Wednesday, August 30, 2017

Goodbye summer 2017

Summer is disappearing quickly, with the first hint of colour appearing in the trees on L'Ile Perrot this week. (Valley Weather Photo)
September is upon us, the start of meteorological fall. As I have mentioned before, forecasters like things neat and tidy, so they divide the seasons into 4 equal portions. Fall does not officially start until September 22nd, but the days are getting longer and the nights noticeably cooler.

Time to take a brief look back at what seemed like a very short summer. Montreal came off a cloudy, cool and wet spring, and that trend seemed to last well into July. As far as heat goes, there was none, only one lonely day above 30C, June 18 at 32.1C (90F). This would be the warmest day of meteorological summer. Montreal usually averages 8 or 9 days above 30C. Overall temperatures averaged close to normal for the three months, 18.7C in June, 20.8C in July, and 20.3C in August. Nothing spectacular, just normal, the cooler days being offset by warmer nights. Our average daytime high for summer 2017 (June through August), was 24.7C (76F). The normal long-term average is 25.1C (77F).

Rainfall was a little different, somewhat exceptional at times, especially for the first half of the summer, when it seemed to rain every second day. June measured 135.2 mm of rain, well above the normal of 87mm. July was wet as well, with 125.4mm, the normal is 89.3mm. The atmosphere dried out a touch in August, with 76mm, the normal is 94.1mm. The dry August has been helped along by the first stretch of dry weather this summer, no rain from the 23rd to the 29th. As far as thunderstorm activity goes, they were few and far between, but when they did occur, they were big. Most notable was the storm on July 31st in St Laurent, that caused flooding and power outages and of course the powerful microburst in NDG on August 22nd. Damage from that storm was significant.

Fall Outlook
At this time, the fall looks warmer and dryer than normal. We are not expecting extremely hot weather, but rather temperatures a degree or two above the long-term average. Rainfall is expected to be near normal, however there is always the risk of a wayward tropical system brushing our region with heavy rain. This historically happens more often than you think. As we enter September, the loss of additional daylight will start the process of the trees changing colour and eventually dropping their leaves. This process will be accelerated by any sub-freezing nights we have. Keep in mind, the average first frost for metro Montreal is October 12, earlier in the outlying suburbs.

Tuesday, August 29, 2017

Historic flooding swamps southeast Texas

My brother-in-law has family in Houston and sent me this photo of major flooding in the northwest suburbs. (Photo Steve Bussiere)
Tropical storm Harvey continues to meander just off the upper Texas coast, sending torrents of rain into metro Houston. Rainfall amounts have reached epic levels, with over 42 inches (1070 mm) at the Houston National Weather Service office since Friday night. That amount of rainfall is well over the normal annual rainfall in Montreal of 785 mm. Look around your neighbourhood and imagine the water at, and even above the roof tops. Rainfall totals will exceed the Texas state record of 48 inches by the time this storm moves away.

This event has entered a territory never seen in modern times in North America. The result of the rain has been catastrophic flooding across southeast Texas. Thousands of water rescues have taken place, and the effort is ongoing. First responders are being joined by 12,000 Texas National Guard troops, as well as numerous Federal assets. Sadly the death toll has reached 7, and is expected to climb. Tens of thousands remain trapped in their homes. Houston is the fourth largest metropolitan area in the US, home to over 4 million residents.

This morning, tropical storm Harvey is located 145 miles south southwest of Port Arthur, Texas, drifting east at 3 mph. The system continues to pump copious amounts of tropical moisture inland over southwest Louisiana and southeast Texas. Forecasters expect another 1 to 2 feet of rain over the region before Harvey finally moves off towards the northeast on Thursday.

As of Tuesday morning, numerous rivers, lakes and reservoirs are rapidly exceeding record flood stage levels with the flood emergency worsening by the hour.

