Greece’s National Meteorological Service has issued an orange weather warning for a sharp deterioration in conditions from the early hours of Tuesday, September 22, through the early morning of Wednesday, September 23.
The warning covers the broader northwestern Aegean region, where heavy rain and thunderstorms are expected, with frequent lightning possible for periods and a chance of localized hail.
Areas expected to see severe weather
On Tuesday, locally heavy rain and thunderstorms are forecast:
- Thessaly, particularly the coastal and offshore areas of Magnesia, from the early hours.
- The Sporades islands and Halkidiki, from the early hours through the afternoon.
- Evia, particularly central and northern parts of the island, from the morning through the afternoon.
On Wednesday, heavy rain and thunderstorms are expected to continue into the early morning in Thessaly, particularly the coastal and offshore areas of Magnesia.
Cold front to bring sharp temperature drop
A cold front arriving from northern Europe is expected to become particularly noticeable on Tuesday.
Temperatures are forecast to fall by as much as 6 to 8 degrees Celsius on Wednesday and Thursday compared with the previous two days.
Several parts of Greece will experience rain and thunderstorms, with the strongest conditions expected mainly across the central, eastern and northern parts of the country.
The weather change is expected to develop in two stages.
The first storm system will arrive from the north tonight and affect the country through Wednesday.
A temporary improvement is expected on Thursday and Friday, although temperatures are not expected to return to the high levels seen in recent days.
Another deterioration is forecast over the weekend, when a new low-pressure system is expected to move toward the region from central Europe.
The exact track and intensity of the second system remain uncertain. Subsequent forecasts are expected to provide a clearer picture of the areas that could be affected and the intensity of the weather.
The sharp change in conditions is linked to the interaction of different air masses, as colder air from central and northern Europe meets warmer air remaining over the southern parts of the continent.
Storms expected overnight
Monday is expected to begin with summer-like conditions and high temperatures. From midday, however, unstable cloud formations will develop over central and northern mainland Greece and inland areas of the Peloponnese.
Showers and thunderstorms are expected during the afternoon, particularly in mountainous and semi-mountainous areas.
Conditions will change significantly overnight as an organized weather disturbance moves in from the northern and northeastern Balkans.
Rain and thunderstorms will become more organized and locally intense, while temperatures begin to fall noticeably.
Particular attention is advised in Halkidiki, the Sporades, Central Macedonia, Thrace and Thessaly. Eastern and southern Thessaly are expected to see locally heavy rain and thunderstorms.
Stronger northerly winds
Northerly winds will also strengthen as the weather system moves through.
Moderate to strong northerly winds are expected over the central and southern Aegean, reaching 5 Beaufort and locally 6 Beaufort in the Cyclades, the Carpathian Sea and Crete.
Winds will gradually strengthen in the Ionian Sea as well, while northerly winds are expected to become significantly stronger overnight in the western and northern Aegean.
