El
Nino likely to arrive over next three months: Australia weather
bureau
3
December, 2014
SYDNEY
(Reuters) - Climate models suggest El Nino weather conditions will
occur over the next three months, although related weather patterns
are already being witnessed, the Australian Bureau of Meteorology
(BOM) said on Tuesday.
Climate
indicators are close to El Nino thresholds, the BOM said, with models
indicating a 70 percent chance of an event arriving by February.
El
Nino is a warming of Pacific sea-surface temperatures that occurs
every four to 12 years. It can trigger drought in some parts of the
world while causing flooding in others.
The
BOM said temperatures in the Pacific have already exceeded the El
Nino threshold but the Southern Oscillation Index has yet to breach
that level yet. The Southern Oscillation Index is a measure of
Pacific air pressure fluctuations.
"Some
El Nino-like impacts have already been seen this spring in Australia
and several regions around the globe, including Asia, South America
and southern Africa," the BOM said. "The Bureau's
December–February Climate Outlook shows a drier and warmer summer
is likely for many parts of Australia."
The
dry weather is impacting Australia's agricultural production, with
output in key commodities such as wheat set to fall as dry weather
curbs yields.
Nearly
all of the Australian east coast and South Australia received less
than half the average amounts of rainfall over the last three months,
denying crops much needed moisture.
El
Niño-like impacts emerge in a number of areas
2
December, 2014
Many
climate indicators remain close to El Niño thresholds, with climate
model outlooks suggesting further intensification of conditions
remains likely. The Bureau’s ENSO Tracker status is currently at
ALERT, indicating at least a 70% chance that El Niño will be
declared in the coming months. Whether or not an El Niño fully
develops, a number of El Niño-like impacts have already emerged.
Several
ENSO indicators are currently close to, or exceed, El Niño
thresholds. These include tropical Pacific Ocean temperatures, which
have now exceeded El Niño levels for a month, and the Southern
Oscillation Index, which has remained at or near El Niño levels for
three months. Other indicators, such as tropical cloud, trade winds
and rainfall patterns, have either remained near average or only
temporarily approached thresholds. This indicates a typical El Niño
ocean–atmosphere interaction may not be fully locked in.
The
majority of international climate models surveyed by the Bureau
suggest further warming of the tropical Pacific Ocean is likely, so
it also remains possible that the ocean and atmosphere will fully
couple in the coming weeks to months. If an El Niño is established,
models suggest it will be weak, or moderate at most. Regardless of
whether an El Niño is declared, El Niño-like effects are likely, as
shown by the Bureau’s December–February Climate Outlook, which
shows a drier and warmer summer is likely for many parts of
Australia. Some El Niño-like impacts have already been seen this
spring in Australia and several regions around the globe, including
Asia, South America and southern Africa.
People will complain about a cool and windy summer in New Zealand. Look at the ocean temperature anomalies around New Zealand, a bit of an anomoly from the rest of the Pacific - cooler than usual.
Kiwis, be careful what you wish for this summer.
People will complain about a cool and windy summer in New Zealand. Look at the ocean temperature anomalies around New Zealand, a bit of an anomoly from the rest of the Pacific - cooler than usual.
Kiwis, be careful what you wish for this summer.
El
Nino may be on its way to NZ
Hang
on to your hats, the chances of an El Nino weather pattern sweeping
New Zealand this summer have increased.
In
its latest climate outlook for December through to February, Niwa
says the equatorial Pacific Ocean has warmed significantly, reaching
El Nino levels towards the end of November.
Some
atmospheric indicators also show patterns consistent with the
development of a weak El Nino.
"International
guidance indicates that the chance for El Nino developing over the
December 2014-February 2015 period is about 75 per cent," Niwa
said.
"This
figure has increased compared to forecasts issued last month."
For
New Zealand, El Nino events have led to stronger, more frequent
westerly winds, bringing droughts to eastern areas and more rain to
western areas.
But
Niwa says near normal rainfall is the most likely outlook for all
regions of New Zealand over summer, with a significant chance of
below normal rainfall (35 per cent) for the east of the North Island.
Summer
temperatures are most likely to be average in all regions except the
east of the North Island, where there's a higher chance of
temperatures being above average.
Ocean
forecast models indicate that sea surface temperatures are likely to
be close to normal around the country over the next three months.
New
Zealand has a slightly elevated chance of having an ex-tropical
system coming within 550km of the country during the 2014-2015
tropical cyclone season, Niwa says.
The
tropical cyclone outlook indicates this risk will be highest between
February and April.
NZ:
El Nino threatens to cool down season
3
December, 2014
Weather
forecasters say there is a high chance that a weak El Nino weather
pattern will develop this summer, bringing cooler and windier
conditions to the Bay of Plenty.
However,
the Eastern Bay will be harder hit than Tauranga if the weather
pattern does eventuate.
Niwa's
seasonal climate outlook for December to February says there is a 75
per cent chance of an El Nino weather pattern developing.
In
New Zealand, an El Nino system typically brings cooler, wetter
conditions, with higher rainfall in regions that were normally wet,
and often drought to areas that were usually dry.
Niwa
National Climate Centre principal scientist Brett Mullan said if an
El Nino pattern did develop, it would bring drier, cooler and windier
conditions to the Bay of Plenty, but it would affect the Eastern Bay
the most.
Dr
Mullan said temperatures would not be particularly hot.
The
report predicts an average summer, with temperature, rainfall and
soil moisture measurements all expected to be near average.
Temperature
had a 45 per cent chance of being near average and a 35 per cent
chance of being above average.
Soil
moisture has an equal chance of being average and below average.
Sea
surface temperatures for the coming three months were expected to be
near average around the coast.
Meanwhile,
the short term weather forecast predicts a 25C high for Sunda
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