Thunderstorms are forecast across much of Saudi Arabia this week, with authorities warning of heavy rainfall in western and southern areas. Heavy rain arrived in the city of Al Namas in Asir province on Monday morning, a day after a hailstorm hit an area near Abha, the provincial capital. The National Centre of Meteorology forecast heavy cloud cover over Tabuk, Madinah, Riyadh, Qassim and the Eastern Province, with heavy rain expected in Najran, Jizan, Makkah and Al Baha, the Saudi Press Agency (SPA) reported. The hailstorm in Asir region was welcomed by Saudi social media users as "good news" signalling the arrival of cooler weather after temperatures of more than 50ºC last month. Temperatures on Monday in the south-western city of Al Baha fell to 26ºC on Monday, SPA said. Torrential rain hit the Lajb valley in Jizan on Saturday, authorities said. Tourists uploaded videos of the downpour on social media. Rain was expected to fall in Jeddah on Monday, where humidity is high after temperatures in the past week of between 37ºC and 44ºC. Temperatures are expected to start falling after peaking at 51ºC, with weather experts predicting "tangible changes" over the next two weeks, SPA reported on Sunday. The hottest place in the kingdom on Monday was Hafar Al Batin in Eastern Province, 430km north of Riyadh, with a temperature of 47ºC, SPA said. July was the planet's hottest month on record, according to the EU climate observatory, while climatologists have said it was likely to have been the hottest month in about 120,000 years.