El Niño 101
You’ve heard a lot about El Niño, but what is it? What does it mean for L.A.?
Wet winter weather is coming, but El Niño is already here!
El Niño is a weather pattern, a warming of the Pacific Ocean near the equator caused by
a weakening of the trade winds that normally push sun-warmed waters to the west. It is
part of the El Niño-Southern Oscillation (ENSO), a naturally occurring phenomenon that
involves fluctuating temperatures in the eastern tropical Pacific Ocean. El Niño is the
warm phase of the ENSO cycle and La Niña is the cool phase.
El Niños were originally recognized by fishermen off the coast of South America as
unusually warm ocean currents that typically appear around Christmastime and last for
several months. The phenomenon was coined El Niño which means “The Little One” or
“Christ Child” in Spanish.
When ocean temperatures are warmer or cooler than
normal, they can affect weather around the world.
Forecasters at the National Oceanic & Atmospheric
Administration (NOAA) began seeing the warmer
waters of the current El Niño in early 2014 and
officially declared its arrival on March 5, 2015 by
upgrading its status from “watch” to “advisory.”
Strong El Niños usually mean above-average
precipitation in the southern tier of the U.S. and
warmer-than-average temperatures in the northern
tier. Rainfall is often below average in the Ohio and
Tennessee valleys and the Pacific Northwest.
In Los Angeles, the normal wet season happens
between October and February. The peak of our wet
weather for this El Niño is expected to occur between
December 2015 and February 2016. After four years
of drought and wildfires, much of the land across L.A.
is incapable of absorbing large amounts of rain,
increasing the potential for flooding and mudslides.
Know the Weather
Alert Lingo!
Watch: Conditions are
favorable for an event and
usually cover a large area
and timeframe.
Advisory: Conditions are
likely to occur but will not be
severe enough to prompt a
warning.
Warning: An event is already
occurring or is likely to occur
immediately. Warnings are
only issued for severe events
that threaten life safety.