Arab Weather - Sinan Khalaf - As autumn begins each year, weather systems gradually begin to change, and the Red Sea depression begins to expand, carrying tropical moisture that eagerly awaits the cool air coming from the north, which will interact with it and form the first rainy conditions after several months of summer and drought.
What is the Red Sea Depression?
The Red Sea Low is a surface thermal depression formed as a result of temperature differences between the waters of the Red Sea and the land of the Arabian Peninsula and Sudan. It is considered a subsidiary extension of the Sudan Thermal Low.
When does the Red Sea depression become active?
The Red Sea Low usually begins its activity with the onset of autumn in mid-September and continues until early May. The behavior of the low varies according to the seasons:
- Summer: High temperatures on land push the Red Sea low pressure system southward toward the Red Sea and eastern Sudan, weakening its influence over Saudi Arabia.
- Autumn: A drop in land temperatures allows the Red Sea low to expand northward toward the Kingdom, setting the stage for cloud formation and rainfall during the Wasm season.
- Winter: The Red Sea low pressure system continues to expand northward, with increased chances of rain in the western and southwestern highlands of Saudi Arabia, especially when cold air masses move in from above.
- Spring: The Red Sea low pressure remains active north of the Arabian Peninsula, but it gradually weakens as the land warms. The chance of scattered rain continues until the beginning of summer.
How does the Red Sea depression affect Saudi Arabia?
The Red Sea Low is the main key to the autumn weather changes, and its impact is felt through:
- Thunderstorms and autumn rains: The rush of cold air from above meets warm, moist air, forming thunderclouds and rain of varying intensity.
- Local flash floods : Accumulating rainfall increases the chances of flash floods in valleys and low-lying areas, especially in the west and south of the Kingdom.
- Temporary rise in temperatures and dry weather: Short heat waves may lead to dry weather with active southeasterly winds.
- Dust and sandstorms : East to southeast winds may stir up sand and sand in some areas, especially in spring.