Significant rainfall expected in Waterloo Region, Guelph

Waterloo Region and Guelph are in for some heavy rainfall over the next day, Environment Canada is warning.

The weather service issued a special weather statement Friday morning, saying that “significant rainfall” was possible late Friday through Saturday.

Rainfall could total 20 to 40 millimetres, with higher amounts possible in some areas, likely on higher ground to the north of the region.

“A low-pressure system will bring widespread rain across southern Ontario this weekend,” the statement says. “Periods of rain will begin over southwestern Ontario late this afternoon and progress eastward overnight. At this point, there is still uncertainty regarding rainfall amounts. Rainfall warnings may be issued for some regions as the event approaches. The rain is expected to taper to flurries Saturday night as colder air moves into the region.”

Precipitation has been well below normal, with just 21.6 mm of total precipitation last month, compared with the average of 63.5 mm, making it the driest February since 1987.

So far in March there has only been about 1 mm of precipitation, said Peter Kimbell, a warning preparedness meteorologist with Environment Canada.

The rain is expected to fall over a stretch of 12 to 18 hours, so is unlikely to come as a heavy downpour that leads to pooling. “It depends how rapidly it falls,” he said. “If you get 20 to 40 mm in an hour, that can be quite a bit.”

The weekend is perhaps typical of March, though, with a range of weather in a short period. The rain and above-normal temperatures will be followed by cold temperatures on Sunday, as well as flurries and blowing snow.

“I’ve been telling people, ‘Hopefully you haven’t changed your winter tires yet.’ Winter tires are better when it’s slippery,” Kimbell added.

The Grand River Conservation Authority is not anticipating any significant flooding, said spokesperson Lisa Stocco.

However, higher flows in local rivers and streams will increase the risk in low-lying areas typically prone to flooding.

GRCA reservoirs will be used to reduce downstream flooding. But river flows will remain high, and the authority is reminding people to use extreme caution around waterways.

The rain is expected to fall over a stretch of 12 to 18 hours, so is unlikely to come as a heavy downpour that leads to pooling