Major flooding is occurring across southeast Texas from tropical storm Harvey. (KHOU)

Sunday, August 27, 2017

Catastrophic flooding across southeast Texas from Harvey

Severe flooding is occurring in Houston, where over 20 inches of rain has fallen from hurricane Harvey. (KHOU) 
What was hurricane Harvey, now a tropical storm, continues to impact southeast Texas late Sunday. The center of Harvey is spinning slowly southeast towards the Gulf of Mexico, while drawing copious amounts of tropical moisture inland. The hardest hit region continues to be the Houston/Galveston metro area, where a flash flood emergency has been declared. Some locations have reported over 20 inches (500 mm) of rain since Friday night. Dayton, Texas leads the way with 27.45 inches (658 mm). The result has been devastating, unprecedented flooding. Both airports in Houston are closed. Thousands of water rescues have taken place since last evening, by both local authorities and the US Coast Guard. Resources continue to pour into the region to help the overwhelmed local authorities. Most highways bisecting Houston are under water at this time, with travel prohibited. So far at least one hospital, the studios of KHOU TV, and several prisons have been evacuated.

Harvey, located 25 miles northwest of Victoria, Texas, is expected to drift into the northern Gulf of Mexico this week, before moving slowly back into east Texas. Heavy rain, perhaps another 20 inches is expected before the storm leaves the area by next Thursday. Catastrophic flooding is forecast to continue, with most rivers and bayous exceeding record flood stage. The record for the most rainfall in Texas is 48 inches (1219 mm) at Medina in August 1978. This record may be challenged with Harvey, with heavy rain forecast through the upcoming week.

Further down the coast, the clean-up is underway in Rockport and Port Aransas, where widespread severe damage occurred on Friday, August 24. Numerous buildings were completely destroyed by Harvey's 130 mph winds and 12 foot storm surge. So far two fatalities and approximately 100 injuries have been reported.

Severe damage occurred in Rockport, Texas, when Harvey made landfall Friday, August 25. (TWC)

Saturday, August 26, 2017

Powerful hurricane Harvey slams Texas coast

A spectacular satellite image showing the eye of hurricane Harvey just prior to landfall Friday night, on San Jose Island, Texas. (NOAA)
A strengthening hurricane Harvey made landfall at around 10pm CDT Friday, August 25, along the Texas Gulf Coast near San Jose Island, north of Port Aransas. Harvey had developed into a major hurricane in the last few hours before landfall Friday, reaching category 4 status with winds of 130 mph. Harvey was the first major hurricane in over a decade to hit the US, the last being Charley in 2004. Harvey managed to go from near death, to a major category 4 storm, in less than 72 hours over the warm Gulf waters. As daylight breaks along the central Texas coast, a better view of the storms impact is coming into focus. There is widespread damage reported, especially on Port Aransas, Port O'Connor and Rockport. Buildings have collapse and injuries are reported. Debris is scattered everywhere, with power out to over 200,000 homes, and that number is growing by the hour. A peak wind of 132 mph was observed at Port Aransas.

Wind damage in Matagorda County, Texas on Friday afternoon.
This morning, Harvey remains a powerful category 2 storm, located 30 miles south of Victoria, Texas. The storm is meandering northwest at 6 mph.  Harvey is forecast to transition into a major, catastrophic rain event, with over 20 inches forecast for most of southern and coastal Texas, including Houston. Victoria, Texas has already measured 16.43 inches (417mm) of rain in just the last 24 hours. Forecast estimates for Victoria run as high as 50 inches (1270mm) for the duration of the storm. This amount of rainfall from a single event is unheard of, with widespread flooding anticipated. To put this into perspective, Montreal receives an average annual rainfall of 785mm (31 inches) for the entire year.

The forecast track for Harvey over the next few days has the storm weakening slowly over land, while moving into east Texas and southwest Louisiana. In addition to the flooding, scattered tornadoes continue to affect east Texas. The tornado risk will persist throughout Saturday.

Friday, August 25, 2017

Extremely dangerous hurricane Harvey set to inundate Texas

The eye of Harvey has become visible Friday morning, as the dangerous storm spins just 80 miles off the coast of Texas. Corpus Chrisite appears to the point of landfall at this time. (NOAA)
Hurricane Harvey is poised to become the first major hurricane, category 3 or higher, to strike the US coast since Wilma in 2005. Harvey, left for dead along the Yucatan coast just a few days ago, has now become an extremely dangerous system. As of 11am Friday morning, Harvey is located about 80 miles southeast of Corpus Chrisite, Texas, with 110 mph (175 km/h) winds. Harvey is moving towards the northwest at 10 mph (17 km/h). Heavy rain and thunderstorms are already impacting portions of the warned area along the central and southern Texas coast. Winds and waves will continue increase as the day wears on, with the worst conditions arriving with the eye of Harvey late this evening. A storm surge of 6 to 12 feet is expected along the immediate coastal area, as Harvey makes landfall by midnight tonight. Evacuations and preparations are being rushed to completion at this hour.

