Colder weather on the way for Montreal - Otis slams Acapulco

This fall in has been extremely warm in Montreal to date, with no frost reported in the city and temperatures running well-above normal. That is about to change as the coldest air of the season arrives this weekend and persists into next week. Frost is possible along with the first snowflakes of the season.

There is plenty of weather to talk about early on this Friday morning, with the temperature sitting at a remarkable 16C (61F) in Montreal. The normal high for this time of year is only 9C (48F), we have been running well-above normal this week. Friday will be another warm and windy day across southern Quebec, with a few showers around and high temperatures approaching 20C (68F).

We have one more day of warmth Saturday as a cold front arrives from the west. Behind this front will be the coldest weather of the season, with our first frost and snowflakes likely next week. Highs will drop Sunday into the single digits, and cool even further to around 4C (39F) for Halloween. The good news is the weather looks dry for trick or treating.

Beyond Tuesday, even cooler air arrives, with moisture invading from the south. There is a chance for some flurries by Wednesday, along with frost and freezing temperatures into Thursday morning. The low in Montreal may be as chilly as -2C (29F), cooler than any weather we have seen since early last spring.

Western Snow

While we have been warm, the west has plunged into the deep freeze for October. Cold weather and heavy snow has occurred across Alberta and into southern Saskatchewan and Manitoba. Record setting lows dropped as cold as -20C (-4F), with up to 20cm of snow falling in some locations close to the Montana border. Estevan, Saskatchewan reported 19cm of snow, while the low in Cardston, Alberta dropped to -20C shattering the record of -17.8C set way back in 1939.

Hurricane Otis slammed into Acapulco, Mexico on Wednesday morning, slicing a path of destruction through the city of 900,000 and nearly destroying the tourist industry in one night. Winds topped 265km/h tearing apart resorts and cutting power to the region. The storm strengthened explosively hitting with little warning, surprising forecasters and emergency planners. Photo: Protección Civil Chilpancingo

Hurricane Otis

Hurricane Otis slammed into the Mexican resort city of Acapulco just after midnight Wednesday as a major category 5 storm, with winds of 265km/h (165 mph). Otis was one of the strongest storms on record to hit the Pacific coast of Mexico. The storm has been blamed for at least 27 deaths, and widespread catastrophic damage expected to reach into the billions of dollars. The resort town was destroyed by a direct hit from one forecasters called a nightmare storm. 

Just 12 hours earlier, Otis was a minimal tropical storm, with not one computer model hinting at anything else. The storm then underwent a record breaking explosive intensification, with winds increasing 115mph in under 12 hours. The storm slammed onshore as a well-developed category 5 hurricane destroying infrastructure and severely damaging nearly 80 percent of the hotels in the popular resort community. Residents and tourists were trapped unable to evacuate in the severe weather conditions. Many hunkered down in high rise hotels as windows blew out and roofs torn away.

The unprecedented strengthening of Otis has forecasters extremely concerned for future storms.

Radar image of powerful hurricane Otis just prior to landfall near Acapulco on Wednesday morning. (NOAA)

Wet and chilly weekend expected for Montreal

Our mild September and early October has resulted in a sluggish foliage season across the Montreal region. That began to change drastically over the past week, with many parts of the city now seeing decent colour. There is still plenty of leaves left to fall, but the windy, wet and cooler weather forecast this weekend will likely accelerate that process. (Valley Weather Photo)

Strengthening low pressure along the US east coast this weekend will result in rainfall across much of southern Quebec into New England. Before then, we can expect a mild, partly cloudy Friday, with temperatures pushing into the upper teens. 

This past week has been rather grey and somewhat cooler that we had been accustomed to for most of September into the first week of October. Daytime highs have been closer to normal of late, in the lower teens, but overnight lows remain very mild, as a result most of the region has yet to see any frost.

After a few breaks of sun late Thursday and perhaps a few more Friday morning, cloud cover will thicken once again as the next weather system moves in. A deep trough will develop over the Great Lakes, with the first Nor'Easter of the season developing off the North Carolina coast moving northeast towards Atlantic Canada by Saturday. At the same time a cold front will be approaching from the west. The combination of the two systems will bring a steady rain to Montreal, starting late Friday and persisting into Saturday evening. Amounts will likely exceed 25mm (1 inch) in Montreal and may approach 50mm (2 inches), especially south and east of the city.

Temperatures will be mild Thursday night, with southwesterly winds blowing, dropping to 13C (55F). The normal low is 2C (36F). Friday and most of Saturday will be mild, in the mid to upper teens, before the aforementioned cold front crosses the region late Saturday. Temperatures will drop back to seasonal values for Sunday at 11C (52F),  Look for some of the coldest nights this fall so far Monday and Tuesday, with forecast lows close to 1C (34F). Some areas may see the first frost of the fall season.

Finally, southwesterly winds will become rather gusty on Friday, before backing to the northwest over the weekend, bringing in the cooler air.

Annular Solar Eclipse on Saturday, October 14

The Annular Solar Eclipse occurs when the Moon passes between the Sun and Earth. Unlike a total eclipse, the Moon is at it's furthest point from Earth, appearing smaller and leaving a "ring of fire" around the sun. The eclipse will only cover about 10 percent of the sun in Montreal on Saturday, starting at 12:11 PM. (NASA Photo)

Most of North America will be treated to an Annular Solar Eclipse this Saturday, October 14. The Annular Eclipse, unlike a total eclipse, leaves a ring of light visible as the Moon passes between the Earth and Sun. The reason for this is that the Moon is currently at its furthest from Earth and does not completely cover the Sun. The path of near totality will stretch from Oregon to Texas, across parts of northeastern Mexico as well as sections of Alaska and the Caribbean. 

All of  Canada will experience at least a partial solar eclipse, with the best presentation of the eclipse in British Columbia. Vancouver will be at 80 percent peak, around 11am local time. The percentage of the Sun covered by the Moon will lower from west to east across the county, with the lowest impact in Atlantic Canada.

In Montreal, we will only experience around 10 percent of the sun blocked by the moon. The show will begin around 12:11PM, reach maximum around 1:17PM and end by 2:23PM. Despite it being only a partial eclipse, you should always protect your eyes and never stare directly at the sun. Eye damage can occur in seconds. Special viewing glasses are available on Amazon, and they would not be a bad investment. Montreal is only months away from the spectacular total solar eclipse occurring on April 8, 2024.

The best way to view the eclipse on Saturday, will be at NASA.gov, which will be live-streaming the event from various locations in the path of near totality.

As far as the weather is concerned for viewing in Montreal this weekend, after a week of unsettled weather and plenty of rainfall, skies should be fair for Saturday, with temperatures near normal, 15C (59F).

