Saturday, January 13, 2018

From record warmth to the biggest snowstorm of the season for Montreal

Every now and then Mother Nature puts on a show to remind us who is in charge. The car above lies buried under the overnight snow on L'Ile Perrot. It has been a wild 24 hours, from record heat to the biggest snowstorm of the season here in southern Quebec. (ValleyWeather Photo)
Winter Storm Warning remains in effect for southern Quebec.

The biggest snowstorm of the year is ongoing in southern Quebec this morning, just 24 hours after record warmth. Police are advising against travel on all area highways as heavy snow continues to fall in Montreal. As of 9am, 30cm is on the ground here on L'Ile Perrot, and the snow is still falling. Zero visibility is being observed in many locations. There have been hundreds of accidents reported across eastern Ontario and western Quebec. The biggest wreck occurred near Prescott, Ontario last evening, when several trucks collided spilling chemicals, and shutting down both directions of Highway 401 overnight. The road remains closed this morning, and the OPP is advising you stay home.

The snow started around 8pm Friday evening in Montreal, after what was a remarkably warm day. The temperature reached plus 9.8C (50F) in Montreal, smashing the old record of 5.3C set in 1986. In addition to the warmth, heavy rain created isolated flooding in many locations. Montreal had its wettest January 12 on record as well, with 17mm falling. A powerful arctic front dropped the temperature below freezing within a couple of hours last evening. The current temperature is -13C (9F). The snow is being caused by low pressure riding along the aforementioned front. The heaviest snow is falling along an axis lined up with the St Lawrence Valley and points immediately south of it to the US border. By the time the snow ends early this afternoon, 30 to 40cm will have fallen. Frigid temperatures will arrive behind the snow, with an overnight low of -24C (-11F) by Sunday morning.

Friday, January 12, 2018

Rapid freeze and snowstorm to follow record high in Montreal

A powerful cold front will drop the temperature in Montreal from record values today to brutal cold by Sunday morning. Along with the cold will come heavy snow tonight and Saturday. (AccuWeather.com)
Winter Storm Warning in effect for Montreal.

A major change in the weather will occur today as a powerful arctic front crosses the St. Lawrence Valley during the evening hours. Before then, we have a very warm and moist air mass over southern Quebec Friday morning. In fact several locations have already registered record high temperatures for the date. Saint Anicet reached 14C (56F) in the wee hours this morning, a remarkably warm temperature for January 12, and the warmest in the country. Montreal's Trudeau Airport is at 6.3C (44F), also a record for the date, surpassing the 5.3C set in 1986.

In addition to the mild weather, we have an area of heavy rain about to move into southern Quebec. A decent amount is forecast today, 15-20mm, creating the potential for some flooding. The rain is in advance of a sharp arctic boundary that will chase the warm air back to the south. The front will arrive in Montreal close to the evening commute, changing the rain to freezing rain and sleet. The temperature swing will be rapid and brutal, dropping from 7C (45F) in Montreal, down to -5C (23F) in just a few hours. A flash freeze is expected, with roads rapidly icing late in the day. The freezing rain should change to snow after 8pm in Montreal. Low pressure is forecast to move along the cold front tonight and Saturday, increasing the coverage of snow in Montreal. The snow will be heavy at times, especially Saturday morning. Accumulations of 15-25cm (6-10 inches) are expected. Gusty northwest winds behind the front tonight and Saturday will produce areas of blowing and drifting snow. The temperature will continue to fall on Saturday, down to a low of -22C (-8F) by Sunday morning. That represents nearly a 30 degree drop in temperatures from this morning.

Widespread weather warnings are in effect today from Ontario across Quebec, into Atlantic Canada and south into New England and New York. If you can, postpone any unnecessary travel from Friday evening thought Saturday afternoon.

Wednesday, January 10, 2018

Major winter storm to impact region after brief thaw

Freezing rain warning in effect for Montreal and Ottawa today and tonight.

Frozen in time. A much needed thaw will begin in Montreal on Thursday, but end just as quickly on Friday. A potent storm system arrives for Saturday, with heavy snow expected. (ValleyWeather Photo)
Temperatures are on the rise today as clouds increase across southern Quebec. A warm front will approach the St. Lawrence Valley this afternoon and overnight along with an increase in moisture. Light freezing rain is forecast to start in eastern Ontario late this afternoon, and move into Montreal by the middle of the evening. The precipitation will be light, perhaps 1-4mm, but any freezing rain can be problematic on the roads. As the temperature continues to rise overnight, up and above the freezing point, any frozen precipitation will taper to a few showers. On Thursday, gusty southerly winds will allow for the temperature to climb to near record levels, between 5C (41F) and 10C (50F) in southern Quebec. The record for Montreal is 9.4C set in 1975.

