Arctic blast keeps LA in deep freeze

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Meteorologists explain continuous frigid temperatures in local area

By Carol A. Clark

A massive blast of artic air pushed into the area and across the state Christmas Eve and many areas have experienced difficulty warming up again.
“This is because of the inversion that occurs this time of year,” said meteorologist Chuck Jones from the National Oceanic Atmospheric  Administration office in Albuquerque. “But it’s not extraordinary by any means to have temperatures below freezing for six or seven days in a row.”
Los Alamos experienced its coldest day this winter, -9 degrees, on New Years Day, said meteorologist Scot Johnson of Los Alamos National Laboratory, adding that the coldest day in 2009 was -2 and the coldest day in 1996 was -11.
“Inversions are stronger in the winter and during an inversion the sun comes up and heats the ground more than the atmosphere,” Johnson said. “Because air settles down closer to the ground, the ground is colder, that’s why White Rock is colder than Los Alamos – they get all that cold air coming in off the canyons.”
In a cycle of natural climate variability, sea
surface temperatures (SST) regularly fluctuate in the tropical Pacific Ocean, according to NOAA. During 2010, SSTs in the tropical Pacific have varied dramatically. The year started with warm anomalies (an El Niño), but by early summer SSTs were below average and additional cooling has led to the development of a La Niña event. The cycle of warmer-than-normal and cooler-than-normal SSTs is often referred to as the El Niño Southern Oscillation, or ENSO. The changes in SST in the tropical Pacific not only affect the distribution of precipitation near the equator, but also result in modified tropical atmospheric circulations that ultimately change the positions of the jet stream and storm tracks in the higher latitudes, including North America.
Climate variability associated with the ENSO cycle has been observed at numerous locations across the globe for many years.  
In New Mexico, wetter than normal conditions are more likely during El Niño events with drier than normal conditions during La Niña events, particularly during the cool seasons of winter and spring.
Johnson said that during a La Niña cycle, temperatures are normally slightly warmer such as Los Alamos experienced through most of December.
“La Niña usually steers storms north of us but this season that hasn’t been the case,” Johnson said. “The tendency, though not certain, is that El Niño brings a good ski season.”