Heavy rain, strong thunderstorms, and possible hail are forecast for northern and central Greece on Thursday, according to an emergency weather bulletin issued by the Hellenic National Meteorological Service (EMY).
The severe weather is expected to affect the regions of Central and Eastern Macedonia, Thrace, Thessaly, the Sporades islands, and Evia throughout the day.
The wider Athens region of Attica may also experience isolated thunderstorms.
The inclement weather marks a sharp change from the hot, dry conditions that have dominated July and will be accompanied by a slight drop in temperature, with highs expected to range from 32 to 36 degrees Celsius (90-97 F).
Winds of up to 6 Beaufort are also forecast for some western and southern sea regions. Authorities are urging the public in affected areas to exercise caution and to avoid unnecessary travel during the storms.