Canada: Adverse weather forecast across southeastern regions through at least early Nov. 24 /update 1

Severe weather is forecast across parts of southeastern Canada through at least early Nov. 24. A storm system moving northeastward over the affected will bring heavy rainfall to eastern Nova Scotia Nov. 23 before transitioning to mixed wintry precipitation, including freezing rain and snow, as it moves over Newfoundland overnight Nov. 23-24. Flooding is possible in areas where heavy rainfall occurs and hazardous travel conditions are likely in areas where more wintry precipitation falls due to slippery roads and reduced visibility caused by blowing snow. Strong winds may cause property damage and power outages in parts of the affected area.

As of Nov. 23, Environment Canada has issued rainfall warnings (the highest level on a three-tier scale) across much of eastern Nova Scotia and southern Newfoundland; rainfall totals of 5-8 cm (2-3 inches) are forecast in the affected areas. A freezing rain warning has been issued over parts of central and western Newfoundland. A Les Suetes wind warning (Les Suetes wind warnings are issued when there is a significant risk of damaging winds) is in place for parts of northeastern Nova Scotia, with winds gusting up to 100 kph (62 mph) possible in this area Nov. 23. A wind warning is also in place for parts of southeastern Newfoundland; winds gusting 60-100 kph (37-62 mph) are expected overnight Nov. 23-24. Officials may update and extend the coverage of weather alerts over the coming hours.

The storm system could produce rounds of heavy precipitation (including rain and snow) and strong winds across the affected area. 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 northern parts of the affected area over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in these 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.

The disruptive weather will likely cause some delays and cancellations at airports in the region. Authorities may temporarily suspend port operations in coastal areas 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 strong winds, 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.