Surge of heat and humidity for Montreal

A perfect retreat during the warm summer weekend, along the St. Lawrence River in LaSalle overlooking the Lachine Rapids. Just a few fair weather clouds dotted the sky the entire weekend, with comfortable daytime highs near 28C (83F), and lows near 16C (60F), along with low humidity. It was an ideal weekend for anything outdoors in Montreal. (Valley Weather Photo)

Widespread heat and humidity warnings are in effect from North Dakota to eastern Ontario and New England and will likely be issued for parts of Quebec for Tuesday.

Some of the warmest temperatures so far this summer are set to surge into southern Quebec and Ontario this week. How warm? Dozens of record highs were established in Manitoba over the weekend, as highs topped out in the middle 30s. Even overnight temperatures remained in the upper 20s. Humidex reading were as high as 45C. That heat is set to arrive Monday and spread east.

For Montreal, Monday will feature hazy sunshine, with a high close to 30C (86F). A few clouds and perhaps an isolated shower or thunderstorm are possible late in the day, but the risk is low. Warm southwest winds will develop Monday and increase on Tuesday, gusting 20-50km/h at times.

That breeze will usher in very high humidity, along with temperatures as warm as 35C (85F) across some southern Québec locations on Tuesday. Morning lows on Tuesday and Wednesday will be very warm, in the middle to upper 20s for most locations. Some smoke from northern Quebec forest fires is possible, especially in the Ottawa Valley.

On Sunday, parts of northwest Ontario, including Sioux Lookout, flirted with the 100F (37.8C) mark. There is a chance that some locations from Windsor, Ontario east towards western New York may reach 100F Tuesday. I think Montreal will remain below our all-time record high of 37.6C (99.6F) set on August 1, 1975. We should easily challenge the daily record high of 33.3 (91.9F) set in 1921.

Along with the heat will be high humidity levels, pushing humidex values into the middle 40s for most locations. A cold front late Tuesday is expected to produce some very strong if not severe thunderstorms along and south of the St. Lawrence Valley. There is an isolated risk of some supercell storms, that could produce strong winds, hail, heavy rain and even an isolated tornado. The threat would be between 6pm and midnight for southern Quebec.

Warm but less-humid weather will continue for the rest of the week, with seasonably warm highs in the upper 20s.

The fire situation remains serious across central, western and northern Quebec. Any type of outdoor fire remains prohibited across all of Quebec north of the St. Lawrence River, and is highly discouraged in other regions. To date, 295 fires have occurred in Quebec this year, consuming more than 102,000 hectares of forest. Of those fires, 227 were caused by human activity, with 56 blamed on lightning according to SOPFEU.

Beneficial rain for Montreal - fire danger remains high in northern Quebec

One of 200 wildfires burning across Quebec, this one located near Chisasibi, west La Grande and Radisson. (SOPFEU)

A slow moving front brought some much needed moisture to the entire southern Quebec region on Thursday. It was a slow, steady rain the produced 20-25mm across the region. While June was wet in Montreal, the rain was very localized in nature as we all know. This rain was widespread and at a manageable rate.

The moisture will certainly reduce the wildfire risk from the Saint Lawrence River south, but it remains high across northern and central portions of Quebec. There are over 200 wildfires currently burning across the province, with at least two out of control. As a result, an outdoor burn ban is in effect across most of the province north of the St. Lawrence River. This means if you have camping plans in the Laurentians, you will not be allowed campfires.

The region of far northern and western Quebec has had a very dry and warm spring and summer to date. A large area of the northwest Quebec recorded between 50 and 75 percent of normal precipitation for June.

The fires have resulted in the evacuation of several communities. SOPFEU, the provincial forest fire agency has over 900 firefighters and personnel battling the fires. This includes over 100 firefighters from British Columbia, Alberta and Prince Edward Island. Over 20 aircraft and 50 helicopters are assisting in the battle.

Warm and dry weather is expected to return to the province over the next week, with high temperatures exceeding 30C (86F) once again, along with very little rainfall. 

Most of the fires this year have been started by human activity, at last count 225. This displays firsthand the negative impact we can have on the forest fire season. This is why the fire ban is so important and backed by fines of up to $5000. According to SOPFEU, an additional 52 fires have been started by lightning strikes.

The current wildfire situation in Quebec, with an outdoor burn ban in effect for all of the province north of the St. Lawrence River. (SOPFEU)

Much calmer weather week ahead for southern Quebec

The weekend was spectacular across southern Québec, with sunny, warm weather. Conditions were less humid and thankfully no thunderstorms. (Valley Weather)

We are looking at the calm after the thunderstorms for most of southern Quebec. Last week was filled with multiple rounds of thunderstorms, wind damage, power outages, flooding and searing heat. By stark contrast, the weekend was calm and spectacular, finally dry for many, warm but less humid. 

