Freezing Rain Warning issued by Environment Canada for significant ice accretion on Wednesday. Expect 20 to 30mm of freezing rain over a 24 hour period.
Orange Warning – Impact Level: High/Forecast Confidence: High
This story will be updated.
By now many of you may have read on social media of the possibility of a significant ice storm on Wednesday for portions of southern Quebec and the Ottawa Valley. The possibility does exist, but it is a rather complicated forecast. The event is shaping up similar to the April ice storm of 2023.
Very warm air will prevail for the Montreal region to start the week, with highs surging into the teens for Monday and Tuesday. Strong southwest winds will develop on Monday, gusting up to 70km/h at times. The warm temperatures will rapidly melt the snow and ice pack, contributing to the ongoing flooding occurring along portions of the Châteauguay River as well as other locations. Flood warnings have been issued for several municipalities in southern Quebec, Ontario and northern New York. Pay close attention to what your local municipal officials are telling you regarding ice jams and rising water.
Ice jam flooding along the Châteauguay River in Châteauguay on Sunday. Flooding was also occurring in Huntingdon and points south as rapid snowmelt continues due to the very warm temperatures.
Ville de Châteuguay
Potential Ice Storm
By Wednesday, deepening low pressure over the central Unites States will move northeast towards the Great Lakes, while Arctic high pressure to the north will begin to drain cold air into the St. Lawrence Valley. Temperatures will fall towards the freezing point by early Wednesday morning, as precipitation begins to overspread the region from the south.
At this time a very pronounced thermal boundary will traverse the region close to the US border, with freezing rain and snow to the north and plain rain falling to the south. Where that boundary establishes itself will determine who receives the freezing rain. Precipitation amounts will be significant from eastern Ontario across southern Quebec into northern New Brunswick, with 20-40mm of rain possible. If just half of that fell as freezing rain, we would have significant impacts. Further north heavy snow and blowing snow are likely.
Stay tuned to future forecasts and weather warnings that will be issued as the event unfolds. Prepare now for what could be a significant weather event in Montreal, with perhaps tree damage and prolonged power outages. Plan on delays on the road and at the airport Wednesday into Thursday across a large part of eastern Ontario into southern and central Quebec..
Behind this storm, more wintry weather is possible, as temperatures drop below freezing through the weekend, with snow possible by Sunday.
As I mentioned in a previous post, March and April can be extremely volatile weather months, with large swings in temperature. Montreal will experience that this week as have other parts of North America. Late last week, a severe weather outbreak, with tornadoes, occurred from Michigan to Oklahoma, with at least 8 fatalities reported.
On Sunday, a powerful cold front swept across southern Alberta. Medicine Hat went form a very warm 15C (59F) at noon down to 0C (32F) in just a couple of hours, with heavy snow and 100km/h plus winds occurring. Welcome to Spring in North America!