Historical Rainfall Forecast
Wind is only one component of this dangerous storm, water will be the big story. Harvey is forecast to meander around southern and eastern Texas for the next 3 to 4 days, with torrential rainfall. Unbelievable rain estimates of 15 to 25 inches (300 to 600mm) are being forecast with up to 35 inches locally. This amount of rainfall will certainly lead to catastrophic inland and fresh water flooding. Emergency officials are preparing for widespread flash flooding across all of Texas and into Arkansas and Louisiana. Water temperatures in the Gulf of Mexico are in the upper 80s, with plenty of moisture and energy available to fuel this storm.

Midday Friday radar from Corpus Christie, Texas, shows the eye of Hurricane Harvey less than 80 miles from the Texas Gulf Coast.

Thursday, August 24, 2017

What caused all the damage in N.D.G.?

Power poles were snapped in half in the Montreal borough of N.D.G. after severe thunderstorms on Tuesday, August 22. (Hydro Quebec Photo)

The strong thunderstorm that rolled across the island of Montreal late in the afternoon of Tuesday, August 22nd, downed hundreds of trees and snapped hydro poles in half like toothpicks. Most of the damage was centered around the Montreal borough of N.D.G. Thousands were left without power, with widespread damage to cars and buildings. As mentioned on this blog early Tuesday morning, all the ingredients were coming together for a particularly potent afternoon of thunderstorms activity. Mother Nature did not disappoint.

So what caused all the damage? According to Environment Canada, it was a microburst generated by a severe thunderstorm cell as it swept east-northeast across the city. Thunderstorms by nature are extremely complex entities, with rising and sinking air, as well as tremendous temperature variations from the upper atmosphere to ground level. The National Weather Service definition of a microburst is that cold air from within the storm descends from the middle and upper levels of the atmosphere, often from several thousand feet high. As the cold air reaches the surface of the earth, it rolls out rapidly, usually in the same direction the storm is moving. As the air rolls out, it is rapidly compressed causing the wind speed to increase dramatically. The wind can be enhanced by local geography, topography and buildings. Microbursts are small scale weather phenomena, typically affecting an area only a few square kilometres in direct proximity to the parent storm. This was quite evident in N.D.G., with most of the major damage confined to a small area.

Winds within a microburst can often reach 100km/h or more and in extreme cases, as high as 240km/h. Microbursts are much more common than tornadoes, and responsible for most of the damage generated by thunderstorms here in Canada. In the case of the N.D.G storm, winds were estimated of at least 100mk/h. When examining the damage from N.D.G., it becomes immediately apparent this was caused by a microburst and not a tornado. In a microburst, all wind flows out, with debris lying in straight lines parallel to the outward winds. In a tornado, the wind flows inward, with debris lying helter skelter at all angles.

EF-1 Tornado
In addition to the storms in the Montreal region, Environment Canada has confirmed that an EF-1 tornado, with winds up to 175km/h, touched down in Lachute at 6:10pm Tuesday, August 22. The tornado tore up trees and damaged over 350 homes. Some of the structures had their roofs torn off resulting in 40 people being evacuated.

Tuesday, August 22, 2017

Thousands without power after strong thunderstorms sweep Montreal

Sherbrooke Street West in N.D.G after strong afternoon thunderstorms. (Photo via Twitter @EffieInMtl)
Lines of strong thunderstorms have been impacting southern Ontario and Quebec on Tuesday. Severe thunderstorms watches remain in effect along with scattered warnings. Even a tornado watch was posted for Eastern Ontario and upstate New York.

As of 5:15PM, nearly 100,000 Quebec homes were in the dark, including 58,000 in Montreal. The N.D.G. neighborhood of Montreal was impacted with strong straight line winds that tore down hundreds of trees, some onto homes and cars. Damage is widespread. Crews are on the scene starting what will likely be a lengthy clean-up. A peak wind gust of 81km/h was recorded at Trudeau Airport. Looking at the damage in N.D.G., the wind appeared to be much stronger there.  Heavy rain also accompanied the fast moving storms.

