[Vision2020] 9-8-2011: NOAA’s Climate Prediction Center: La Niña is back

[Ted Moffett]

http://www.noaanews.noaa.gov/stories2011/20110908_lanina.html

NOAA’s Climate Prediction Center: La Niña is back

September 8, 2011

La Niña, which contributed to extreme weather around the globe during
the first half of 2011, has re-emerged in the tropical Pacific Ocean
and is forecast to gradually strengthen and continue into winter.
Today, forecasters with NOAA’s Climate Prediction Center upgraded last
month’s La Niña Watch to a La Niña Advisory.

NOAA will issue its official winter outlook in mid-October, but La
Niña winters often see drier than normal conditions across the
southern tier of the United States and wetter than normal conditions
in the Pacific Northwest and Ohio Valley.

“This means drought is likely to continue in the drought-stricken
states of Texas, Oklahoma and New Mexico,” said Mike Halpert, deputy
director of the Climate Prediction Center. “La Niña also often brings
colder winters to the Pacific Northwest and the northern Plains, and
warmer temperatures to the southern states.”

Climate forecasts from NOAA’s National Weather Service give American
communities advance notice of what to expect in the coming months so
they can prepare for potential impacts. This service is helping the
country to become a Weather Ready Nation at a time when extreme
weather is on the rise.

Seasonal hurricane forecasters factored the potential return of La
Niña into NOAA’s updated 2011 Atlantic hurricane season outlook,
issued in August, which called for an active hurricane season. With
the development of tropical storm Nate this week, the number of
tropical cyclones entered the predicted range of 14-19 named storms.

The strong 2010-11 La Niña contributed to record winter snowfall,
spring flooding and drought across the United States, as well as other
extreme weather events throughout the world, such as heavy rain in
Australia and an extremely dry equatorial eastern Africa.

La Niña is a naturally occurring climate phenomenon located over the
tropical Pacific Ocean and results from interactions between the ocean
surface and the atmosphere. During La Niña, cooler-than-average
Pacific Ocean temperatures influence global weather patterns. La Niña
typically occurs every three-to-five years, and back-to-back episodes
occur about 50 percent of the time. Current conditions reflect a
re-development of the June 2010-May 2011 La Niña episode.

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Vision2020 Post: Ted Moffett