Greece, Cyprus: Adverse weather associated with Storm Carmel forecast across southern and central Greece and Cyrpus through at least Dec. 20

Event

A low-pressure system developing in the Mediterranean near Rhodes in the Dodecanese Islands has been named Storm Carmel and is forecast to bring heavy rainfall, strong winds, and thunderstorms to southern and central Greece and Cyprus through Dec. 20. Much of Greece is experiencing cold temperatures and snowfall in higher elevated areas ahead of the impact of the storm.

The Hellenic National Meteorological Service has warned that Storm Carmel will bring heavy rain and thunderstorms to the islands of the northern and eastern Aegean from early Dec. 18 and the Sporades Islands, Cyclades Islands, Evia, eastern Thessaly, eastern Sterea, and eastern Peloponnese regions Dec. 18-19. Crete will experience the effects of the storms from late Dec. 18-20. Snowfall is forecast in mountainous areas of mainland Greece and Crete through Dec. 19, with the heaviest snowfall in elevated areas of Thessaly, eastern Sterea, Evia, and eastern Peloponnese regions. Strong winds are also expected in the Aegean Sea. Heavy rainfall, strong winds, rough seas, and thunderstorms are expected across Cyprus from late Dec. 18 through Dec. 20. Cypriot civil defense officials have warned the public to take appropriate measures ahead of the storm's arrival.

As of Dec. 17, authorities have issued the following watches and warnings across Greece:

Orange heavy rainfall warning (the middle tier on a three-tier scale): North Agean Islands.
Yellow thunderstorm warning: Northeast Aegean, East Macedonia, and Central Macedonia regions.
Yellow rain warning: Thrace and East Macedonia regions.
Yellow snow warning: Thrace, East Macedonia, Epirus, Central Macedonia, West Macedonia, West Sterea, and West Peloponnese regions.
Yellow low temperature warning: Northeast Aegean, Thessaly, Thrace, East Macedonia, Epirus, Central Macedonia, West Macedonia, West Sterea, East Sterea and Euboea, West Peloponnese, East Peloponnese, and Attica regions.
Yellow wind warning: Ionian Islands, Thessaly, Central Macedonia, and East Sterea and Euboea regions.

Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Hazardous Conditions

The storm could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity. Where precipitation falls as rain, flash, and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water and in urban areas with easily overwhelmed stormwater drainage systems. Sites located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation could fall as snow in the higher elevations over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. Power outages could occur throughout the affected area.

Transport

Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.

The disruptive weather will likely cause some delays and cancellations at regional airports. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.