Sunday, February 18, 2018

Flood risk on the rise this week in southern Quebec

Heavy rain, record warmth and melting snow will increase the risk of flooding this week in southern Ontario and Quebec. (AccuWeather.com)
Near record breaking warmth is forecast this week across southern Ontario and Quebec. A large ridge of high pressure located off the southeast US coast, will pump unseasonably warm and humid air northward. A frontal boundary will become established along the northern periphery of the high pressure. Along this boundary, several waves of low pressure are expected to bring significant rainfall through late Wednesday. Conditions in Montreal will start off dry and mild on Monday, with daytime highs approaching 5C (41F). Clouds will thicken late in the day, along with rain developing by evening. Intermittent rain is expected in the St. Lawrence Valley through Wednesday evening, with 20 to 40mm (0.5-1.5 inches) possible. The combination of above freezing temperature, rapid snowmelt and potential ice jams, will increase the risk of flooding across the entire region. Widespread flood watches are in effect south of the border across New York and New England, with a special weather statement covering the flood risk here in southern Quebec.

As far as daytime high temperatures go, Tuesday and Wednesday will be the warmest days of the week, potentially challenging the record highs. We have a decent shot at the record set Tuesday in Montreal, which was 10C (50F) set in 1994. Wednesday and Thursday may be a little more difficult, with the current records dating back to a very warm February in 1981, at 13.9C (56F) and 15C (59F) respectively. The current forecast calls for highs of 8 to 12C (45F to 54F) both days. The overnight lows Monday through Wednesday should remain above freezing as well, near 5C (41F).

A cold front arrives late Wednesday, accompanied by flurries and cooler temperatures.

Wednesday, February 14, 2018

Mild weather returns to Quebec and Ontario

The warmer weather will help melt away some of the ice and snow that has accumulated over the last two weeks. (ValleyWeather)
A pattern change is well underway this week that will see mild weather to end the month of February across eastern North America. Temperatures are forecast to be well above normal values through next week. The only exception should be this Saturday, behind a cold front, when the high will be -7C (19F). Otherwise, look for temperatures at or above freezing. Thursday, a warm front will produce periods of drizzle in Montreal, with a mild high of 6C (43F). Rain is forecast to develop late Thursday along the aforementioned cold front, temperatures will remain above freezing into Friday morning. On Friday, the rain will eventually change to snow before ending. Little accumulation is expected at this time. The temperature will drop all day to overnight lows of -18C (0F) by Saturday morning. The weather this weekend will remain fair and dry.

The cold weather will be very brief in Montreal, with temperatures warming overnight Saturday into Sunday. Sunday through Tuesday, we can expect highs between 0C and 3C (32-38F). Depending on which commuter model output you prefer, the weather for the remainder of next week will either be very warm and wet, or mild with mixed precipitation. The details still need to be fine-tuned, but one thing is certain, the weather will be warmer than the long-term average for late February.

Friday, February 09, 2018

Another round of snow expected in Montreal

A major accident south of Montreal Wednesday, claimed the life of a 70 year old motorist. Excessive speed in very poor road conditions caused this wreck and many more. (CBC Photo)
After the little storm that could crossed the region on Wednesday, February 7, Montreal has now accumulated over 185cm of snow this season. Huge mountains of the white nuisance are everywhere, as municipalities struggle to find new locations to dump it. More is on the way this weekend.

The driver of this transport was very lucky Wednesday evening, surviving a plunge off the Route 342 overpass at Highway 30 in Vaudreuil/ Dorion. (neomedia.com Photo)
Taking a look back at this weeks storm, 15cm fell at Trudeau Airport, with 20cm from L'Ile Perrot across the South Shore towards the US border. In the Eastern Townships, Cowansville measured 35cm. The track of the system actually introduced heavier snow into southern Quebec than previously expected, at least by Environment Canada. The overall amounts in southern Quebec were poorly forecast, and warnings issued very late. The storm generated terrible road conditions. There were numerous major accidents, snarling traffic in the city and especially to the south. Highway 20 was closed in both directions near Mont-Saint-Hilaire after a fatal 50-vehicle pileup. Provincial Police were forced to close both Highway 30 on the South Shore near St Constant, and Highway 10 towards Sherbrooke for lengthy periods. My 45-minute commute home Wednesday evening took 2.5 hours to complete. Highway 40 towards Vaudreuil was blocked for over one hour by multiple collisions, forcing traffic onto alternate routes, clogging them.

