From Wednesday we will see high pressure build bringing a southerly airflow across the UK and temperatures pushing up into the mid 20s for much of the southern half of the UK, with the warmth likely to peak on Friday and Saturday as the mercury rises into the high 20s. However, the risk of heavy rain and thunderstorms arriving from the west will not be far behind.

Met Office Chief Meteorologist Matthew Lehnert said: “There is a Met Office rain warning in force for northern England and northern Wales today as a low pressure system eastwards moves across the country. Within the warning area, many places will see 20-30mm of rain, with a few isolated spots possibly seeing around 60-80mm of rain over the course of the warning.  

“It will be drier for many by Tuesday, as the low pressure moves off into the North Sea. Parts of Scotland will continue to see frequent showers, with around 30mm of rain possible over a few hours for Glasgow and Edinburgh. Elsewhere will be largely dry with cloud and sunny spells for many.”

From mid-week, a weak ridge of high pressure will build from the west, providing more settled conditions than of late and allowing temperatures to rise into the low to mid 20s Celsius for many and potentially up to 26 or 27C in isolated spots in the southeast.

Deputy Chief Meteorologist Dan Harris, said: “A general warming trend is expected through much of this week, as the weather settles down for a time. Whilst some southern areas are already likely to reach the mid 20s by Wednesday, it’s not until Thursday that the warmer weather will become more widespread, with parts of Scotland also reaching the low 20s. Most places will be dry with sunshine, although some early mist and low cloud could mean a slow start for some areas.

“We are likely to see the warmest weather on Friday and Saturday, with low to mid 20s widely and a peak of 29C most probable in the southeast; at this stage the odd 30 Celsius here on Friday cannot be ruled out. A frontal system arriving into the west and southwest later on Friday, which could be preceded by thunderstorms, does complicate matters somewhat; after a very muggy night in the southeast overnight into Saturday.”

The rain will continue to move northeast on Saturday, with relatively warm conditions also then moving into northern areas. Slightly cooler, and largely cloudy conditions with a few showers are expected to follow in from the west, with some brighter breaks developing and it is likely to remain warm in the far east and southeast.

Temperatures are expected to decline closer towards average on Sunday and into early next week, although the southern half of the UK at least has a small chance of seeing a return of hotter weather should a renewed pulse of warm continental air develop.