More tree damage in N.D.G. (Photo via Twitter @DJVminD)

Elevated risk of severe thunderstorms today

A severe thunderstorm watch is in effect for southern Quebec today.
Environment Canada has issued a severe thunderstorm watch for southern Quebec already today. A cold front will slice into a very warm, humid and unstable air mass, located here in the St. Lawrence Valley. The ingredients are coming together for a severe weather outbreak across eastern Ontario into Quebec. The storms are already beginning to fire up in the Ottawa Valley this morning, and will increase in aerial coverage this afternoon.

Any storms that do develop, will have the potential to produce very strong winds, torrential rain, hail and even isolated tornadoes. Warnings will be issued when storms are threatening an exact location. The watch is just a general indicator of the risk for any one region. If outdoors today, seek shelter immediately when threatening weather and especially lightning approach. Listen for warnings, which may be issued at anytime today. High temperatures will be near 30C (86F) today, cooling off after the frontal passage.

Monday, August 21, 2017

Eclipse Day weather for Montreal

Monday, August 21, 2017, Eclipse Day in North America.
Today is the day millions of sky gazers have been waiting for, Eclipse Day 2017. The Great American Eclipse as it has been dubbed, will move at more than 2400 km/h (1500 mph) from coast to coast, the first to do so since 1918. The eclipse will begin at 10:15 AM Pacific time in Newport, Oregon, moving rapidly across the US over the span of 1 hour and 33 minutes, and sliding into the Atlantic near McClellenville, South Carolina at 2:49 PM ET. Outside of the 70 mile wide path of totality, the rest of the US and southern Canada will be treated to a partial eclipse.

Here in Montreal, we can expect close to 60 percent of the sun to be shadowed by the passing moon. The eclipse will begin at 1:21 PM, reaching peak at 2:38 PM and ending at 3:20 PM. The forecast for today is perfect. Sunrise was at 6:02 this morning, with some high cirrus clouds present. The sky should be mostly clear today, perhaps a few wispy clouds, it will be warm and humid, with high temperatures close to 30C (86F).

Remember, damage to your eyes can occur in seconds, avoid looking directly into the sun without proper eclipse eye wear. Standard sun glasses will not protect your eyes from damage. For a safe alternative, the event will be streamed online by various news outlets as well as NASA. I plan on paying close attention to the weather during the eclipse for any notable changes, as well as the surrounding landscape. Enjoy and be safe!

Friday, August 18, 2017

Clear skies forecast for partial eclipse in Montreal

Nearly 60 percent of the surface of the sun over Montreal will be covered by the moon on Monday, August 21 at 2:38pm. (Photo:
As the final countdown draws close for the start of the total eclipse on Monday, August 21, attention will be focused on the all important weather forecast. Millions of people around the US and Canada will be eager for clear skies to view, what is for many, a once in a lifetime event. The narrow path of totality, spanning only 70 miles (113km) wide, will be the main focus for viewing on Monday. But interest is high, even here in Montreal, where approximately 60 percent of the sun will be covered by the shadow of the passing moon. The eclipse will begin at 1:21 pm in Montreal, peaking at 2:38pm and ending at 3:12pm. The eclipse will be traveling across North America at approximately 1700 mph (2735 km/h), so pay attention! Totality, or in the case of Montreal the peak period, will only last for 2 to 3 minutes at any given location.

Partial eclipse of the sun; if skies remain clear on Monday, Montreal will be in for a rare celestial treat.
In a summer that has had more clouds than sun, there was a good bet that Monday's weather would impede viewing in Montreal. At the moment, that does not appear to be the case. Sunshine and warm temperatures are expected for southern Quebec. Some clouds are possible, especially along the US border and in eastern Ontario, but at worst, the skies would be partly cloudy. The best viewing weather is expected to be across western regions of the continent, with clear skies forecast across southern Albert and British Columbia south into the Pacific Northwest and the northern Rockies. As the eclipse travels southeast across the US, more clouds, along with showers and thunderstorms are possible from the Midwest into the Southeast. Other regions from the Great Lakes into the Northeast have a 50/50 chance of full on clouds or clear skies. It will likely be a daytime decision as to where some will choose to settle in and view this spectacular event. One guaranteed location for clear, safe and extensive viewing, will be online at the NASA website. Live steaming will occur at Eclipse Live. NASA will draw on the resources of 11 spacecraft, at least three aircraft, more than 50 high-altitude balloons and the astronauts aboard the International Space Station.

