Wet, windy and warm weather expected for Montreal

Despite the calendar, temperatures are on the rise across most of North America. The last two weeks of December are expected to produce very mild temperatures and very little in the way of snowfall for the Montreal region. A big storm system Monday will bring windy and rainy conditions to most of southern Quebec.

Winter officially arrives on December 21st, but you would not know that by our current weather. As I write, the temperature in Montreal is already 4C (39F) on our way to at least 8C (48F) Friday. The normal high for today's date is -3C (27F). But our weather is anything but normal this fall and winter, and that trend will persist through at least the end of the month.

What does that mean for practical weather?  Well basically we are looking at well-above normal temperatures for most of North America through the holiday period. That starts today, with very strong high pressure anchored in the Atlantic, pumping unseasonably warm air northward.

Meanwhile a strong, almost tropical like system will develop in the Gulf of Mexico today, moving northward over the weekend with abundant moisture. During a typical winter and at this time of year, that track would result in a big snowstorm for parts of the east coast and Quebec. Bit, this is not the case this month. The storm will deepen and move rapidly northward towards New York state and eventually across eastern Quebec. After a mild weekend, we can expect clouds to increase Sunday, ahead of steady soaking rain Sunday night and Monday. This system will be a snow eater, devouring what is left of our snowpack here in the south and significantly reducing it further north. We will have to watch for any potential flooding from the combination of heavy rain and melting snow.

At this time, many parts of our region will likely see at least 25-35mm of rain. Gusty southeast winds may reach 50-70km/h late Sunday. Temperatures will be very warm, approaching 10C (50F) by Monday. A trailing cold front late in the day Monday will bring in marginally cooler air on northwest winds, with any leftover precipitation changing to flurries before ending Tuesday morning. Little accumulation is expected at this time.

The balance of the travel week before Christmas appears to be fair, with seasonable temperatures.