When does marking start? What are the prevailing weather systems in this period?

<p style=";text-align:left;direction:ltr">Arab weather - Sinan Khalaf - As soon as October begins every year, memories of the &quot;mark&quot; and its rain, which are known for their thunderous nature, begin to be reflected in the soil, which is quickly covered with plants, announcing the end of the summer and drought months.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>When does marking start?</strong></p><p style=";text-align:left;direction:ltr"> The marking “rainy season” for this year begins on October 16 and lasts until December 6 and has a duration of 52 days, and it is called by this name because it marks the earth with greenery and plants. ).</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>Tag entry tags</strong></p><p style=";text-align:left;direction:ltr"> There are several clear signs of entering the marking, including: Migratory birds begin to cross the sky of the Arabian Peninsula, Sidr honey is harvested, and the movement of clouds from west to east in response to the western jet stream, and the atmosphere moderates significantly at night as a result of the apparent movement of the sun to the south, in addition to medium dust waves As a result of the upper depressions that descend towards the region.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>The entry of the mark and the ebb of the seasonal depression:</strong></p><p style=";text-align:left;direction:ltr"> With the beginning of the days of marking, the seasonal depression begins to recede and decline, to be gradually replaced by the Arab air high, which is largely responsible for pushing the moist air masses from the Arabian Sea towards the Kingdom, in conjunction with the presence of the Red Sea depression to the east of it, which works on a gradual and continuous decrease in temperatures and the refraction of the severity of the atmosphere warm.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>Marking and the beginning of the activity of the Red Sea depression:</strong></p><p style=";text-align:left;direction:ltr"> The marking is considered the beginning of the actual activity of the Red Sea depression, as it begins to deepen to affect the Levant and the northwestern parts of the Kingdom. The air coming from the north and the Levant region creates a state of atmospheric instability that causes thunder clouds and rain.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>The effect of the Mediterranean depressions:</strong></p><p style=";text-align:left;direction:ltr"> The increased activity of the European high altitude pushes cold air masses towards the eastern basin of the Mediterranean Sea, which is responsible for the formation of air depressions outside the tropical range or depressions of the Mediterranean Sea. Thunderstorms and heavy.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>Direct impact of the Siberian air altitude on the region at the end of the label:</strong></p><p style=";text-align:left;direction:ltr"> The Siberian high air at the end of the marking period begins to directly affect the Kingdom and this leads to a significant decrease in temperatures, which calls for wearing winter clothes, and a decrease in temperature occurs, especially at night hours.</p><p style=";text-align:left;direction:ltr"></p><p style=";text-align:left;direction:ltr"> <strong>From the memories of the tag</strong></p><p style=";text-align:left;direction:ltr"> Strong cases were often repeated during the marking period, and the closest to memory is what happened in November 2013 in the capital, Riyadh, as well as large areas of the Kingdom when torrential rains formed and heavy rains continued in large parts of the country. The largest valleys in the Kingdom took place in November 2008 when the rains continued It was heavy for several days, and the strength of the tagging was repeated in many years, the most important of which were 2012, 2004, 1997, and the tagging period may also be weak, as happened in the 2010 marking.</p>