Enjoy the mild weather, winter set to return

Toronto quarterback Ricky Ray, shown above, along with his teammates, the Calgary Stampeders and fans, battled steady snow Sunday night during the 105th Grey Cup in Ottawa. (TSN)

Despite the quick 5cm of snow that fell on the 105th Grey Cup Sunday in Ottawa, and across southern Quebec, it has been a mild week once again. In keeping with the last blog entry, the temperature roller coaster ride continues. There was no better example of this than the snow and biting cold Sunday and early Monday, followed by windy and warm weather Tuesday. On Tuesday, Toronto reached 17.1C (63F), Ottawa 11C (52F), remarkably after an early morning low of -13.7C (8F), and Montreal 6C (43F), after a low of -11.7C (10F). A series of weak weather systems will keep the temperature bouncing around through the first week of December. Expect the weather to remain fairly mundane in Montreal, with more clouds than sun and temperatures well above normal.

Cold weather is forecast to return to eastern Canada by December 10th. (AccuWeather)

Cold Weather Returns
There are strong indications that we will see a major pattern change by December 10th or so. Expect much colder air to return, and last through Christmas, along with frequent opportunities for measurable snow. The jet stream is expected to become more amplified, allowing storms to move slower, gain strength and gather moisture from the Gulf of Mexico and Atlantic Ocean. The exact details are hard to pinpoint at this time, but temperatures will return to normal levels and eventually below normal in Montreal. This would put daytime highs well below freezing. There is a good chance of a snowstorm around the 11th of December and again near Christmas. The cold weather is expected to stay with us right through the end of December.

Weather whiplash in southern Quebec

The first snow of the season in Vaudreuil last weekend, did not last long, as warm air returned by mid-week. (ValleyWX)

After a record breaking warm October in Ontario and Quebec, November is proving to be anything but certain. If you are not sure which jacket to grab in the morning, you are not alone. The change in temperature from day to day is enough to give you whiplash. With a predominate west to east "zonal" flow in place across Canada, weather systems have been moving rather quickly, producing highly variable weather. On Sunday, November 19, Montreal recorded the first measurable snowfall of the season, with anywhere from 2-5cm falling. Monday was windy and bitter cold, with snow flurries and temperatures at -6C (21F), windchill values were as cold as -18C (0F) However, just 24 hours later the temperature was 8C (48F), with bright sunshine. This pretty much describes the month we have had in Montreal, from mid-winter cold, to near record-breaking warmth and back again, at times in just a few hours.

That brings us to this weekend, where pretty much the same pattern is in place. The current weather is being produced by a potent cold front slipping across the St. Lawrence Valley. A steady rain in Montreal, will slowly taper to a few flurries tonight. Gusty west winds will increase up to 50km/h this evening. Temperatures in southern Quebec today are in the 5 to 10C (40 to 50F) range. Behind the front, cold air will surge into the region, with lows down to -4C (26F) by Sunday morning. Sunday will be windy and cold, with flurries and temperatures remaining steady. Yet another clipper system will arrive late Sunday into Monday, with some light snow and chilly temperatures. However, the cold will not last long. By Tuesday, more mild air will surge into the region, with temperatures well above normal expected for most of the upcoming week. As long as this flat, zonal pattern remains in place, the arctic air will remain trapped across the far north, with any storm systems being rather weak and moisture starved. I expect a change by the second week of December.

Freezing rain warning for southern Quebec

Freezing rain warnings are in place for southern Quebec this afternoon and tonight.

Strengthening low pressure will rapidly move from the central plains into the Great Lakes tonight, and down the St. Lawrence Valley on Sunday. Waves of precipitation are expected over the next 24 to 36 hours from southern Ontario into Quebec. Along the path of the storm, mixed precipitation is forecast. North and west of the system, snow will be the dominate precipitation, with as much as 25cm expected in the Laurentians and upper Ottawa Valley. South of the track towards the US border and in the Townships, look for mostly rain.