October heatwave over - stormy weather expected for Thanksgiving weekend

The last appreciable rainfall in Montreal fell on September 19. Only 0.8mm has fallen at Trudeau Airport since. That all changes this weekend as our heatwave comes to an end, and heavy rain moves in. Some locations will receive a months rainfall in 48 hours. Between 50-80mm is possible for our region.

Rainfall warning in effect for metro Montreal.

UPDATE, Saturday, October 7: Weather warnings remain in place as heavy rain continues to fall across southern Quebec. As of 12pm, close to 65mm had fallen in Montreal, with another 40mm possible. That would bring amounts over 100mm (4 inches), a record for the date. As a result of the prolonged dry period we just experienced, little flooding is occurring so far. The exception is water accumulation on roadways, especially where leaves are blocking sewer grates. Drive carefully.

Our October heatwave will come to an end on Friday, but with potentially one more record to break before it ends. The forecast high Friday is 25C (77F), the record for the date, set in 2005, is 26C (79F). We have a shot at it, but increasing clouds may hold back afternoon temperatures just a touch. This will be the last day of our current remarkable heatwave. Montreal managed another record high on Wednesday, reaching 28.5C (85F), surpassing the 2005 record of 26C (79F). Dozens of records for heat and humidex, as well as warmest minimum temperatures have been established across eastern North America this week. Included in that was the warmest October high temperature for Montreal, dating back to 1871, with Tuesday's high of 29.3C. We will likely establish another record for the warmest overnight Friday, having only dropped to 19C (66F) so far. The record was 16.7C set in 1937. The normal high for October 6 is 15C (59F), but what is "normal" anymore.

The unusual heat is over, and our attention turns to a frontal boundary slowly mowing across Ontario. Ahead and along the front, heavy rain is occurring, along with some thunder. It has been 16 days since our last rainfall for most of us. A trace did fall at Trudeau on Tuesday morning as a few isolated thunderstorms bubbled up. We need the rain and we will get it. Showers and thunderstorms should develop this afternoon in Montreal, transitioning to a steady rain overnight and all day Saturday. Total rainfall amounts between Friday and Sunday for southern Quebec will be in the 50-80mm range. Most regions should absorb the rainfall, but there could be some minor water accumulation and flooding in low lying areas.

Tropical storm Philippe, located south of Bermuda on Friday morning, is forecast to weaken and move across Maine and into central Quebec this weekend, adding deep moisture and gusty winds to our forecast. (NHC)

The frontal boundary and parent low pressure will stall over Quebec on the weekend, maintaining showers throughout Thanksgiving and into next week. Adding to the moisture will be the remains of tropical storm Philippe, located 315 kilometres south of Bermuda Friday morning. Philippe is forecast to become post-tropical and move inland across Maine and into southern Quebec by Sunday.

Along with the rain this weekend, will be gusty winds, up to 50km/h, especially Sunday. Temperatures will be the other big story, falling way back to normal values for early October. The low Saturday morning will be 15C, rising to the upper teens Saturday, falling back to the lower teens late in the day and remaining there Sunday, with a high of 13C (55F) expected. The cooler weather will remain with us all next week.

Record breaking warmth to start October - much colder weather for Thanksgiving

The weather has been nearly perfect over the last two weeks across the Montreal region, making for a rather unseasonable yet picturesque view at Point-du-Mouilin in Notre-Dame-de-L'Ile Perrot over the weekend. The upcoming week will feature hazy sunshine and record-breaking warmth. We can expect a dramatic change as we head into the upcoming holiday weekend. (ValleyWeather)

It has been an absolutely spectacular stretch of weather to end  September and start October in Montreal. Strong high pressure has been dominating our weather over the last two weeks, with cool nights and warm pleasant days. Winds have been calm for the last several days. The only glitch in the forecast has been some high clouds at times and hazy skies in the upper atmosphere, generated from western wildfires, something we have become all too familiar with in 2023.

The forecast for this week is for much of the same, very warm temperatures and sunshine. Southwest winds will drive temperatures 10 to 15 degrees above normal values, with record highs likely through the middle portion of the week. The high on Tuesday is forecast at 29C (85F), the normal high is only 15C (59F). We should break the the record high for Tuesday of 26.7C (80F) set in 1953. On Wednesday and Thursday, highs will be close to 30C (86F). The record highs for those days are 26.7C (80F) and 26C (79F) respectively, both set in 2005. Overnight lows will be warm as well, in the 13C to 17C (55-63F), well above the normal low for early October of 5C (41F).

One more record will likely fall this week, showing us just how mild 2023 has been. We have not recorded a high temperature below 16C (61F) since May 25, a stretch of 132 days. The record in question was established 136 years ago in 1887, when daytime high temperatures remained above 16C for 133 consecutive days, from May 1st to September 10, 1887. Our current run will likely end during the Thanksgiving long weekend, as a cold front and strong low pressure will finally bring Montreal some rain, along with much cooler temperatures. Until then enjoy the summer-like warmth.

As far as precipitation is concerned, we need some moisture, as it has not rained in Montreal since September 19. The aforementioned high pressure has been deflecting all the significant weather systems around southern Quebec. For the month of September, we managed only 27mm of precipitation, well below the normal value of 83.1mm.

By Friday, some showers are possible, with more significant rainfall on Saturday. High temperatures will fall from the upper 20s into the low teens by Saturday and Sunday.

Spectacular weather forecast for Montreal to end September

Strong high pressure will remain in control of the weather over southern Quebec during the entire upcoming week. We can expect near-perfect fall weather, sunshine and highs in the low to middle 20s. The only exception was a few high clouds from tropical storm Ophelia over the weekend, and gusty northeast winds from the same system on Monday.

Strong high pressure is in control of the weather across southern Quebec, with nothing but sunshine and warm temperatures expected through the entire upcoming week. The area of high pressure is forecast to remain in place across the central portion of the province, keeping any inclement weather well south of our region. 

Cloud cover from the remains of tropical storm Ophelia can be seen south of the Saint Lawrence Valley across central New York and Vermont on Monday morning. (NOAA)

The remains of tropical storm Ophelia, which made landfall Saturday in North Carolina, are located across the middle Atlantic states, with showers and gusty winds. Clouds from this system reach as far north as central Vermont and New York. The only practical weather expected here in southern Quebec from Opehila, will be a gusty northeast wind, between 30-50km/h expected during the daylight hours Monday. Winds should ease after sunset.

The first day of fall was Saturday, greeted with summer like sunshine and warm high temperatures in the low to middle 20s. This trend will persist right through the upcoming week and even beyond into next weekend. High temperatures will be in the 20s (68-75F) with overnight lows either side of 10C (50F). I see no end to this perfect fall weather before next Monday or Tuesday at the earliest, with a cold front arriving from the northwest.

