Authorities issued heightened alerts Thursday as a powerful weather system nicknamed Byron began sweeping across the country, bringing heavy rain, thunderstorms and gale-force winds that are expected to last through early Saturday.
The Hellenic National Meteorological Service updated its emergency severe-weather bulletin, warning of a significant deterioration beginning Thursday. Nine regions – including the capital – have been placed on elevated readiness, with the national Risk Assessment Committee scheduled to meet again at midday Thursday.
Forecasters said the brunt of the storm will hit eastern and southern parts of the country, with intense downpours and thunderstorms predicted from Thursday through the early hours of Saturday. Some storms are expected to produce hail, while winds in the southeastern Aegean on Friday could reach 8-9 on the Beaufort scale.
Heavy rainfall and thunderstorms are expected across the Ionian islands, Central Macedonia – particularly Halkidiki, Pieria and Imathia – as well as Thessaly, the eastern mainland – including Athens – southern Evia, the eastern and southern Peloponnese, the Cyclades, Crete and the eastern Aegean islands from Chios southward, along with the Dodecanese.
On Friday, storms are forecast to intensify, with red alerts issued for Pieria, Imathia, Halkidiki, Thessaloniki, Thessaly, the Sporades, Evia, the eastern Aegean islands and the Dodecanese, with localized high risk also in the Cyclades and Crete.
Elsewhere in Greece, conditions will remain unsettled, with intermittent cloudiness, scattered showers and occasional thunderstorms. Snow is expected in mountain areas of central and western Macedonia and Epirus.
Winds will vary widely, with eastern regions facing easterly to southeasterly winds of 4 to 6 Beaufort – increasing to 7 and briefly 8 in parts of the Aegean – before shifting to northeasterly up to 7 Beaufort in the north by late afternoon. Western and southern areas will see westerly to northwesterly winds of 4 to 5 and locally 6 Beaufort.
Temperatures will dip slightly, especially in western and northern Greece, reaching 15-16 degrees Celsius (59-61 Fahrenheit) in the north, 19-20 C (66-68 F) in Crete, the Cyclades and the Dodecanese, and 17-18 C (63-64 F) elsewhere.
On Saturday, rain and scattered thunderstorms – possibly strong in the early morning – will continue in northern mainland regions, the eastern Aegean, the Cyclades, Crete and the Dodecanese. Cloudy conditions with brief showers are expected elsewhere, with isolated storms near western coastal and island areas. Snow is forecast for northern mountain ranges. Winds will ease, and temperatures are not expected to change significantly.