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ViewPoint
Analyzing Industry Issues from an Independent Perspective
El Niño
Following a winter of extreme cold, it’s hard to
process the mild start to the 2015 winter season.
Meteorologists predict this year’s El Niño could be
the strongest in the past 50 years.
El Niño is a weather condition referring to a weak,
warm current generally materializing in December
along the coast of Ecuador and Peru. Spanish for “the
Christ child,” the phenomenon was first observed by
South American fishermen in the 1600s, who noticed
some years brought unusually warm water to their
coast, typically around Christmas. The condition is
characterized by prolonged warming in the Pacific
Ocean sea surface temperatures, when compared
…El Niño could be the
strongest in the past 50
years...
with the average temperatures. The trade winds,
which normally blow west toward Indonesia, relax in
the central and western Pacific, allowing normally cool,
nutrient-rich waters off of South America to
significantly warm. As this warm water spreads
eastward, the hot, humid air moves with it causing
changes to the position of the jet stream winds. The
result affects weather not only in North and South
America, but as far away as Africa and Antarctica.
Typically, this anomaly happens at irregular intervals of
two to seven years and can last anywhere from nine
months to two years, with the average interval length
being five years. When this warming occurs for seven
to nine months, it is classified as El Niño "conditions;”
when its duration is longer, it is called an El Niño
"episode."
Previous El Niño Years
1902-1903
1905-1906
1911-1912
1914-1915
1918-1919
1923-1924
1925-1926
1930-1931
1932-1933
1939-1940
1941-1942
1951-1952
1953-1954
1957-1958
1965-1966
1969-1970
1972-1973
1976-1977
1982-1983
1986-1987
1991-1992
1994-1995
1997-1998
2002-2003
2006-2007
2009-2010
The above table shows the historical El Niño periods
since 1900, with the years highlighted in red described
as “major” El Niño events. According to NOAA’s data
analysis, the ten strongest El Niños of the past century
show they are occurring more frequently and
becoming progressively warmer.
Pacific Decadal Oscillation (“PDO”)
Although El Niño occurs cyclically and independent of
any long-term warming trend, there is observational
evidence to suggest that rising global temperatures
may be linked to stronger, more frequent El Niño
episodes. These higher temperatures tend to produce
more extreme weather events.
Another factor affecting weather trends is the Pacific
Decadal Oscillation, which refers to the special pattern
of the sea surface temperature anomalies in the
Northern Pacific Ocean. A positive PDO indicates the
eastern Pacific Ocean is warmer than the central and
western. Observations have been made as to the
…occurring more
frequently and
becoming progressively
warmer…
correspondence between the presence of strong El
Niño years and a prolonged warm period, such as in
1982-83 and 1997-98.
The National Center for Atmospheric Research’s
Kevin Trenberth notes that the effects of El Niño tend
to be augmented by the presence of positive or
warm PDO. Some scientists say the current El Niño
may impact the length of time the PDO remains
positive. Though there are differing opinions from
scientists as to whether the current positive PDO is
representative of a multi-decadal shift to warmer sea
surface temperatures along the North American
Pacific Coast. Gerald Meehl, also from the National
Center for Atmospheric Research, notes that positive
PDO index may undo the perceived break in global
warming experienced over the past decade.
Countrywide Implications
The predicted winter will start off rather mild across
most of the country, including the Pacific Northwest
through the Northern Plains. Later in the season,
several weeks of classic winter weather over the
eastern third of the country is expected. This period
will likely feature several winter storms from the
south central Plains to the Northeast, with a higher
than typical threat for significant snow and mixed
precipitation
deep
into
the
South.
(www.theweathernetwork.com)
The vast majority of past El Niño winters featured an
active storm track across the southern United States,
with a turn up the East Coast to New England. Aboveaverage precipitation from Southern California to
Florida and up the East Coast to Maine is likely to
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occur. This will likely also include a higher threat for
severe weather near the Gulf Coast, including
Florida.
A unique feature of the upcoming winter, as
compared to other strong El Niño winters of the
past, is the expected persistence of the warmer
than normal ocean-water temperatures south of
Alaska. Meteorologists have referred to this
feature as “the Blob” and it has been a key
contributor to the dominant weather pattern
across North America for the past two years. This
pattern has been associated with extended periods
of warm and dry weather in the West and two of
the coldest winters in recent memory in the Great
Lakes and Northeast. If “the Blob” does persist
through the upcoming winter, then the threat for a
cold conclusion to winter in the East will increase.
(www.theweathernetwork.com) “The Blob” has
been cited as the most significant factor in bringing
the bitterly cold winters of 2014 and 2015.
"We just don't know exactly yet whether or not
we're going to see the pattern turn cold and
snowy," AccuWeather Expert Long-Range
Forecaster Paul Pastelok said. "...There is an
opportunity that [the weather] could change on us
as we get into February and early March."
(www.necn.com)
New England
El Niño conditions have historically resulted in dryer
than normal conditions in the fall (September –
November) and warmer than normal conditions in the
pre-winter months (November and December).
