
The latest prediction by the Bureau of Meteorology retains the 70 per cent or more likelihood that an El Nino will form this year with sea-surface temperatures in the equatorial central and eastern Pacific remaining well above average.
So far, though, there are few signs that the atmosphere is responding to the oceanic priming, suggesting that if an El Nino forms it is less likely to be as strong as some models were indicating earlier this year.
Warm in the eastern - but also the western - Pacific. Photo: NOAA
With typical El Ninos, the eastern Pacific is warm relative to the west, reversing or stalling the easterly trade winds. During such events, much of Asia and Australia have relatively dry and warm years, while the Americas often have wet years.
Advertisement
One aspect that is intriguing scientists is the fact that much of the Pacific – not just the east – is unusually warm. In fact, June may have experienced the largest departure in sea-surface temperatures of any month on record, climatologists say.
Japan Meteorological Agency noted this week that monthly sea-surface temperatures were ''remarkably'' above average in regions ranging from near Japan to the coast of North America, and from Mexico to the Philippines.
Global average surface temperatures – including land and near-surface readings – were 0.32 degrees above the long-term average, making last month the hottest June in records going back to 1891, JMA said, citing preliminary figures.
If June is the hottest month, it would add to the warmest May and the equal warmest April, increasing the likelihood that 2014 will top 2005 and 2010 as the warmest year on record.
The fact the El Nino-like conditions in the ocean are waiting for the atmosphere to respond is one reason for the recent warmth.
The release of ''stored heat is helping to warm up the global atmosphere'', Andrew Watkins, manager of Climate Prediction Services at the Bureau of Meteorology, said. "It's not unexpected that these months have been so warm given the amount of heat that must have come out of the Pacific."
Meteorologists are also watching the Indian Ocean, where warmer-than-usual conditions in the east are helping to stall the development of an El Nino. One benefit of unusual warmth in this region is that moisture is streaming over the Australian continent, bringing much needed rain to south-eastern parts.
Central western and south-western NSW had their best rains this week in three months and more is on the way, according to Weatherzone.
Sydney, though, will probably see another week of above-average maximum temperatures and little rain – continuing a trend of the past month and longer.
Friday will be the coolest day, with a maximum of 17 degrees, but other days should have tops of 18-21 out to next Wednesday, the bureau said.
'On its way'
Max Gonzalez, a senior meteorologist at Weatherzone said that while some Pacific waters had cooled off lately, sub-surface temperatures were as much as 3 degrees warmer than normal in parts of the centre and east.
“The strength of the event may not be as strong as we are thinking a couple of months ago but an El Nino is still on its way," Mr Gonzalez said.
The bureau's Dr Watkins said computer modelling suggested an El Nino effect is still likely, although not until later in the year than earlier thought.
A bout of westerly winds a fortnight ago hinted at the atmosphere coupling with the ocean to reverse the trade winds and reinforce El Nino conditions, but things then settled back to normal.
"It's starting to pick up a little bit again," Dr Watkins said, with meteorologists studying the persistence of weakening of the trade winds. "We're still in that waiting phase" to see whether the event is a short one or more prolonged.
Read more: http://www.smh.com.au/environment/w...ing-el-nino-20140716-ztoz4.html#ixzz37edyzbNg
Date
July 16, 2014 - 5:17PM
Read later
Peter Hannam
Environment Editor, The Sydney Morning Herald
View more articles from Peter Hannam
Follow Peter on Twitter Follow Peter on Google+ Email Peter
inShare
submit to redditEmail articlePrintReprints & permissions
Stirred up: Satellite image of Typhoon Rammasun approaches the Philippines. Photo: NOAA
Expectations of a strong El Nino weather event in the Pacific are being pared back but warmer-than-usual conditions are expected to persist, meteorologists say.
The latest prediction by the Bureau of Meteorology retains the 70 per cent or more likelihood that an El Nino will form this year with sea-surface temperatures in the equatorial central and eastern Pacific remaining well above average.
So far, though, there are few signs that the atmosphere is responding to the oceanic priming, suggesting that if an El Nino forms it is less likely to be as strong as some models were indicating earlier this year.
Warm in the eastern - but also the western - Pacific. Photo: NOAA
With typical El Ninos, the eastern Pacific is warm relative to the west, reversing or stalling the easterly trade winds. During such events, much of Asia and Australia have relatively dry and warm years, while the Americas often have wet years.
Advertisement
One aspect that is intriguing scientists is the fact that much of the Pacific – not just the east – is unusually warm. In fact, June may have experienced the largest departure in sea-surface temperatures of any month on record, climatologists say.
