A slow-moving cold front will produce thunderstorms with locally heavy rainfall across eastern Europe on Wednesday.
Ahead of this front, temperatures will soar well above normal from parts of Belarus and Ukraine into western Russia.
Cooler air rushing in from the west will result in seasonably cool air from Germany into Poland and the Baltic States; however, where this cool air clashes with warm air, heavy thunderstorms will erupt.
The threat for thunderstorms will exist from eastern Romania into Moldova, central Ukraine, eastern Belarus and western Russia.
While any thunderstorms can produce dangerous lightning and strong winds, the greatest concern will be for flash flooding as the storms will be slow-moving.
Areas from Kiev to Minsk will be at threat for the heaviest rainfall as thunderstorms can produce rainfall rates of more than 25 mm (1 inch) per hour.
Ahead of these storms, temperatures will soar well above normal from parts of Ukraine into western Russia, including Volgograd and Moscow.
The high temperatures will be in 25-26 C (77-79 F) in Moscow on Wednesday and Thursday. The normal high this time of the year is 19.4 C (67 F).
The cold front will arrive late Thursday into Friday bringing the threat for showers and thunderstorms along with more seasonable temperatures.
In Volgograd, temperatures will soar to 32 C (90 F) or higher each day through Sunday. The normal high temperatures this time of the year is only 24.4 C (76 F).
Thunderstorms will be possible both Saturday and Sunday ahead of the frontal boundary with some relief expected from the scorching heat early next week.