Tornadoes, very large hail, and destructive winds forecast for parts of Russia on June 9 and 10

The European Storm Forecast Experiment (ESTOFEX) has issued its highest risk level — Level 3, for severe convective storms forecast to develop over parts of Russia between 09:00 UTC on June 9 and 06:00 UTC on June 10, 2025. This storm could produce tornadoes, some of which could be strong, damaging winds, and large to very large hail.

According to ESTOFEX, a deepening frontal wave is crossing the region, with embedded elevated thunderstorms already developing north of a lifting warm front. As the system evolves, storm coverage is forecast to increase along both warm and cold frontal boundaries.

In the highest-risk area, conditions in the lower atmosphere are forecast to be very favorable for dangerous thunderstorms. The air near the surface will be unstable, and wind patterns at different altitudes are expected to be strongly curved and fast-changing. This setup supports the formation of rotating thunderstorms, known as supercells, which have the potential to produce strong tornadoes and very large hailstones.

Further south, a well-mixed boundary layer may favor the formation of a linear convective system capable of advancing rapidly eastward, resulting in swaths of damaging wind gusts. The combination of forecast tornadoes, very large hail, and damaging wind gusts meets the criteria for a Level 3 classification.

Surrounding regions are under Level 2 and Level 1 alerts. Storms developing within these zones may also reach severe to extremely severe intensity and require close monitoring.

A Level 2 storm alert has been issued for Ukraine, Moldova, and Romania. The atmosphere is forecast to be moderately to strongly unstable, especially over Romania where the Carpathian Mountains are expected to trigger storm development. While wind conditions will be less intense than in Russia, the storms that form may still bring large hail, strong wind gusts in isolated areas, and heavy rainfall.

In Georgia, storms moving from the Caucasus Mountains into unstable lowland areas may result in isolated large hail events, prompting a Level 1 alert.

Eastern Spain has also been assigned a Level 1 risk. Although convective initiation is uncertain, forecast profiles show MLCAPE up to 1 500 J/kg, moderate shear, and elevated lifting condensation levels (LCLs), supporting a conditional risk for large hail and severe wind gusts.

ESTOFEX defines convective threat levels as probabilistic forecasts for severe weather occurring within a 40 km (25 miles) radius of any given point. These levels are determined through statistical verification using observed severe weather reports archived in the European Severe Weather Database (ESWD). The system quantifies the likelihood of severe convective storms based on past forecast performance and is used operationally across Europe.

Level 0 applies to areas not included in Levels 1, 2, or 3. It implies an insignificant risk of severe convective weather, with less than a 5 % probability of occurrence within 40 km (25 miles) of a location.

Level 1 indicates a 5–15 % probability of a severe convective storm occurring within a 40 km (25 miles) radius. It is the most commonly issued threat level and reflects environments with a low but present potential for severe weather phenomena such as large hail, severe wind gusts, or localized excessive rainfall.

Level 2 is issued when the probability exceeds 15 %. It represents a significant severe weather risk and indicates greater forecast confidence. Although this level does not explicitly include extremely severe weather criteria, the likelihood of such events, such as very large hail or strong tornadoes, is slightly increased, typically in the 3–5 % range.

Level 3 is the highest threat category and is reserved for scenarios where the probability of extremely severe weather exceeds 15 %. This level is rarely issued and corresponds to forecasts for major convective outbreaks. Examples include derechos, widespread tornadic activity, or extensive large-hail-producing supercells.