Freezing Rain Warning
Environment Canada has a wide range of warnings in effect for this afternoon and especially overnight. In Montreal, a freezing rain warning has been posted. A mix of snow and rain this afternoon, will transition to rain tonight as the temperature rises from -2C (28F) up to 4C (39F) by morning. Expect between 2-4mm of ice in Montreal. North of the city and in Ottawa, the freezing rain will last longer, with as much as 15mm possible. In Ottawa, the rain will change back to snow overnight, with as much as 10cm before it ends on Sunday. As the storm moves east of Montreal on Sunday, a strong cold front will sweep the region. Cold air will surge back into Ontario and southern Quebec, with any mixed precipitation changing back to all snow and ending in the afternoon. A couple of centimeters of snow are possible in the St. Lawrence Valley Sunday. Temperatures will fall back below freezing by noon on Sunday. Strong winds will also develop on Sunday, gusting up to 60km/h across the entire area. Travel will be highly variable and quite dangerous at times this weekend. Expect icy patches in the city. North and west of Montreal, conditions will quickly deteriorate, with lowering visibility and snow covered roads. The weather will improve on Monday.

Strong weekend storm to bring rain and snow to Quebec

Cold air will follow the weekend storm into eastern Canada and the US. Expect temperatures to be well below normal, along with lake effect snow and snowshowers. (AccuWeather.com)

A strong fall storm is forecast to develop over the Midwest US on Friday, moving across the Great Lakes and eventually down the St. Lawrence Valley this weekend. The strengthening storm is expected to bring a messy mix of rain and snow to eastern Ontario and southern Quebec. Precipitation is expected to start Saturday in Montreal, in the form of wet snow, likely mixing with and changing to rain in the city. A heavy wet snow mixed at times with freezing rain is forecast at this time north of Montreal into the lower Laurentians, as well as in the Ottawa Valley.

As much as 20cm of snow is possible north of Montreal. At this time, the forecast track of the storm is not set in stone. A change of a few kilometres will mean the difference between snow or rain for several locations. Temperatures will be cold on Friday in Montreal, warming slightly Saturday to above freezing, before cooling off Sunday. Strong winds and dropping temperatures are expected in the wake of the storm on Sunday. Winds are expected to be above 50km/h Sunday. The temperature will remain below normal next week along with the chance for some light snow or flurries.

Record cold weekend - can the snow be far behind

The first cold air of the season blasted into southern Quebec last weekend. Some locations in Quebec and Ontario recorded their first measurable snow as well. Montreal only had a trace, but more is on the way, soon.  

Temperatures across southern Quebec are slowly moderating to start the work week, after record cold Friday and Saturday. Friday was an absolute shock to the system, as a record low temperature of -8.9C (16F) in Montreal, combined with howling winds over 50km/h, to produce mid-January like windchill values. After the warm fall we have had, it was a wake up call. More cold occurred Saturday, with a record low of -9.7C (14.5F), the old record low was -8.3C (17F) set in 1973. Those temperatures were at Trudeau Airport on the island, it was much colder in the suburbs. On Saturday, the mercury remained below freezing all day with a high of -1.3C. Thankfully the wind slowly diminished for Remembrance Day services. Some snow accompanied the cold air, with a trace to 1cm in Montreal. There were some icy spots on Friday, but roads were mostly clear in the city. The cold and threat of snow had motorists scrambling to get their winter tires on. The deadline in Quebec is December 15, but that is laughable at best. Trust me when I tell you, we will have significant snow before then, guaranteed.

Saturday was beautiful, but cold. The chilly St Lawrence Seaway looking south into New York State at  Johnstown, Ontario. (ValleyWX)

First Measurable Snow

With the arrival of the first arctic air of the season, and the ground now partially frozen, the first measurable snow can't be too far behind. A clipper-type low will arrive late Wednesday into Thursday, with a light rain and snow mix. Any accumulations will be confined to the higher elevations and points north of Montreal. Behind this weak system, cooler air will filter back into the region for Friday. By next weekend, a much stronger storm will approach from the southwest, once again look for a mix changing to a cold rain in Montreal. This storm has the potential to produce measurable snow in some locations, along with gusty winds. By Sunday, cooler air returns, with any precipitation changing back to flurries. At this time, next week looks colder than normal, with the chance for more snow by mid-week.