Japan Meteorological Agency noted this week that monthly sea-surface temperatures were ''remarkably'' above average in regions ranging from near Japan to the coast of North America, and from Mexico to the Philippines.
Global average surface temperatures – including land and near-surface readings – were 0.32 degrees above the long-term average, making last month the hottest June in records going back to 1891, JMA said, citing preliminary figures.
If June is the hottest month, it would add to the warmest May and the equal warmest April, increasing the likelihood that 2014 will top 2005 and 2010 as the warmest year on record.
The fact the El Nino-like conditions in the ocean are waiting for the atmosphere to respond is one reason for the recent warmth.
The release of ''stored heat is helping to warm up the global atmosphere'', Andrew Watkins, manager of Climate Prediction Services at the Bureau of Meteorology, said. "It's not unexpected that these months have been so warm given the amount of heat that must have come out of the Pacific."
Meteorologists are also watching the Indian Ocean, where warmer-than-usual conditions in the east are helping to stall the development of an El Nino. One benefit of unusual warmth in this region is that moisture is streaming over the Australian continent, bringing much needed rain to south-eastern parts.
Central western and south-western NSW had their best rains this week in three months and more is on the way, according to Weatherzone.
Sydney, though, will probably see another week of above-average maximum temperatures and little rain – continuing a trend of the past month and longer.
Friday will be the coolest day, with a maximum of 17 degrees, but other days should have tops of 18-21 out to next Wednesday, the bureau said.
'On its way'
Max Gonzalez, a senior meteorologist at Weatherzone said that while some Pacific waters had cooled off lately, sub-surface temperatures were as much as 3 degrees warmer than normal in parts of the centre and east.
“The strength of the event may not be as strong as we are thinking a couple of months ago but an El Nino is still on its way," Mr Gonzalez said.
The bureau's Dr Watkins said computer modelling suggested an El Nino effect is still likely, although not until later in the year than earlier thought.
A bout of westerly winds a fortnight ago hinted at the atmosphere coupling with the ocean to reverse the trade winds and reinforce El Nino conditions, but things then settled back to normal.
"It's starting to pick up a little bit again," Dr Watkins said, with meteorologists studying the persistence of weakening of the trade winds. "We're still in that waiting phase" to see whether the event is a short one or more prolonged.
Read more: http://www.smh.com.au/environment/w...ing-el-nino-20140716-ztoz4.html#ixzz37edyzbNg
El Nino may be on hold but monsoon stares an Indian Ocean 'bump'
VINSON KURIAN
SHARE · COMMENT · PRINT · T+
THIRUVANANTHAPURAM, JULY 15:
The El Nino event generated by the warming of the tropical Pacific Ocean has not still got the desired response from the atmosphere to make it the ‘feared wholesome’ for the Indian monsoon.
A general lack of atmospheric response over last month has resulted in some cooling of the tropical Pacific and averted a full-fledged El Nino just yet, the Australian Bureau Meteorology said.
NO All-CLEAR YET
Now, will this trend hold to give the grudging all-clear for the Indian monsoon?
No, not yet, the Bureau appeared to warn. This is because of likely adverse weather signals arising from India’s own backyard.
The agency is referring to a tendency for a negative phase of the Indian Ocean Dipole event to develop in the Indian Ocean, something that even other models have been referring to over the past month or so.
The Indian Ocean Dipole or IOD in short mimics the El Nino-La Nina events of the tropical Pacific in the Indian Ocean to trigger associated impact for a concurrent Indian response.
CHANGES TRIGGERED
Changes are occurring in the Indian Ocean, the Australian agency noted. The Indian Ocean Dipole (IOD) index has been below -0.4 deg Celsius (the negative IOD threshold) since mid-June.
But this would need to remain negative into August to be considered as an event. Negative values are rare when the central Pacific is warmer than normal. Which now explains why the monsoon has suffered thus far during the monsoon - a rare negative IOD tending to coincide with a warming phase in the tropical Pacific.
A negative phase of the IOD, of the type which is apparently being triggered, results from the anomalous warming of the East Indian Ocean relative to the west.
This causes monsoon flows from below the Equator to stop short and rain down over the vast ocean far to the south and southeast, with only residual moisture allowed to proceed into the Bay of Bengal.
In the positive phase of the IOD, the exact reverse is enacted, in which the west of the Indian Ocean adjoining south Arabian Sea warms boosting monsoon flows into mainland India.
The Australian Bureau noted that the warming of the tropical Pacific Ocean over the past several months had primed the climate system for an El Nino in 2014.