Heading into January and February, the North Atlantic
region often sees slightly warmer and wetter than
normal conditions. Storms moving west to east will
carry warm air, thereby limiting artic air. As a result, it
is likely the Northeast will experience more mixed
precipitation events of sleet, freezing rain and rain,
rather than the excessive snowfall of the 2015 winter.
El Niño has a tendency to supercharge the southern jet
stream with moisture, a key ingredient in providing
powerful coastal storms typical to the Northeast in the
winter.
David Robinson, the state climatologist at Rutgers
University, said historically there have been five strong
El Niño events that provide a meaningful comparison
to what is unfolding this year however, they do not
appear predictive. In terms of snow, for example, one
winter had snowfall twice the historic average, two
were close to average and two were among the least
snowy on record. "There's a little bit of leaning
toward the warm side ... there is a little bit of leaning
towards the wet side," said Robinson. "If I sound a
little ambivalent, if I sound a bit uncertain, I am."
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"The top story that can't be ignored is the very strong El
Niño. That's going to be a major factor in the winter
forecast," said Mike Mihalik, a meteorologist at
Weather Works, a private weather firm. "Warmer
temperatures are probably the thing we're most
confident about." It doesn't mean it will be completely
snow-free either. WeatherWorks was careful to note
the winter of 1982-1983, another strong El Niño year,
when the majority of the winter was relatively snow free
due to warm conditions, however a massive storm left
two feet of snow in February. If El Niño weakens
towards the end of the winter, it could allow for strong
coastal storms to develop with abundant cold air.
The Midwest
One fairly localized but distinct product of El Niño is a
tendency for drier-than-usual winters across the lower
Midwest, especially in the Ohio Valley. A typical winter
brings a stream of low-pressure centers approaching the
lower Midwest from either the southwest or northwest.
The split stream favored by El Niño tends to push these
lows either well north or well south of the Ohio Valley,
leaving the area with better-than-usual odds of
relatively mild temperatures and light precipitation
during the core of winter. (www.kxan.com)
The other implication is the effect on the ice coverage
across the Great Lakes, which were 80% covered last
winter. On average, winter temperatures across the
Great Lakes region are higher than normal and keep ice
levels below average. There remains a chance of heavy
snowfall, due to potential lake effect snow with a
blast of cold air picking up the warmer surface water.
The Gulf Coast
According to NOAA, the single most reliable El Niño
outcome in the United States, occurring in more than
80% of El Niño events over the last century, is the
tendency for wet wintertime conditions along and
near the Gulf Coast, thanks to the enhanced
subtropical jet stream. (The same upper-level jet
stream also tends to suppress Atlantic hurricane
activity, by fostering subsidence and stable air and
boosting the upper-level wind shear that inhibits
tropical cyclone formation). This increases the
potential of flooding.
Severe weather is often associated with El Niño
during the winter months across the southeast
region, a finding reinforced in a 2015 study led by
John Allen (International Research Institute for
Climate and Society). The study found that the risk of
tornadoes across south Texas and Florida is roughly
doubled during El Niño. Florida’s worst outbreak on
record occurred on February 22-23, 1998, during the
intense 1997-98 El Niño. A total of 12 tornadoes
killed 42 people, mainly in a swath running along
Interstate
4,
through
central
Florida.
(www.kxan.com) In El Niño years, an average of 15
tornadoes occur in southern and central Florida; with
20 on average during a strong El Niño year.
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Summary & 2016 Hurricane Outlook
NOAA predicts, with 90% probability that El Niño will
last through the winter. It is important to remember
that the forecast is for the winter season as a whole and
does not project when and where storms may occur. “A
strong El Niño is in place and should exert a strong
influence over our weather this winter,” said Mike
Halpert, deputy director, NOAA’s Climate Prediction
Center. “While temperature and precipitation impacts
associated with El Niño are favored, El Niño is not the
only player. Cold-air outbreaks and snow storms will
likely occur at times this winter. However, the
frequency, number and intensity of these events cannot
be
predicted
on
a
seasonal
timescale.”
(www.weather.com)
The story doesn’t end with winter, El Niño may have
an effect on the hurricane season for 2016.
Observations by Assured Research show a pattern of
an increase in the number of hurricanes following an
El Niño year, since 1950.
In the chart above, an El Niño reading of 1.0 or above
indicates a strong El Niño year, as shown in the
circled blue peaks. There is a corresponding low
number of hurricanes during those years, which
almost doubles in the following hurricane season.
What’s to come in 2016 is unknown but Holborn will
be monitoring the information. Reach out to
Holborn to further discuss emerging issues and
industry topics such as this one. www.holborn.com
Holborn Corporation is an independent reinsurance brokerage firm, which
was founded in 1920 and is headquartered in New York. Through the
adoption of an Employee Stock Ownership Plan (ESOP) in 1998, it became
exclusively owned by its employees. For additional information, please visit
our website at www.holborn.com.
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