Climate: Better El Niño forecasting ahead?

Early warning could help regional preparedness efforts

A new climate model could help project El Niño conditions a year in advance.

A new climate model could help project El Niño conditions a year in advance.

By Summit Voice

FRISCO — Forecasting the emergence of El Niño well in advance has long been a goal of climate scientists and a team of German researchers say they may have devised a model that extends the lead time to a year.

Published recently in the Proceedings of the National Academy of Sciences, their paper describes how the model uses high-quality data of air temperatures as the basis for making long-term projections about El Niño, a warm phase of a periodic Pacific Ocean cycle that affects climate and weather around the world.

“Enhancing the preparedness of people in the affected regions by providing more early-warning time is key to avoiding some of the worst effects of El Niño,” said Hans Joachim Schellnhuber, director of the Potsdam Institute for Climate Impact Research, who co-authored the paper with Josef Ludescher, of Justus-Liebig Universität Giessen. Continue reading

Global warming may drive more active La Niña pattern

Broad tree-ring record provides accurate ENSO history

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Researchers say tree ring records show that El Niño activity during the 20th century has largely been outside the range of natural variability.

By Summit Voice

Climate scientists have long suspected that global warming has an influence on the Pacific Ocean El Niño- La Niña cycle (El Niño-Southern Oscillation), but instrumental records tracking the shift between above- and below average sea surface temperatures don’t go back far enough to provide context for any recent changes in the pattern.

But scientists working at the International Pacific Research Center, University of Hawaii at Manoa say a new tree ring record extending back about 700 years has helped decipher long-term trends. The tree ring samples from both the tropics and mid-latitudes in both hemispheres support the idea that the unusually high ENSO activity in the late 20th century is a footprint of global warming said Jinbao Li, lead author of the study published online in the journal Nature Climate Change. Continue reading

Global warming: USGS study shows 20 percent decline in Rocky Mountain snow cover since 1980

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Sparse January snow across the Colorado Plateau in January 2013. Bob Berwyn photo.

Drop linked primarily with warmer spring temperatures

By Summit Voice

SUMMIT COUNTY — Long-time skiers often say that skiing was better in the good old days, and new research from the U.S. Geological Survey suggests that those claims are based on more than nostalgia — notwithstanding the occasional bumper crop of powder like in 2010-2011.

After taking an in-depth look at snowfall and temperature records, federal scientists said warmer spring temperatures since the 1980s have caused an estimated 20 percent loss of snow cover across the Rocky Mountains of western North America — especially at lower elevations where temperatures have the greatest effect. Continue reading

Climate: Drought conditions edge westward

Wet, cool spring brings relief to Midwest

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The most severe areas of drought encompass parts of the central-southern plains, spreading southwest into parts of Colorado and New Mexico.

By Bob Berwyn

FRISCO — Drought woes have eased in the Midwest after a wet spring, but the far West,  California in particular, are facing continued dry conditions. California has reported its driest year to-date on record, with only 27 percent of normal precipitation for January through April. That doesn’t bode well for the state’s water supplies, although at least reservoir storage is close to normal in California.

New Mexico and Nevada are in bad shape when it comes to reservoir storage and there’s little relief in sight at the end of the snow season. Forecasters with the National Oceanic and Atmospheric Administration said dry soil conditions in the southwest could contribute to higher than average temperatures this summer. Continue reading

Report: Global warming not a big factor in 2012 drought

Natural climate variability the biggest player, scientists say

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Drought conditions persist across the central part of the country.

By Bob Berwyn

SUMMIT COUNTY — Last summer’s crippling Great Plains drought can’t definitively be linked with global warming, according to a team of federal scientists from various agencies. In a new report issued this week, the researchers said the drought was probably caused by a confluence of natural climate variations that might only come together in a similar constellation once a century.

Cyclical variations in ocean temperatures — especially the combination of a cooler-than-average Pacific Ocean and a warm phase of the North Atlantic Multidecadal Oscillation may have nudged the region toward drought conditions, but those factors tend to be more of a factor in suppressing winter precipitation. Continue reading

Climate: Study looks at changing monsoon patterns

Natural climate variables so far outweigh global warming impacts

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The North American monsoon is an important climate factor in the Rocky Mountains.

By Summit Voice

SUMMIT COUNTY — The timing and amount of monsoon rains in the northern hemisphere have important economic and environmental ramifications, for example for farmers in Asia and the wildfire season in the southwestern U.S.

