JEDDAH — Heavy thunderstorms capable of triggering flash floods are forecast across parts of Jazan, Asir, Al-Baha, Makkah and Madinah on Sunday, according to the National Center for Meteorology (NCM). The rainfall may be accompanied by hail, while active winds stirring up dust and sand are expected to continue across parts of the affected regions. Light to moderate thunderstorms are also forecast over parts of Tabuk, Al-Jouf, Hail, Al-Qassim and the Northern Borders, while active winds stirring up dust and sand may also affect parts of Najran. Fog may form over coastal parts of the Eastern Province and Makkah Region. For temperatures, Makkah, Madinah, Dammam and Buraidah are forecast to record the highest temperatures at 40°C, followed by Riyadh at 39°C. Hail, Jeddah and Jazan are forecast to reach 36°C, Najran 35°C, Tabuk and Sakaka 33°C, Arar 32°C, Abha 28°C and Al-Baha 25°C. Humidity is forecast to reach 100 percent in Dammam, 90 percent in Jeddah, 85 percent in Jazan, 80 percent in Abha, 75 percent in Al-Baha, and 70 percent in Makkah and Tabuk. Humidity levels are expected to reach 65 percent in Buraidah and Arar, 60 percent in Hail, 55 percent in Sakaka, and 35 percent in Riyadh, Madinah and Najran.