Sharjah was colder but dustier. The National Centre for Meteorology and Seismology (NCMS) said that visibility was less than 100 metres on Monday after strong northwesterly dust winds lashed some areas of the UAE on Sunday. Poor visibility and a further drop in temperatures are expected on Tuesday. Fujairah airport was closed due to low visibility, according to a section of the media. NCMS confirmed the previous warnings about northwesterly active and strong winds, associated with blowing of dust and sand. Visibility will decline below 100 metres over most areas of the country. It advised residents not to go into the sea as well as the seas would be rough, a condition which may last for a few days. Visibility on Sharjah roads was less than 100 metres on Monday evening. The lowest visibility standard set for driving on the UAE roads is 300 metres. The NCMS reported a visibility of 600 metres at Fujairah airport by 2.25pm on Monday. On Monday, the Sharjah International Airport recorded the lowest visibility of 1,600 metres and a maximum temperature of 23.6°C, three degrees less than on  Sunday. In some coastal areas of the Gulf, it was a dark, nightfall-like hazy scene by 4.30 pm on Monday. Meteorologists in Sharjah said the dust particles “hanged on” in the air for another wind to carry them away. If Sunday morning’s low visibility in some areas was attributed to fog formation, Monday’s was mostly due to dust and sand in the air. The NCMS said that the hot air mass that affected the country during the past days has changed and the region will be under the influence of an extension of low pressure persisting over the north and east of Iran and an extension of high pressure coming from the northwest (northern and central Saudi Arabia). This system caused a fresh northwesterly wind flow that became strong over the sea and the western areas, moving gradually to the rest of the country. A powerful sandstorm blowing over the Gulf has disrupted air traffic in Yemen, and closed schools and sent hundreds of people to hospital with respiratory problems in Saudi Arabia.