North Atlantic pressure variations driving variable pattern
FRISCO — Weather patterns affecting the UK are becoming more volatile, climate researchers concluded in a new study, concluding that the trend is being driven by extreme variations in pressure over the North Atlantic.
The month of December is showing the biggest variation, but contrasting conditions, from very mild, wet and stormy to extremely cold and snowy are a clear sign of less stable weather, University of Sheffield scientists reported in a study published last month in the Journal of Climatology.
Winter weather conditions are commonly defined using the North Atlantic Oscillation, a south-north seesaw of barometric pressure variations over the North Atlantic which determine the strength of the westerly winds that shape North Atlantic weather systems. Continue reading “Climate: UK weather trends toward extremes”→
New study helps track seasonal shifts in North Atlantic storm track
By Summit Voice
FRISCO — Just as weather forecasters in the western U.S. look at El Niño and La Niña to help get a handle on season outlooks, European meteorologists are carefully analyzing the North Atlantic Oscillation for climate clues. The job is easier in some years, according to a new study carried out by the National Oceanography Centre.
The research shwoed that the relationship between our winter weather and the strength of the airflow coming in from the Atlantic – one of the factors used by forecasters to predict the weather – is stronger in some years than others. The results were recently published in the Royal Meteorological Society publication Weather.
NOAA calls for warmer-than-average conditions in the West
By Summit Voice
SUMMIT COUNTY —This year’s wavering El Niño isn’t just vexing Colorado forecasters. Forecasters with the National Oceanic and Atmospheric Administration say that getting a handle on the winter forecast has been tough.
“This is one of the most challenging outlooks we’ve produced in recent years because El Niño decided not to show up as expected,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “In fact, it stalled out last month, leaving neutral conditions in place in the tropical Pacific.” Continue reading “‘Wavering’ El Niño vexes winter weather outlook”→
SUMMIT COUNTY — Climate experts are still hedging their bets when it comes to an outlook for the coming winter, with the official outlook from NOAA’s Climate Prediction Center showing no strong trend toward above- or below-average precipitation.
A somewhat murky El Niño outlook is clouding the picture, with sea surface temperatures in the equatorial Pacific ranging above average, but cooling down from just a month ago.
“It’s vexing … the models are just not up to the task,” Wolter said. Overall, he said he’s “guardedly optimistic” that Colorado will see at least close to an average snowfall year, which would would be critical to maintaining water supplies in the state’s depleted reservoirs. Continue reading “Weather: El Niño, or La Niña’s ghost?”→
Sea ice in breeding areas declining by 6 percent per decade; entire age classes are being lost
By Summit Voice
SUMMIT COUNTY — Along with declining habitat for polar bears, harp seal populations in the far north are also taking a big hit from global warming, according to researchers who documented reduced winter sea ice cover in key harp seal breeding grounds.
That decline has resulted in sharply higher death rates among seal pups in recent years, according to a new Duke University-led study. The researchers documented some movement of breeding harp seals to more stable sea ice environments, but thousands are still returning to traditional breeding grounds, where entire generations of seals are being lost.
“The kind of mortality we’re seeing in eastern Canada is dramatic. Entire year-classes may be disappearing from the population in low ice years – essentially all of the pups die,” said David W. Johnston, research scientist at the Duke University Marine Lab. “It calls into question the resilience of the population.” Continue reading “Global warming: Harp seal habitat vanishing fast”→
Warming sea surface temperatures linked with drought cycles
By Summit Voice
SUMMIT COUNTY — The Mediterranean has long been identified as an area that will feel global warming impacts because of water scarcity in the region, a rapidly increasing population, and climate modeling that projects increased risk of drought.
And now, a new NOAA study shows that wintertime droughts are becming increasingly common in the region, and human-caused climate change is partly responsible. In the last 20 years, the Mediterranean region has experienced 10 of the driest 12 winters on record, according to data compiled by the Cooperative Institute for Research in Environmental Sciences (CIRES).