Friday
A cold start with frost for many. High pressure extends across the south & east, bringing a fair day to much Britain. A good amount of sunshine, but clouding over from the west as fronts approach from the Atlantic. Rain across Ireland will extend into western Scotland by afternoon, and western coasts elsewhere after dark. Light winds, but freshening southerlies will affect the west. Cool, 7 to 9C for most, up to 12C in the far south-west.
Friday night
Thickening cloud extends to all regions overnight. Rain will increasingly set in across western Britain, turning heavy into the night, and slowly spreading across Scotland, northern England, and into central-eastern England before dawn. Southerly winds will increase to gale force around exposed coasts and hills in the north. Temperatures briefly dipping to 3 or 4C early in the night, then rising from the west to 7 to 10C.
Saturday
A trough of low pressure and an occluded front pushes east across the country, bringing a belt of persistent and heavy rain. This will clear from western regions in the morning, but affects eastern areas into the afternoon. Brighter skies develop in the west and some sunshine should break through. Strong southerly winds in the east, veering westerly behind the front. Temperatures only 7 to 10C in north & east, rising to 13C south & west.
Sunday
A ridge of high pressure builds from the south-west. A dry and bright day for most places. Largely cloudy. A few patches of rain may linger toward the south-east. A little sunshine. Fronts arriving from the Atlantic bring thickening cloud, plus rain or drizzle to western parts of Ireland & Scotland later. Winds mostly light, but a brisk northerly breeze affects the south-east. A cool start, daytime highs reaching 7 to 12C.