As a result, climate researchers have been trying to determine how the Earth’s steady warming will affect those seasonal rainfall patterns, and so far, the jury is still out. Some recent research has suggested that the timing of the North American monsoon might be delayed, while other studies have indicated that there could be an overall increase in monsoon precipitation.

In one of the latest studies, scientists with the International Pacific Research Center, University of Hawaii at Manoa, say that monsoon rainfall patterns appear to more influenced by natural long-term swings in ocean surface temperatures. The Interdecadal Pacific Oscillation or mega-El Niño-Southern Oscillation, which has lately been in a mega-La Niña or cool phase is one key factor, and shifts in the Atlantic Multidecadal Oscillation, also contributes to the intensification of monsoon rainfall. Continue reading

Colorado: No El Niño, no La Niña – what’s driving the weather?

Spring outlook trends toward warm and dry conditions

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The Madden-Julian Oscillation has played a role in Colorado weather this winter.

By Summit Voice

FRISCO — With neither El Niño or a La Niña conditions in the Pacific Ocean, long-range weather forecasters have been struggling to develop confidence in their outlook for the coming spring season — a critical time for much of the West in terms of getting some relief from drought conditions.

A wet and cool spring could at least take the edge off the drought in some areas, helping to maintain stream flows and reduce the potential for massive and dangerous wildfires. Conversely, a return to last year’s very dry and warm spring pattern would spell trouble for places like Colorado.

So if the El Niño-La Niña cycle isn’t driving the weather, what is? What we do know is that conditions over the Pacific Ocean are the key to understanding exactly what path storms will take across the western United States, and that conditions in the North Atlantic can also be a factor. Continue reading

Colorado: Some headwaters areas seeing ‘extreme’ drought

All of Summit and Eagle counties in the red zone this month

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All of Colorado is currently experiencing some level of drought, with the driest conditions on the southeastern plains, while even some high-mountain headwaters areas are currently designated as being in extreme drought.

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Automated streamflow and snowpack gages around Colorado help water managers calculate seasonal outlooks.

By Bob Berwyn

FRISCO —Snowpack levels and moisture content are so low that all of Summit County — a key headwaters source region for the Colorado River — has been colored red on the U.S. drought monitor map, signifying “extreme” drought conditions.

Summit County residents and visitors are in for an unpleasant surprise when the snow melts in a couple of months. Dillon Reservoir, the centerpiece of the area’s summer recreation activities, is going to be lower than at anytime during the past 10 years. Denver Water has continued to shunt water through the Roberts Tunnel during the early winter and according to the latest projections, the reservoir will probably drop another 10 feet by March. Continue reading

Morning photo: Feels like April

No good news from Colorado water powwow

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A stream flow gage along Straight Creek, in Dillon, Colorado.

FRISCO —A January thaw has raised stream flows in the Colorado high country close to normal — but only because the warm temperatures are resulting in unseasonable runoff. All in all, Colorado could be facing one of the driest periods on record barring a miraculous turnaround in spring precipitation. And that’s not unheard of. A snowstorm that started March 17, 2003 dumped more than seven feet of snow on parts of the Front Range and Continental Divide and helping to end the early 2000s drought. Will it happen again? Nobody knows, because those types of one-shot weather events are unpredictable. But water managers say that even record-breaking spring snowfalls might not bring the state snowpack back to average. Continue reading

Colorado: Are January red flag fire warnings in the mountains part of a new climate reality?

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Click on the map for red flag fire warning details.

*UPDATED: The red flag warning was lifted Thursday (Jan. 24) afternoon as cooler weather moves into the area. Check http://www.crh.noaa.gov/den/ for the latest.

January fire warnings, nearly unprecedented 30 years ago, have become more common the last decade

By Bob Berwyn

SUMMIT COUNTY — Illustrating the persistence of extraordinary drought conditions in parts of Colorado, the National Weather Service issued a Red Flag fire warning for the Rocky Mountain foothills west of Denver north to the Wyoming border and encompassing areas that were scorched by last summer’s High Park Fire.

Boulder-based National Weather Service forecaster Mike Baker said the agency decided to post the warning after three wildfires were reported Wednesday (Jan. 24) within the span of an hour. All three fires were above 8.500 feet elevation on the east slope of the mountains along the Front Range, Baker said. Continue reading

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