Meteorologists are warning that a third heatwave in the United Kingdom is becoming increasingly likely over the coming days, with temperatures forecast to reach around 30°C in some regions.

A strengthening area of high pressure is developing from the Azores towards Portugal and Spain, which is expected to influence weather patterns across France and southern Britain by the weekend.As a result, warmer air is forecast to spread northwards, raising temperatures significantly in parts of England.

In London and the south-east, heatwave conditions are defined as three consecutive days of temperatures reaching at least 28°C, while northern regions have lower thresholds of around 25°C.

Forecasts suggest that parts of Greater London and the Home Counties could briefly meet these conditions by the end of the week, with Sunday potentially seeing peaks of 30°C.If this occurs, it could mark one of the earliest heatwave declarations in some parts of England.Despite this, much of the UK is expected to remain just below official heatwave criteria for the remainder of the week.

Northern areas such as Scotland, Northern Ireland, and parts of northern England are likely to stay cooler, with temperatures generally ranging between 20°C and 24°C due to the influence of Atlantic air and the position of the jet stream.

The UK Health Security Agency has issued yellow heat health alerts across several regions, including London and the south-east, highlighting increased risks for vulnerable populations.

While conditions are expected to be hot, the air mass may initially be less humid than previous heatwaves, potentially making the heat feel slightly more comfortable.

However, forecasters note there is still some uncertainty regarding how long the warm spell will persist and whether more intense heat will develop later in the week.