Coastal low pulls away leaving Montreal with a perfect stretch of late summer weather

Wind gusts of up to 117km/h accompanied tropical storm Lee, as the system moved into Nova Scotia and New Brunswick over the weekend. The storm brought down trees and power lines, knocking out power to over 400,000 customers across Atlantic Canada.  Over 100mm of rain fell in the Gaspe region of Quebec. Another coastal storm is brining more rain to the Quebec on Tuesday. (Nova Scotia Power)

Rain is falling across southern and eastern Quebec on Tuesday morning, some of it quite heavy. Montreal was once again on the western edge of most of the significant weather on Monday, as a coastal low moved along the eastern seaboard to lie near Bar Harbor, Maine on Tuesday. The storm will lift northeast into New Brunswick today, while an upper low spins overhead bringing us a windy, wet, cool and very fall like day.

Skies will begin to clear out Wednesday morning, as high pressure moves into the region and slowly drifts south and east across Quebec and New England. We can expect a prolonged period of near-perfect late summer weather, with moderating temperatures into the low 20s (70-75F) for daytime highs, accompanied by wall to wall sunshine. The beautiful weather will last into the upcoming weekend and the first day of fall Saturday.  Overnight lows will be seasonably cool, either side of 10C (50F).

Rainfall amounts Tuesday will be in the 10 to 15mm range for Montreal, while 30 to 50mm has already fallen across parts of the Townships, Beauce and into the Gaspe regions. More rain is forecast today. Today's rain across the Gaspe comes on the heels of over 100mm that fell from tropical storm Lee over the weekend.

Lee pounded Nova Scotia and Atlantic Canada Saturday, with hour upon hour of tropical storm force wind gusts up to 117km/h in Halifax, well over 100km/h at many other locations. Power was out to almost 400,000 homes and businesses across Nova Scoita, New Brunswick and eastern Maine. Towering waves and a storm surge damaged coastal roads and produced flooding. All in all the region fared better than expected, especially considering how long Lee lingered over the area and how strong the storm was in the days leading up to landfall. Lee moved inland west of Yarmouth and into the Bay of Funday during the early morning hours on Saturday, September 16.

Montreal to remain on extreme western edge of hurricane Lee

Sunrise over hurricane Lee early Friday morning on the NOAA visible satellite image. The extreme southern tip of Nova Scotia is visible at the top of the image. Lee had 140km/h winds and was located 740 kilometres southeast of Cape Cod moving north at 26km/h. (NOAA) 

Widespread weather warnings are in place from coastal New England into Atlantic Canada early Friday morning, as hurricane Lee races northward. Montreal will remain on the far western edge of the storm, with little weather forecast.

Early Friday morning hurricane Lee was located 740 kilometres south, southeast of Cape Cod, moving north at 26km/h. The storm has winds of 140km/h, extending outward from the centre up to 165km, with tropical storm force winds (63km/h) up to 520km from the centre. Lee is churning up the ocean into 15 to 20 foot swells along with a storm surge of 1-3 feet spreading from New Jersey to Nova Scotia. The result is very dangerous sea and surf conditions all along the east coast from North Carolina to Nova Scotia.

The updated forecast track of Hurricane Lee across Atlantic Canada provided by the Canadian Hurricane Centre. (CHC image)

A hurricane watch and tropical storm warning is now in effect for portions of the Nova Scotia and New Brunswick coast as well as inland locations, with Lee forecast to make landfall as a category one hurricane or strong tropical storm sometime Saturday afternoon. Winds in excess of 100km/h along with 50 to 100mm (2-4 inches) of rain are expected in the warning area and northeast across interior Nova Scotia and into Prince Edward Island as well as the Gaspe region of Quebec. The heavy rain and gusty winds will also impact the Lower North Shore of Quebec.

Heavy rain has been falling already this week in many locations in Nova Scotia, and there is a serious risk for flash flooding over the next 48 hours for many parts of that province. Hugh waves and rough surf will impact the immediate coastal counties as well as the maritime and coastal offshore waters. Coastal flooding and damage to infrastructure is possible, along with power outages and tree damage.

Montreal and southern Quebec will remain on the extreme western edge of the storm, with gusty northeast winds (20-40km/h) expected along with cloud cover from Lee, but no precipitation.

Lee will continue to accelerate to the northeast on Saturday into the Gulf of Saint Lawrence and eventually southwest Newfoundland, while becoming extra-tropical in nature. Heavy rain and gusty winds will continue along the path of the weakening storm.

Hurricane Lee taking aim at Atlantic Canada

The forecast track of hurricane lee as the storm approaches New England and Atlantic Canada this weekend. Lee is currently located 675 KM south, southwest of Bermuda. A tropical storm warning is in effect for the island nation, with gusty winds and up to 50mm of rain possible. (Canadian Hurricane Centre)

Once powerful category 5 hurricane Lee is forecast to approach the New England and Atlantic Canada coast over the upcoming weekend. Lee is located on Wednesday afternoon, 1635 kilometres south of Nantucket, Massachusetts. Lee is moving north, northwest at 15km/h, with winds of 175 km/h, now category 2 strength. Forecasters expect Lee to turn towards the north while accelerating over the next 24 to 48 hours. Gradual weakening is expected, as the storm encounters much cooler ocean water, but Lee will remain a strong storm.

The storm is expanding in size as well, and remains very dangerous. Pounding surf and dangerous rip currents are expected along the entire eastern seaboard for the southeast US northward into Atlantic Canada.

A NOAA satellite image of powerful hurricane Lee in the open waters of the Atlantic Ocean, well south of New England on Wednesday afternoon.

At this time computer models have shifted the track of Lee westward, indicating a potential landfall west of Yarmouth, either on the New Brunswick coast or far down-east Maine. Heavy rainfall, strong winds and a dangerous storm surge are forecast along the immediate coastal area near landfall. As the storm expands in size, wind and rain will impact large portions of eastern New England, as well as far eastern Quebec, Nova Scoita, New Brunswick and Prince Edward Island. At landfall, Lee is expected to be a category one hurricane or strong tropical storm. The storm will move across the Gulf of Saint Lawrence and into Newfoundland by Sunday while weakening.

As far as southern Quebec is concerned, we will remain on the far western edge of any weather from Lee, with perhaps a few clouds and gusty northeast winds in the 30-50km/h range over the weekend. This forecast is subject to change for all regions depending on the final track of Lee, but at the moment, the models have been fairly consistent with the storm approaching the coast near the mouth of the Bay of Fundy, close to the Maine/New Brunswick border.

September heatwave for Montreal as temperatures soar into the 30s

Despite the arrival of meteorological fall on September 1st, some of the the warmest temperatures of the summer are set to invade southern Quebec this week. The warmer than normal weather has not stopped some of the trees from beginning the process of changing colour and dropping their leaves.

