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 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 March 11, 2015 by Bob Berwyn
Southern Ocean winds and currents are key regulators of global temperature and carbon cycles.
Strengthening eddies drive heat deep into the sea
FRISCO — Shifting wind patterns across the Southern Ocean around Antarctica are having a big effect on the carbon cycle and on the heat transfer between the ocean and the atmosphere.
The changes are so profound that they are actually delaying the effects of global warming, according to a new study published in the Journal of Physical Research.
“Considering the Southern Ocean absorbs something like 60 percent of heat and anthropogenic CO2 that enters the ocean, this wind has a noticeable effect on global warming,” said lead author Dr Andy Hogg from the Australian National University Hub of the ARC Centre of Excellence for Climate System Science. Continue reading
Filed under: Antarctica, climate and weather, climate change, Environment, global warming | Tagged: circumpolar antarctic current, climate, global warming, southern annular mode, Southern Ocean | 1 Comment »
Posted on March 6, 2015 by Bob Berwyn
Southern mountains get huge snowpack boost
Early March storms helped bring the Colorado snowpack to near normal.
FRISCO — Colorado’s statewide snowpack continues to track near average for the winter, as two weeks of wet weather helped especially to bolster water supplies in the southern mountains.
But despite substantial accumulations statewide, the snowpack is still below average, at 87 percent of normal as of March 1. SNOTEL data shows that, during the nine-day period of February 20 through March 1, the state received 2.0 inches of snow water equivalent, 181 percent of the normal for that period.
Preliminary numbers from early March show an additional 7 percent gain between March 1 and March 5 — but with only 20 percent of the mountain snowpack accumulation season remaining, time is dwindling to close the gap and reach typical statewide peak snowpack levels. Continue reading
Filed under: climate and weather, Colorado, Snow and weather | Tagged: climate, Colorado, Colorado reservoir storage, Colorado snowpack | 1 Comment »
Posted on March 6, 2015 by Bob Berwyn
Record warmth in West outweighed late-winter chill in the East
Warm temps in the West, chilly in the East.
FRISCO — While TV news and weather stations focused on snowstorms in the Northeast, continued record warmth in the West helped drive the average winter temperature across the lower 48 states to well above average, resulting in the 19th-warmest winter on record.
According to the new monthly update from the NOAA National Climatic Data Center, the average temperature for the winter (December – February) was 34.3 degrees Fahrenheit, 2.1 degrees above the 20th century average.
But for February, the average temperature was slightly below average (0.7 degrees Fahrenheit) across the contiguous 48 states, ranking near the median value in the 121-year period of record. Continue reading
Filed under: climate and weather, climate change, global warming | Tagged: climate, climate change, climate science, February 2015 U.S. temperatures, global warming, US winter warmer than average | 1 Comment »
Posted on March 5, 2015 by Bob Berwyn
Impacts unclear, though Gulf Coast could see rain surplus
NOAA’s El Niño map shows widespread above-average sea surface temperatures.
FRISCO — A long overdue El Niño once anticipated as a potential drought-buster for California has emerged, but may not have a huge impact on North American weather.
Forecasters with NOAA’s Climate Prediction Center made the announcement this week after measuring ocean surface temperatures in the Pacific. Those temps have been running above average for several months but just now crossed the El Niño threshold. the climate experts said in their monthly outlook. Continue reading
Filed under: climate and weather, El Niño | Tagged: California drought, climate, El Nino, NOAA, weather | Leave a comment »