First arctic blast of the season for southern Quebec

A strong arctic cold front will precede the coldest air of the season in southern Quebec. Some light snow and a rapid freeze is expected late Thursday night in Montreal. (AccuWeather.com)

The first shot of polar air this fall season is forecast to invade southern Quebec late Thursday and Friday. Expect gusty winds, some snow and ice and a hard freeze by Friday morning. Arctic air has taken up residence in western Canada, with temperatures in the minus teens. A portion of the same airmass will arrive behind a potent cold front late Thursday. The front should cross southern Quebec shortly after midnight early Friday morning. Temperatures will rise to around 8C (48F) on Thursday, along with an increase in clouds. 

Frigid Friday

The arctic boundary that will cross the Great Lakes and southern Quebec late Thursday, will be accompanied by gusty winds and periods of rain changing to our first snow of the season. In Montreal a dusting to 1cm may fall, along with plummeting temperatures. Some higher elevations of Quebec and New England can expect as much as 5cm. Locations near the Great Lakes and across northwest Quebec may receive even heavier amounts. By Friday morning, the temperature in the city will be at a bone-chilling -11C (12F). This will come as quite the shock to the system after the extremely warm fall we have experienced. Friday will be windy and frigid, with high temperatures no better than -5C (23F). Gusty winds in excess of 50km/h will produce windchill readings near -18C (0F). Temperatures will moderate closer to normal levels as we head into the weekend. Saturday looks sunny at this time, with perhaps a few flurries or showers on Sunday. The average high/low for this time of year in Montreal should be plus 7C (45F) and -1C (30F) respectively.

Canada’s new weather supercomputers will improve forecasts and warnings

I had the absolute privilege of meeting the current President of the World Meteorological Organization and Assistant Deputy Minister for the Meteorological Service of Canada, David Grimes, in Dorval on Thursday. (Photo: Robert Frank)

Canada has moved to the forefront of weather computer modeling with the delivery of two High Performance Computers (HPC) from Shared Services Canada (SSC) and IBM. These high-performance computers were officially dedicated at a service at the Canadian Meteorological Centre in Dorval on Thursday, November 2. Minister of Public Service and Procurement, Carla Qualtrough was on hand for the unveiling. But, as a weather nerd, it was Assistant Deputy Minister for the Meteorological Service of Canada and current President of the World Meteorological Organization, David Grimes, who caught my attention. It was an absolute honour to talk to him about the new computers and weather in general. A video presentation of last weekend’s intense storm, as displayed by the new supercomputer modeling output, was beyond impressive. According to Grimes, these computers will make Canada, “one of the best modeling centers in the world”. “Our early-warning system has been greatly enhanced,” he added. The new HPC solution is the fastest recorded computer platform within the Government of Canada, and among the fastest in the world. 

The super computers will allow for complex weather programs and models, involving over 10 billion data points, to be processed much quicker. The end result for Canadians will be more accurate and timely forecasts and warnings. What was exciting for me to discover was that my Davis Vantage Vu weather station, in my backyard on L’Ile Perrot, is likely one of those data points. Information is pumped into these computers from all around the country and the world. Weather knows no boundaries. If you are processing weather data and uploading it to the web, it will likely be used in one calculation or another.

Computer weather modeling has become crucial in recent years.  It allows forecasters to input current weather data, along with additional information, variables and parameters, to basically map out how weather systems will move in both the short and long-term. According to Grimes, a typical model run can take around seven hours, but that will gradually be reduced over the next decade, down to almost real time within ten years.

The HPC is five times faster than the old Environment and Climate Change Canada (ECCC) computers, processing data at an astonishing 2.444 trillion calculations per second. The HPC is primarily for ECCC weather predictions, but additional organizations will also benefit from this resource. Health Canada for air quality alerts, Fisheries and Oceans Canada to support ocean modeling and Public Safety Canada to support environmental emergency prevention – just to name a few. Today’s new supercomputers are 70 million times faster than Environment Canada’s first supercomputer purchased in 1974.

The new ECCC supercomputers were dedicated to; Kenneth Hare above, and Harriet Brooks below.
(ECCC Photo)

The new supercomputers were named for two late distinguished Canadian scientists: Harriet Brooks, Canada’s first female nuclear physicist, who worked with Marie Curie and contributed to research on radon gas, and Kenneth Hare, Canadian environmental science advocate, who warned about carbon-driven climate change long before many others were paying attention.