Greece: Adverse weather forecast across much of country through at least Jan. 23

Adverse weather is forecast across much of Greece through at least Jan. 23. As of Jan. 19, the Hellenic National Meteorological Service has issued an orange level (the middle level on a three-tier scale) Emergency Deterioration of Weather Bulletin warning of worsening weather conditions across much of the country from the afternoon of Jan. 20. Snowfall and a drop in temperatures is forecast predominantly across northern and central parts of mainland Greece over the coming days. Snowfall will commence in elevated parts of northern Greece Jan. 20 before spreading to lower elevations in northern Greece and mountainous parts of central Greece overnight Jan. 20-21. The snowfall will extend southward to the Peloponnese and Crete Jan. 21 whilst also ceasing in some northern and north-central regions. Light snowfall will linger in central and southern regions Jan. 22.

Heavy rainfall and thunderstorms are forecast in parts of northeastern and northwestern mainland Greece Jan. 20-21 and in eastern and southern island regions Jan. 21. Strong wind gusts, lightning, and hail may accompany storms. Strong winds are forecast in and around the Aegean Sea through early Jan. 23. Authorities have not issued any weather warnings regarding the storm as of Jan. 19; however, officials will likely issue new alerts as weather conditions change over the coming days.

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, as well as 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 areas.

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 airports in affected regions. Authorities may temporarily suspend port operations if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see 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.