I received this press release today from NOAA about la nina:
FOR IMMEDIATE RELEASE - February 27, 2007
*** NEWS FROM NOAA ***
NATIONAL OCEANIC & ATMOSPHERIC ADMINISTRATION
U. S. DEPARTMENT OF COMMERCE
LA NIŅA MAY SOON ARRIVE
On the heels of El Niņo, its opposite, La Niņa may soon arrive.
In a weekly update, scientists at NOAA's Climate
Prediction Center noted that as the 2006-2007 El
Niņo faded, surface and subsurface ocean
temperatures have rapidly decreased. Recently,
cooler-than-normal water temperatures have
developed at the surface in the east-central
equatorial Pacific, indicating a possible transition to La Niņa conditions.
Typically, during the U.S. spring and summer
months, La Niņa conditions do not significantly
impact overall inland temperature and
precipitation patterns, however, La Niņa episodes
often do have an effect on Atlantic and Pacific hurricane activity.
"Although other scientific factors affect the
frequency of hurricanes, there tends to be a
greater-than-normal number of Atlantic hurricanes
and fewer-than-normal number of eastern Pacific
hurricanes during La Niņa events," said retired
Navy Vice Adm. Conrad C. Lautenbacher, Ph.D.,
under secretary of commerce for oceans and
atmosphere and NOAA administrator. "During the
winter, usual La Niņa impacts include drier and
warmer-than-average conditions over the southern United States.
"NOAA's ability to detect and monitor
the formation, duration and strength of El Niņo
and La Niņa events is enhanced by continuous
improvements in satellite and buoy observations
in the equatorial Pacific," Lautenbacher added.
"These observing systems include the TAO/TRITON
moored and Argo drift buoys, as well as NOAA's polar orbiting satellites."
La Niņa conditions occur when ocean surface
temperatures in the central and east-central
equatorial Pacific become cooler than normal.
These changes affect tropical rainfall patterns
and atmospheric winds over the Pacific Ocean,
which influence the patterns of rainfall and
temperatures in many areas worldwide.
"La Niņa events sometimes follow on the heels of
El Niņo conditions," said Dr. Vernon Kousky,
research meteorologist at NOAA's Climate
Prediction Center. "It is a naturally occurring
phenomenon that can last up to three years. La
Niņa episodes tend to develop during March-June,
reach peak intensity during December-February,
and then weaken during the following March-May."
"The last lengthy La Niņa event was 1998-2001,
which contributed to serious drought conditions
in many sections of the western U.S.," said
Douglas Lecomte, NOAA's Climate Prediction Center drought specialist.
NOAA will issue the U.S. Spring Outlook on March
15, and its Atlantic Hurricane Season Outlook in
May. Both outlooks will reflect the most current La Niņa forecast.
"While the status of El Niņo/La Niņa is of vital
importance to our seasonal forecasts, it is but
one measure we use when making actual temperature
and precipitation forecasts," said Kousky.
NOAA, an agency of the U.S. Commerce Department,
is celebrating 200 years of science and service
to the nation. From the establishment of the
Survey of the Coast in 1807 by Thomas Jefferson
to the formation of the Weather Bureau and the
Commission of Fish and Fisheries in the 1870s,
much of America's scientific heritage is rooted in NOAA.
NOAA is dedicated to enhancing economic security
and national safety through the prediction and
research of weather and climate-related events
and information service delivery for
transportation, and by providing environmental
stewardship of the nation's coastal and marine
resources. Through the emerging Global Earth
Observation System of Systems (GEOSS), NOAA is
working with its federal partners, more than 60
countries and the European Commission to develop
a global monitoring network that is as integrated
as the planet it observes, predicts and protects.
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On the Web:
Weekly Updates & Diagnostic Discussions
Climate Prediction Center's ENSO Page