Heat Warning in effect for Montreal

Strong high pressure will expand a heat dome that has been present most of the summer over a large portion of the United States, northeastward into upstate New York, northern New England, southern Ontario and Quebec including the metropolitan Montreal region.

Widespread heat warnings and advisories are in place across most of eastern Ontario, southern Quebec and New England on this Labour Day Monday, as a very warm and humid airmass invades the region. Daytime highs this week will be some of the warmest recorded all summer long, with temperatures forecast in the low 30s, and humidex values approaching 40C. Overnight lows will remain warm and muggy, dropping only into the upper teens and low 20s.

Warm southwest winds throughout the week will provide little in the way of relief as they draw deep tropical moisture northward from the Gulf of Mexico.

By Thursday, a cold front will approach slowly form the northwest, with a chance for showers and thunderstorms. Cooler weather will arrive by next weekend.

To date, Montreal has only recorded 8 days of temperatures at 30C or higher. Six of those occurred in May and June, with only 2 days through the normally hot and humid months of July and August. You can blame a stubborn pattern of persistent clouds, heavy rainfall and thunderstorms for the cooler than average summer.

So for the next week in Montreal, expect very warm and humid conditions, feeling almost oppressive at times. Limit outdoor activities during the warmest part of the day and drink plenty of water. The warm and humid weather can be particularly difficult and the very young and old as well as those with respiratory issues. 

Strong thunderstorms move across the Montreal region

Rounds of strong thunderstorms are moving across the Montreal region on Wednesday. The main severe weather threat will be from torrential downpours and intense lightning.

Severe Thunderstorm Watch for Montreal

A severe thunderstorm watch is in effect across southern Quebec including the metropolitan Montreal region through late afternoon Wednesday. A series of cold fronts is producing lines of strong thunderstorms across eastern Ontario and southwestern Quebec. Thee main threat will be heavy rain and intense, frequent lightning.

Pre-dawn thunderstorms moved across the island of Montreal early in the day, producing very heavy rain and minor flash flooding in several locations. The morning commute was slower than normal due to water accumulation. Intense rain produced a quick 20 to 30mm of rain in less than one hour. The storms were accompanied by vivid lightning, hundreds of strikes, resulting in power outages to over 40,000 Hydro-Quebec customers, mainly in Vaudreuil-Dorion, Hudson and Saint Lazare.

The threat for thunderstorms will diminish by early this evening as the fronts clear our region. Cooler, dry air will move into southern Quebec tonight, with chilly overnight lows around 10C (50F) in Montreal. Thursday will be a spectacular day, with sunshine, low humidity and a high of 21C (70F). Some late summer heat returns for the weekend and into the first week of September.

Powerful category 4 hurricane Idalia making landfall in Florida

Satellite image of powerful category 4 hurricane Idalia just off the Florida coast early Wednesday morning. (NOAA)

Idalia strengthened rapidly overnight into a category 4 hurricane, with winds reaching 130mph (215km/h). Early Wednesday morning, the center was located just off the Florida Gulf Coast, 95km west of Cedar Key, moving north, northeast at 30km/h.

Idalia will move inland early this morning, with a storm surge in excess of 12 feet expected along the coast. Coastal flooding, heavy rain, flooding and tornadoes will move across the Big Bend area of northern Florida today, spreading into Georgia and the Carolinas this afternoon and tonight. Forecasters expect Idalia to remain a hurricane into Georgia, with widespread power outages and significant damage expected.

Once Idalia emerges along the southeastern coast, flooding will spread northward into the Carolinas. Idalia is expected to slowly weaken over the course of the next 12-24 hours while inland. The storm however will become reinvigorated once it moves back over the open waters of the Atlantic. Expect Idalia to be around well into the upcoming Labour Day weekend.

Along the Florida coast early Wednesday morning, water levels are rising rapidly and evacuations and preparations have been rushed to completion. It is now time to hunker down and wait and see what Idalia does.

This story will be updated today.

Florida Gulf Coast braces for Hurricane Idalia

A NOAA satellite image of rapidly strengthening hurricane Idalia in the southeastern Gulf of Mexico early Tuesday morning. The storm brushed by the western tip of Cuba overnight. Florida is the next target for Idalia, with landfall expected Wednesday near Cedar Key. (NOAA Image)

Idalia has become a hurricane in the southeastern Gulf of Mexico early Tuesday morning, located 600 kilometres south southwest of Tampa Bay. Idalia has strengthened into a hurricane as of the most recent advisory, with 75mph (120 km/h). Idalia is moving faster this morning, towards the north at 22km/h.

The hurricane is forecast to deepen rapidly today, approaching the Big Bend region of Florida by early Wednesday morning, before crossing the state and emerging on the Atlantic Coast later in the day.

Forecasters at the National Hurricane Centre are expecting Idalia to strengthen to a major category 3 hurricane before landfall, with winds exceeding 120mph (195km/h). Isolated tornadoes are possible as well across interior portions of Florida and Georgia during landfall on Wednesday.

The official National Hurricane Center forecast track of Hurricane Idalia through the upcoming Labour Day weekend. (NHC Image)

Hurricane, tropical storm and storm surge warnings are posted for a large swath of the Florida Gulf Coast, as well as the east coast of the US from Florida northward into the Carolinas. Storm surge near landfall is expected to be in the 8 to 12 foot range, producing catastrophic flooding and damage along the immediate coast. Heavy rain, in excess of 200mm (8 inches) is likely across Florida into Georgia and South Carolina. Coastal flooding is likely as far north as Cape Hatteras on the Outer Banks of North Carolina.

Idalia is entering deep, warm waters in the southeastern Gulf of Mexico, with rapid intensification expected Tuesday. Widespread evacuations have been ordered for coastal counties along the Florida Gulf Coast, and Governor Ron DeSantis has issued a state of emergency. 

Final note at this time, Idalia is expected to remain well south of New England and eastern Canada with no impacts forecast.

The lost summer of 2023

A spectacular double rainbow taken in Laval last week. Will a nice fall be waiting at the end of the summer rainbow, time will tell. (Photo T. Tsoukatos)

The nights are getting longer and a touch cooler in Montreal, and the trees are showing colour. Where has summer 2023 gone? It has not been a very good one from coast to coast to coast. Fortunately in Montreal, all we have to complain about is washed out BBQ's and family outings. Other parts of the country and across North America have been hit by extreme weather that has caused billions in damage and several fatalities. Montreal has received record amounts of rainfall this summer, and in August, only two days above 27C (80F).

Across the country, wildfires have scorched millions of hectares, over 3.5 million in Quebec alone. Several of the fires, like those in Halifax earlier this year and most recently Kelowna and Yellowknife, have displaced tens of thousands of residents and destroyed hundreds of homes. In Canada, four firefighters have died in the fierce wildfires this season.

Across the Prairies, crops have withered in prolonged intense heat and drought, while hail and grasshoppers, yes locust, have destroyed many more acres. 

There are those who don't like the term climate change, I won't debate that here, but our planet is certainly in distress of late.

Heavy rain from the remains of Hurricane Hilary flooded the parking area at Dodger Stadium in Los Angeles on Sunday. Hilary was the first tropical system in nearly 85 years to impact California. (Facebook Photo)

Expanding out further across North America, the central and southern portion of the continent is baking in extreme heat that has shattered records that have stood for over a century. Over the weekend, a powerful Hurricane Hilary moved into Baja California and eventually northward into California and Nevada, dropping amounts of rain in a 24 hour period not usually measured over the course of the entire year. Up to 250mm (10 inches) of rain fell across interior portions of southern California and the hills east of Los Angeles. Flash flooding and mudslides were the result, with a state of emergency declared in California. 

What's left of Hilary is moving northward Monday morning, spreading rain as far north as Montana, southern Alberta and B.C. Any rain would be most welcome across that region.

As I write Monday morning, the tropical Atlantic has become very active with 5 systems of interest including tropical storms Emily, Franklin and Gert. A fourth system in the Gulf of Mexico, may be named later today and impact coastal Texas later this week.

The latest Canadian community to be threatened by wildfires is Kelowna, B.C.. Thousands were evacuated over the weekend as the McDougall Creek fire spread rapidly towards West Kelowna. Hundreds of firefighters have been on the frontlines holding back the flames and saving many homes. (CityTV)

Nearly 12 million hectares have burned across Canada this year to date, the worst fire season on record. If you have not been directly impacted by fire, then you likely have been by the widespread smoke and poor air quality. Environment Canada had issued special weather statements and air quality alerts 897 times from 2017 to 2022. In 2023 to date, 3166 such statements have been issued by the government agency impacting everyone across the country. 

Lastly severe weather and tornadoes have been occurring in our region. While thunderstorms are not uncommon in Quebec and Ontario in July and August, the frequency and severity of the storms have been rather unusual. Damage and power outages along with flash flooding have occurred across both the Ottawa Valley and Saint Lawrence Valley as well as the Townships, Laurentians and Quebec City region. We have had multiple days with rare tornado watches or warnings across our region.

Severe thunderstorm watch posted for southern Quebec

In what has become an almost weekly event in Montreal this summer, a severe thunderstorm watch has been issued for Thursday. The main threat today will be heavy rain, but there is also the risk for strong winds and hail. The storms will arrive in the city during the late afternoon and early evening hours.

Another severe thunderstorm watch has been issued for most of southern and eastern Ontario, and southern Quebec through the evening hours Thursday. A cold front will move into moist unstable air late this afternoon across our region, with strong thunderstorms expected. The storms will develop around midday in Ontario shifting east and northeast into Quebec. The biggest threat today, as it has been most of this summer, will be heavy rainfall and the potential for flash flooding. This is especially true outside Montreal where the ground is saturated from recent heavy rainfall. Gusty winds are also possible along with the slight risk for an isolated tornado. Be weather aware today if you have any outdoor plans. As always lightning is extremely dangerous, so when the thunder roars go indoors.

The front should clear our region overnight setting the stage for a pleasant, cooler and less humid Friday. Enjoy it, the humidity and rain/storm threat returns for the weekend.

We have a very progressive weather pattern in place that has pushed front after front across the Saint Lawrence Valley every other day. The result has been more heavy rain for many parts of the province since the middle part of June. While the storm earlier this week produced only 11.4mm of rain in Montreal, amounts increased quickly once you left the island. On Ile Perrot, I measured 18mm, with 24mm falling in Saint Anicet, Quebec City 70mm and Gaspe 157mm. Large parts of southern and eastern Quebec recorded between 50-100mm.

This trend of alternating rainy and sunny days will continue into next week, as our excessively wet summer persists.

Another round of heavy rain and thunderstorms on the way for Montreal

Precipitation was well-above normal in Quebec and Ontario during the month of July, and it appears that trend is continuing into August. Widespread rainfall warnings are in effect for a large portion of the region.

Wash. Rinse. Repeat. What a summer it has been across North America and particularly here in eastern Canada. We managed two rare spectacular weather days days in a row without severe thunderstorm, flood or heavy rain warnings, but sadly that has come to an end. Widespread rainfall warnings and special weather statements are now in effect across Ontario and Quebec as strong low pressure is forecast to move across the region.

Our attention now turns to a moisture latent low pressure system and warm front lifting northeast from the Great Lakes down the Saint Lawrence Valley over the next 36 hours. Heavy rain is already falling in the Ottawa Valley and will move into Quebec during the day today. The rain will come in waves, with showers and embedded thunderstorms. Amounts will range from 25mm (1 inch) up to as much as 75mm (3 inches). Some of the storms may become strong, with heavy rain and gusty winds, especially overnight Monday.

Unseasonably strong low pressure is forecast to move down the Saint Lawrence Valley over the next 24 hours resulting in heavy rain and thunderstorms for southern Quebec and severe weather over the Ohio Valley into the Northeast and New England. (AccuWeather.com)

While August has been a little better in the Montreal region, with only 9mm of rain at Trudeau Airport since the start of the month, other parts of Quebec have not been so fortunate, with a soggy July basically turning into a soggy August. Quebec City had a record breaking 264.7mm of rain in July, and already 19.8mm to date for August. They will addd to that total considerably this week.

The rain has produced widespread flooding in many parts of the province and across New England. Over the weekend, more heavy rain lifted northward across Maine and into New Brunswick and Nova Scotia. Halifax measured 60mm of rain in just a few hours Saturday morning, with more flooding reported.

Over the upcoming week, the heavy rain and thunderstorms will result in additional flash flooding from the Ohio Valley across the northeast and New England and into southern Ontario, Quebec and Atlantic Canada. Dry air will try to return by Friday, but it will be short-lived, with more showers by the weekend for Montreal.

Temperatures will be in the low to middle 20s for highs and middle teens for lows. The weather will feel quite muggy for most of the week.

Montreal's soggy July comes to an end

A flash of lightning turns night into day over Ile Perrot last Friday evening. It was just one of  the many thunderstorms generated this July from warm and moist air locked into the region. A record-breaking 212mm rain fell in Montreal for the month.

That was one wet July, record-breaking for many parts of the province. In Montreal, 212mm (8.4 inches) of rain was measured at Trudeau Airport. Many parts of the island had even more rainfall. There were multiple instances of flash flooding from heavy thunderstorms. That amount broke the record of 182.6mm (7.2 inches) set in 1980 at then Dorval Airport. The McGill University record from downtown Montreal set back in 1958 (246mm) was also eclipsed, with 265mm (10.4 inches) falling. The normal for a typical July in Montreal is 89mm (3.5 inches), so we were 237 percent of the normal value, so it was wet to say the least.

