The Met Office has issued a rare red weather warning for extreme heat in central and southern England and Wales on Wednesday and Thursday. The warning will be in place between 9am on Wednesday and 9pm on Thursday. The Heat-health Alert Service was launched to warn of impending high temperatures that could pose a risk to public health. Specifically designed for health and social care professionals, as well as those involved in mitigating the dangers of prolonged hot weather, the service currently operates exclusively across England.The warning comes as the UK is set to bake in record-breaking temperatures which could soar to more than 38C.According to the Met Office, the sweltering heat could last until at least Thursday, sparking weather warnings and concerns for vulnerable people.Forecasters have said there is “growing confidence” this week could break the record for the hottest June temperature of 35.6C, which was set in 1976 in Southampton.The UK Health Security Agency (UKHSA) warned people to expect significant impacts across health and social care services along with a rise in deaths, particularly among those aged 65 and over or with health conditions.The extreme heat could also bring disruptions to rail, road and air travel, with the possibility of some tarmac melting, according to the Met Office.Met Office issues red warning for extreme heat (Met Office)What the Heat-Health Alert colours mean, according to The Met Office.Green (summer preparedness) - No alert will be issued as the conditions are likely to have minimal impact on health. However, during periods where the risk is minimal it is important that organisations ensure that they have plans in place and are prepared to respond should an alert (yellow, amber, or red) be issued.Yellow (response) - These alerts cover a range of situations. Yellow alerts may be issued during periods of heat which would be unlikely to impact most people, but those you are particularly vulnerable (E.g. the elderly with multiple health conditions and on multiple medications) and are likely to struggle to cope and where action is required within the health and social care sector specifically. A yellow alert may also be issued if the confidence in the weather forecast is low, but there could be more significant impacts if the worst-case scenario is realised. In this situation the alert may be upgraded as the confidence in both the weather forecast and the likelihood of observing those impacts improves.Amber (enhanced response) - An amber alert would represent a situation in which the expected impacts are likely to be felt across the whole health service, with potential for the whole population to be at risk and where other sectors apart from health may also start to observe impacts, indicating that a coordinated response is required. In addition, in some circumstances a National Severe Weather Warning Service (NSWWS) Extreme Heat warning may be issued in conjunction with and aligned to the HHA. This situation would indicate that significant impacts are expected across multiple sectors.Red (emergency response) - A red alert would indicate significant risk to life for even the healthy population. A red warning would be issued in conjunction with and aligned to a red NSWWS Extreme Heat warning. Severe impacts would be expected across all sectors with a coordinated response essential.