As the northern hemisphere moves into late spring, several areas are expected to experience a taste of summer heat this week with temperatures well above average for the end of April.
Across some eastern states of the US, conditions are expected to reach 6-8C above normal, peaking at about 30C (86F) in Washington DC.
Western Europe, including the UK, could also experience some of the warmest weather of the year so far. Temperatures of 25-28C are likely across parts of Germany, France and southern Britain, especially later in the week, with high pressure bringing dry and sunny conditions.
Far higher temperatures are expected across Pakistan and parts of north-west India. An ongoing heatwave will nudge temperatures to 7C above normal until the end of the month across several regions including Punjab, Islamabad and Kashmir. A peak of 48-49C is likely across parts of the Sindh region, and the authorities have issued public warnings urging people to take precautionary measures against the extreme heat.
A change in weather is predicted in Pakistan at the beginning of May, bringing some relief to those suffering from the heatwave. Moist air from the Arabian Sea is likely to raise humidity levels, triggering thunderstorms and heavy rainfall, with lightning, hail, dust storms and strong winds likely to create hazardous conditions.
Meanwhile, severe storms could affect parts of the US early this week, particularly the upper midwest. Strong winds, tornadoes and large hail have been reported in recent days in areas including Texas and Colorado. The threat of severe weather will continue over the coming days and spread north-eastwards.
As warm, moisture-laden air surges north across the Great Plains and into the midwest, it will interact with colder air to produce unstable atmospheric conditions. This is likely to trigger severe thunderstorms and an increasing chance of tornadoes.
Damaging winds, heavy rain and large hail are also likely, with flash flooding possible in the stormiest areas. The storm risk will spread into the north-east before easing midweek.
