Forecasts suggest that weakening and eventually reversing winds could produce a major south-southwest sudden stratospheric warming (SSW) event, potentially the earliest on record in 75 years of observations. The event’s causes are uncertain, although the current record-setting El Niño may have contributed.
A potentially record-early event
Geoff Knight, the Met Office’s chief climate scientist, told the BBC: “This appears to be the earliest on record over the 75 years we’ve been observing… Most experts agree this is a very rare event.”
The earliest major SSW events recorded to date occurred in 1969 and 2025, both on November 28.
It is not clear why major SSW events sometimes occur so early. The timing may simply reflect the natural variability of weather patterns.
Possible link to El Niño
However, scientists know that in “normal” El Niño years, the phenomenon can typically weaken the polar vortex in winter.
El Niño’s unusually warm Pacific waters directly disrupt weather patterns in the tropics. At the same time, pulses of atmospheric energy known as planetary waves can affect the polar regions.
These waves can displace the polar vortex and disrupt its circulation.
The current record-setting El Niño is pushing global weather patterns into uncharted territory. Knight suggested that El Niño “could have helped stack the dice on this south-southwest event. But this is so rare that there isn’t enough evidence.”
The relationship between a strong El Niño and the early onset of SSW events remains unclear and requires further research.
Source: www.bbc.co.uk
