Storm caused highly localised damage in southern and eastern Lithuania

The August 1 storm was local but exceptionally strong in some areas, with wind speeds potentially reaching 28 metres per second near Avižieniai, Lithuania’s Hydrometeorological Service said, according to LRT. A preliminary analysis found that the damage was caused by a powerful squall rather than a tornado.

Very rapid storm-cloud formation was observed on the evening of August 1 in southern and eastern districts, including Alytus and Vilnius counties. The strongest storm cells produced intense rainfall and a localised but powerful squall, causing significant damage in some areas.

On Saturday evening and during the first half of Sunday night, 34.6 millimetres of rain fell in Trakų Vokė, 30.3 mm in Vilnius city’s Šnipiškės district and 17 mm at Vilnius Airport. These amounts meet the threshold for a hazardous weather event.

The strongest part of the storm moved along a narrow strip through the northwestern part of Vilnius, bypassing the city’s meteorological stations. The highest wind gust recorded there was only 13 metres per second. Elsewhere in southeastern Lithuania, Meteo LT stations recorded gusts of up to 16 metres per second, but experts assessed that winds were considerably stronger in the areas where the greatest damage occurred.

Data from third-party weather stations showed wind speeds of 20 to 24 metres per second in some locations. An initial analysis of Vilnius weather radar data estimated that winds near Avižieniai may have reached 28 metres per second, a speed with significant destructive power.

The service said the storm was difficult to forecast because of its unusually rapid development, its late timing and a lack of detailed data. The storm clouds formed at about 9 p.m., when falling temperatures and decreasing atmospheric energy would normally weaken storms.

The storm cells also developed and dissipated within roughly half an hour, bringing heavy rain and strong winds over highly localised areas. Numerical forecast models did not fully account for the atmosphere’s complex thermodynamic conditions, further complicating the forecasting process.

The Hydrometeorological Service said its forecasting methods are continually being improved to reflect the complexity of atmospheric processes. The preliminary data on the storm will be уточined in the near future.