Canada, US: Severe weather forecast across parts of southeastern Canada and the northeastern US through at least July 11

Severe weather is forecast across parts of southeastern Canada and the northeastern US through at least July 11. Periods of heavy rainfall and thunderstorms associated with the remnants of Hurricane Beryl moving over the region are expected over the coming days. Strong wind gusts, lightning, hail, and possible tornadoes may accompany storms. Heavy downpours may trigger flooding in low-lying areas and landslides on unstable slopes.

As of early July 10, Environment Canada has issued red rainfall warnings (the highest level on a three-tier scale) across the Ontario Peninsula and southern parts of the rest of the affected area. Grey special weather statements are in place across the rest of the affected area. Rainfall totals of 2.5-8 cm (1-3.1 inches) are expected across the affected areas, with rainfall rates of 2-4 cm (0.8-1.6 inches) per hour possible. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming hours and days.

The US National Weather Service has issued flood watches and advisories across parts of the affected region, as isolated flood warnings for some river catchments. The NWS's Weather Prediction Center has forecast a moderate risk (the second highest level on a four-tier scale) of excessive rainfall over parts of northeastern New York, central and northern Vermont, and north-central and western New Hampshire July 10-11. There is a slight risk of excessive rainfall across the rest of the affected area. The Storm Prediction Center has warned of an enhanced risk (the middle level on a five-tier scale) of severe thunderstorms with a threat of isolated tornadoes for parts of central and western Upstate New York July 10-11. There is a slight risk of severe storms for surrounding areas of central and western Upstate New York, northern Pennsylvania, western Massachusetts, south-central and southern Vermont, and southwestern New Hampshire.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows will likely render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger intermittent flight delays and cancellations at airports in the region though these are unlikely to be severe or prolonged. 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 that see heavy rainfall and potential track inundation. Localized business disruptions may occur in low-lying areas.