Wet and windy fall storm on the way for southern Quebec

A strong fall cold front will produce a wide variety of weather across southern Quebec and Ontario Wednesday into Thursday. Mild temperatures and strong southerly winds on Wednesday in Montreal, will be replaced by cold. blustery west winds and flurries by Thursday. Winds may gust as high as 90km/h. Rainfall is expected to be heavy at times with 20 to 50mm across southern Quebec.

A special weather statement is in effect for the Montreal region for 10-20mm of rainfall and gusty south winds up to 80km/h during the day and evening hours Wednesday. Weather warnings have also been posted for the St. Lawrence Valley northeast of Montreal for heavy rain and some mixed precipitation. Meanwhile across northern New York and New England, wind advisories have been hoisted for Wednesday. Additional weather warnings may bee needed as the system evolves over the next 24 hours.

The culprit is a deepening area of low pressure across the upper Midwest, that is forecast to move across central Ontario towards James Bay on Wednesday, and then eastward across northern Quebec on Thursday. The storm will drag a strong cold front across the Great Lakes and into southern Quebec during the midday hours Wednesday.

Tuesday was a cloudy, chilly day in Montreal despite high pressure trying to nose into the region. Clouds will thicken and lower early Wednesday, as winds increase from the south gusting 50-70km/h. Rain should arrive by late morning, becoming heavy at times throughout the afternoon, before tapering off to flurries late in the evening as the cold air arrives. The temperature in Montreal will rise quickly Wednesday morning, up to 9C (49F), before dropping in the evening, back below the freezing point to -2C (29F) by Thursday morning. The high will struggle back to the freezing point Thursday. Thursday will blustery and chilly in the St. Lawrence Valley, with perhaps a few snow showers around. There may even be some isolated heavier snow squalls at times.

This storm is rather dynamic, producing a wide variety of weather across eastern North America. Heavy snow is falling across the western Great Lakes and upper Midwest. Freezing rain and mixed precipitation is expected across central Ontario into portions of central Quebec. Strong winds are forecast for much of the eastern Seaboard and Northeast. Severe thunderstorms and isolated tornadoes are occurring across the southern US from Louisiana and Arkansas into Mississippi and Alabama. Some locations in Ontario and western New York will see another round of lake effect snow as colder air pours into the area behind the departing storm.