Information on update: Warning extended northwards with heavy showers now expected more widely over Scotland and trimmed northwards away from parts of Wales and the Midlands where impactful showers now look less likely. Heavy showers are expected across much of the UK on Friday. Within the warning area these showers and thunderstorms will be slow-moving and may cause localised surface water impacts.
Rainfall totals will vary considerably and not all locations will be affected by the heaviest showers. However, where the showers do occur there is potential for 20-30 mm of rain in a short space of time and during the course of the day there is a chance that some places could see as much as 80-100 mm build up. For further details see https://www.metoffice.gov.uk/weather/warnings-and-advice/uk-warnings