Full list of UK counties set to roast in hours as weather maps reveal 25C Iberian blast

Parts of are set to sizzle within hours as new show temperatures soaring to 25C thanks to an sweeping up from the south. The latest forecast from , valid for 3pm on Thursday, May 1, shows a large swathe of turning red as the mercury rises. That's now less than 48 hours away.

According to the , the hottest temperatures are expected in , where highs of 25C are forecast. Just behind are , and Cambridgeshire, all expected to see temperatures around 24C, while Hertfordshire, Surrey and Suffolk could also hit 23C or 24C. Further north, temperatures will be cooler but still pleasant, with parts of the Midlands and northern England reaching between 18C and 21C. is expected to see highs of around 13C to 18C, while will enjoy temperatures of around 21C and 22C.

• Greater London
• Kent
• Essex
• Suffolk
• Norfolk
• Cambridgeshire
• Hertfordshire
• Surrey
• Lincolnshire
• Northamptonshire
• Bedfordshire
• Buckinghamshire
• Leicestershire
• Oxfordshire
• Berkshire
• East Sussex
• Rutland
• West Midlands
  

The surge in temperatures is being driven by what meteorologists call a Spanish plume, also known as an Iberian blast.

According to the , this is a setup where very warm air travels northwards from the Iberian Peninsula - including Spain and Portugal - and interacts with cooler Atlantic air.

While it can sometimes trigger thunderstorms, it often brings sudden heat spikes, especially in spring.

The Met Office explains: "The very warm air moving northwards from Spain towards the UK will rise as hot air is less dense than cold air.

"As this unstable air rises it cools, leading to the formation of clouds, in this case cumulonimbus or thunder clouds."

For now, however, the focus is on the sunshine.

According to the , Tuesday will be sunny and warm across much of the country, with some rain in the far north.

Wednesday looks similar, with lots of sunshine and highs well into the 20s across southern England.

On Thursday, forecasters say it will be "very warm and sunny" for most, with a risk of heavy showers or thunderstorms arriving later on Friday.

By the weekend, things are expected to cool down.

In the long-range forecast, the Met Office said: "Temperatures will most likely be closer to average for most of the UK.

"However, conditions will probably turn more changeable overall, with dry, settled periods interspersed with wetter weather."