Saturday
A slack pressure gradient across the British Isles with higher pressure to the east of the UK, although low pressure over the Atlantic beginning to make inroads. Thickening cloud and patchy rain moving into Ireland and western parts of Britain through the day. Chance of local showery bursts, some of them thundery, through the late morning and into the afternoon. Many eastern counties should stay dry with sunny spells with the best of the sunshine for the far northeast of Scotland. Highs at 18 to 26C, warmest southeast.

Saturday night
A cloudy night across the British Isles on Saturday with isolated showers affecting Ireland, Wales, western Scotland and western parts of England. The best chance of clear skies over the far northeast of Scotland. A mild and muggy night with overnight lows at 12 to 16C.
 

Sunday
Various fronts will be pushing across Britain and Ireland from the southwest, with a slack southerly airflow maintaining a humid and rather cloudy picture for most places. Patchy rain, focused around western areas in the morning, but an increasing risk of rain developing more widely through the day, with some heavy and thundery bursts tracking slowly into east and northeastern areas. South & southeast England may stay mainly dry and it will be very warm. Highs 18 to 26C.

Monday
Little change in the overall pattern, with a humid south to southwesterly airflow prevailing as low pressure remains to the northwest. Outbreaks of showery rain from early in the day moving from west to east across the country and, once again, local heavy bursts are expected to develop for some. These tending to ease through the afternoon. Between the showers, and through the afternoon, there will be good spells of sunshine. High temperatures at 17 to 24C.