UK Faces Storm-Free Autumn, but El Niño Signals Potential for Wetter Winter

The United Kingdom has experienced an unusually calm start to its autumn storm season, with no named storms yet making landfall. This quiet period is attributed to dominant high-pressure systems that have deflected the deep Atlantic lows typically responsible for bringing turbulent weather.

Reasons for the Calm Autumn

As autumn progresses, cooler temperatures in polar regions usually create a stronger contrast with the tropics, fueling a more potent jet stream. This jet stream is a key driver of storm development and delivery to the UK. However, this season, the jet stream has largely remained to the north or northwest of the UK. Consequently, south or southwesterly winds have brought warmer-than-average conditions, with high pressure exerting more influence and resulting in reduced rainfall for many areas.

This meteorological setup has led to only occasional gusts of stronger winds across the northwestern parts of the UK, with minimal disruption. The heaviest rainfall has been concentrated in Scotland and Northern Ireland, while parts of England and Wales have experienced significantly drier conditions than usual. Some regions in England have recorded only a tenth of their typical rainfall by mid-October.

The dry weather has had notable impacts, particularly in southern England, where exceptionally low reservoir levels have prompted the Environment Agency to declare severe drought conditions in some areas.

Potential for Change

Forecasters anticipate a shift in weather patterns through the coming week, with changes expected in the position and strength of the jet stream. This alteration could allow deeper low-pressure systems to affect more parts of the UK, heralding a transition to more widespread wet and windy conditions. The potential exists for the season's first widely disruptive weather spell to emerge later in the week.

Longer-term forecasts from the Met Office suggest an increased likelihood of rainfall and storminess for the UK in late autumn and early winter. The outlook for October, November, and December indicates a doubled chance of wetter weather and a 1.3 times greater chance of windier conditions, consistent with patterns observed during previous El Niño events.

Storm Naming and Seasonality

Storms are typically named when potentially damaging winds are forecast, but can also be named for heavy rainfall or disruptive snow. The naming system, initiated to raise public awareness and encourage preparation for severe weather, began in Europe in 2015. The UK, Ireland, and the Netherlands form a collaborative naming group, with their meteorological agencies selecting names based on expected impacts and likelihood.

While storms can occur year-round, analysis shows they are most frequent during the winter months of December, January, and February, with storm activity generally increasing from late summer through autumn. The storm-naming season consequently begins in September.

It is not uncommon for the first named storm to arrive after November 1st; in approximately half of the years since 2015, the first storm of the season occurred after this date. May remains the only month in the past eleven years to have had no named storms.