This will be the last post in this series covering the Super El Nino’s of 1982-83, 1997-98 and 2015-16.
Links to part 2 and part 1
The El Nino
in the equatorial Pacific continues to quickly strengthen.
The El Nino
of 2015-16 is in the same class as the El Nino’s of 1982-83 and 1997-98, and it
set new records in the NINO4 and NINO3.4 regions in the western and central
Pacific.
The 2015-16
El Nino broke warming records in the central Pacific, represented by the
NINO3.4 and NINO4 indices. At its peak in November 2015, the NINO3.4 SST
anomaly reached 3.0°C, breaking the previous record of 2.8°C set in January
1983. In the NINO4 region,
What are the
current conditions.
We have a very strong El Nino signal with SST anomalies well above average off the Coast of South America and out across the Eastern into Central equatorial Pacific. This is a classic El Nino signature.
As I’ve said
in the other El Nino post, an SST anomaly in Nino3.4 of 1.5°C is considered a
strong El Nino. The El Nino is
considered very strong or “super” when the anomaly is just over 2.0°C. If the
models are right, the forecasted anomaly by early winter 2026-2027 will be
3.5°C to 4.0°C which would be historic and off the chart.
While the relative anomaly for the week centered on 29 July was +1.5°C, placing El Niño in the category of a strong event, since then a further increase of 0.3°C, taking Niño 3.4 to +1.8°C.
This means just 0.2°C remains before the phenomenon officially reaches the +2°C threshold used to define a very strong El Niño, although the peak of the event is expected to occur between October and December. Meanwhile, the Niño 1+2 region, off the coast of Peru, has already reached a 3.2°C relative anomaly, an exceptional value, Nino 3 is at 2.5°C with Nino 4 at 0.2°C.
We can see
the subsurface has a lot of hot water. These super warm temperatures extend
down around 650 feet.
The
Madden–Julian Oscillation (MJO), an intraseasonal variation in the tropical
atmosphere that occurs on timescales of approximately 30 to 60 days, is
forecast to move across the western Pacific and subsequently into the central
Pacific. The current forecast indicates a reorganization of the MJO and its
eastward propagation over the coming weeks, in an evolution that could interact
positively with El Nino and contribute to even more intensification.
As I've said before, the MJO is a pulse of convection that moves from west to east and can cause significant variations in tropical winds. As it passes across the Pacific, the weakening of the easterly winds can favor the formation of an oceanic Kelvin wave, which also propagates eastwards along the equator. During the warm phase, these wave lead to downwelling, this helps increase the heat content in the upper layer of the ocean, reducing the impact of the cold waters that would normally reach the surface.
The
stratospheric polar vortex interacts with the polar jet stream and with the
phases of the El Nino/La Nina pattern to influence weather in the Eastern U.S.
and Europe.
The polar vortex sits above the Arctic and is linked to the jet stream. Both of these can be impacted by El Nino, bringing a lot of changes to the weather patterns. When the PV is strong it helps look the cold up over the Arctic. But a weak PV can lead to many more arctic air intrusions into the central and eastern U.S.
If the polar vortex remains strong this winter, it will mean an overall mild winter in spite of El Nino
Here's a look at the general precipitation pattern based on the relative strength of the El Ninos.
Departure
from average snowfall for El Nino winters since 1959
Details on the Super El Nino of 2015-2016
Average
sea-surface temperature anomalies in November 2015, when the El Nino event
peaked in the NINO3.4 region. The chart shows SST anomalies compared to the
1981–2009 average.
While some aspects of the 2015- 2016 El Nino were similar to the El Ninos of 1982/83 and 1997/98, it was also much different in important ways. Unlike the 1982/83 and 1997/98 El Ninos, which had the above-average SST anomalies in the eastern into central equatorial Pacific; the super El Nino of 2015-2016 had the well above average SST in the western and central equatorial Pacific but were milder near the coast of South America. The El Nino episode reached its peak strength during November-December 2015.
All of this is why this is looking to be a possibly record breaking El Nino,
Regional Impacts
Like the other Super El Nino’s the winter of 2015-16 had major snowstorms. There were also multiple smaller snowstorms and a significant ice storm in early-to-mid February, producing ice accumulations of 0.25–0.75 inches in parts of New England.
Overall, the
Northeast and Middle Atlantic Region saw well above average temperatures, and generally
below average snowfall. Shifted storm track: The very strong El Nino altered
the position of the northern jet stream over eastern North America, had had a
very strong southern subtropical jet, creating conditions for occasional heavy
snowfalls amid generally warmer and wetter background conditions. The entire
winter was more or less dominated by a zonal flow that kept frigid Arctic air
mostly to the north, resulting in a slow start to the winter season.
December
2015 set records for warmth across the Northeast and northern Middle Atlantic Region. January 2016 brought more variability in the
pattern. While brief cold snaps and lake effect snow occurred in Northwest
Pennsylvania western and northern New York State. But in spite of those cold
snaps, the overall average temperatures remained above average. February
started out warm but then the coldest air of the season moved in around
February 14. The event was short-lived and February ended up well above average
across the Northeast and northern Middle Atlantic. The Winter came to an end generally as the end
of February approached.
Temperatures
Precipitation
As with the
past Very Strong El Ninos there were major snowstorms.
The
Biggest snowstorm of the season.
It started
as a shortwave trough that came ashore onto Pacific Northwest on January 19, 2016. The disturbance dropped south and east and continued to strengthen over the
Great Plains, As the disturbance got over Central Texas an area of low pressure
developed. This tracked east strengthening along the Gulf Coast due to all the
tropical moisture. The primary low, transferred energy to the Coast where a new
low-pressure area began to develop on January 22. The
coastal low tracked up the East Coast and rapidly deepened, off the middle
Atlantic Coast.