Rainfall amounts were 200-300 percent above normal values across southern Quebec this past month. Many regions established new monthly rainfall records. Meanwhile west-central Quebec and northern parts of the province remained usually hot and dry. This allowed many forest fires to continue burning. Over 1.5 million hectares have burned in Quebec this year to date. (ECCC Image)

At my home on Ile Perrot, I recorded 183.2mm (7.2 inches). Both Quebec City (265mm) and Sherbrooke (258mm) also established new monthly records. Sherbrooke measured 81.1mm in one day on July 10.

The heavy rain across portions of  Quebec City, the Saguenay and Eastern Townships south into Vermont and upstate New York produced widespread, historic flooding in many locations.

Along with the rain was plenty of humidity and severe weather. Besides the flash flooding and hail, three tornadoes occurred in July in the province. Two EF-0 tornadoes, capable of 130km/h winds occurred at Mirabel and Saint Thomas on July 13. Meanwhile on July 18, an EF-1 tornado occurred at Brompton in the Eastern Townships. The storm, capable of winds of up to 155km/h, resulted in damage to homes a barn, crops, several trees and hydro poles.

 As if that was not enough, July also featured multiple days of poor air quality from forest fire smoke and days on end of fog and elevated humidex readings in many parts of Quebec. Montreal reached a steamy humidex of 42C (107.6F) on both July 5 and 6. However, the cloud cover and frequent rain did result in lower daytime highs in general across southern Quebec, but the same conditions produced very mild overnight temperatures yielding above normal temperatures overall in many parts of the region. The average in Montreal was 22.8C (73F), above the normal of 21.2C (70.1F).

Northern parts of the province into Labrador were downright hot this past July. On July 4, the warmest temperature ever recorded at Kuujjuaq near Ungava Bay was observed at 34.3C (93.7F). This smashed the previous high of 25.6C (78.1F) set in 1962. 

August has started off cooler than normal, but dry for a moment or two. That will change tonight and Thursday, as a warm front will result in more heavy rain and thunderstorms across the Montreal region. The weekend at this time looks dry and warm, but rain returns once again to start next week.

Severe thunderstorm watch in effect for Montreal

By now you know the drill in Montreal. We have a very unstable, warm and humid airmass in place, with a cold front arriving this evening. There is a risk for very strong thunderstorms today, a few capable of flooding downpours, strong winds, dangerous lightning and hail. Be weather aware today and  pay close attention to any weather warnings that may be issued. The best chance for thunderstorms will be very late this afternoon into the early evening in Montreal.

You know the drill by now in Montreal with this July producing countless thunderstorm days. A severe thunderstorm watch has been issued for southern Quebec for Friday afternoon into the evening hours. Thursday's heavy rain has left behind a very warm and humid airmass across the region. The low clouds and fog are in the process of burring off Friday morning, leaving behind a very muggy, warm and unstable airmass across our area. Temperatures will rise close to 30C (86F) this afternoon under partly cloudy, humid and hazy skies.

A rather strong cold front will arrive from Ontario this evening, igniting some strong to severe thunderstorms in the Montreal region. The storms will be scattered in nature, so not everyone will see one today. If they do occur, some will be capable of very heavy rainfall, gusty winds and hail. There is even the risk for rotation with some of the cells, so an isolated tornado can't be ruled out. The strongest storms will be from Montreal south and east of the city to the US border. Most of the activity will be in the late afternoon into the evening hours, before moving south into New York State by midnight and weakening overnight.

Saturday will cloudy and much cooler, with scattered showers and temperatures in the low to middle 20s.

We are closing in on the rainfall record for the wettest July in Montreal. As of Friday morning, Trudeau Airport had measured 176.2mm (6.93 inches) of rain for July. The all time record was 182.6mm (7.18 inches) set way back in 1980. We could break the record today, if storms occur close to the airport in Dorval. Many parts of the city have already received well over 200mm (8 inches) of rain this month.

Another round of heavy rain forecast for southern Quebec

Another round of heavy rain is expected across the Montreal region during the morning commute on Friday. While excessive amounts of rain are possible, we are not expecting any severe weather at this time.

Environment Canada has posted a special weather statement for southern Quebec including metro Montreal, for the overnight period into Friday morning. Another round of heavy rain along with embedded thunderstorms is expected to drop 30 to 50mm (1-2 inches) of rain across the region, with more possible in the most persistent storms. Some flash flooding is likely once again.

Thursday will be the best day of the week, expect mostly sunny skies, with a warm high of 28C (83F). Clouds will be on the increase this evening, as low pressure over Michigan moves northeast to lie near Cornwall, Ontario early Friday morning, and Quebec City by late in the day. Thunderstorms will develop during the pre-dawn hours, moving through Montreal during the morning commute. At this time I am not expecting any severe weather (strong winds, hail), just heavy rain. Some flash flooding is possible, along with ponding of water on area roadways. There will be a break in the rain mid-morning, with more precipitation developing during the afternoon hours.

Isolated thunderstorms during the afternoon will bring the threat for more heavy rain. Showers will persist into Saturday before skies begin to clear out late in the day. Temperatures will be cooler on Friday along with the clouds and precipitation, with a high of 22C (72F) expected. The highs over the weekend will be around 26C (79F), with lows of 18C (65F).

Waterways across all of southern Quebec are running high at this time, and the ground is saturated in many locations. Lac Memphremagog in the Eastern Townships, southward into northeast Vermont was under a flood warning on Wednesday, responding to the copious amounts of rain that has fallen in that region over the last week. 

July has been excessively wet across our all of southern Quebec, northern New York and New England. Montreal, Trudeau Airport has measured 106.8mm of rain through Wednesday. Other locations across the metro region have received even more, well in excess of 150mm. Meanwhile, 225.4mm has already fallen in Sherbrooke since July 1st, with 202.6mm in Quebec City, 141mm in Trois-Rivieres and 108mm in Vaudreuil-Dorion.

There is some good news in the forecast, the blocking pattern that has kept us so wet this month is showing some signs of relaxing it's grip next week. While the week will not be entirely dry, there will be a decent stretch of sunny, warm weather with precipitation finally at or slightly below normal for the week.

First two Quebec tornadoes of 2023

One final note, the Northern Tornadoes Project from Western University in Ontario has concluded its investigation into last Thursday's severe weather.  They determined that 6 tornadoes occurred along with 5 significant wind downbursts during the severe weather outbreak July 13 across Ontario and Quebec. In Quebec, two tornadoes occurred, both rated as EF-0, with estimated winds of 130km/h. One was reported near Saint-Thomas with second observed close to Mirabel Airport. Other storms produced hail and flash flooding in Montreal and Laval along with widespread tree damage and power outages.

