Climate: El Niño stalls, outlook uncertain

Above-average temperatures to persist across much of the country

Sea surface temperature anomalies as of Sept. 20. Graphic courtesy NOAA.

By Bob Berwyn

SUMMIT COUNTY — This year’s El Niño is likely to be one of the weaker versions of the event in recent memory, according to experts with the National Climatic Data Center, who discussed the fall outlook and reviewed the long, hot summer at teleconference last week.

That could weaken potential impacts, particularly across the southern tier of states, where an “average” El Niño often brings above-average precipitation.This could be especially important for states like New Mexico, which just experienced its driest and warmest 24-month period on record, and farther east, where Oklahoma was also parched during a record-hot summer.

During an El Niño, sea surface temperatures in the eastern and central equatorial Pacific surge to above average, often shifting the storm track to the south. It’s part of a cyclical shift in sea surface temperatures and related wind patterns that can affect weather patterns worldwide.

Sea surface temps have hovered at slightly above average the past few months in the region where El Niño formation is measured, but haven’t reached the formal threshold yet. An area of cooler water in the north Pacific may be a factor.

The North Pacific is not cooperating … there’s a cold area near Alaska. It’s not quite a perfect setup for a warm event in the tropics,” said NOAA scientist Huug van den Dool.

“It’s probably too late to get a major El Nino … it’s going to be somewhat weaker than we expected a few months ago,” he said, explaining that there’s still a chance for enhanced precipitation across the South. An average El Niño footprint would normally also result in below-average precipitation in the northern tier of states.

A map from the National Climatic Data Center shows where the summer heat wave was centered. Click on the graphic to visit the NCDC online.

El Niño or not, the Climate Prediction Center says there’s a good chance the next three months will bring mostly above average temperatures to a big swath of the country, from the eastern edge of the Great Basin through the central and northern plains, up into the Great Lakes region and New England.

The three-month precipitation outlook is for near-normal total for much of the country, with a chance of above-normal rainfall in the southeast, and drier-than-normal conditions in the Pacific Northwest.

Looking back, Jake Crouch, of the NCDC, said it was the third-warmest summer on record for the U.S. and second-warmest summer for the northern hemisphere. A total of 33 states reported their warmest year to-date on record.

The year to-date is the ninth-warmest on record globally.

Colorado: Does El Niño bring early snow?

Historical stats don’t show big impact on date of first snow

Summit County and a small surrounding area dodged the drought bullet in late July and early August, with rainfall anywhere from 130 to 200 percent of normal, but rainfall maps show that most of the state still experienced well-below average rainfall during that span.

A similar pattern was evident for the three-month precipitation history in Colorado, with just a few pockets of above-average rainfall in the north-central mountains and the western San Juans.

SUMMIT COUNTY — Talk about living in a bubble — the latest three-month summary and outlook from the National Weather Service in Boulder shows that the rainy conditions in Summit County, and a small surrounding area, were the exception in Colorado the past 30 days. Much of the state continued to suffer through extremely dry conditions, especially the eastern plains, where precipitation was just 5 to 50 percent of normal. As a result, much of the state is still experiencing serious drought. Visit the Boulder NWS website to see the full power point presentation. Continue reading

Climate: Global July temps the 4th-highest ever

Cooler than average readings reported from Australia, South America

Red areas mark above-average temperatures, with blue designating areas that were cooler than average in July.

SUMMIT COUNTY — Already on record as the hottest month of all time in the U.S., July 2012 will now go into the books globally as the fourth-warmest on record.

According to the global temperature analysis released today by the National Climatic Data Center, the average combined land and sea surface temperature for July was 1.12 degrees above the 20th century average. The land surface temperatures alone was the third-warmest on record at 1.66 degrees above the 20th century average.

Last month marked the 36th consecutive July with above-average temperatures and the 329th consecutive month overall with higher-than-average readings. According to the NCDC, the last time July global temps were below average was in 1976.

The warmest temps were reported from southeastern Europe, Canada and the U.S. Much cooler than average temperatures continued in Australia, northern and western Europe, eastern Russia, Alaska, and southern South America.

Even in a transition phase between a cooling La Niña and an emerging El Niño, global ocean temperatures were well above normal, with the highest monthly departure from average since July 2010.

For the year to-date, the combined average land and sea surface temperature is the 10th-warmest on record.

Information compiled from the NOAA National Climatic Data Center, State of the Climate: Global Analysis for July 2012, published online August 2012, retrieved on August 15, 2012 from http://www.ncdc.noaa.gov/sotc/global/2012/7.

Climate: Extreme rainfall events increasingly common

Increased atmospheric water vapor seen as key ingredient

Extreme rainfall events have increased in the past few decades.

By Summit Voice

SUMMIT COUNTY — Parts of the U.S. have seen clear statistical trends more extreme precipitation events in the past few decades, according to a new paper from the American Meteorological Society based on extensive research from federal and state agencies, as well as academic sources.

Increased water vapor in the atmosphere, as outlined by many climate change models, may be one of the key factors in the the observed changes, according to the researchers, who said that weren’t able to measure statistically significant changes in severe thunderstorms.

But for extreme precipitation, “there is strong evidence for a nationally-averaged upward trend in the frequency and intensity of events,” the paper concludes. About 76 percent of all stations reported increases in extreme precipitation. Continue reading

Colorado: Will El Niño be a drought buster?

Drought likely to persist for several more months

The National Climatic Data Center temperature map for June 2012 clearly shows the extraordinary heat centered over Colorado.