The commute this week in Montreal has been slow and painful at times. The extremely cold weather has been slow to moderate, making roads snow covered and slick. (ValleyWeather Photo)
Major Winter Storm
By Friday, a strong arctic boundary will move across Ontario into southern Quebec by the supper hour, bringing a quick end to our thaw. Expect steady rain to develop in Montreal ahead of the front, along with very mild temperatures to start to the day. As the front moves south of Montreal, the mercury will drop quickly, from a high of 6C (43F), down to -7C (19F) by Saturday morning. Any precipitation will change to freezing rain and eventually snow from west to east. How much of each type of precipitation has yet to be determined, but it will be significant. The front will stall across central New England on Saturday, with deepening low pressure moving along it. Freezing rain and snow will continue all day Saturday, with blowing snow and dropping temperatures. My current thinking is 10 to 20mm of rain will fall on Friday, followed by 15 to 25cm of snow overnight into Saturday. This is subject to change as the track of the low pressure becomes more clear. Due to the nature of this event, amounts could vary significantly by region, depending on your local temperature and how fast the changeover occurs. The mess will freeze solid over the weekend, as temperatures drop back to below normal values. Skies will slowly clear Sunday, with a daytime high of only -12C (10F).

Monday, January 08, 2018

Thaw equals relief from the bitter cold for Montreal

Warmer air is trying to push into Montreal this week. Before then, we can expect a messy mix of snow and perhaps freezing rain. The mild air will be pushed out of the region by Saturday. (ValleyWX Photo)
What a difference a few hours can make in weather forecasting and observations. If you would have asked me just a few days ago if I thought we were going to have a thaw this month, I would have likely said no. Yet here we are, just a couple of days away from a forecast high of 8C (47F) in Montreal. The first phase of this thaw will persist for about 48 hours in Montreal. I expect it will be a difficult transition to above freezing temperatures, as the ground is so cold, along with a very firmly packed snow base.

Before we look at the future, let's just take a quick peak at the recent weekend cold snap. If you thought the weather was brutal Friday and Saturday in Montreal, it was. Strong low pressure moving across Atlantic Canada, relentlessly pushed gusty north winds and biting cold into southern Quebec. At Trudeau Airport, the wind gusted over 50km/h (31 mph) for nearly 42 consecutive hours from January 4th to the 6th. At the same time, plummeting temperatures produced wind chills colder than -30C (-22F) for 53 consecutive hours. The peak wind gust measured was 70km/h, with the coldest windchill -40C. The wind, combined with 10cm of fresh falling and blowing snow, produced visibility under a few kilometres for several days. Near blizzard conditions were observed at times on the flat farmland south of Montreal towards the US border, from early Friday into Saturday morning.

January Thaw
Our much anticipated January thaw will come in two parts, the first this week, and another mild stretch around the 20th. A surge of warm air is arriving today on southwest winds. The initial warm air advection is producing a moderate snowfall of 10 to 15cm in the St. Lawrence Valley. The temperatures will continue to warm this week, rising above the freezing point by Thursday. The milder weather will come with more precipitation, in the form of freezing rain and rain late Wednesday and Thursday. By Friday night, colder air will return, along with a transition from rain to snow in Montreal. Saturday could be quite stormy, as another system approaches from the US southwest. By the weekend, temperatures will fall back to more normal values which are -6C/-15C. If you have travel plans late Friday and Saturday, you will want to play close attention to updated forecasts later this week.

Saturday, January 06, 2018

Wicked Nor'Easter to ease grip - milder air on the way

Frigid cold and blowing snow made travel difficult in southern Quebec on Friday. (ValleyWeather)
The powerful winter storm that made headlines from Florida to Labrador, will slowly begin to ease its grip on southern Quebec today. For over 24 hours, Montreal has experienced winds in excess of 60km/h, combined with bitter cold and light snow. Visibility at times has been close to zero, especially southwest of the city. On Friday, the Surete du Quebec were advising against travel outside the metro area. Roads were snow packed, icy and visibility was poor. Numerous highways were closed after cars and truck hit the ditch. The wind and cold produced dangerous windchill readings in the middle minus 30s. The frigid weather will persist today, with a high of -20C (-4F) and windchill values between -30 and -40C. The good news is that we will see a moderation in temperatures starting Sunday and persisting this week. We may even see high temperatures nudge above the freezing point by Thursday or Friday. Unfortunately the warmer weather will come at a price, with 5-10cm of snow forecast to start the week, and a messy mix to end it. That mixed precipitation may include a prolonged period of freezing rain. However, the devil is in the details, it will depend on the storm track next weekend. This will have to be watched closely. In any event, temperatures are expected to be closer to normal for the second half of January.

