NOAA
ANNOUNCES THE RETURN OF EL NIÑO
Sept.
10, 2004 — NOAA declared today that
El
Niño is back but this time around in a weaker state. "El
Niño conditions have developed in the tropical Pacific and are
expected to last through early 2005," said Jim Laver, director
of the NOAA Climate Prediction
Center. "At this time it is not clear what, if any, impacts
this event will have on ocean temperatures in the classical El Niño
region along the west coast of South America and on temperature and
precipitation in the United States." (Click the NOAA satellite
image for larger view of El Niño taken Sept. 7, 2004. The warm
sea surface temperatures in the eastern Pacific Ocean are represented
in red. Click here for high resolution
version, which is a large file. Please credit “NOAA.”)
Impacts
depend on a variety of factors, such as the intensity and extent of
the warming in the tropical Pacific. NOAA will continue to monitor the
situation in the tropical Pacific and will provide more detailed information
on possible impacts due to this event in coming months.
In the release of the El
Niño Diagnostic Discussion, the NOAA Climate Prediction Center
scientists noted that sea surface temperatures (SSTs) were more than
0.5 degrees C above average in the central and western equatorial Pacific
during August 2004. By early September, positive SST departures greater
than 0.5 degrees C (~1 degree F) were found between 160 E and 120W,
with departures greater than 1 degree C extending from 170 E eastward
to 140 W.
"The increase and eastward expansion of warmth in the central equatorial
Pacific during July through August indicate the early stages of a warm
(El Niño) episode," said Vernon Kousky, NOAA's lead ENSO
forecaster. He added, "Through the end of August conditions were
not yet indicative of a basin-wide El Niño, particularly due
to the presence of below normal sea-surface temperatures in the far
eastern equatorial Pacific near the South American coast." The
lack of basin-wide warming indicates that this El Niño is likely
to be much weaker than the 1997-1998 event.
NOAA declares
the onset of El Niño conditions when the three-month average
sea-surface temperature departure exceeds 0.5 degrees C in the east-central
equatorial Pacific [between 5 degrees -5 degrees S and 170 degrees W-120
degrees W]. To be classified as a full-fledged El Niño episode,
these conditions must be satisfied for a period of at least five consecutive
three-month seasons.
El Niño
is associated with changes in sea surface temperatures in the tropical
Pacific Ocean and can have significant impacts on weather around the
world. El Niño episodes occur about every four to five years
and can last up to 12 to 18 months.
The El
Nino/Southern Oscillation (ENSO) Diagnostic Discussion is a consolidated
effort of NOAA and its funded institutions. NOAA will continue monitoring
El Niño developments and provide monthly updates through its
El Niño/Southern Oscillation (ENSO) Diagnostic Discussion. The
next update will be issued on October 7, 2004, in association with the
U.S. Winter Outlook.
NOAA is dedicated
to enhancing economic security and national safety through the prediction
and research of weather and climate-related events and providing environmental
stewardship of the nation’s coastal and marine resources. NOAA is part
of the U.S. Department of Commerce.
Relevant Web Sites
NOAA
El Niño/Southern Oscillation (ENSO) Discussion
NOAA
El Niño/La Niña Page
NOAA Climate Prediction Center
NOAA
Gets U.S. Consensus for El Niño/la Niña Index, Definitions
Media
Contact: Carmeyia Gillis, NOAA Climate Prediction Center,
(301) 763-7000 ext. 7163
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