On Wednesday, September 23, an active cyclonic system that formed over the Black Sea is unfolding across Ukraine. According to the Ukrainian Hydrometeorological Center, as reported by RBC-Ukraine, the main impact of the weather falls on the Left Bank: heavy rain, thunderstorms and strengthening winds are forecast there, and a yellow alert level has already been declared in several regions. Meteorologists emphasize that the most difficult weather conditions are expected in the eastern and southeastern regions of the country, where the cyclone's frontal zone is passing most intensely.
Cyclone's Area of Influence and the Nature of Precipitation
Across Ukraine as a whole, the day will see variable cloudiness with clearings, and brief rain will fall over most of the territory. However, in certain regions the precipitation will take a pronounced form: heavy rain is possible during the day in Poltava, Sumy and Chernihiv oblasts. These areas, together with the eastern and southeastern directions, fall within the zone of heightened attention for meteorological services, where local downpours may be accompanied by thunderstorm activity and sharp changes in conditions.
Temperature Background: From 18 Degrees on the Plain to Frost in the Mountains
The temperature regime on September 23 will be uneven. In most oblasts, daytime air will warm up to 13–18 degrees above zero, while in the Carpathians the thermometer will reach 7–12 degrees. For contrast: on September 22 the temperature on Pop Ivan Mountain dropped to −1 degree, and a thin layer of snow formed in places. Such a spread between the plain part of the country and the highlands clearly demonstrates the vertical unevenness of the weather, characteristic of the transitional autumn period.
Wind Regime: The Left Bank and the Right Bank in Different Conditions
The wind on this day will have a pronounced regional character. On the Right Bank a northwesterly wind of 5–10 m/s is expected, which corresponds to moderate conditions. The picture on the Left Bank is different: a southeasterly wind will blow at 7–12 m/s, with gusts up to 15–20 m/s. It is precisely such gusts, combined with downpour rain, that form the basis for declaring a yellow alert level in the Left Bank regions lying on the cyclone's front.
Contradictory Data
Here it is worth noting a terminological mismatch between the headlines of several publications and the actual forecast figures. The sources' headlines use the phrase "storm wind," yet the text of the Ukrainian Hydrometeorological Center's forecast itself puts the maximum gusts on the Left Bank at 15–20 m/s. On the generally accepted scale this corresponds to a strong wind, whereas a storm is usually considered wind of 25 m/s and above. Thus, one viewpoint — the headline one — emphasizes the "storm" nature of the phenomenon, while the other — the Hydrometeorological Center's actual data — describes a strong, but not storm, wind. For the reader this means: one should not expect the kind of destruction typical of a true storm, however, gusts up to 20 m/s combined with downpours are capable of damaging weakly secured structures and hindering traffic.
Broader Context: Groundwater Level and Precipitation Regime
Experts had previously also drawn attention to the prolonged decline in the groundwater level in Ukraine. Among the causes cited were changes in the precipitation regime, high temperatures and long rain-free periods. The current cyclone, bringing intense precipitation to the Left Bank, may become one of the episodes capable of partially compensating for the moisture deficit accumulated during the preceding dry periods. Nevertheless, a one-off downpour does not eliminate the systemic imbalance of the water regime, which, according to expert estimates, forms over a considerably longer interval.
