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SCIENCEMonday 11 January 2016
All the winter’s a weird weather stage; Here are the players
SETH BORENSTEIN scientist Jennifer Francis. the cold Arctic air escapes Pacific, unusually low sea heavy rain that flooded the
AP Science Writer For a winter this dramatic, and plunges into lower lati- ice levels in the Arctic’s Bar- Mississippi River Valley isn’t
WASHINGTON (AP) — Get it may help to consult the tudes, treating the United ents Kara sea area; a cool usually an El Nino signature
ready for weather whiplash program: States and Europe to the patch of water off Green- though, Cohen said.
as powerful climatic forces polar vortex — a swirling land, likely from melting ice
elbow each other for star- THE CAST air mass that carries spine- sheets and glaciers; winter ACT TWO
ring roles in a weird winter The star is El Nino, a vet- chilling temperatures. storm Frank that hit Eng- The switch flipped: The Arc-
show. eran of this stage for a few The North Atlantic Oscilla- land; and of course man- tic Oscillation and its North
The spine-chilling polar vor- decades now. This natu- tion is a bit player with a made climate change. Atlantic sidekick went neg-
tex is taking center stage in ral warming of the central big influence over Europe’s ative big time.
Europe and bringing persis- tropical Pacific occurs ev- weather. As with its Arctic ACT ONE “When it’s a negative AO,
tent cold to much of North ery two to seven years or cousin, the more negative This was last month. El Nino that’s when people start
America — except in Holly- mentioning the words ‘po-
wood, where soggy El Nino Flagstaff resident Ruth Tilman sweeps off her car after a storm in Flagstaff, Ariz. on Thursday, Jan. 7, lar vortex’,” Halpert said.
won’t give up the spotlight. 2016. A series of El Nino-related storms dumped heavy snow on the region. This time, there’s cold air,
El Nino delivered a balmy but it’s mostly dry so far,
Christmas Eve to the east- (AP Photo/Josh Biggs) despite El Nino, which still
ern U.S. and shattered na- spawns a series of rain-
tional records with a warm, so, and changes weather its index, the colder the appeared in classic form, storms hitting California.
wet and wild December, worldwide, especially in continent becomes. tying 1997-1998 for the Meteorologists say wetter
but meteorologists say the Americas and Asia. It The jet streams also are im- strongest on record. The weather could bring heavy
the situation is about to is closely associated with portant to watch. These riv- Arctic Oscillation was very snowstorms, but that’s not
change. heavy rain in California, ers of air heavily influence positive, trapping cold air likely for another week or
“The biggest thing is this and general warming. It local weather everywhere, in northern latitudes. With more, although cities along
whiplash,” said University has less effect in Europe be- carrying storms and clear- so many warm, wet days the Great Lakes may get
of Oklahoma meteorology cause that’s further away. ing skies around the planet. further south, spring flow- lake effect snow.
professor Jason Furtado. With its flipside, La Nina, it is Usually in the winter, the jet ers popped up and trees So far the east-moving mois-
“It’s going to be a shock for known as the El Nino South- stream that affects most bloomed in December. ture from El Nino is staying
people.” ern Oscillation, and it lasts people in the United States “It’s not surprising we were south of the Arctic plunge,
The center of the cold about a year. and Europe moves rela- 70 degrees on Christmas but that may change.
blast starts this weekend in Playing off against El Nino is tively straight from west to Day,” said Mike Halpert of For now, the AO is dominat-
the U.S. in the upper Mid- the Arctic Oscillation, and east. But when it weakens, the National Oceanic and ing in its fight with El Nino,
west, and then moves to its index measures differ- it can plunge south and Atmospheric Administra- especially in Europe, Co-
the Hudson Bay area next ences in atmospheric pres- north and even get stuck tion’s Climate Prediction hen said. NFL players and
week, while in Europe it sure between the Arctic at times, creating odd ex- Center in College Park, fans will likely brave tem-
starts in the east and north and mid-latitudes. When tremes. Maryland. peratures around one be-
and then spreads, Furtado the AO is positive in the win- Still other characters may El Nino often spawns winter low zero in Minneapolis.
said. Europe may have to ter, polar air stays trapped be a factor in making the tornadoes in the southern
get used to temperatures up north and the weather is jet streams oscillate more U.S. and they appeared ACT THREE
20 or so degrees below nor- relatively mild further south. wildly: A huge blob of on cue, killing two dozen No spoilers here. Will the
mal. When the AO is negative, warm water in the northern people in just four days. The polar vortex hold the stage
“Temperature will be domi- for weeks or months? Will
nated by the impact of the the cold AO and wet El
polar vortex,” said Judah Nino combine for whopper
Cohen, seasonal forecast snowstorms?
chief for the private Atmo- Rutgers’ Francis doesn’t
spheric and Environmental think the moisture and the
Research company outside cold can keep avoiding
Boston. It will feel similar to each other, saying “we’re
2013 and 2014, he said. going to have major ma-
Americans became pain- jor dumps of snow. We just
fully familiar with the polar don’t know where.”
vortex during those winters. Furtado predicts El Nino
This time, America’s winter will push aside the cold in
temperatures will depend America, but not in Europe,
on when the wet and warm where it has less of an influ-
El Nino pushes itself back to ence. Cohen is less certain
prominence, Furtado said. about what will happen as
“We have all of these large these forces morph and in-
and unusual events hap- teract over time.
pening all at the same time “There’s a lot going on; the
and I don’t think it has ever weather has been crazy,”
happened before,” said Cohen said. “Expect the
Rutgers University climate unexpected.”q