Wednesday, August 16, 2017

The tropics are heating up

Hurricane Gert is located in the open waters of the Atlantic, while three other areas of disturbed weather are being closely monitored for development. (Weather Nation)
Hurricane Gert is churning northeast through the Atlantic Ocean this morning, 765km south of Yarmouth, Nova Scotia. Gert is the second hurricane of the 2017 season, and the earliest G named storm dating back to the 2005 season. Gert is forecast to remain well offshore along the east coast, however large swells are being generated by the storm. Wave heights along the Nova Scotia coast are expected to be as high as 2 metres through Thursday. On the south coast of Newfoundland, the waves may reach up to 4 metres and 5 metres in the Grand Banks.

As we head into the thick of the Atlantic hurricane season, the tropics are heating up. No less than three areas of disturbed weather in the far eastern Atlantic Ocean have the potential to become tropical systems. A tropical storm is named when winds reach 39mph. The storm is officially a hurricane at 74mph. Forecasters at the National Hurricane Centre in Miami will be closely monitoring the systems for potential development and to evaluate the risk to the Caribbean and eastern seaboard.

Eclipse Weather
Monday, August 21st will be an historic day, as a full solar eclipse takes place across portions of the United States. Here in Montreal, 60 to 70 percent of the sun will be blocked by the passage of the moon, reaching a peak at 2:38pm. At this time, the weather looks perfect for viewing in Montreal and southern Quebec. High pressure will be in control, with sunshine and warm temperatures in the upper 20s.

Monday, August 14, 2017

Partial eclipse to darken the skies over Montreal

The partial solar eclipse on Monday, August 21st, will darken 60 percent of the sun over Montreal.
On Monday, August 21, 2017, a narrow swath of North America, from southern Oregon to the Carolinas, will be treated to a very rare celestial phenomenon:  A total eclipse of the sun will occur on this date, starting on the Pacific Coast at 9:06AM PDT and exiting the Atlantic Seaboard at 4:06PM EDT. The eclipse will produce total darkness for a period of one to three minutes along a 70 mile (113km) wide path stretching diagonally across the US from Oregon to South Carolina. The percentage of sun covered by the moon will decrease rapidly as you move away from the main path. Here in Montreal, our partial eclipse of the sun will start at 1:21PM, reaching close to 60 percent coverage by 2:38PM and ending by 3:12PM. Across southern Canada, the amount of sun covered will vary from 90 percent in Vancouver, to 70 percent in Toronto and less than 50 percent across Atlantic Canada. 

A narrow path of total darkness will sweep across the US from coast to coast during the solar eclipse.
Residents in cities along the path of totality are preparing for a massive influx of people coming to view the rare event. Gridlock is expected on the more than 20 interstates that crisscross the path. Over 200 million residents live within a day’s drive of the path of totality. Hotels along the path have been booked for well over a year for this date. 

If crowds aren’t your thing, you can watch the event live on your computer or mobile device, streamed by NASA at   NASA also has an entire website devoted to the eclipse,

The Royal Astronomical Society of Canada has a list of viewing events planned from coast to coast. The list can be accessed on their website,

 A reminder to those who plan on watching the eclipse live and in person, make certain you use protective eyewear. Staring directly into the sun does damage to your retinas and can result in permanent vision loss. More information on eyewear can be found here

 With darkness lasting for up to three minutes at each location along the path of totality, the sudden loss of daylight can drop temperatures by as much as 10 degrees. It can also play havoc with wildlife, creating confusion, albeit for a short period of time. According to NASA, eclipses occur due to the special coincidence of the moon and the sun being the same angular size. The sun is 400 times wider than the moon, but it is also 400 times farther away, so both coincidentally appear to be the same size in our sky. A total solar eclipse occurs when the moon crosses the path between the sun and the earth. This happens, on average, once every 18 months, with locations varying around the world. The last total eclipse visible in Montreal was on February 26, 1979. I was in 7th grade at the time in Verdun and very excited, to say the least. The school chose to keep students indoors, however, and the day was cloudy, limiting the effects in Montreal. The next total eclipse visible in the US and Canada will not occur until April 8, 2024, traveling from Texas northeast to New England. It will pass right over Montreal.  Let’s hope for a sunny day!

