Environment Canada has issued a rainfall warning for Toronto and much of the GTA, cautioning that significant weather could hit the area on Thursday night and into Friday.

Niagara, Hamilton, Halton, Peel, York and Durham area also affected by the weather statement.

The agency says a major storm is expected to bring 25 to 50 millimetres of rain.

The system will bring warming temperatures and to the area and will likely cause snow to melt, meaning ponding and flooding will be a concern.

Rivers and streams could also become more dangerous due to rising water levels.

Residents are advised to clear their catch basins and to keep small children and pets away from fast-moving water.

CityNews meteorologist Natasha Ramsahai said Toronto and the GTA will be cloudy with a chance of light freezing drizzle on Wednesday morning, then a chance of some showers in the afternoon. There’s a high of 2 C in the forecast and a low near -7 C.

Click here for the full forecast.

Two weather systems, one from Alberta and one from Texas, are tracking toward the Great Lakes, where they are expected to merge and intensify on Thursday, Environment Canada said.

The weather will warm up because of it, but there will also be increased precipitation and potentially damaging winds.

The rain will likely hit southwestern Ontario near midday Thursday, then spread east.

Thunderstorms are also a possibility and strong winds will be a concern along the shores of the Great Lakes. Southerly winds in the 30-60 km/h range, with gusts of 70-80 km/h, are possible.