Bulgaria is expected to come under increasingly unstable weather conditions in the coming days as a Mediterranean cyclone moves over the region, bringing rain, thunderstorms, and a heightened risk of hail in several areas.
Climatologist Georgi Rachev, speaking in a forecast for bTV, said cloud development will begin rapidly over western parts of the country as early as Saturday afternoon. Conditions are expected to shift from clear and mild mornings to rapidly developing afternoon storm activity.
He described the expected pattern as one of strong convective development. ?Powerful cumulus-rain clouds will develop, associated with lightning, lightning and thunder. In a number of regions, there is also a possibility of hail,? Rachev said, noting that warm and humid air flowing in from the south is driving the instability.
The forecast suggests a typical May weather setup, where conditions can change quickly within a single day. ?The morning will be clear, nice and fresh, and in the afternoon ? boom-boom, thunderstorms. The closer to the mountains, the more,? he added, emphasizing that mountainous areas will see the most active storm formation.
Rachev also pointed to the Western Balkans as the core zone of storm development, including Bosnia and Herzegovina, Serbia, and southwestern Romania. This broader system is expected to influence western Bulgaria as well, where thunderstorm activity may become more pronounced.
According to the forecast, Sunday will bring a drop in temperatures as cooler air moves in. In western regions, daytime highs are expected to remain below 20C, while southeastern Bulgaria will stay relatively warmer.
After this brief cooling phase lasting through Tuesday, temperatures are expected to gradually rise again. Around May 24, values are projected to reach approximately 20?22C, which Rachev described as seasonal norms. ?22 degrees around May 24 is the normal weather,? he said, while noting that atmospheric instability will continue despite the warming trend.
The pattern is expected to persist with a familiar daily cycle: morning sunshine followed by afternoon cloud buildup, rainfall, and thunderstorms across many regions.
Along the Black Sea coast, conditions are expected to be comparatively calmer, with fewer precipitation events. Sea temperatures have already reached around 15?16C and continue to increase gradually. Cities such as Varna and Burgas may experience a brief cooling and rainfall on Sunday, but temperatures are expected to recover afterward to around 20?23C.
Rachev described the overall situation as characteristic of the season, highlighting May's highly changeable nature. ?May is a very unstable month. It changes three seasons,? he said, explaining that strong daytime heating leads to moisture buildup and subsequent afternoon storms.
He concluded that the coming period represents a classic example of transitional spring weather in Bulgaria, marked by alternating sunshine, precipitation, and thunderstorms within short intervals.