Tuesday, August 08, 2017

Montreal's summer weather in one word, unsettled

Damage in Saint-Joseph-de-Beauce from a confirmed EF-1 tornado on Saturday, August 5. (Radio Canada Photo)
If there is a word I have overused this summer, it is unsettled. I don't know how else to describe the days where we have sunshine, clouds and the ever present risk of showers or thunderstorms. There have been many. Since May 1st, Montreal's Trudeau Airport has recorded precipitation of a trace or more, on 65 of 100 days through August 8. On many of the other days, the weather has been overcast and cool, not exactly a summer of champions. Some like the cool weather, I don't. Our summers are too short to begin with, I like them to be warm.

This past weekend was just terrible, more clouds than sun, breezy, cold and at times wet. This followed a very stormy Friday, that had rounds of strong thunderstorms impacting southern Quebec. The wind gusted close to 80km/h at Trudeau Airport along with heavy rain. There were numerous reports in the city of downed trees. Some locations such a Napierville and St Constant reported major flooding as more than 100mm (4 inches) of rain fell on Friday alone. A sate of emergency was declared in Napierville. Thousands were also left without power. On Saturday, more strong storms occurred in Quebec, this time east of Montreal. Environment Canada confirmed the provinces fifth tornado of the season, and EF-1, capable of winds up to 170km/h. The storm struck Saint-Joseph-de-Beauce, south of Quebec City. Widespread damage was reported to trees and homes, along with power outages.

The forecast for the balance of the week into the upcoming weekend does not look great. Following the trend well established this summer, expect unsettled weather at best. Tuesday and Wednesday will be the best days of the week, with more sunshine than clouds and mild highs near 27C (81F). The rest of the week into the weekend will be partly cloudy and humid, with numerous showers and isolated thunderstorms. The best chance for rain will be in the afternoon each day. This trend will last well into next week, with temperatures close to normal. The normal high is 26C (79F) and low 15C (59F).

Solar Eclipse
Expect a rare celestial treat for North Americans on Monday, August 21. A solar eclipse will be visible across a large portion of Canada and the US. I will post details on the timing of the partial eclipse here in Montreal, later this week.

Wednesday, August 02, 2017

More strong thunderstorms possible through Friday

Flooding after Monday's severe thunderstorm under Cote-de-Liesse at Hickmore. Firefighters opened the manhole cover to release the flood waters. (CTV News)
Warm and humid weather is expected to continue Wednesday through Friday across metro Montreal. Montreal has not recorded a 30C plus temperature since June 18, when the mercury hit 32.1C (90F). The 30C free month of July, was only the eighth time in recorded history that this has occurred in Montreal. Weather records at Trudeau date back to 1942. The streak will come to an end today, if the city reaches the forecast high of 31C (88F). Strong thunderstorms are possible this afternoon, and again right through Friday evening, as the warm and humid air remains in place. Several impulses of energy will rotate through the warm air mass, generating the thunderstorms. Any storms that do develop will be possible of producing heavy rain, just like the storm Monday afternoon in central Montreal.

Flood waters gather in the parking lot along the Trans Canada Highway at Cote-Vertu on Monday, July 31. (Valley Weather)

Severe Thunderstorm Produces Flooding
On Monday afternoon, a strong isolated thunderstorm cell moved from Laval across north central Montreal towards Trudeau Airport between 4 and 5pm. The storm brought torrential rain, with between 33mm and 37mm falling in less than one hour in Saint Laurent and Dorval. The result was flooding of several basements and highways. Our parking garage and ramp here at The Suburban flooded rapidly from the torrential rain. Strong wind gusts in excess of 85km/h brought down several trees. Lightning and wind knocked out power to over 17,000 Hydro Quebec customers in metro Montreal. The thunderstorm also produced pea size hail. The storm rapidly dissipated as it swept southeast across the Island of Montreal. The isolated nature of this particular storm produced the heavy rain and flooding in a narrow swath through the city. I measured no rain at all on L'Ile Perrot, just 20 kilomteres to the southwest of Trudeau Airport.