WASM – The WASM Regional Center issues detailed weather bulletins for Saudi Arabia and the Arab Gulf countries for the 2020-2021 season for the periods of October and November and the December-January period based on the advanced climate model developed within the WASM Regional Center specializing in medium and long-range forecasts.
Autumn Season - WASM Period (October and November)..
A dry and warm period warmer than usual with little rainfall expected during this period over some areas, especially western Saudi Arabia and the Madinah region, and starting from the second half of November, rainy conditions increase significantly over western and northwestern Saudi Arabia and the Red Sea coasts, with heavy rainy weather events expected in those areas.
An ineffective extension of the Red Sea low is expected to dominate during this period, bringing dry and warm conditions with little rainfall concentrated in mid and late October, and starting from November the influence of the Siberian high-pressure system increases, and weather systems begin to change during the second half of November as cold air masses approach the region and chances of weather instability increase.
Winter Season (December and January)..
Weather conditions intensify especially in the second half of December due to the activity of East Mediterranean and northern Arabian Peninsula lows, which leads to the concentration of rainy conditions over central, eastern and northern Saudi Arabia in general, particularly the Riyadh region and parts of Qassim, the Eastern Region, Kuwait, Iraq, Arab Gulf countries, the UAE and the Sultanate of Oman.
A strong high-pressure system is expected to dominate northern and eastern Europe as well as North Africa with the presence of atmospheric lows southwest and sometimes west of Europe, which causes the activity of the Mediterranean front over the eastern Mediterranean region and the continuation of atmospheric lows in the area.
Summary..
A dry and warm autumn and a rainy and cold winter stronger than usual over Saudi Arabia, with improvement in autumn season performance during the second half of November starting from western Saudi Arabia regions, and weather conditions will be stronger than usual in terms of precipitation and coldness during the second half of December and January over eastern and central Saudi Arabia, Arab Gulf countries, the UAE and northern Sultanate of Oman, and rainfall is expected to concentrate during the winter season unlike previous seasons which concentrated in the autumn season.