Information on update: Parts of East Anglia removed from warning, which has also been extended a little further west and northwest to account for latest observations and data. Clearing skies over southeast England this evening and overnight, which has already led to the development of mist and some patchy fog, is likely to allow increasingly widespread and in places dense fog to form. Visibility will fall below 100m in some places. The fog will gradually lift and clear to mist and haze during Saturday morning, persisting longest where visibilities are poorest early on. For further details see https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings