Wettest August on record for the Montreal region

The longer nights and cooler mornings  have allowed some trees to begin showing their colours across Southern Quebec. Despite the forecast for a cool Labour Day weekend in Montreal, it looks like we are in for a warm and wet fall, just as the entire year has been. (Valley Weather Photo)

Powered by the remains of tropical storm Debby, Montreal has added another dubious weather record to the books, the wettest August dating back to 1871. With just a few days left in August and meteorological summer, Trudeau Airport sits at 229.3mm of precipitation, just over 10 inches of rainfall for the month. The previous benchmark was 224.8mm set in 2011. We will add to the record on Saturday, with another 10-20mm of rain forecast before we say goodbye to one soggy summer.

The total rainfall for the three summer months is also a record for the city, currently at 450mm. That of course is at the airport in Dorval, as many already know, amounts are much higher in other parts of the city. For example, I have measured 484.2mm here on Ile Perrot. 

Many are still paying the price for the abundant rainfall as municipalities struggle to pick up the tons of debris leftover form the flooding caused by both Beryl and Debby. The wait for insurance adjusters and contractors has been long, and many homeowners are facing the likelihood of not being covered or being under insured for the damage. Many are dealing with the health impacts caused by moldy basements, not to mention the overall stress of the event. 

With summer coming to an end, we are getting a brief glimpse of what fall may look like. For the short-term, Montreal will be cool and dry for a day or two. High pressure will give us a sunny and cool Thursday at 21C (70F), followed by slightly warmer temperatures Friday, 25C (77F). Rain arrives on Saturday, with showers and thunderstorms persisting into Sunday. Skies will clear out for holiday Monday, with a chilly high near 18C (65F).

Beyond that we can expect a period of dry weather and warming temperatures next week. The general outlook from both Environment Canada and the National Weather Service for our region, is for above normal temperatures and precipitation during the fall months of September through November.

An early taste of fall weather for southern Quebec

Another rainbow in the skies over Montreal as our wet summer continues. Skies will begin to slowly clear on Thursday, with a return to more summer-like temperatures this weekend as highs rise into the middle and upper 20s. (Valley Weather Photo)

Our super wet summer persists across southern Quebec, with another 25-50mm of rain falling on the region since Monday. The culprit this time, a potent upper level low that is slowly drifting across the region with showers, thunderstorms and unseasonably cold temperatures. It has provided Montreal with a very early taste of fall weather. I have even seen a hint of colour in some of the trees as the days begin to shorten.

The high temperature failed to reach 21C (70F) in Montreal on Tuesday afternoon, the first time since June 10. We are sitting at a very cool and wet 14C (56F) as I write this blog Wednesday morning, and temperatures will not budge too much today. Adding to the fall-like feel will be rounds of rain, some of it rather heavy at times across southwestern Quebec and eastern Ontario. Another 15-25mm of rain is quite possible today, with highs struggling to reach 16C (60F), well-below the normal high of 24C (76F).

Since Monday, 47mm of rain has fallen at my home on Ile Perrot, with my monthly total now sitting at 233.8mm and counting. Slightly less at Trudeau, with 196mm, owing to the fact the airport received less rain during tropical storm Debby on August 9. The all-time record for the entire month of August is 224.8mm set in 2011. While many parts of the city, including here on Ile Perrot have already surpassed that amount, we will have to see if it is officially broken at the airport.

Expect one more cold and wet day Wednesday, before the upper level low slides to the east, and high pressure begins to move in. That will allow for pleasant weather beginning Thursday afternoon and lasting though the weekend. We can also expect temperatures to rise into the middle and eventually upper 20s by Sunday, as summer weather returns. The next chance for showers and thunderstorms won't be until Monday. 

More heavy rain expected across southern Quebec

Laval, Québec on Friday August 9. More rounds of showers and thunderstorms are possible on Sunday, with 30-40mm falling on already saturated ground across the Montreal region. The summer of 2024 is quickly becoming know as the summer of the flood. Major flash flooding has now occurred on two separate occasions in both Toronto and Montreal as well as across Vermont and New York. (Association des Pompiers de Laval)

Special Weather Statement in effect for southern Quebec and eastern Ontario for 30-40mm of rain from Sunday afternoon into Monday morning. Some flooding and water accumulation is possible, especially in low-lying areas.

A common scene this summer in central Canada. This time is was Mississauga, Ontario on Saturday. (TWN)

Low pressure and a frontal boundary will slowly move across southern Quebec over the next 36 hours, generating showers and thunderstorms. Some of the showers will be slow moving, and capable of producing heavy rain. This will not be like tropical storm Debby on August 9. The storms will be scattered in nature and the hope is that the rain will spread out and not concentrated. However the ground is saturated in southern Quebec and waterways are full, so any additional rainfall is not welcome at this time.

Showers will be possible through Wednesday of the upcoming week, along with much cooler temperatures by Tuesday.

The summer of 2024 is quickly becoming known as the summer of the flood across eastern Canada. For the second time this summer, as with Montreal, the GTA experienced major flooding on Saturday. The culprit is an upper level low slowly moving across the Great Lakes and heading for southern Quebec. On Saturday, the low developed rounds of thunderstorms that moved off Lake Ontario and into the Toronto region dumping 128.3mm of rain at Pearson Airport. 

Toronto has now had its wettest summer on record, with 475.8mm falling, smashing the 2008 record of 396mm. Montreal is not far behind, with 415.8mm since June 1st at Trudeau Airport. There has been even more precipitation at other locations across southern Quebec. The trend will persist with more rounds of storms expected today and showers through the middle portion of the week.

The storms also generated a tornado with significant damage near the communities of Drumbo and Ayr in southwestern Ontario. The damage will investigated today by the Northern Tornadoes Project from Western University to determine the rating.

More rain and thunderstorms for flood weary Montreal

After all the flooding in Montreal last weekend, it was nice to see the sun this week. Unfortunately the airmass is quite warm and humid, and has produced isolated thunderstorms. There has also been some smoke and haze from western wildfires.

Severe Thunderstorm Watch in effect for metro Montreal.

We have a risk of isolated strong thunderstorms Thursday afternoon, with heavy rain, hail and gusty winds possible through sunset.

The clean up continues in Montreal after the historic rainstorm last week associated with tropical storm Debby. Highway 13 finally reopened Thursday morning, after being closed to flooding and a damaged pumping station since last Friday night.

Environment Canada map displaying the accumulated rainfall across our region from tropical storm Debby. The heaviest rainfall, between 150-200mm (6-8 inches), locally more, was centered in the St. Lawrence Valley, and particularly the West Island, Ile Perrot and Vaudreuil.

Montreal has been under a warm and humid airmass this week, with frequent afternoon and evening thunderstorms across the southern portion of the province. The good news is that the storms have been widely scattered and have occurred in areas that received slightly less rainfall from Debby.

Montreal will remain in an unsettled weather pattern through at least next Monday. Primarily we will be affected by the departing upper level low to the east of our region, with scattered storms moving from north to south. As with any thunderstorms, heavy rain is possible, but it will not impact the entire island as Debby did. Temperatures will be quite warm Thursday through Saturday, rising to near 30C (86F) as it did Wednesday afternoon.

Over the weekend, we have another Great Lakes low pressure and associated frontal boundary expected to slide across southern Quebec. Showers and scattered thunderstorms are likely each day, with the possibility of 15-25mm of rain falling by Monday, perhaps more in thunderstorms. The hope is we avoid any additional flooding.

Hurricane Ernesto's forecast track will keep the storm far away from southwestern Quebec. The only Canadian location that will likely be impacted is Newfoundland. (ECCC)

HURRICANE ERNESTO

It is important to note that hurricane Ernesto will not impact the weather in southern Quebec as some were posting on social media Wednesday. The storm will be far out in the open waters of the North Atlantic.

Ernesto strengthened into a hurricane Thursday morning, 915 km southwest of Bermuda with 140km/h winds. The storm was moving north at 22km/h. A hurricane warning is in effect for Bermuda, with the centre expected to pass close to the island nation Saturday as a major hurricane. The storm will produce dangerous surf all along the US coast and into Atlantic Canada. Ernesto may brush Nova Scotia, but most likely will affect southeastern Newfoundland sometime next week. 

Tropical Storm Debby hammers Montreal with historic rainfall

The service roads and ramps off Highway 40 at Cote-Vertu were once again closed this morning due to major flooding. The roads were closed during the evening commute as well, as more heavy rain hit the city. In all between 100-175mm of rain fell in Montreal Friday, an historic amount of rain for one day. (Photo: Oliver Sutton)

A spectacular rainbow has just appeared in the eastern sky here on Ile Perrot after an historic weather day. Tropical Storm Debby dumped two months worth of rain on the region in just a few hours. At my home on Ile Perrot, 175.8mm (6.9 inches) of rain since the pre-dawn hours. This is the most rain I have ever recorded at any location I have lived in in the 48 years I have been observing the weather.

A remarkable 105mm of that total fell between 4pm and 8pm. Normal rainfall for August is just over 94mm. The rainfall today crushed both the daily record of 76.2mm set in 1917 and the monthly record for August set on the 29th back in 1893.

Highway 40 was once again closed Friday evening due to flooding. (Transport Quebec)

The result was as expected, numerous highways and ramps were closed during the morning commute creating gridlock, once again focused around our office at Cote Vertu. Our building flooded again, as it did back in July during Hurricane Beryl. Many drivers were once again stranded as their vehicles became inundated with water. Some of the same roads have been closed by Transport Québec again this evening due to significant water accumulation.

The rain that hit the city late Friday was even heavier, with more highway closures, including the Decarie Expressway.

On top of the heavy rainfall, winds gusted close to 80km/h at Trudeau Airport as the final heavy rain pulled across the region. The result has been widespread power outages to over 120,000 Quebec homes and businesses.

The good news is the rain is now over for Ile Perrot, with the back edge pulling across the city as I write. If the rain has not ended in your location, it will soon. Saturday should be sunny and dry, allowing many to assess the damage and begin the cleanup process. Once again insurance adjusters will be busy.

Debby brings major flooding to parts of Montreal

Major flooding has closed the ramps off Highway 40 at Cote-Vertu. Nearly 65mm of rain fell early Friday morning in Montreal, with more on the way. Photo: Oliver Sutton

Heavy rainfall warning in effect for southern Quebec. Rainfall totals may exceed to 100mm.

The first wave of precipitation has delivered major flooding to parts of the Montreal region Friday morning. Nearly 65mm of rain fell from the remains of hurricane Debby, flooding much of the same area affected by Beryl last month.

Sections of Highway 40, including ramps and service roads were closed at Highway 13 and Cote-Vertu. The result was traffic chaos during the morning commute. If you can work from home today do so. More rain is on the way this afternoon, and totals should easily surpass the all-time August record for the city 85.3mm, set on August 29, 1893.

Several homes and businesses have also been flooded this morning. There are sections of road closed, including Highway 40. 

Waves of tropical moisture will drop heavy rain across the city, with more flash flooding possible.

This story will be updated.

Widespread heavy rain warnings posted for southern Quebec and Ontario

Tropical storm Debby made another landfall in South Carolina early Thursday morning. The storm center was located 100km west of Myrtle Beach, moving northwest at 11km/h. The remains of Debby will move into New York State on Friday, bringing heavy rain to Montreal. (Photo: Stephen B. Morton)

Heavy rain warning has been issued for southern Quebec and eastern Ontario including metro Montreal for 50-100mm of rain tonight through Saturday morning. Flood Watch for upstate New York including the St. Lawrence Valley.

The remains of tropical storm Debby will impact southern Quebec and Ontario starting Friday. A swath of deep tropical moisture will set up to the north and west of the track of Debby, interacting with a cold front pushing southeast across Ontario. Rain will begin late Thursday evening and persist through Friday. The rain will be heavy at times, along with embedded thunderstorms.

Forecast amounts are expected to be in the 50-100mm range (2-4 inches). Where the heaviest rain falls will be determined by the final track of Debby, expected to lift north from South Carolina towards Lake Champlain by Saturday morning.

The Canadian Hurricane Centre forecast track of tropical storm Debby from coastal South Carolina northeast across our region and into Atlantic Canada.

The various models have the heaviest rain falling along the St. Lawrence Valley, but scenarios range from right along the International Border to locations far northwest of Montreal across the lower Laurentians and Ottawa Valley.

The expected accumulations of rain are cable of producing local flash flooding, similar to what we experienced during Hurricane Beryl in July. Aside from the heavy rain, we can expect gusty winds, up to 50km/h along with very muggy conditions in the tropical airmass.

Conditions should improve on Saturday, but the airmass will remain unstable, with a risk of scattered showers into Sunday.

Debby made landfall along the Florida Gulf Coast on Monday as a category 1 hurricane. The storm was located 100km west northwest of Myrtle beach early Thursday morning. Debby has weakened to a tropical storm, with 75km/h winds. The storm will move slowly inland today, before increasing in forward speed towards the northeast this evening and Friday. Debby is already responsible for hundreds of millions of dollars in damages as well as six fatalities across the southeastern US.

Tropical storm Debby to impact southern Quebec

Flash flooding in Charleston, South Carolina, after tropical storm Debby produced over 300mm of rain on Tuesday. Debby is expected to bring heavy rain to Montreal by Friday. (Photo: Henry Taylor) 

Special Weather Statement issued for Montreal, for heavy rainfall in association with the remains of tropical storm Debby, expected by Friday.

Tropical storm Debby, located in the Atlantic Ocean, 85km southeast of Charleston, South Carolina at 11am Wednesday morning, is slowly meandering northeast at 7km/h. The storm has brought historic flooding to portions of northern Florida, southeast Georgia and South Carolina since late Sunday. Hundreds of thousands of homes and businesses were left without power after the storm made landfall in the Big Bend region of Florida early Monday morning.

Since Monday, Debby has been slowly moving across Georgia and is now back over the open waters of the Atlantic. Debby has strengthened a little Wednesday morning, with winds of 95km/h (60 MPH). Debby should make landfall in South Carolina later this evening before moving off towards the northeast into the middle Atlantic states.

The latest forecast track for tropical storm Debby, has the system passing southeast of Montreal early Saturday morning. Heavy rain, up to 100mm is possible across our region, but that may change as the event draws closer. Flash flooding is possible across a wide area from the US southeast into eastern Quebec. (NHC)

Significant rainfall, in some cases over 500mm (20 inches) is occurring across portions of the US southeast. This has resulted in significant fresh water flooding. The flood threat will spread all along the path of Debby into the Northeast, New England and eventually southern Quebec. Regions along the storm track can expect 50-200mm (2-8 icnhes) locally.

Debby is forecast to merge with a frontal boundary by Friday as the depression moves across northern New England to lie near Lake Champlain by early Saturday morning. The strom will then move into southern Quebec.

At this time we expect a swath of heavy rain across southern Quebec and eastern Ontario, including the metro Montreal region. It is too early to determine exact amounts, but the region could possibly see 50-100mm (2-4 inches) of rain between Friday morning and Saturday evening. Additional showers are expected into Sunday. The final track of Debby will determine where the heaviest rain occurs.

Many parts of New England and extreme southern Quebec have already experienced a very wet June and July. There has been significant flash flooding in parts of Vermont this summer, so any additional rain will only add to the saturated ground. 

Weather watches and warnings may be required as the event draws closer. Until then enjoy the spectacular weather Wednesday and Thursday in Montreal, with sunshine and high temperatures in the upper 20s.

Hurricane Debby pounds Florida Gulf Coast

Hurricane Debby produced significant fresh water and surge flooding in Florida on Sunday, including at Fort Myers beach shown above. (Photo: Andrew West)

Historic rainfall expected...

Hurricane Debby moved inland Monday morning across the Big Bend area of Florida's Gulf Coast. Debby reached hurricane status briefly overnight, with 80mph (129km/h) winds. Storm surge flooding started on Sunday from Fort Myers Beach northwards across Tampa Bay, Cedar Key and points north. A storm surge of up to 10 feet were observed at many locations, with coastal infrastructure and roads under water.

As Debby moved inland near Steinhatchee, Florida, strong winds and isolated tornadoes cut power to over 275,000 Florida homes and businesses. Power outages and wind damage are now spreading northward into southern Georgia.

At 8am Monday morning, Debby was located about 95km north, northwest of Cedar Key, very close to Horseshoe Beach, where winds gusted to 95mph (152km/h). Debby was moving north, northeast at 17km/h, with a central pressure of 979mb.

Hurricane Debby is expected to weaken to a tropical storm while meandering across the southeastern US for most of the upcoming week. The slow movement of the storm is expected to produce historic rainfall and catastrophic flooding across Georgia and the Carolinas. (NHC)

As Debby moves inland, the system is expected to weaken to a tropical storm. But wind will not be the big story with Debby, it will be the rainfall. Torrential, tropical rainfall is forecast all along the storms track from Georgia into the Carolinas. Rainfall of 200mm (8 inches) to as much as 500mm (20 inches) is expected. Catastrophic to historic flooding is anticipated in many parts of north Georgia and southeast South Carolina. 

Debby is expected to move into the Atlantic briefly Tuesday before a second landfall in South Carolina. Debby is expected to slow down considerably, meandering across the region for the better part of the upcoming week. The remains of the system will spread clouds and rainfall northward into waterlogged New England and perhaps even southern Quebec by next weekend. We will have a better handle on local impacts, if any, as the week progresses. For the time-being, the big story will be the life-threatening flooding expected across the southeastern United States.

Hot and humid weather persists across southern Quebec

The hot and humid weather during the past week across our region has been broken at times by occasional showers, thunderstorms and even rainbows!

Heat Warning in effect for southern Quebec

Widespread heat warnings and advisories are in place for much of southern Ontario and Quebec as well as a large part of the northern and central US, including both the Champlain and St. Lawrence Valley. The combination of very warm temperatures and high humidity will push humidex values into the upper 30s for many, with even a few 40C readings. Montreal managed a humidex reading of 40C (104F) on Wednesday afternoon. The current heatwave included an all-time record high of 35.9C (96.7F) at Gaspe Airport on July 29. This surpassed the previous all-time high of 34.8C (94.6F) set in 1983. Records at that locations date back to 1915.

It has been a very humid stretch of weather across most of eastern North America over the past week, with humidex values approaching 40C in Montreal. Over the past week, daytime highs have been at or over 30C (86F), with the exception of Wednesday, when clouds and thunderstorms managed to keep the high at 28C (83F). The trend will persist into the upcoming weekend, with highs near 32C (90F) Friday, and close to 30C both Saturday and Sunday.

The warm, humid airmass will generate a few isolated thunderstorms Friday afternoon, just as it did Thursday. However, most of the region will remain dry. Overnight, conditions will very warm and muggy, with some valley fog possible, and lows near 22C (72F). 

We an expect a very warm and humid weekend. A few weak low pressure troughs may generate some scattered showers and thunderstorms. That threat will increase Monday, as a stronger cold front arrives from Ontario. We can expect an increase in aerial coverage of showers and storms, with a increase chance of heavy rainfall. Cooler and finally some less-humid weather is expected by midweek next week.

It has been a very wet summer here in eastern Canada. Many region including Montreal, Toronto and especially parts of Vermont have been hit with significant flash flooding. In the case of northeast Vermont, some locations have had major flooding on more than one occasion. Rainfall totals for the July included 124mm at Trudeau Airport, with 215.4mm at Pearson Airport in Toronto.

I see no end in sight for our wet summer, especially with the expected increase in tropical activity during August and September.