Aerosynoptic conditions in Moscow and the Moscow region during the day of September 9, 2023 were determined by the influence of a secondary cold atmospheric front approaching the Moscow region from the northeast at a speed of 70-90 km/h. In the morning, variable (mainly layered-cumulus) clouds were observed, which thickened with the approach of the front (Fig.1). In a free atmosphere at all altitudes a north-easterly wind of up to 50-90 km/h was observed.

In the afternoon, when the air warmed up to 16-19 degrees, precipitation up to 0,2 mm was predicted. 

In accordance with this forecast, in agreement with the Customer, four aircraft were lifted into the air from 4:00 to 7:00 MSK: one AN-12 (№ 18) and three AN-26 aircraft (№ 02, 53 and 50) to monitor weather conditions and impact on clouds at a distance up to 200 km to the north and north-east of Moscow. From 9:41 to 11:06 MSK, taking into account the planned landing of the aircraft, 3 more AN-26 aircraft (№ 28, 29 and 36) were lifted into the air to replace them. Then, throughout the day, periodic replacement of aircraft was carried out due to the consumption of fuel and reagent. 

The main objects of impact were layered cumulus clouds moving towards the city from the northeast, in order to disperse the clouds (in the morning) and exclude precipitation (in the afternoon). Taking into account the positive temperature at the upper boundary of the clouds, the seeding were carried out with coarse and hygroscopic powders. 

As a result of cloud seeding with the simultaneous use of up to 4-5 aircraft, the destruction of clouds was observed (Fig. 2-4) and precipitation in the city was completely excluded.

 Since due to weak warming, cumulus clouds did not develop, work on improving weather conditions in Moscow was completed in agreement with the Customer at 20:00 MSK.

A total of 12 flights were carried out on September 9, 2023.

Fig.1. Cloud image in the visible range for 10:00 MSK.  
Fig.2. Digital map of the upper cloud boundary at 9:00 MSK.  
Fig.3. Digital map of the upper cloud boundary at 9:50 MSK.  
Fig.4. Digital map of the upper cloud boundary at 11:00 MSK.