Climate: Study shows how smoke from distant wildfires can affect tornado formation

A tornado near Lakeview, Texas. Photo courtesy NOAA.

A tornado near Lakeview, Texas. Photo courtesy NOAA.

New study could help produce better tornado forecasting

Staff Report

FRISCO — Under certain conditions, wildfire smoke transported thousands of miles can intensify tornadoes in U.S., according to University of Iowa researchers, who studied how smoke from agricultural burning in Central America affected tornado conditions in the United States.

The research specifically looked at the smoke impacts on an April 27, 2011 tornado outbreak that spawned 122 twisters, killing 313 people, considered the most severe tornado event since 1950. Continue reading

Climate: Urban areas amplify global warming impacts

Extreme heat events piling up in cities around the world

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South American cities in particular have seen an increase in heat waves, according to a detailed new UCLA study that tracked climate more than 200 urban areas.

Staff Report

FRISCO — The world’s urban areas are shaping their own local climate by affecting regional wind fields, and that is resulting in more frequent heatwaves, researchers say, reporting a climate “double-whammy” of global warming and an intensifying urban heat island effect.

Human activities and the built environment trap heat and prevent cities from cooling down, said UCLA geography professor Dennis Lettenmaier.

“Everything’s warming up, but the effect is amplified in urban areas,” Lettenmaier said after studying  217 urban areas across the globe and finding that prolonged periods of extreme heat increased significantly in 48 percent of them between 1973 and 2012. Continue reading

Climate study predicts doubling of extreme La Niñas

Will global warming intensify extreme weather swings?

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How will climate change affect ENSO?

Staff Report

FRISCO — Global warming could increase the frequency of extreme La Niña events in the Pacific Ocean, with more droughts in southwestern United States, floods in the western Pacific regions and increased Atlantic hurricane activity.

The international study, published in Nature Climate Change, used advanced modeling to show how increased land-area heating, combined with more frequent El Niños, will feed a cycle of extreme La Niñas. Continue reading

U.S. Tornado activity again below normal in 2014

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Tornado numbers low for third year in a row.

Scientists say they can’t pinpoint and long-term trends

Staff Report

FRISCO — The number of tornadoes in the U.S. was below average for the third year in a row, NOAA scientists said last week. A preliminary count shows there were about 800 tornadoes in 2014, the lowest number since 1982 and about 20 percent below the long term average. Continue reading

Climate: Extended droughts spell trouble for Southwest birds

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Some birds won’t nest at all during drought years.

Some Sonoran Desert species skip breeding entirely during extreme drought

Staff Report

FRISCO — Drought-driven delayed nesting by some southwestern bird species may lead to crashing populations, scientists said in a new study that looked closely at Sonoran Desert bird species, such as Black-tailed Gnatcatchers and Verdins.

The research suggests drought conditions are delaying nesting by two weeks or more for some species. Despite recent rainfall, drought conditions persist in much of the Southwest, making life tough even for species adapted to a dry environment.

Delayed nesting makes the birds more vulnerable to nest predators and parasites, according to the scientists with Point Blue Conservation Science and the U.S. Geological Survey finds that increased drought frequency in southwestern North America results in increased instances of delayed nesting. Continue reading

What drives extreme fires? It’s mostly the weather

Forest Service scientists study aftermath of Rim Fire to assess effectiveness of forest health treatments

A NASA Earth Observatory image shows smoke plumes from the Rim Fire in August, 2013. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response.

A NASA Earth Observatory image shows smoke plumes from the Rim Fire in August, 2013. NASA image by Jeff Schmaltz, LANCE/EOSDIS Rapid Response.

Staff Report

FRISCO — A detailed new study of fire behavior of the 2013 Rim Fire in Yosemite provides a nuanced view of the effectiveness of forest health treatments.

The Rim Fire was the largest recorded fire in the Sierra Nevada region, and U.S. Forest Service researchers said in their study that the fire burned with moderate to high intensity on days the Rim Fire was dominated by a large pyro-convective plume, a powerful column of smoke, gases, ash, and other debris — regardless of the number of prior fires, topography, or forest conditions. Continue reading

Is melting Arctic sea ice shifting the jet stream?

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Is melting sea ice shifting the jet stream?

Study finds robust link between Arctic ice decline and severe Eurasian winter weather

Staff Report

FRISCO — If you feel like you’ve been on a weather roller coaster, maybe it’s because the jet stream has been behaving like one more and more often in recent years.

Instead of flowing around the mid-latitudes of the northern hemisphere with a few ripples, some years, the high-altitude river of air has been more like a writhing, out-of-control fire hose, snaking and looping, carrying huge surges of warm air north and cold. polar air south. At times, the jet stream has been getting stuck in that pattern for longer stretches. Continue reading

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