After mild few weeks, fall rains and temperatures en route to eastern Canada

Tuesday, October 15, 2013, 8:56 AM -

Most parts of eastern Canada have basked in above seasonal warmth and relatively clear skies for much of October so far, but true fall-like weather is set to return, starting with Tuesday night rains in Ontario.

We are going to see a pattern change in the next week for the #GTA. Temperatures dropping by the weekend :(

— Emily Vukovic (@EmilyTWN) October 15, 2013

An approaching Colorado Low is targeting the province, bringing up to 20 mm of rain to a swath from Wawa and Sault Ste. Marie down to the south and southwest.

"We do have a potential for nocturnal thunderstorms," Elena Lappo, a meteorologist at The Weather Network, said Tuesday morning, adding the chance will be greater in the province's Nickel Belt and cottage country.

TUNE IN: Keep your eyes on The Weather Network on T.V. as we track this system.

Most of it will have moved through the southwest and Greater Toronto Area by the morning, leaving behind a few lingering showers as the system moves on to Ottawa and beyond.

The expected amounts may not seem like much, but the system will bring an end to what has been an otherwise dry and sunny stretch of fall, with several southern Ontario cities experiencing above-seasonal warmth for most of October.

Many parts of the province already got a few millimetres on Sunday, but those rains notwithstanding, October has been also notably drier, as well as warmer, than the seasonal norm.

And once the low passes, expect cooler temperatures, more in line with what fall in Ontario is supposed to look like.

Heavier rains in the Maritimes

The return of fall will hit the east coast harder than in Ontario.

That Colorado Low passing through will combine with moisture from another system in the North Atlantic to bring significant rainfall to parts of Nova Scotia, with the south shore on track for up to 45 mm.

In New Brunswick, however, some rain in the north is expected, but for the most part, the province should escape the kind of soaking in store for Nova Scotia.

"It's stuck between the two systems, so it won't get that much rain," Lappo said.

If you actually like it when there's stormy skies above, check out the latest active weather videos in our gallery.