Ontario rain: Six things you need to know

Saturday, April 12, 2014, 6:44 PM -

After a few days of what can only be described as lovely weather (notwithstanding fierce winds on Thursday), much of southern Ontario and Quebec is on tap for some major rainfall.

Although it is only April, there is even a chance of thunderstorms in the region, while further north, still more snow.

This comes at a time when the eastern Ontario town of Belleville is under a state of emergency due to flooding from the spring melt.

ON LOCATION: The Weather Network's Natalie Thomas will be in Belleville Saturday. Tune in for on-the-ground updates.

Here are six things you need to know about the incoming system.

What's the time frame?

Because the rain will be due to a series of disturbances rather than a single system, the region is looking at several days of rain.

More westerly regions should see the first drops begin to fall by Saturday afternoon, and across southern Ontario and Quebec the rains will intensify by Sunday night. You should expect some kind of rainfall event all the way through to Tuesday morning.

BEAT THE TRAFFIC: How will your commute be affected? Rely on Beat the Traffic for real-time traffic updates that matter to you. Visit www.beatthetraffic.com and download the app on iTunes or Google Play and get there sooner!

In Quebec, the heaviest rains are expected overnight Sunday to late Monday night.

In northwest Ontario, snow - yes, snow - will also begin overnight.

How much rain is on the way?

This depends on location, but certainly areas further north and east are in for the highest amounts when all is said and done.

Up to 80 mm could fall on the most at-risk areas, with the least amounts in the Greater Toronto Area and Niagara peninsula, where less than 15 mm is expected.

Even after the past few days of warm temperatures and sunshine, more northerly areas will still have some snow pack, making for increased potential for localized flooding.

Belleville, Ont., is already experiencing flooding, and declared a state of emergency late last week.

Will there be snow?

Northern Ontario can't catch a break this spring.

Snow is possible as far south as North Bay, with the heaviest amounts expected in the Nickel Belt in a band reaching across the shores of Lake superior.

Around 5-10 cm is expected in the worst-hit areas, with locally higher amounts.

The snow may begin as rain in some more southerly areas, followed by a transition period of mixing before it becomes full-on snow as overnight temperatures drop.

NEXT: What about Thunderstorms?

There will be a risk of thunderstorms

It may seem like a little early in the season to talk about this but, in fact, there will be a risk of thunderstorms.

If any form, they will be observed mostly in southwestern Ontario through to the Kingston area.

The biggest risk will be Saturday night into Sunday, but forecasters do not expect any developing thunderstorms to be severe.

Are there any warnings in place?

For Ontario, there are currently no watches or warnings in place.

Even in the north, where snow is expected, there is currently only a special weather statement in effect for the Nickel Belt, while in southern Ontario, a special weather statement is in place for rainfall, stretching from the shores of Lake Huron through to Ottawa, and north.

The statement does not cover communities along the Lake Erie shore, while on Lake Ontario, it includes on Durham Region.

Quebec also has a special weather statement in place for rainfall, but more seriously, Environment Canada has issued rainfall warnings for Montreal and several other areas.

The agency is warning of up to 45 mm of rain on Sunday only, which could combine with melting snow to make for localized flooding.

There could also be a short period of freezing rain on Sunday morning.

What about temperatures?

Certainly, people across the region have been basking in warmth since late this past week.

Friday's temperatures weren't as high as the 20-degree-plus readings of Thursday, but they were still comparatively toasty.

Temperatures will continue to be nice, but early next week, a big cooldown is in the cards, due to Arctic air moving through the Prairies that is also on its way to eastern Canada.

In southern Ontario, the drop in temperatures starts on Monday, and below seasonal temperatures will have set in by Tuesday.

IN DEPTH: Read Dr. Doug Gillham's analysis of this latest battle between winter and spring.