By Summit Voice

SUMMIT COUNTY — A tilt toward El Niño conditions in the Pacific Ocean could start putting a dent in the western drought, according to the latest update from the Western Water Assessment climate summary.

El Niño, when sea surface temperatures in the equatorial Pacific climb above average, can help deliver average to above-average summer and fall moisture to Colorado and the Intermountain West, including drought-busting September rains in 2003 that helped end Colorado’s last serious drought.

El Niño doesn’t guarantee a wet winter. During many previous episodes, mid-winter conditions have been relatively dry, as the main storm track dives far to the south. But springtime during an El Niño phase can deliver copious precipitation to the Front Range and to the mountains along, and just east of, the Continental Divide.

The climate summary for June 2012 draws a number of comparisons to conditions in 2002, when conditions were even more dry across parts of western Colorado.

2002 extreme drought conditions were more widespread across Colorado than they are this year.

Continue reading

Goodbye La Niña — are you ready for El Niño?

Impacts on Colorado uncertain

Warmer-than-average sea surface temperatures are spreading west from the coast of South America, potentially heralding a developing El Niño.

The three-month precipitation outlook from NOAA’s Climate Prediction Center highlights a chance for above-average moisture in the Southeast and a small arc of the Southwest.

By Bob Berwyn

SUMMIT COUNTY — A classic El Niño may be developing across the eastern Pacific, with warmer-than-average water temperatures starting to spread westward from the coast of South America, according to NOAA’s Climate Prediction Center.

For the month of June, the pattern of sea surface temperatures overall remained in a neutral phase, but with growing positive (warmer than average) equatorial Pacific sea surface temperature anomalies, NOAA has issued an El Niño watch, reflecting a likely emergence of of El Niño in the late summer or fall. Continue reading

Global warming: More lightning, less rain?

New study suggests severe thunderstorms will become more common

A thunderstorm on July 18, 2011 dropped an all-time 24 hour rainfall total on Summit County.

By Summit Voice

SUMMIT COUNTY — Global warming could result in fewer but more intense thunderstorms, with a 10 percent increase in lightning activity for every 1 degree Celsius of warming, according to a new study by scientists at Tel Aviv University.

The increase in more severe storms could up the chances for flash floods, wildfires and even damage to power infrastructure, according to Professor Colin Price, head of the university’s Department of Geophysics, Atmospheric and Planetary Sciences.

The researchers tested their climate models in real world conditions in Africa and the Amazon, and regions where climate change occurs naturally, such as Indonesia and Southeast Asia, where El Niño cyclically changes the atmosphere. Continue reading

Climate change triggered ancient reef shutdown

El Niño cycles seen as key factors in coral reef ecology. Photo courtesy NOAA.

Extreme El Niño cycles seen as cause of coral decline

By Summit Voice

SUMMIT COUNTY — A period of dramatic El Niño-La Niña cycles that started about 4,000 years ago resulted in the near-total collapse of some Pacific coral reef ecosystems, according to a new study that took a close look at long-dead reef skeletons along the Pacific Coast of Panama.

The cross-sections of reef covered the last 6,000 years and showed a “reef shutdown” that lasted about 2,500 years, according to the study, published last week in Science. Similar gaps in coral growth were found as far away as Australia and Japan. Continue reading

Climate: New research may enable earlier El Niño forecasts

Most El Niños since 1958 began with a previously unidentified subsurface discharge of warm water about 18 months before the peak of the events

A NOAA graph of June 25 sea surface temperature anomalies shows a spear of warm water spreading east from South America along the equator.

By Summit Voice

SUMMIT COUNTY — Not every El Niño is the same, but all of them start with a massive discharge of sub-surface warm water from the equatorial western Pacific.

That discharge starts much earlier than previously recognized, and may provide an early warning for the onset of El Niños, which can affect much of the world with weather anomalies, including flooding rains in some places and drought in other areas. It’s also seen as a mechanism for recharging the tropics with warm water.

The new El Niño study was authored by Nandini Ramesh and Raghu Murtugudd, associated with the University of New South Wales Climate Change Research Centre and published in the journal Nature Climate Change.

The scientists studied El Niño episodes between 1958 and 2011 to try and find a pattern. In the process, they showed that El Niños in the 1980s and 1990s started with warm sea surface temperature anomalies near the dateline that spread eastward, while earlier episodes started with anomalies off the west coast of South America and spread to the west. Continue reading

Colorado: Will the monsoon bring drought relief?

Summer rainfall outlook still uncertain

Post-La Niña monsoons sometimes miss Colorado.

By Bob Berwyn

SUMMIT COUNTY — The biggest uncertainty for the course of this summer’s fire season is whether the monsoon will arrive on schedule — or perhaps even a bit early — to soak Colorado with beneficial rains, and for now, the answer is still uncertain.

The larger Pacific weather patterns are in a transitional phase. With winter’s La Niña officially over, it’s unclear if and how quickly an El Niño might form, or whether neutral conditions will persist over the Pacific for the next few months.

The El Niño-La Niña cycle drives not only the winter storm track, but also has an effect on summer weather patterns. El Niño is marked by warmer-than-average sea surface temperatures in the eastern equatorial Pacific, while La Niña is signalled by cooler waters.

Some forecasters have suggested that a quick shift to a strong El Niño could bring better chances  for a solid monsoon season to Colorado, but forecasting skills for the summer rains are not completely reliable. Continue reading

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