Wednesday, March 24, 2021

Weather whiplash - from record spring warmth to snow

A warm front may produce some scattered thunderstorms across southern Ontario and Quebec late Thursday and early Friday morning. Record warm air will then surge into Montreal on Thursday.

Montreal managed to sneak in a record high on Tuesday afternoon, reaching 19C (66F), surpassing the previous mark of 18.6C (65F) set in 1979. It was our second record high this month, with a third likely on Thursday in Montreal as temperatures are expected in the upper teens and even low 20s. The record to beat for March 25 is 16.7C (61F) set in 1996. Before then, a warm front will lift across southwestern Quebec Wednesday evening and overnight. We can expect some much need showers and even a few scattered thunderstorms. Thursday will be partly sunny, breezy and very warm, with gusty southwest winds pulling in the warmth from the deep southern US. Enjoy Thursday, as the weather will turn stormy into Friday. 

The first of two strong low pressure systems will move across southern Ontario and Quebec on Friday, accompanied by much cooler temperatures, strong winds and heavy rainfall. There may even be some wet snow in some locations. The second storm on Sunday may bring more snow to the region.

SPRING SNOW

I really thought we would end the month quietly, but it appears it may go out like a lion. We have a pair of storms forecast to impact southwestern Quebec starting Friday, along with much colder temperatures. The first system will deliver a steady rain and strong winds Friday, with as much as 35mm of rainfall. The high will drop down to 9C (48F), with overnight lows Saturday morning near the freezing point. Even with the heavy rainfall, I am not expecting any flooding at this time as it has been a very dry month to date. Only 9.8mm of precipitation has fallen at Trudeau Airport. The rain will taper off to a few showers or perhaps even some flurries by Saturday morning. We will have a brief break Saturday afternoon before the second system arrives.

A second potent storm will move across the Great Lakes and close to Montreal late Sunday into Monday. Computer models have been having a difficult time with the exact track of this storm. The European model is even hinting at a decent snowstorm for parts of our region. At this time, I am leaning towards a warmer solution, with mostly rain for the city. We are expecting another 15-20mm of rain, however that may change depending on the actual storm track.

We can expect some wet snow as well at the onset of the precipitation. Parts of southern Quebec, especially north of Montreal, may see a significant wet snow event. Temperatures will be much colder Sunday, with a high of 4C (39F) expected. Overnight lows will likely drop to near the freezing point.

Conditions should begin to improve late Monday, with temperatures closer to normal.

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