Yellow fog warning issued for parts of Wales 

Nation.Cymru staff

Dense fog could disrupt travel on Monday morning across parts of Wales, with a yellow weather warning forecasting visibility below 50 metres in places.

The warning runs from 6pm on Sunday until 11am on Monday, with fog expected to develop overnight and prove slow to clear.

Parts of 15 Welsh council areas are covered: Blaenau Gwent, Caerphilly, Cardiff, Conwy, Denbighshire, Flintshire, Gwynedd, Merthyr Tydfil, Monmouthshire, Newport, Powys, Rhondda Cynon Taf, Torfaen, the Vale of Glamorgan and Wrexham.

Drivers could face difficult conditions and longer journeys, while delays to buses and trains are possible. Flights could also be delayed or cancelled.

Rural parts of Wales may experience particularly stubborn fog as temperatures fall close to freezing, with frost possible.

Niamh Murray, a Met Office operational meteorologist, said conditions were creating the “perfect recipe” for fog.

“With autumn and winter and getting fog during this time of year, we get much longer nights, and that allows temperatures to sort of fall away,” she said.

“We get a longer period of cooling and also the temperatures are much lower, so they’re much closer to the temperature that we need for the air to become saturated and therefore form fog.”

Light winds, rather than completely still conditions, also help fog develop. Clear skies allow temperatures to fall during the longer autumn nights.

Fog could form outside the warning area, although it is expected to be patchier and less disruptive.

Monday’s Welsh forecast suggests fog and frost will gradually clear, allowing sunshine to develop during the afternoon. Temperatures are expected to reach around 11C.

The weather will become more unsettled from Tuesday, with rain arriving from the south alongside a brisk southeasterly breeze. Further rain is forecast on Wednesday, followed by brighter but colder conditions on Thursday.

Ms Murray said the change would bring welcome rainfall across much of the UK.

“Most places are likely to see 10 to 20mm and there is a chance that we could see some places seeing 30mm,” she said.