While the majority of climate models suggest an El Nino remains likely for the spring of 2014, most have eased their predicted strength.
If an El Nino were to occur, it is increasingly unlikely to be a strong event, the Bureau said.
(This article was published on July 15, 2014)
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VINSON KURIAN
SHARE · COMMENT · PRINT · T+
THIRUVANANTHAPURAM, JULY 15:
The El Nino event generated by the warming of the tropical Pacific Ocean has not still got the desired response from the atmosphere to make it the ‘feared wholesome’ for the Indian monsoon.
A general lack of atmospheric response over last month has resulted in some cooling of the tropical Pacific and averted a full-fledged El Nino just yet, the Australian Bureau Meteorology said.
NO All-CLEAR YET
Now, will this trend hold to give the grudging all-clear for the Indian monsoon?
No, not yet, the Bureau appeared to warn. This is because of likely adverse weather signals arising from India’s own backyard.
The agency is referring to a tendency for a negative phase of the Indian Ocean Dipole event to develop in the Indian Ocean, something that even other models have been referring to over the past month or so.
The Indian Ocean Dipole or IOD in short mimics the El Nino-La Nina events of the tropical Pacific in the Indian Ocean to trigger associated impact for a concurrent Indian response.
CHANGES TRIGGERED
Changes are occurring in the Indian Ocean, the Australian agency noted. The Indian Ocean Dipole (IOD) index has been below -0.4 deg Celsius (the negative IOD threshold) since mid-June.
But this would need to remain negative into August to be considered as an event. Negative values are rare when the central Pacific is warmer than normal. Which now explains why the monsoon has suffered thus far during the monsoon - a rare negative IOD tending to coincide with a warming phase in the tropical Pacific.
A negative phase of the IOD, of the type which is apparently being triggered, results from the anomalous warming of the East Indian Ocean relative to the west.
This causes monsoon flows from below the Equator to stop short and rain down over the vast ocean far to the south and southeast, with only residual moisture allowed to proceed into the Bay of Bengal.
In the positive phase of the IOD, the exact reverse is enacted, in which the west of the Indian Ocean adjoining south Arabian Sea warms boosting monsoon flows into mainland India.
The Australian Bureau noted that the warming of the tropical Pacific Ocean over the past several months had primed the climate system for an El Nino in 2014.
While the majority of climate models suggest an El Nino remains likely for the spring of 2014, most have eased their predicted strength.
If an El Nino were to occur, it is increasingly unlikely to be a strong event, the Bureau said.
(This article was published on July 15, 2014)
Post Comment
RELATED
NEWS
Monsoon showing signs of revival: Skymet
Retail, wholesale inflation cools in June as cereal prices dip
TOPICS
Monsoon Watch | weather |
What's this?What's this?
Tweet
inShare
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1. Comments will be moderated by The Hindu Business Line editorial team.
2. Comments that are abusive, personal, incendiary or irrelevant cannot be published.
3. Please write complete sentences. Do not type comments in all capital letters,
or in all lower case letters, or using abbreviated text.
(example: u cannot substitute for you, d is not 'the', n is not 'and').
4. We may remove hyperlinks within comments.
5. Please use a genuine email ID and provide your name, to avoid rejection.
Warming of the tropical Pacific Ocean over the past several months primed the climate system for an El Niño in 2014. However, a general lack of atmospheric response over the last month has resulted in some cooling of the tropical Pacific Ocean.
While the majority of climate models suggest El Niño remains likely for the spring of 2014, most have eased their predicted strength. If an El Niño were to occur, it is increasingly unlikely to be a strong event.
Changes are also occurring in the Indian Ocean. The Indian Ocean Dipole (IOD) index has been below −0.4 °C (the negative IOD threshold) since mid-June, but it would need to remain negative into August to be considered as an event. Negative values are rare when the central Pacific is warmer than average. Model outlooks suggest the IOD is likely to return to neutral by spring. Conditions in the Indian Ocean may have contributed to the above-average rainfall experienced in southeast Australia during June.
While the majority of climate models suggest El Niño remains likely for the spring of 2014, most have eased their predicted strength. If an El Niño were to occur, it is increasingly unlikely to be a strong event.
Changes are also occurring in the Indian Ocean. The Indian Ocean Dipole (IOD) index has been below −0.4 °C (the negative IOD threshold) since mid-June, but it would need to remain negative into August to be considered as an event. Negative values are rare when the central Pacific is warmer than average. Model outlooks suggest the IOD is likely to return to neutral by spring. Conditions in the Indian Ocean may have contributed to the above-average rainfall experienced in southeast Australia during June.