The start of autumn rains in Iran depends on weather conditions and various factors that can be clearly observed in the examination of weather maps for October 28, 2026. To identify potential autumn waves, in addition to precipitation and temperature, it is necessary to accurately examine moisture transfer, pressure changes, and the displacement of atmospheric currents.
The Role of Atmospheric Rivers in Precipitation
One important phenomenon in this regard is the atmospheric river; a long and relatively narrow band of water vapor that can transport a significant amount of moisture to a region. These flows can create heavy precipitation when they encounter ascending systems. Therefore, to confirm the presence of such a flow over Iran on October 28, examining moisture transfer maps is essential.
Jet Stream and Its Impact on Precipitation
Another factor that affects precipitation predictions is the jet stream or fast-moving air current at high altitudes in the atmosphere. The change in the path of this current can influence the movement of low-pressure systems and the intrusion of cold air. The simultaneous presence of a trough at the 500 hPa level with sufficient moisture can create conditions for air ascent and precipitation formation.
In northern Iran, moisture from the Caspian Sea and the collision of moist winds with the Alborz mountain range provide the conditions for orographic ascent. This process increases the likelihood of cloud formation and precipitation as air rises when it encounters the mountains. Conversely, stability and subsidence in the central and southern regions can hinder the growth of rain-bearing clouds.
Therefore, the entry of a rain wave into the country depends on the simultaneity of moisture, air ascent, and suitable conditions in different layers of the atmosphere. These factors together can herald autumn rains in Iran.
