Posted on March 17, 2015 by Bob Berwyn
Finding a signal amidst the climate noise isn’t easy
Does La Niña increase the odds of tornadoes?
Study finds links between ENSO and tornado frequency in the Southern U.S. Photo courtesy NOAA.
FRISCO — Teasing out a link between large-scale atmospheric patterns and specific weather events isn’t easy against the backdrop of natural variability.
But a new study of the El Niño-La Niña cycle in the Pacific Ocean suggests that La Niña — the cool phase of the cycle — increases the frequency of tornadoes and hail storms in some of the most susceptible regions of the United States.
During La Niña, both vertical wind shear and surface warmth and moisture increase significantly in the southern states, making conditions favorable to severe storm occurrence.
The study, published in the current issue of the journal Nature Geoscience, may help provide more information for medium- and long-range extreme weather forecasts. Continue reading
Filed under: climate and weather, extreme weather, global warming | Tagged: climate, El Nino, ENSO, extreme weather, La Niña, tornadoes | Leave a comment »
Posted on March 14, 2015 by Bob Berwyn
‘The risk of high-impact heat waves is likely to increase’
Monsoonal summer thunderstorms help regulate heatwaves. bberwyn photo.
FRISCO — Summer heatwaves, already getting longer and hotter because of human-caused global warming, are set to get even worse, as the overall climate-warming trend disrupts atmospheric circulations that bring relief from long spells of hot weather.
A recent study by scientists with the Potsdam Institute for Climate Impact Research one measurement of accumulated summer storm energy has already declined by 10 percent since 1979. The researchers linked the findings to changes in the Arctic caused by man-made global warming. Continue reading
Filed under: Arctic, climate and weather, extreme weather, global warming | Tagged: Arctic sea ice, extreme weather, global warming, heatwaves | 1 Comment »
Posted on March 12, 2015 by Bob Berwyn
A NASA visualization of Hurricane Floyd approaching the Florida coast in 1999. Hurricane Floyd formed from a tropical wave moving off the coast of Africa to become one of the largest and strongest Atlantic Hurricanes on record.
Spatial cloud coverage offers clues to tropical storm formation
FRISCO — Closely monitoring thunderstorms over Africa may help meteorologists develop better forecasts for Atlantic hurricane development.
“Eighty-five percent of the most intense hurricanes affecting the U.S. and Canada start off as disturbances in the atmosphere over Western Africa,” said Tel Aviv University Prof. Colin Price, who recently published a new study on hurricane formation in Geophysical Research Letters. “We found that the larger the area covered by the disturbances, the higher the chance they would develop into hurricanes only one to two weeks later.”
Working with graduate student Naama Reicher of the Department of Geosciences at TAU’s Faculty of Exact Science, Price analyzed satellite images of cloud cover to track the variability in cloud cover blocking the earth’s surface in West Africa during hurricane season.Using infrared cloud-top temperature data gathered from satellites, Prof. Price assessed the temperatures of the cloud tops, which grow colder the higher they rise. He then compared his cloud data with hurricane statistics — intensity, date of generation, location, and maximum winds — from the same period using the National Hurricane Center data base. Continue reading
Filed under: climate and weather, extreme weather, tropical storms and hurricanes | Tagged: Atlantic hurricanes, Cape Verde hurricanes, climate, extreme weather, hurricane forecasting, hurricane formation, tropical storms | Leave a comment »
Posted on February 12, 2015 by Bob Berwyn
A NOAA satellite image of Hurricane Bob, which raked the New England coast in 1991.
Historic record shows series of intense storms during eras of warmer sea surface temps
FRISCO — Climate researchers say New England’s coastal communities may need to prepare for major hurricane strikes sooner rather than later as the Atlantic Ocean continues to warm.
“We may need to begin planning for a category 3 hurricane landfall every decade or so rather than every 100 or 200 years,” said Jeff Donnelly, a scientist at Woods Hole Oceanographic Institution in Massachusetts, explaining that new research findings show that a string of giant storms pummeled the region during the first millennium, from the peak of the Roman Empire into the height of the Middle Ages. Continue reading
Filed under: climate and weather, extreme weather, global warming | Tagged: climate change, extreme weather, global warming, hurricanes, New England | Leave a comment »
Posted on February 11, 2015 by Bob Berwyn
Warmer atmosphere means more moisture, more rain
FRISCO — After carefully reviewing data from hundreds of stream gauges, University of Iowa scientists say they’ve identified a clear trend of increasing floods during the past 50 years.
“It’s not that big floods are getting bigger, but that we have been experiencing a larger number of big floods,” said Gabriele Villarini, a civil and environmental engineer and corresponding author on the paper, published Feb. 9 in the advance online edition of the journal Nature Climate Change. Continue reading
Filed under: climate and weather, extreme weather, global warming | Tagged: climate change, extreme weather, flooding, Midwest floods, NASA, University of Iowa | Leave a comment »
Posted on February 9, 2015 by Bob Berwyn
Can Chinook salmon survive global warming?
Research documents more fall and winter flooding
FRISCO — Threatened Chinook salmon have been able to adapt to many changes over millennia, but climate change presents a big new threat, as many rivers around Puget Sound have seen bigger fluctuations in stream flows during the past 60 years.
“There’s more flooding in late fall and winter,” said Eric Ward, an ecologist at NOAA Fisheries’ Northwest Fisheries Science Center. “This is happening when the eggs are in the gravel or when the juveniles are most susceptible.”
More pronounced fluctuations in flow can scour away salmon eggs and exhaust young fish, especially when lower flows force adult fish to lay eggs in more exposed areas in the center of the channel. Continue reading
Filed under: climate and weather, endangered species, Environment, extreme weather, global warming | Tagged: Chinook salmon, climate change, endangered species, extreme weather, global warming, Puget Sound | 1 Comment »
Posted on February 3, 2015 by Bob Berwyn
A tornado near Lakeview, Texas. Photo courtesy NOAA.
New study could help produce better tornado forecasting
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
Filed under: climate and weather, extreme weather | Tagged: 2011 tornado outbreak, climate, extreme weather, tornadoes, wildfire smoke | Leave a comment »