Just one of the many power poles and infrastructure under assault in Nova Scotia form the Blizzard of 2018. (Nova Scotia Power Photo)
The Blizzard of 2018
As bad as conditions were in southern Quebec, we were on the far western edge of this powerful storm. The coastlines were hammered with record setting tides and surf. Widespread flooding and major damage was reported along the New England coast on Thursday. Boston Harbor measured a new record high tide, surpassing those of the famous Blizzard of 1978. Flooding and coastal damage was also observed in Nova Scotia. In Nova Scotia, winds were fierce, with a peak gust of 170km/h (105mph) at Grand Etang on Cape Breton Island. The wind, rain and snow cut power to over 140,000 customers according to Nova Scotia Power. In Quebec, heavy snow and blowing snow stretched from the Eastern Townships towards the Gaspe and Lower North Shore. Winds reached over 100km/h in many sections of the lower St Lawrence Valley, closing highways and business. The storm had a tremendous impact on air travel, with over 4000 flights cancelled on Thursday alone across eastern North America. Several airports are still working through the backlog of passengers this weekend. In the deep south, some airports remained closed Friday, covered in a blanket of snow and shivering in record cold.

Major flooding from record setting high tides was reported along the New England coast. (Photo: Duxbury, Massachusetts Fire Department)

Friday, January 05, 2018

The 20th Anniversary of the Ice Storm of 1998



Top: The view from my home in Verdun. Middle: Help would arrive from numerous states and provinces. Finally, over 16,000 Canadian Armed Forces troops would help in the relief efforts. 
January 5th marks the start, here in southern Quebec, of the great ice storm of 1998. Over a one week period, close to 100mm of freezing rain, nearly destroyed the power grid here in Quebec. Widespread damage occurred, along with the deaths of at least 30 people. My complete story can be found here at The Suburban.

Wednesday, January 03, 2018

Powerful coastal storm to brush Montreal - arctic cold returns

Heavy equipment clearing the latest snowfall in Saint Laurent on Wednesday morning. With the recent deep freeze, the mounds of snow are growing rapidly. (ValleyWX)
Happy New Year! The cold air has briefly retreated in southern Quebec, allowing the extreme cold warning to expire, finally. Temperatures "warmed" to -14C (7F) on Tuesday, with 5cm of fresh snow. The snow caused the usual chaos on Montreal highways, with numerous accidents reported.
Montreal will remain on the western edge of a powerful east coast storm. (AccuWeather)
Strong Coastal Storm
Our attention now turns to a rapidly developing low pressure area off the Florida coast. The storm is forecast to deepen into a major Nor'Easter within the next 24 hours, while skirting the Atlantic seaboard. Snow and freezing rain is expected from northern Florida into Atlantic Canada. This morning, snow is falling as far south as Tallahassee, Florida. The ice and snow has caused wide ranging delays to air and ground travel along the entire east coast. Heavy snow is forecast along the Carolina coast into Virginia Beach today. As the storm strengthens on Thursday, heavy snow will overspread coastal New England and Atlantic Canada. In addition to the snow, winds will increase along the path of the storm, gusting in excess of 100km/h at times. Coastal areas from Cape Cod into Nova Scotia can also expect some flooding and beach erosion. Widespread power outages are possible in New England and the Maritimes.

The hardest hit regions can expect up to 40cm (14 inches) of snow. Here in southern Quebec, we will remain on the extreme western edge of the system, with light snow and strong northeast winds developing from east to west Thursday afternoon. If the track of the system remains constant with the forecast models, we can expect 5 to 10cm of snow late Thursday into Friday morning. Across the Eastern Townships and into the Gaspe and far eastern Quebec, 15 to 30cm of snow is likely. Travel will be extremely difficult for anyone going south or east of Montreal on Thursday and Friday.

Fresh Arctic Blast
Behind the storm, a fresh blast of arctic air will surge into the region, along with strong north winds. Temperatures will drop to -18C (0F) during the day Friday, with overnight lows expected by Saturday morning between -25C and -30C (-13C to -22C). Daytime highs on Saturday will be frigid, near -22C (-7F) in Montreal. Combined with the strong winds expected, the windchill will be as cold as -40C. Warnings will be likely. By Sunday, we can expect a warming trend, with a high all the way up to -10C (14F). More snow is on the way for Monday and Tuesday.