Days of rain ahead for southern Ontario, rising flood risk

February 19, 2018 — After a chilly weekend, southern Ontario sees the first day of a substantial warm-up to close out the Family Day long weekend -- but the welcome warmth will be accompanied by some substantial rainfall.

After a chilly weekend, southern Ontario sees the first day of a substantial warm-up to close out the Family Day long weekend -- but the welcome warmth will be accompanied by some substantial rainfall. 

"Gulf of Mexico moisture tracking into the region along a semi-stationary boundary will bring excessive rainfall for parts of southern Ontario through Wednesday," Weather Network meteorologist Nadine Hinds-Powell said early Monday.

For a more comprehensive look at weather conditions in the GTA, here's a detailed analysis.

WEATHER HIGHLIGHTS

  • Rain begins in the southwest late morning/early afternoon, reaching the GTA by evening, lasting into Wednesday morning
  • 30-50 mm expected over much of the south, locally higher in the southwest
  • Risk of thunderstorms in the southwest Monday night, non-severe
  • Melting snow, still frozen ground make for elevated risk of localized flooding

Spring Is Ahead!Will winter linger into spring? The Spring Forecast premieres Monday February 26 – All day event


Light rain begins through southwestern Ontario in the late morning and early afternoon, becoming heavier by the overnight through the southwest and the Greater Toronto Area. All the way through Tuesday into Wednesday morning, there will be several periods of heavier rain through those same areas, and east of Toronto, finally ending Wednesday through the afternoon.

A widespread 30-50 mm is possible over much of the south over the course of this event, highest in the southwest.

The upside to all this will be rising temperatures, gradually increasing Monday to hit the low double digits by Tuesday and Wednesday.

With the warmth and moisture, there will even be a chance of thunderstorms Monday night for parts of the southwest inland from Lake Huron, though likely non-severe.

The prolonged period of rainfall is likely to raise river levels and trigger localized flooding in some areas where there is still snowpack, with the ground not able to absorb the rain.

A flood warning has been issued for the entire Grand River watershed, while the Toronto and Region Conservation Authority has a watershed statement in effect.

Keep on top of active weather by visiting the ALERTS page.

This warm pattern is not how February was expected to end. It was initially thought that the Arctic air would remain locked in place through the end of the month, but a couple of tropical cyclones (among a few other factors) in the Pacific Ocean have interrupted and delayed the expected pattern.

WATCH BELOW: Dog has had enough with winter and takes it out on the shovel