Friday
Showers around many western coasts early morning, but soon spreading inland across northern Britain & Ireland, turning heavy, locally with thunder. May merge into an hour or more of rain for western Scotland & Northern Ireland. Scattered showers for Wales & the Midlands by afternoon. The south & south-east of England should remain dry most or all day. Intermittent sunshine, best in the east. Breezy, particularly in the north & west. Temperatures 16 to 21C.
Friday night
Showers fading from inland regions, but will continue to affect coastal areas in the west and north-west. Clear spells developing in the east, but cloud is likely to thicken across southern Britain. Remaining breezy in the north, winds dropping light in the south-east. Toward dawn, patchy showery rain may encroach toward south-west England. Overnight lows typically 10 to 13C, locally 7 or 8C in the north.
Saturday
Low pressure to the north-west brings breezy and showery weather to north-western Britain and much of Ireland. Lighter winds in the south. High pressure toward the east gives several hours of dry weather for eastern England & Scotland. Some uncertainty about detail and timing, but a front threatens to spread rain in from the south-west, and may become persistent across the south and south-east of England. Highs 17 to 21C.
Sunday
A complex pressure situation means confidence of detail is fairly low. Low pressure located north of Scotland is likely to produce cool and showery conditions for northern areas of Britain & Ireland. A slow moving front may also affect central & southern regions, giving cloudy skies and threat of persistent rain. However, locally it may remain dry for most of the day. Fairly light winds. Highs 16 to 21C.