The January
22–24, 2016, snowstorm dumped over 20 inches of snow in the Northeast and over
10 inches for people in the Southeast." The higher elevations in the eastern mountains
were struck by amounts of over 2 feet of snow. The storm was given the nickname
Snowzilla and it produced snowfall amounts of 3 ft to near 4 ft in parts of the
Mid-Atlantic and Northeast.
Early on
January 24, as the nor’easter was pulling away from New England, the system
began to become elongated, as a secondary low developed to the southwest of the
storm's central low. The storm lingered into January 25, as the blizzard left
the East Coast of the United States.
Here is a
look at the track. As well as the general setup and snow impact.
The storm
ranked as a Category 5 "extreme" event for the Northeast on the
Regional Snowfall Index, and a Category 4 event for the Southeast. It was the
first winter storm to rank as a Category 5 winter storm since the 2011
Groundhog Day blizzard.
It had a remarkably
similar storm foodprint from the January 1998 blizzard.
I-95
Corridor
During the
winter of 2015-2016, Along the I-95 the vast majority of seasonal snowfall fell
during Snowzilla.
New York
City recorded a total of approximately 32.8 inches of snow in Central Park
Baltimore
experienced significant snowfall, with a total accumulation of approximately
57.4 inches for the season,
Philadelphia
recorded a total snowfall of approximately 27.5 inches, making it one of the
moderately snowy winters in recent years.
Boston
received a total of approximately 36.1 inches of snow, which was significantly
milder compared to the record-breaking 110.6 inches the previous winter.
Washington,
D.C. received an estimated total of 31.2 inches of snow.
The lake snow belts
The El Nino kept most of the cold air bottled up north. But there were periodic cold snaps that
allowed for a few lake effect snow events, but they were short-lived and often
followed by rapid melting. As a whole
the snow belts saw slightly below to below average seasonal snow totals.
The other Super El Ninos serve as a potential tease of what could come during the 2026-2027 winter season if the temperatures in the Pacific Ocean continue to grow.
Typical El Nino Pattern.
Summary
The winter of 2015–2016 in the Northeast was dominated by warmth and a delayed snow season due to El Nino, yet storm events like the Blizzard of 2016 and lake effect snow episodes created localized heavy snow accumulations, making it a winter of contrasts with an overall mild but eventful profile
the seasonal
snow fall totals were for the most part below average in most areas. The winter
was mild for most of the Northeast and northern Middle Atlantic, with the
heaviest snow confined to the snowbelt and the January 2016 blizzard.
The season
was unusual warm overall interlaced with intense cold outbreaks, with parts New
York State, Pennsylvania, and New England seeing temperatures that got quite
cold in mid-February. The Mid-Atlantic, to experience generally
warmer-than-average conditions for December through February.
What does looking back at these Super El Nino’s tell us about the upcoming Fall and overall winter pattern?
Fall 2026
Temperatures
Overall,
these should run average to slightly above average for September, October and
November.
Precipitation
Generally,
the southern tier of New York State, Pennsylvania and the rest of the Middle
Atlantic should run around average, with a chance for southern Maryland and Delaware
to run above average. Northern parts of the region should end up generally below average.
This summer
has seen a lot of severe weather. September
should see severe chances winddown across New York State and New England. But
across Pennsylvania, New Jersey, Maryland, Delaware there could still be quite
a bit of severe activity.
Winter
2026 -2027
Going over the
El Nino’s of 1982-1983, 1997-1998 and 2015-2016 we saw they had similarities and
dissimilarities. We also saw that
wintertime outcomes came down to several factors, not one individual storm. Looking
back, we can see no two El Nino events are the same, each season has its own atmospheric
setup.
So, what can
we decipher?
Each of the
Super El Nino’s had an active screaming southern subtropical jet. So, this winter should be the same, this will
keep the main storm track extend across southern California, through Texas and
along the Gulf Coast up into the Southeast CONUS.
An active Subtropical
Jet should support increased precipitation across the Mid-Atlantic, with the rest of the Northeast seeing overall drier conditions.
In the
North, conditions look more volatile with a more variable pattern. The Great
Lakes will should end up with average to slightly above average temperatures. There
should be many Fast‑moving clippers, sudden snow squalls, sudden cold
snaps, and bursts of bitter air that will intermingle with thaws. While the
snowbelts will end up with slightly below average-to-average snowfall; these
cold snaps and milder periods will lead to rapid freezing and melting cycles
making maintaining a deep snowpack difficult. Overall temperatures in the rest
of the Northeast and northern Middle Atlantic should end up slightly below to
below average, but there will be cold outbreaks.
It does look
like the Northeast and Northern Middle Atlantic will be in the battle zone as
all the features interact. The strong
southern jet along with shortwaves dropping south and east out of western
Canada and the Pacific Northwest, could cause headaches from time to time as
these two things interact, allowing for areas of lower pressure to form in the
southern Plains. Some of these will end up becoming lake cutters and Appalachian
runners.
The pattern is also going to feature a secondary storm track up and along the East Coast. As disturbance move west to east along the southern Jet. The history of these very strong El Nino’s show there a chance for Appalachian snowstorms that move into the interior Northeast. Super El Ninos also make for an environment that supports major Coastal Storms (Miller A Nor’easters) each one of the Super El Nino’s had at least one. Temperatures are going to be very volatile during the entire winter. But based on past history the snowiest part of the winter should be January into February. As these disturbances approach and move through temperature and storm track will determine whether they bring rain, sleet, or heavy snow across interior areas with the coastal zones generally trending toward rain and mixed precipitation. I anticipate at least one blizzard this winter.
Right now, we have to wait and see how things evolve.
I will
release the first part of my official 2026-2027 winter outlook sometime in
October.
