The phenomena are expected to be most intense in western parts of Greece but will gradually spread to the rest of the country over the course of Friday night.
Strong rain and storms throughout the country are forecast on Saturday but will abate as the day progresses, though rain may continue in eastern Macedonia-Thrace, the eastern Aegean and the Dodecanese islands on Sunday.
Southerly winds are forecast for Friday, with wind velocity reaching up to 7 on the Beaufort scale. Storms in the afternoon in the northern parts of the country with temperatures ranging from 10C-19C.
Clouds and heavy rain are expected in the afternoon in the western parts with temperatures between 16C-19C, rain and storms in the afternoon in the eastern parts with temperatures between 13C-20C, clouds and rain over the islands, 14C-22C, storms in the afternoon in Athens, 15C-20C; the same for Thessaloniki, 15C-18C.