Flash flooding - power outages sweep Montreal region

One of at least a dozen underpasses that flooded in Montreal after severe thunderstorms on Thursday afternoon. The flooding created traffic gridlock in the central part of the city, with the afternoon commute lasting late into the evening for many. (Photo Courtesy Ragini Patel)

I have been a weather enthusiast since just shortly after I could walk, and days like yesterday still amaze me as to how powerful mother nature can be. It was an extremely active day across eastern Ontario and southern Quebec, with several waves of severe thunderstorms. 

A supercell thunderstorm, one of several observed on Thursday across Quebec and Ontario, advancing on downtown Montreal during the late afternoon hours. (Photo Courtesy George Michel Boutros)

Environment Canada posted rare tornado watches for most of the region, and the storms delivered just after the noon hour, first in the Ottawa Valley, and then unfortunately, during the afternoon commute in Montreal.

Several supercell storms showed rotation, with a confirmed tornado touching down in Barrhaven, southwest of downtown Ottawa. The tornado, yet to be rated, produced significant damage to homes and cars, with at least one injury.

As the storms pressed east, more rotation was observed along the Ottawa River, with a funnel cloud reported in Vaudreuil-Dorion. There was also a confirmed tornado in Mirabel, north of Montreal. This prompted tornado warnings for the entire Island of Montreal. Wind damage was reported across Ile Perrot and the West Island, with several trees and branches down. Wind gusts to 111km/h (68.9 mph) was observed at Trudeau Airport, along with 2cm hail. Dozens of tress were toppled, many on the West Island along the Saint Lawrence River. Power outages mounted, with Hydro-Quebec already having trouble with transmission lines form the north due to forest fires. In all, nearly 500,000 were left without power in the province. This morning that number is down to 216,000 across Qubec, with 86,000 on the Island of Montreal. 

The Barrhaven, Ontario tornado. (Photo via Twitter@TheTaoOvMan)

Flash Flooding

The big problem for most of Montreal turned out to be water not wind. Torrential rain fell with the storms, this time over the central portion of the city. I measured officially 20.4mm in only a few minutes at my home on Ile Perrot, but the storms moved over my location quickly. Such was not the case in Montreal, where 38.2mm fell at the airport, with reports of up to 100mm in several neigbourhoods just to the east of the airport and towards the downtown core. 

At least a dozen underpasses flooded in the usually locations. Oddly enough on just about the 36th anniversary of the Decarie Flood of 1987, the Expressway once again flooded Thursday afternoon. It created traffic gridlock in the central part of the city. Other areas flooded included Cote-des-Neiges, Cote-St-Luc and Lachine, where several cars were inundated up to their roofs.

The severe weather pushed east of the city, with more rotation and funnel clouds observed around Trois-Rivieres.

Friday will be the calm after the storm, with lower humidity and a pleasant high of 26C (79F) under bright sunshine. A rare gem indeed, in what is turning out to be a very odd weather year across our region.

The calm after the storm, as the setting sun reflects off the debris clouds behind the cold front late Thursday on Ile Perrot. (Valley Weather Photo)

Elevated risk for strong thunderstorms in Montreal

Strong to severe thunderstorms are likely Thursday afternoon across the region, with another round of flooding possible in parts of southern Quebec, New York and Vermont. The main risk in metro Montreal will be gusty winds, small hail and heavy downpours. The greatest risk will be between 4-7pm for the city. Isolated tornadoes are possible across the region today.

Severe Thunderstorm Watch posted for southern Quebec

Flood Watch for New York and Vermont

There is an elevated risk of severe thunderstorms across southern Quebec and eastern Ontario during the afternoon and early evening hours today. Storms will develop in eastern Ontario and the Ottawa Valley around 2pm, arriving in Montreal during the afternoon commute. Heavy rain, frequent lightning, strong winds and isolated tornadoes are possible. This system has a history of strong thunderstorms across southern Ontario, Michigan and in the Chicago area last evening.

The last thing the region needs is more rain at this time, unfortunately that is exactly what is in the forecast. A warm front is in the process of lifting north of the St. Lawrence Valley Thursday morning, which will result in some brief showers and isolated thunderstorms for the next hour or so. After that Montreal will be in the warm sector for a few hours before strong low pressure and a trailing cold front arrive from the west.

Look for strong thunderstorms during the afternoon hours, producing 15-25mm of rain in some spots. This is not what the flood ravaged regions of the Townships Quebec City and Vermont need right now.

The threat for severe weather will diminish after sunset this evening. Look for muggy weather today and throughout the upcoming weekend. The high today in Montreal will be 27C (81F), with humidex reading well into the 30s.

Major flooding stabilizes in Quebec/Vermont - but more rainy humid weather expected

Water surges along the Montmorency River near the town of Saint-Brigette-de-Laval northeast of Quebec City. Flooding has forced numerous families from their homes in parts of southern Quebec after torrential rain fell Monday and Tuesday. (Photo via Facebook)

The historic flooding across Vermont and parts of southeastern Quebec is stabilizing on Wednesday as rivers fall near or below flood stage. The severe flooding was the result of a months worth of rain in leas than 48 hours across the region. Montreal remained on the western edge of the heaviest precipitation, and still managed 25mm to locally 50mm of rainfall. Across the Townships, Quebec City, the Charlevoix region and into Vermont and New York, between 100 and 200mm of rain was reported.

In Quebec, dozens of families have been evacuated along the Saint-Francois River in Sherbrooke, with several homes flooded. A local state of emergency is in effect in Sainte-Brigitte-de-Laval after the Montmorency River surged through parts of the community, washing out roads and flooding homes.

The Lamoille and Gihon Rivers combined to produce catastrophic flooding in Johnson, Vermont. Between 100-200mm of rain fell in 48 hours across the state producing severe flooding. All 14 counties in the state have received a federal disaster declaration. The water is receding slowly on Wednesday but sadly more rain is in the forecast. (Reddit Photo via Twitter)

South of the border, the entire state of Vermont has been declared a federal disaster area. Several agencies including FEMA are on the ground Wednesday assessing the damage caused by major flooding. Communities along the spine of the Green Mountains were the hardest hit, with the Town of Ludlow basically cut off from the rest of the state. Damage is severe, with dozens of roads in the state damaged or impassable. Every dwelling in downtown Montpelier, the state capital, sustained water damage after the Winooski River left its banks. Images are heartbreaking, showing the worst flooding since tropical storm Irene in 2011.

