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NOAA
ISSUES UNSCHEDULED EL NIÑO ADVISORY
El Niño Makes a Comeback
Sept. 13, 2006 — Scientists at
the NOAA Climate Prediction Center reported today that El Niño conditions have
developed in the tropical Pacific and are likely to continue into early 2007.
Ocean temperatures increased remarkably in the equatorial Pacific during the
last two weeks. "Currently, weak El Niño conditions exist, but there is a
potential for this event to strengthen into a moderate event by winter,"
said Vernon Kousky, NOAA's lead El Niño forecaster.
Some impacts from the developing
El Niño are already evident in the pattern of tropical precipitation. During
the last 30 days, drier-than-average conditions have been observed across all of
Indonesia, Malaysia and most of the Philippines, which are usually the first
areas to experience ENSO-related impacts. This dryness can be expected to
continue, on average, for the remainder of 2006.
Also, the development of weak El
Niño conditions helps explain why this Atlantic hurricane season has been less
active than was previously expected. El Niño typically acts to suppress
hurricane activity by increasing the vertical wind shear over the Caribbean Sea
region. However, at this time the El Niño impacts on Atlantic hurricanes are
small. "We are still in the peak months of the Atlantic hurricane season,
and conditions remain generally conducive for hurricane formation," said
Gerry Bell, NOAA's lead seasonal hurricane forecaster.
Typical El Niño effects are
likely to develop over North America during the upcoming winter season. Those
include warmer-than-average temperatures over western and central Canada, and
over the western and northern United States. Wetter-than-average conditions are
likely over portions of the U.S. Gulf Coast and Florida, while
drier-than-average conditions can be expected in the Ohio Valley and the Pacific
Northwest.
The term El Niño refers to the
large-scale ocean-atmosphere climate phenomenon linked to a periodic warming in
sea surface temperatures across the central and east-central equatorial Pacific
(between approximately the date line and 120 degrees west). El Niño represents
the warm phase of the El Niño/Southern Oscillation, or ENSO, cycle, and is
sometimes referred to as a Pacific warm episode. El Niño originally referred to
an annual warming of sea surface temperatures along the west coast of tropical
South America.
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