Record breaking warmth to start October - much colder weather for Thanksgiving

The weather has been nearly perfect over the last two weeks across the Montreal region, making for a rather unseasonable yet picturesque view at Point-du-Mouilin in Notre-Dame-de-L'Ile Perrot over the weekend. The upcoming week will feature hazy sunshine and record-breaking warmth. We can expect a dramatic change as we head into the upcoming holiday weekend. (ValleyWeather)

It has been an absolutely spectacular stretch of weather to end  September and start October in Montreal. Strong high pressure has been dominating our weather over the last two weeks, with cool nights and warm pleasant days. Winds have been calm for the last several days. The only glitch in the forecast has been some high clouds at times and hazy skies in the upper atmosphere, generated from western wildfires, something we have become all too familiar with in 2023.

The forecast for this week is for much of the same, very warm temperatures and sunshine. Southwest winds will drive temperatures 10 to 15 degrees above normal values, with record highs likely through the middle portion of the week. The high on Tuesday is forecast at 29C (85F), the normal high is only 15C (59F). We should break the the record high for Tuesday of 26.7C (80F) set in 1953. On Wednesday and Thursday, highs will be close to 30C (86F). The record highs for those days are 26.7C (80F) and 26C (79F) respectively, both set in 2005. Overnight lows will be warm as well, in the 13C to 17C (55-63F), well above the normal low for early October of 5C (41F).

One more record will likely fall this week, showing us just how mild 2023 has been. We have not recorded a high temperature below 16C (61F) since May 25, a stretch of 132 days. The record in question was established 136 years ago in 1887, when daytime high temperatures remained above 16C for 133 consecutive days, from May 1st to September 10, 1887. Our current run will likely end during the Thanksgiving long weekend, as a cold front and strong low pressure will finally bring Montreal some rain, along with much cooler temperatures. Until then enjoy the summer-like warmth.

As far as precipitation is concerned, we need some moisture, as it has not rained in Montreal since September 19. The aforementioned high pressure has been deflecting all the significant weather systems around southern Quebec. For the month of September, we managed only 27mm of precipitation, well below the normal value of 83.1mm.

By Friday, some showers are possible, with more significant rainfall on Saturday. High temperatures will fall from the upper 20s into the low teens by Saturday and Sunday.