Remnants of Hurricane Beryl to Bring a Deluge of Rain Across Southern Ontario Starting Wednesday
/While Southern Ontario has been enjoying tropical-like weather the past few days, we are about to experience another taste of the tropics as the remnants of Hurricane Beryl track into the region. Now classified as a post-tropical depression, Beryl has had quite the journey since forming on June 28th in the central tropical Atlantic.
Beryl set a new record for the earliest Category 5 storm in recorded history, reaching that status on July 2nd after making landfall as a high-end Category 4 hurricane on the island of Carriacou. Jamaica, as well as the Cancun, Cozumel, and Tulum regions in Mexico, were also heavily affected.
After making landfall in Texas as a Category 1 hurricane on July 8th, Beryl quickly weakened as it tracked inland across the Houston area. In the wake of the storm, several million customers were left without power in Texas, along with reports of flash flooding and tornadoes.
The post-tropical system that was once Hurricane Beryl has taken a northeasterly turn after making landfall in Texas. It is currently located over Illinois as of Tuesday afternoon and is on track to reach the Great Lakes region later on Tuesday.
While the remnants of Beryl won’t bring hurricane-like conditions to Southern Ontario, the biggest concern will be the significant amount of moisture associated with the system. Flash flooding is possible as some areas could see up to 100 mm of rain over the next two days.
thunderstorm risk
There could also be a potential tornado risk associated with this system as it tracks through the region on Wednesday. At this point, the strongest risk appears to be stateside over parts of Pennsylvania and Upstate New York. However, we can’t rule out the risk of a tornado on our side of the border, especially in the Niagara region and extending across Lake Ontario into Prince Edward County and Kingston.
Based on the latest data, there is a slight risk of severe thunderstorms in the Niagara and Kingston areas. This is driven by the threat of one or two tornadoes along with damaging wind gusts. The primary threat window is between the late morning and early evening hours. Hail isn’t expected to be a big concern with these tropical-related thunderstorms, with hail up to nickel-sized.
There is also a marginal risk for thunderstorms extending from Deep Southwestern Ontario through the Greater Toronto Area and into Extreme Eastern Ontario along the international border. This risk is mainly due to the very questionable isolated tornado potential with the thunderstorm activity during the day on Wednesday. It’s unlikely, as we expect the main environment to be contained to the Niagara region and on the other side of the border, but we wanted to highlight it as it will all come down to the exact track of the system.
The rain is expected to begin just after midnight, starting with Deep Southwestern Ontario (Windsor, Chatham, Sarnia, etc.). It will continue to spread north and east throughout the early morning hours on Wednesday.
We will see the heaviest rain during the morning and afternoon across Southwestern Ontario and the Golden Horseshoe region. It’s important to note that this rain will come in the form of embedded thunderstorms with intense, localized downpours. This will lead to significant variations in the rainfall totals between locations.
Rain will continue on and off throughout the day on Wednesday, with several rounds of brief thunderstorms bringing quick downpours. By late Wednesday morning, Eastern Ontario will begin to see rain, starting with some steady rain lasting through the early afternoon and transitioning into more sporadic thunderstorms later in the evening.
We expect the bulk of the rain to taper off overnight Wednesday into Thursday morning. The exception to this is around Georgian Bay, which will see continued rainfall through Thursday morning and afternoon, along with the Ottawa Valley.
In terms of expected rainfall totals, the exact impact will be highly dependent on which locations experience thunderstorm activity. We are looking at a general 20-40 mm of rain from just the system. But once we factor in the thunderstorms, most locations should range from 30 to 50 mm across much of Southern Ontario.
There are two regions we believe are most likely to see over 50 mm: along the Lake Huron shoreline and into Eastern Ontario along the St. Lawrence River. This includes Sarnia, London, Goderich, Kincardine, Kingston, and Brockville. Rainfall totals here are expected to reach 50-75 mm, with locally upwards of 100 mm in some spots.
Lower rainfall totals of between 20 to 30 mm are expected for the Ottawa Valley and parts of Central Ontario where thunderstorm activity is less likely.