The Met Office has issued an explanation as Brits brace for another weather warning. The UK Health Security Agency (UKHSA) has declared yellow heat alerts, though some regions are expected to experience more unsettled conditions.
Yellow Heat Alerts in Place
The alerts, which indicate minor impacts on health and care services, cover the East Midlands, eastern England, London, and the South East. They are active from 3pm on Wednesday until 8pm on Monday, June 22. The Met Office warns that temperatures in the South East could reach heatwave criteria by the weekend.
"Friday is likely to see very warm, locally hot conditions for south-east and some eastern areas of England, with higher humidity and the chance of a few thunderstorms," a UKHSA spokesperson said on Monday.
"There is considerable uncertainty for the duration of the very warm conditions however, as a weak weather front moving east into Saturday may bring slightly lower temperatures and fresher conditions. However, there is the potential that the weather front stalls toward the South East allowing very warm or hot conditions to linger across, or near to the far south or South East, perhaps then becoming more extensive again into the following week."
Wednesday Forecast: Cloudy Start
The Met Office forecast for Wednesday warns of a "cloudy start with some rain or drizzle," turning "brighter in the north and northwest with scattered showers." Some warm bright spells are expected to develop towards the southeast, while it remains humid in the south.
Thursday to Sunday: Hot and Humid Sunshine
From Thursday to Sunday, the Met Office predicts "plenty of dry weather in the south with increasing amounts of hot and humid sunshine, and a risk of thunderstorms." More changeable conditions are expected elsewhere, with spells of rain and average temperatures.
Jonathan Vautrey, meteorologist at the Met Office, warned that rising temperatures and humidity will likely come with overcast skies for many. "By Friday there is potential for 30C across parts of south-eastern England," Mr Vautrey said.
"The exact detail of the temperatures is going to be dependent on cloud amounts, because, whilst it is going to be warmer this coming week, there's actually going to be a reasonable amount of cloud around at times as well - so it's not going to be sort of wall to wall sunshine every day."
"But those temperatures are going to be rising nonetheless," Mr Vautrey added, "and with that, it's also going to be increasingly humid this time around. So I think people will certainly be noticing how muggy it starts to feel during the second half of this weekend, and some quite uncomfortable nights for sleeping well, with overnight temperatures in the high teens across south-eastern areas of England."
Regional Variations
By the end of the week, the West Midlands, parts of the West Country, and areas of Wales are likely to experience warm temperatures around the mid-teens, Mr Vautrey said. Scotland and Northern Ireland, however, are expected to see more cloudy weather and rain over the course of the week, with temperatures unlikely to rise above 20C to 21C.
Yellow Heat Health Alert Impacts
According to the UKHSA website, a yellow heat health alert means there is likely to be a "greater risk to life of vulnerable people" and an "increased use of healthcare services" by this same demographic. There is also an "increased potential for indoor environments to become very warm" and a likely rise in water-related incidents, including "risks from cold water shock and drowning."
