A weak cold front trailing southwest from low pressure over the Gulf of St. Lawrence slipped south and east of the region Saturday night. Behind the front, high pressure will build from Ontario early Sunday morning to Quebec by evening. A southwest flow at jet stream level, however, will limit the drying and cooling from the high pressure as it allows the aforementioned front to lift back north toward the area Sunday. Skies will remain overcast and there will be patchy fog.
A jet stream disturbance passing over the frontal zone will cause a zone of showers to pass over the region. Rain will be steadiest Sunday morning, tapering to spotty drizzle in the afternoon. Total rainfall will average from 0.10″ to 0.50″ across the region. Patchy fog and drizzle will continue overnight with temperatures steady overnight.
The warm front will lift north of the area by early on Monday and breezes from the southwest will deliver unseasonably mild air. Much of the day will be dry and a few peeks of sun will occur, which will boost temps well into the 60s! Scattered showers will accompany a cold front as it crosses the region Monday night. These showers should dump another 0.10″ to 0.25″ in most places, and there could even be a rumble of thunder in a few places.