A developing positive Indian Ocean Dipole (IOD) coupled with a rapidly intensifying Super El Niño in the Pacific Ocean, could significantly influence weather patterns across the Northern Hemisphere during the 2026–27 winter according to the latest long range seasonal forecasts.
The emerging IOD characterised by warmer than normal waters in the western Indian Ocean and cooler waters in the eastern basin, is expected to persist through autumn and into early winter. Meteorologists say this tropical ocean pattern may work in tandem with the strengthening Super El Niño, amplifying atmospheric circulation and altering jet stream behaviour across North America and Europe.
The Indian Ocean Dipole is a climate phenomenon caused by contrasting sea surface temperatures between the eastern and western Indian Ocean. During a positive IOD warm waters in the west enhance rainfall over parts of East Africa, while cooler waters in the east suppress rainfall near Indonesia and Australia.
Recent ocean analyses indicate that the eastern Indian Ocean is cooling while western waters continue to warm, signalling the onset of a sustained positive IOD event. Seasonal models suggest the pattern is likely to strengthen through the coming months.
Scientists say changes in tropical trade winds that are helping drive the Super El Niño are also contributing to the development of the positive IOD, effectively linking the two ocean systems.
Forecast models indicate that the ongoing El Niño is strengthening rapidly and could become one of the strongest on record.
Sea surface temperatures across the eastern tropical Pacific are already several degrees above average, while subsurface ocean measurements reveal an intense warm water pool, known as a Kelvin Wave rising toward the surface. Climate models project El Niño conditions to exceed the threshold for a Super El Niño later this year.
Researchers say such powerful tropical warming significantly alters atmospheric circulation, affecting rainfall, storm tracks and temperature patterns far beyond the Pacific.
Climate scientists say the simultaneous occurrence of a positive IOD and Super El Niño creates a stronger tropical atmospheric response than either phenomenon alone.
The combined system is expected to modify the position and strength of the Pacific jet stream, influencing winter weather across large parts of the Northern Hemisphere. Enhanced tropical convection over the Pacific and Indian Oceans can generate atmospheric wave patterns that extend into North America and Europe.
Seasonal forecasts suggest the United States could experience a split winter pattern.
A strong high pressure system is expected over Canada, while persistent low pressure systems may dominate the southern United States. This setup could bring:
●Warmer than normal conditions across much of Canada and the northern United States.
● Cooler and wetter weather across the southern U.S., particularly Texas, the Gulf Coast and the Southeast.
●Increased opportunities for winter storms and snowfall across parts of the Central Plains, Midwest, Mid Atlantic and interior Northeast.
●Reduced snowfall across southern Canada, the Pacific Northwest and parts of the northern Great Lakes.
Europe likely to see milder, wetter winter
Forecast models indicate that Europe may experience a predominantly milder than average winter driven by stronger westerly winds from the Atlantic.
The projected pattern favours:
●Above normal temperatures across much of Europe.
●Wetter conditions over northwestern and northern Europe due to enhanced Atlantic storm activity.
●Below average snowfall across many lowland regions, although northern Europe and higher mountain ranges could still receive significant snow during individual cold outbreaks.
Meteorologists caution that seasonal forecasts indicate broad climate trends rather than day to day weather. The intensity and duration of both the positive IOD and Super El Niño, along with interactions with other atmospheric patterns, will ultimately determine how winter unfolds.
Scientists are continuing to monitor ocean temperatures and atmospheric circulation as both climate phenomena evolve over the coming months.