The good news is that outside of a few isolated showers on Wednesday, we actually have a relatively dry day ongoing. Temperatures and humidity levels will be more comfortable for the clean-up effort to begin. Unfortunately it will not last.

The same stubborn upper level low over Hudson Bay will continue to control the weather into next week, with fronts pinwheeling into the region. A warm front Thursday will generate more showers and thunderstorms, followed by the arrival of a cold front late in the day. Showers and thunderstorms will persist into Friday across the entire region. The temperature and humidity will also be on the rise making the outdoors rather uncomfortable into the weekend. More showers and storms are likely both Saturday and Sunday.

As far as new rainfall amounts are concerned, between 15-25mm is very possible in the most persistent thunderstorms by late Friday. Some areas in hard-hit central and southern Vermont may have as much as 50mm (2 inches) by Friday night. Keep in mind the ground is beyond saturated across most of the region (excluding Montreal) and any rain will cause sharp rises in waterways as well as potential flash flooding. Also with all the flood water flowing eventually into Lake Champlain, the lake is expected to rise by as much as 30-45cm (1 to 1.5 feet). This will also help to increase levels and flows in the Richelieu Valley.

Rainfall warning for metro Montreal

The storm system moving northward into our region Monday, has a history of severe flash flooding. Rainfall warnings are in effect for southern Quebec. Above, rushing flood waters inundate a parking lot in Orange County, New York on Sunday afternoon. (New York State Police Photo)

A slow moving saturated weather system is moving northward along the eastern seaboard on Monday, spreading more heavy rain and tropical moisture northward into New England and Quebec.

Environment Canada has expanded the heavy rainfall warnings westward to now include the City of Montreal. Look for rain, heavy at times to develop later this morning, accompanied by occasional thunderstorms. Amounts may exceed 50mm (2 inches) over the next 24 hours, with the heaviest rainfall expected over eastern and southeastern regions. The rain should taper off Tuesday morning, but the rest of the week will remain warm and humid with more thunderstorms.

Major flooding is occurring across New York and Vermont. The photo above was taken in Canandaigua, New York on Sunday. (Canandaigua Fire Department Photo)

So far around 5-10mm has fallen in southern Quebec, but radar is showing heavy rain just south of the international border, moving northward. I believe if any flooding were to occur in southern Quebec, it would be southeast of Montreal, in the Townships and Beauce. However, we will have to see where the axis of heaviest precipitation lines up later this afternoon and evening.

On Sunday, the storm system produced devastating flash flooding in the Hudson Valley of New York, spreading northward into southern Vermont. Radar estimates of up to 300mm have been reported in New York, described as a 1-in-1000 year flood for places such as West Point and Rockland. More heavy rain is falling today in Vermont, with strong wording from the National Weather Service about the potential impacts from flooding. Numerous water rescues have already been carried out. So far one fatality has been reported in New York State. In Vermont, between 25 and 100mm of rain has already fallen, with more on the way. Vermont Gov. Phil Scott has declared a state of emergency.

There is widespread damage and roads washed out in many places. Keep this in mind if your travels take you south into New York or New England.

Major flood event unfolding over the next 24-48 hours across portions of our region

Torrential rain and thunderstorms are likely to produce major flooding over the next 48 hours across southeastern Quebec, New York and New England.

Serious language is being used by several forecasters regarding heavy rain and the potential for dangerous flooding across a large portion of southeastern Quebec and northern New York and New England over the next 48 hours. If you live in a flood prone area pay close attention to weather conditions and additional warnings.

Heavy rainfall warnings are now in effect for a large portion of southern Quebec, just east and southeast of the metro Montreal region, including parts of the South Shore, the Townships and Quebec City. At this time, 25 to 50mm (1-2 inches) of rain is forecast for Montreal, with up to 100mm (4 inches) or more southeast of the city and across Vermont and northern New York. Flash flood watches and warnings are numerous across the northeastern US and New England. Isolated amounts may approach 200mm (8 inches).

Strong wording from the National Weather Service in Burlington, Vermont, comparing this event to that of Hurricane Irene back in 2011. Major flooding is anticipated, extending into southeastern Quebec. (NOAA/NWS)

Deep tropical moisture is moving northward into very unstable, humid air. The circulation along a warm front will draw in copious amounts of moisture from the Atlantic Ocean into our region. Rounds of heavy rain and thunderstorms are forecast to develop tonight and persist into Tuesday morning across the entire region. The rain will be torrential at times, with some locations along the US border and in the Champlain Valley receiving up to 50mm in less than an hour. The ground is already saturated in those locations, so any additional rainfall will simply runoff into local waterways producing major flooding.

Flash flooding has already been reported in southern New York and across northeast Pennsylvania on Sunday.

The National Weather Service in Burlington, Vermont is comparing the rain potential to that of Hurricane Irene back in 2011 that devastated parts of Vermont. They are calling this potentially a 100 year flood event for Vermont and portions of New York. The same wording is now be extended northward into parts of southern Quebec, especially the Eastern Townships.

Unsettled, humid weather to persist into next week for Montreal

A towering thunderstorm developing in the tropical airmass across the West Island of Montreal during Thursday afternoon. (ValleyWeather Photo)

A heat warning remains in effect for metro Montreal through Saturday. The combination of warm temperatures and high humidity will make it rather uncomfortable for outdoor activities.

A weak cold front is in the process of moving across southern Quebec early Friday afternoon. The front is expected to produce some widely scattered showers and thunderstorms, with the bulk of the activity occurring south and east of the city. The front will wash out over the next 24 hours, leaving us in the same warm and humid airmass well into next week.

Several rounds of showers and possible thunderstorms are forecast right through Tuesday. Most of the time the weather will be dry, but when the storms do occur, they have the potential to produce torrential rain locally, with the risk for flooding.

A flood watch is in effect for northeast New York and Vermont Friday, where flooding has already occurred this week. Conditions have been fairly dry in the Montreal region, with only a few millimetres falling at my home on Ile Perrot this week. Other parts of southern Quebec, New York and New England have reported much higher amounts, mainly in areas that have received persistent thunderstorm activity.

Thursday was suffocating, with a high of 32.5C (90F) in Montreal, with humidex readings close to 40C. Montreal was actually one of the "cooler" locations, with many spots reaching into the middle 30s. The temperature remained warm overnight in the low to middle 20s. The heat prompted a record consumption of power across Quebec. During the afternoon hours, at the peak of daytime heating, a high tension line from Laval to the West Island of Montreal failed, plunging over 200,000 Hydro-Quebec customers into the dark and without air conditioning on one of the warmest days of the year. Traffic lights were out and some intersections became chaotic during the afternoon commute. Most of the power was restored by 5pm. 

Temperatures this weekend will be slightly cooler, in the upper 20s as a result of abundant cloud cover, but the muggy weather will persist.