Overview
- Ensemble runs from ECMWF and NASA model output show a high probability of a strong sudden stratospheric warming in early November that could weaken or reverse Arctic stratospheric winds.
- The Met Office and other forecasters say the event would matter because a changed jet stream can raise the chance of UK cold snaps, but they stress that any surface effects are uncertain and usually lag the stratospheric change by several weeks.
- Forecasters note that individual sudden stratospheric warmings are only reliably predictable about a week before they occur, so officials will reassess impacts as the event draws nearer.
- Near-term weather remains active in the UK with recent named storms, warnings for wind and rain, and light snow on Scottish high ground that are separate from the developing stratospheric signal.
- Scientists point to the record-strong El Niño changing large-scale waves that can trigger stratospheric disruption, and they say historical cases show such events can produce big winter outbreaks but do not always translate into widespread ground-level cold or snow.