A slack pressure regime across the British Isles. A warm front edges slowly north, allowing warm and very humid air to spread back across southern counties. Bursts of rain developing along this front, but very hit and miss. Many places are likely to stay dry throughout much of the daytime. Typically light winds, but expect gusty easterlies in eastern England. Hazy sun, mostly through high cloud. Highs 19 to 22C north, 24 to 27C south.
By the evening, an increasing threat of heavy bursts of rain breaking out across central Britain, although detail is uncertain. Expect some locally prolonged torrential falls, possibly over an inch of rain in a few hours. Thunder and lightning is likely for some areas. Rain spreading north & east across England through the early hours. The south-west and also much of Scotland may escape dry. Staying warm and humid, lows 13 to 17C.
Shallow low pressure over Britain drifts slowly eastwards. Slow-moving areas of rain continuing from overnight, mainly central & northern England. These may fade, but additional thundery showers likely to break out almost anywhere for inland regions during the day. A lot of cloud, but some sun, perhaps best near coasts in south & west by afternoon. Mostly light winds, but breezy on the south coast. Highs 18 to 22C north, 23 to 25C south.
A ridge of high pressure builds from the south-west. Most places will be dry with plenty of sunshine, particularly coasts by afternoon. Risk of scattered showers, mainly in the west early morning, becoming confined to eastern regions of Scotland & England in the afternoon. Cloud thickening across Scotland & Ireland, may bring drizzly rain to the north-west later. Light winds, coastal sea breezes. Highs 18 to 23C, locally warmer south.