UK hot weather forecast to last for weeks as rare 'Omega Block' phenomenon keeps Britain roasting

The unusual event is expected to shunt weather patterns close to the UK, helping to keep temperatures well above average into the middle of next week.

Jim Dale, meteorologist for British Weather Services, said: “The medicane is driving the omega block and a low-pressure system over Spain.

“The omega block is in the middle, sucking up warm air which is in part responsible for the hot weather we have had in the UK this week, and will continue to see in parts of the country into the middle of next week.

“By the time we get to the end of the weekend, eastern and south-eastern parts of the country will see the hottest temperatures before thermometers start to drop off from the north.

“All these weather systems are ultimately linked, and so there is an element of the medicane and the omega block in the synoptic patterns which are behind the hot weather in the UK.”

Britain is expected to sizzle in the hottest day of the year so far today with thermometers possibly hitting 34C.

It could threaten the September record of 35.6C, although forecasters think the mercury will just fall short.

Saturday is likely to be the sixth day in a row that the 30C-mark has been breached in September, setting a new record.

Met Office meteorologist Alex Burkill said: “Saturday is when we are likely to see the peak of this heatwave getting to 33C possibly 34C and that is exceptionally hot for this time of year.”

However, extreme heat and atmospheric instability will trigger violent thunderstorms through the day, the Met Office warned.

A yellow alert for up to two inches of rain is in force across the East Midlands, East England, London and the southeast, Northwest England, Southwest England, Wales, West midlands and the Humber.

Met Office Chief Meteorologist Paul Gundersen said: “Although much of the UK will see high temperatures and sunny skies continue on Saturday, in what has a possibility of being the hottest day of the year so far, there’s also the potential for some thunderstorms, which has resulted in a Yellow Warning being issued for much of central England and parts of east Wales.

“Temperatures will begin to trend downwards from Saturday in the far northwest of Scotland, with a cold front gradually moving south through the weekend, bringing with it the risk of some heavy and thundery downpours on Sunday as well. However, the southeast will hold on to the high temperatures the longest and could still reach 32C on Sunday.”

Parts of the country will start to cool later this weekend, although temperatures across southern regions will remain high until Wednesday, partly thanks to the medicane.

The phenomenon differs from a standard autumn low-pressure storm by having a ‘warm core’ which fuels its development.

Dubbed Storm Daniel by European meteorologists, the storm has left swathes of the Mediterranean knee-deep in floodwater and driven thousands of people from their homes.

Met Office meteorologist Alex Deakin said: “It is actually called a medicane because it is not just a typical area of low pressure that we get across Europe and that we see in the UK which has a cool core, this has signs of a warm core a bit like a tropical cyclone or a hurricane.

“When they happen in the Mediterranean, you get these storms with hurricane like characteristics, and this one is going to drop a lot of rain across Greece and into parts of Libya.”