Climate: Is the Southwest ‘stuck’ in a drought pattern?

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NOAA’s winter outlook offers little relief for Arizona, New Mexico

By Bob Berwyn

FRISCO — Drought conditions may persist across the southwestern U.S. this winter and may redevelop across the Southeast, according to the seasonal outlook from NOAA’s Climate Prediction Center.

“Even though we don’t have La Niña, the atmosphere across the Pacific seems to be stuck in a La Niña mode … It’s been quite surprising to us, how persistent the pattern is,” said Mike Halpert, acting director of the Climate Prediction Center.

Parts of the Southwest, especially New Mexico, have been experiencing one of the driest periods on record, and Halpert said there is “decent agreement” in the CPC’s models on the climate signal that has resulted in the persistent trend. Continue reading

How will global warming affect El Niño?

Study shows how external influences shape Pacific weather patterns

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New research may help show how global warming will affect El Niño.

By Summit Voice

FRISCO — By studying coral samples from a remote Pacific atoll, Australian researchers say they’ve found evidence that external influences can change the intensity of the periodic El Niño cycle. By extension, they said, human-caused global warming could also alter the pattern, though the observational record is too short to determine whether that’s already happening.

The research was led by scientist with the ARC Centre of Excellence for Climate System Science and  published in Nature Geoscience.

“Our research has showed that, while the development of La Niña and El Niño events is chaotic and hard to predict, the strength of these events can change over long time spans due to changes in the global climate,” said one of the paper’s authors, Australian climate researcher Dr. Steven Phipps. Continue reading

Summit Voice: Week in review

Climate, cannabis and apex predators …

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Whither the weather?

By Summit Voice

FRISCO — One of the top news stories in Colorado last week was the dramatic change in the federal government’s position on legal use of marijuana in Colorado. After decades of intolerance, U.S. Attorney General Eric Holder indicated that the feds won’t seek to challenge Colorado’s new pot regime — at least for now. That leaves the state free to administer recreational sales of cannabis, as long as there is a robust state-based regulatory structure. Read the Summit Voice story, which includes the full text of the new guidance from the feds: Feds ease stance on marijuana.

In a couple of email interviews, Summit Voice explored the seasonal weather outlook. Making forecasts three months in advance is dicey at best, an in the absence of a clear El Niño or La Niña signal, meteorologists are struggling even more than usual to pin down upcoming patterns: Climate: With no Niño — what’s a forecaster to do?

For Mexican gray wolves living in the southwestern United States, the news was good. Rather than fighting conservation groups, the U.S. Fish and Wildlife Service backed down in the face of several lawsuits to give the predators a little more room to roam in the deserts of Arizona and New Mexico: Mexican gray wolves will get more room to roam.

A forest study in the eastern U.S. has implications for forest management here in the West, as well, showing that, when it comes to biodiversity, forest species need a mix of towering old growth and cleared areas, which are seen as important for birds just before they migrate: Study: Forest clearings crucial for some birds. Continue reading

Climate: With no Niño — what’s a forecaster to do?

Fall and winter outlook still murky

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Seasonal weather forecasters look out to sea surface temperatures in the equatorial Pacific to get an idea of what weather patterns may bring.

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Without a stron El Niño or La Niña in the outlook, forecasters are not confident of projecting pronounced temperature or precipitation anomalies.

By Bob Berwyn

FRISCO — With no strong El Niño or La Niña on the horizon, forecasters are struggling even more than usual to develop seasonal outlooks for the western U.S. The periodic El Niño-La Niña cycle is a large-scale shift in the Pacific involving a complex interplay of winds, ocean currents and sea surface temperatures.

In the U.S. the warm El Niño phase is associated with wetter than average conditions in the Desert Southwest and California, and can result in below average precipitation in the Pacific Northwest.

La Niña, on the other hand, has been linked with Southwestern drought conditions and heavy precipitation in the Pacific Northwest. That persistent moist flow off the northwestern Pacific can also favor parts of Colorado with good winter snows, but the ENSO climate signal is more marginal in Colorado than in other areas. 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

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

Climate: NOAA drops El Niño watch

Forecasters call for neutral conditions, but say a La Niña is not out of the question

n El Niño never managed to establish itself in the equatorial Pacific this year.

The three-month precipitation outlook from NOAA’s Climate Prediction Center.

By Summit Voice

FRISCO — With sea surface temps cooling to near average in much of the equatorial Pacific, NOAA’s Climate Prediction Center has dropped an El Niño watch that’s been in effect for the past several months.

El Niño is part of a cyclical pattern of sea surface temperature variations that affects global weather patterns. The emerging El Niño forecast last spring and summer offered some hope for drought relief in the parched Southwest and the southern tier of states, where warmer than average Pacific Ocean temps can help boost winter and spring precipitation.

During La Niña years, when cooler-than-average sea surface temperatures prevail in the same region, the storm track often shifts northward, driving storms into the Pacific Northwest and then down across the northern Rockies and northwest Colorado. Continue reading

Colorado: No drought relief in sight?

Forecasters not bullish on big winter

drought conditions persisted across most of Colorado during the past three months.

Temps from mid-September to mid-October average 1 to 3 degrees above average in western Colorado and 1 to 3 degrees below average east of the Rockies.

By Summit Voice

FRISCO — This winter’s iffy weather pattern doesn’t hold the promise of significant drought relief, according to the National Weather Service’s Boulder office, which released its winter winter weather outlook this week.

There’s a reasonable expectation that the state will see more storms than last winter, but forecasters don’t expect those storms to be as intense or long-­‐lasting as those commonly observed during stronger El Niño or La Niña episodes, as the storm track is expected to be inconsistent in what looks to be either a weak El Niño or even neutral Pacific ocean conditions. Continue reading

Colorado: Forecasters still grappling with winter outlook

An El Niño often brings decent October precipitation to the high country, but signals are mixed this year.

No clear signal means water managers will be biting their nails for a few months

By Bob Berwyn

FRISCO — Without a strong El Niño or La Niña signal, Colorado weather watchers are struggling even more than usual to get a sense of how much snow to expect this coming winter, critical information for water managers who have seen reservoir storage dwindle to below 70 percent of average for this time of year.

Even if winter snowfall is close to normal, some reservoirs are unlikely to refill completely next spring, leaving utilities in the position of hoping for an above average winter.

“We’re far from through this. The story has yet to unfold,” Blue River Basin water commissioner Troy Wineland said after participating in a weekly statewide water webinar, explaining that many local streams are flowing well below seasonal averages. A few others are close to average due to upstream releases of stored water, he said. Continue reading

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