After the brief break on Friday, the weather will become unsettled again in Ontario and Quebec. Snow is expected from late Friday evening through Sunday night. The precipitation will not come from one major system, but rather weak impulses of energy riding along a frontal boundary draped just south of Montreal. The snow will be light most of the time, but we are still expecting 10 to 15cm by Sunday evening. There may even be some freezing drizzle sprinkled in for good measure. The temperatures will be rather mild this weekend, around -4C (25F) both Saturday and Sunday, with a low of -8C (18F) both nights.

Tuesday, February 06, 2018

Montreal on northern edge of quick moving winter storm

We are running out of places to pile the snow. A quick moving winter storm will give Montreal another 10 to 15cm of snow on Wednesday.
Southern Quebec and Ontario will be on the northern edge of a winter storm, quickly moving form the lower Mississippi Valley to southern New England on Wednesday. Skies will be partly cloudy overnight in Montreal, with chilly overnight lows of  -13C (9F). Clouds will increase early Wednesday morning, followed by snow, moving from southwest to northeast through the midday. The snow could become heavy at times from Montreal south into New York and Vermont. Precipitation should taper of to a few flurries by midnight. The temperature will be cold throughout the snowfall, with a daytime high near -8C (18F) in Montreal. Total storm accumulations will be in the order of 10cm from Montreal north and west towards the Ottawa Valley. Along and south of the St. Lawrence River, 10 to 15cm is likely from Cornwall towards the south shore of Montreal. Across the Eastern Townships and south into New England and New York, 15-30cm is forecast. Winter storm warnings are in place from Sherbrooke south into the US. In the St Lawrence Valley of New York, a winter weather advisory is in effect. No warnings are in effect at this time for Montreal.

Regardless of the weather warnings, steady snow, along with gusty northeast winds between 20 and 40 km/h, will make travel poor during the afternoon commute in Montreal. Snowfall rates of 2 to 3cm per hour are possible, especially south and east of Montreal. Expect icy, snow covered roads and reduced visibility.

Monday, February 05, 2018

Active weather week ahead - more snow for Montreal

The last remains of yesterday's cloud cover and snow slip south of Montreal early this morning, leaving behind bright sunshine. The temperature fell quickly after skies cleared, along with strong northwest winds and blowing snow. (Valley Weather Photo)
More snow is forecast this week, as an active and unsettled weather pattern remains in place. On Sunday, rather weak low pressure managed to produce 10 to 20cm of fresh snow across portions of eastern Ontario and southern Quebec. In Montreal, 13.2cm of snow fell, bringing the seasonal total to 167cm. This amount already represents 80 percent of the normal snowfall for the entire season (209.5cm). The city of Montreal will start removing the snow from borough streets tonight, the sixth cleanup this season. The municipality had budgeted for five. We still have the thick of the snowfall season to go, as most of Montreal's historically big snowstorms have occurred in February and especially March.

We will start adding to this total as early as Wednesday. A developing storm system will move along the edge of our current arctic airmass, passing across Pennsylvania and extreme southern New England. A broad area of snow will occur north and west of the storm track from southern New England into Southern Quebec by Wednesday afternoon. Montreal will likely remain on the northern edge of this storm, with 10 to 15cm likely for the city. As you head south and east, amounts will increase to between 15 and 25cm from the Eastern Townships into northern Vermont and New York. A winter storm watch has been posted for a wide swath of New England and the Northeast US. Weather warnings may be required for a portion of southern Quebec as well.

The temperature will be cold with the storm, likely remaining in the -10C (14F) range on Wednesday across southern Quebec.  Expect the steadiest snow in Montreal between noon and midnight. Skies should slowly clear by Thursday morning. By the weekend, another area of low pressure will bring more snow to Ontario and Quebec. This system bears watching at this time.

