Environment Canada has put London, and most of the province, under a special weather statement warning of mild conditions and then the return of below-zero temperatures Monday night.
The national weather service says a strong system bringing heavy rain could also cause wind gusts up to 90 km/hr ith it heavy rain and heavy winds.
Forecasters predict anywhere from 15 mm to 30 mm of rain and wind gusts up to 80 km/h before the system tapers off on Monday.
In New York, Governor Andrew Cuomo is warning people in flood-prone areas around Buffalo to move valuables up from the basement, pack a bag and prepare for the possibility of evacuation. Temperatures there are expected to approach 15C today and they could get 95-mile-an -hour winds.
*with files from Lisa Brandt
