A weather warning has been issued across parts of the UAE as heavy rain and hail storms swept the eastern areas of the Emirates. Flooding streets and gusty winds were reported in areas of Sharjah with videos posted to Twitter showing hail hitting the ground. The National Centre of Meteorology issued an alert, calling for people in the region to stay away from wadis and areas where flash flooding my occur. The stormy weather followed a day of cloudy skies and high humidity. The rain was reported in Al Bataeh and Al Madam in Sharjah, inthe eastern part of the emirate, and in Al Ain and Al Dhafra in Abu Dhabi. The bureau warned of clouds associated with rain and strong winds of up to 45kph. It said the wind would blow dust and sand, reducing visibility at times. The weather prompted a red "take action" warning on the north-eastern border with Oman, asking people to be "extremely vigilant" because hazardous weather events of "exceptional severity" are expected. Forecasters also issued an orange "be prepared" alert along the southern border with Saudi Arabia. It is not unusual for rain storms to occur during the UAE's summer. In July last year, while many people baked in the scorching summer heat, parts of the UAE were lashed by flash floods, thunderstorms and lightning. During the summer, the monsoons bring water-soaked clouds from India to the Arabian Peninsula. This causes the phenomenon known as khareef in Oman, where the desert turns green, and it also brings rain to the UAE's mountainous east. Hail occurs when strong currents of rising air, otherwise known as updrafts, carry droplets of water up high enough to freeze – as the higher you go, the colder it gets. And the stronger an updraft, the larger a hailstone can grow. Updrafts can be caused by the sun heating the ground, which causes the surrounding air to rise, creating the perfect conditions for hail, even in the hot UAE desert. This type of phenomenon occurs most often during early summer, according to forecasters. This is because the surface temperatures are high enough to create instability associated with strong thunderstorms, but the upper atmosphere remains cooler.