Friday, February 02, 2018

The Blizzard of ‘78 - still the benchmark storm after 40 years

A National Guard troop inspects a storm ravaged car in coastal Massachusetts in February 1978. (AP)
Every city has a meteorological benchmark that helps establish where current and future winter storms sit in history. For Montreal, it has always been the Blizzard of ‘71 for snowstorms. While other storms have come close, none have equaled March 3 to 5, 1971.

For Boston and southern coastal New England, that benchmark storm is February 5 to 7, 1978. The ‘70s had some historically wicked winter storms, including one that swept across Indiana, Ohio, Michigan and southwest Ontario in January 1978. That storm established new records for lowest barometric pressure for a landlocked storm. However, just one week later, Mother Nature unleashed an even bigger storm on the US. The blizzard of ‘78 started innocently enough in Boston on the morning of February 6, 1978, as low pressure slowly developed east of Virginia in the Atlantic Ocean. The system would have been just another Nor¹Easter had it not been slowed by strong arctic high pressure over eastern Canada. The high pressure resulted in the storm becoming nearly stationary for over 36 hours east of Cape Cod.

Thousands of cars were abandoned for days. This is US Route 128 in Needham, Massachusetts.
The snow started very lightly early Monday morning, luring most residents of Boston into a false sense of relief. As a result, schools and businesses remained open despite the predictions for heavier snow. By the time businesses and schools were let out in the early afternoon, the storm was a full-fledged blizzard. Thousands of motorists were sent out into the teeth of the storm, quickly becoming trapped on snow-clogged area highways. Many were rescued by cross country skiers and snowmobiles, others remained in their cars for days. It took the authorities, including National Guard troops, nearly a week to clear the roads of abandoned cars. The snow and wind had a tremendous economic impact, closing down the region for over a week. The death toll from the storm was 100, fourteen of which occurred from motorists trapped in their cars. As the system inched its way along the coast, wave after wave of heavy snow fell across southeast Massachusetts, Rhode Island and Connecticut. Boston and its suburbs were the hardest hit, along with coastal New Hampshire. A record 27 inches (69cm) of snow fell on Boston, with 27.6 inches in Providence.

Total dedication! (Boston Herald Photo)
The most devastating impact of the storm was from the powerful hurricane force winds that accompanied the blizzard. The wind not only created zero visibility, but also pounded the coast with a relentless storm surge. Successive high tides created widespread destruction along the New England coast. Over 11,000 homes were damaged or destroyed during the storm. A peak wind gust of 100mph (160km/h) was observed on Plum Island, Massachusetts. Coastal flooding also occurred in New Hampshire and Maine. The final tally surpassed $500 million in damages from the Blizzard of '78.

On a side-note, the power of the storm was felt as far as Montreal. On February 6, 1978, Montreal measured winds of 76km/h, accompanied by 7cm of snow.

Tuesday, January 30, 2018

Once in a blue moon...

Time-lapse image of a total lunar eclipse and "blood" moon 
(Photo Fred Espenak - NASA.com)
Once-in-a-blue-moon is a non-astronomical term referring to the presence of two full moons within a single month. Oddly enough, this phenomena is not that rare, occurring on average every 2.5 years. As a matter of fact, we will see two blue moons this year, Wednesday morning and again in March.

The thing that makes this particular blue moon special is the celestial trifecta accompanying it early Wednesday morning. The full Wolf moon will be in Perigee, the moons closest approach to the earth. This makes it appear as a super moon, up to 14 percent larger, and 30 percent brighter by some estimates. There will also be a full lunar eclipse occurring, as the moon enters the shadow of the earth, essentially cutting off the sunlight that reflects off the moon. This will create a rusty orange appearance, or blood moon. In a nutshell: a super moon blood moon and lunar eclipse all at once.  This is truly a are event, happening the last time on March 31, 1866.

Here in Montreal, there is a very small window of opportunity for viewing this event. We will only experience a partial eclipse, as the moon will set before totality occurs. You will have to be awake in the pre-dawn hours, watching the western horizon for this spectacular show. The eclipse will start at 6:48AM EST, with moonset in Montreal occurring at 7:17am. Thankfully the weather will be clear, crisp and cold, perfect for viewing. Enjoy, and as always, be safe!