The Met Office has warned that extreme temperatures are predicted as tropical air blasts Merseyside.
Temperatures today have reached a high of 26C , but tomorrow the region can expect to bask in 31C.
Across the country, the story is the same as temperatures climb over the next couple of days - potentially reaching record breaking levels by Thursday with 39C.
Heatwaves are extreme weather events, but research shows that with climate change they are likely to become more common, perhaps occurring as regularly as every other year.
This week's heat is down to the jet stream coming from North Africa - a fast-moving ribbon of air in the atmosphere that shapes the weather.
Dr Mark McCarthy from the Met Office National Climate Information Centre, said: “Reaching 40.0 C in the UK is an unprecedented event in the observational records of UK climate.
"Historically UK summer heatwaves would typically tend to peak in the low 30s Celsius with extreme events reaching the mid-30s.
"This year temperature records across Europe have been falling and there is a significant chance of seeing the July maximum temperature record and possibly even the all-time UK temperature record of 38.5C being broken.
"40C is also a possibility this week."
Tomorrow (July 25) will be a hot and sunny day in Merseyside with light winds. It will feel humid as we head into the afternoon with a risk of some scattered thundery showers then, and again through the evening.
