the extreme weather that has seen
record-breaking wildfires in california
and the strongest hurricane to hit
louisiana in 160 years
looks set to get worse on thursday
september 11th the u.s climate
prediction center said the weather
pattern known as la nina had officially
formed this is why la nina is important
la nina brings dry warm weather to the
southwestern u.s
it brings cool wet weather to an area
reaching from the pacific northwest and
southeastern alaska
to the northern plains and central
canada la nina which means
little girl in spanish is a complex
ocean atmosphere phenomenon that occurs
every few years in the pacific ocean
under normal conditions
winds from the pacific ocean push warm
water from the west coast of south
america towards indonesia
as the warm water moves westward cold
water rises
when la nina occurs winds the pacific
grow much stronger
they push even more warm water towards
indonesia causing more cold water to
rise near the west coast of south
america
this could worsen the drought in the
southwestern u.s this winter while
bringing a cooler wetter winter to other
parts of north america
these changes in sea surface temperature
are felt around the planet
la nina can lead to more rain in
australia and indonesia stronger
hurricanes and typhoons
and more lightning in some parts of the
world la nina is the reverse of el nino
the opposite weather pattern which can
also cause more extreme weather
the national oceanic and atmospheric
association or noaa
has observed water temperatures in the
equatorial pacific ocean
remain 0.5 degrees celsius above average
for over three months
trade winds blowing from east to west
across the equatorial pacific
send warm surface waters to the eastern
pacific generating a low pressure
area over which storms form el nino
occurs when the winds reverse for
periods as long as several months
causing warm water to spread over the
central and eastern pacific
this reorganizes rainfall and
atmospheric circulation bringing
unseasonal and intense weather which can
cause brush fires in australia
and flooding in south america the
climate prediction center says there's a
50 to 60 percent chance that the 2015 el
nino will continue through spring
el nino will likely provide some
rainfall relief to drought stricken
california
but it's not expected to have drastic
global effects
el nino tends to increase precipitation
along u.s coastlines
but the midwest and northwest tend to
see a decrease from the average
the frequency of precipitation is also
affected in comparison to average
frequency
el nino also tends to suppress hurricane
activity in the atlantic ocean by
causing higher wind
shear which spreads storms out over a
larger area
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