High pressure has settled into eastern Ontario and southern Quebec to start the work week. This will keep low pressure well to our south across the Ohio Valley, eastward into the middle Atlantic states. This region will be the focus of heavy rainfall Monday along with thunderstorms. Flash flooding has occurred or is expected from Ohio east towards New York City. Flood watches are in effect from Virginia to southern New England.

Meanwhile here in Montreal and across southern Quebec and eastern Ontario, we can expect nothing but sunshine, with highs between 28C and 30C (83-86F). Overnight lows will remain pleasant, dropping into the middle teens. 

The next chance of shower activity will not be until Thursday, with the arrival of a cold front. Showers and scattered thunderstorms are possible. Skies clear out for Friday, with another fair weekend expected at this time.

Rainfall has been highly variable across our region this July. Parts of Ontario and Quebec have measured well over 100mm of rain to date, while Trudeau Airport sits at 24.5mm. I have recorded a paltry 2.6mm at my weather station on Ile Perrot. Municipalities on the West Island are still cleaning up from the major flood on June 22, while nearly 1900 homes were flooded in the Ottawa area on July 1st.

Thunderstorms cut power to over 125,000 customers across Quebec in sweltering heat

A powerful gust front enters the Montreal region form the north on Thursday evening, the leading edge of severe thunderstorms. Thunderstorms have been occurring everyday during our current heatwave, however this was the first cells that have targeted the Montreal region. The storms knocked out power to over 125,000 across the province. (Photo: Brenda Gartshore)

Heat warning remains in effect for southern Quebec and eastern Ontario.

For the third consecutive day, strong thunderstorms developed across southern Ontario, central and southern Quebec. The storms produced wind gusts of up to 100km/h, with 96km/h at Trudeau Airport. In addition to the winds, as with previous days, there were thousands of lightning strikes.

The result was predictable, with over 125,000 Hydro-Quebec customers left without power, and 250,000 in Ontario. Here in Quebec, the utility has been working all night, lowering the number to 50,000 clients early Friday morning, including 10,000 in Montreal and Laval. In addition to the downed power lines and in some cases utility poles, there was also damage to trees and several homes reported. The storms were moving quickly, which lowered the flood risk in Montreal.

The loss of power comes as we enter day three of a sweltering heatwave, that has pushed temperatures well into the 30s from Ontario to Atlantic Canada.

Here in Montreal, the temperature reached 32.3C (90F) on Wednesday, and 32.5C (91F) Thursday. Parts of Ontario reached the middle 30s, including Toronto at 36C (96F). Record highs stretched across Atlantic Canada as well. If you add in the elevated humidity levels, temperatures felt like the middle 40s for millions of Canadians.

Friday will be much of the same, hot and humid, into the 30s, with a risk of afternoon and evening thunderstorms. The thunderstorms have been potent, but isolated in nature. One firsthand example was Thursdays storm in Montreal. Trudeau Airport measured 23.5mm of rain in less than one hour, while at my weather station located on Ile Perrot, 24 kilometres to the southwest, I recorded nothing.

A weak cold front will move across the Montreal region overnight, bringing in only slightly cooler air but lowering the humidity considerably. The weekend will be partly sunny, with high temperatures in the upper 20s to near 30C.

Eastern Ontario hammered by storms - heat persists in Montreal

It was Ottawa's turn on Canada Day, as torrential rain turned parts of the city into a lake, including Highway 417 above at Bayshore Road. Record rainfall amounts exceeded 110mm in just a few hours as storms trained over the National Capital Region for hours. (OPP East Photo)

Heat Warning in effect for Montreal.

Severe Thunderstorm Watch issued for southwestern Quebec.

Another severe thunderstorm watch has been issued for the Montreal region on Thursday. Fortunately for flood weary parts of southern Quebec, the activity has remained west of the city over the last 48 hours across hard-hit Eastern Ontario. That may change Thursday.

Temperatures continue to be dangerously hot across a large portion of eastern Canada, with highs soaring into the middle 30s and humidex values in the middle 40s.

The high heat and humidity spawned several clusters of severe thunderstorms on Canada Day, with hours of torrential rain in the Ottawa region. The storms forced cancelation of the Canada Day celebrations on Parliament Hill, as well as many local events. The rain also set a July record for Ottawa, with 111.4mm falling in just a few hours. Like Montreal two weeks ago, that amount of water was too much for the urban sewer system to handle. Numerous roads and homes were flooded, with widespread damage to cars and basements reported.

More flooding in the central part of Ottawa near Highway 416. (OPP)

On top of the flash flooding, strong winds, over 100km/h in places, knocked down trees and power lines in a wide area from the Ottawa River south to the St. Lawrence Valley and west into southern parts of the province. Over 100,000 customers lost power between Ontario and far western Quebec.

The storms prompted tornado warnings for the second consecutive day. They also generated over 20,000 lightning strikes from Ontario south into upstate New York.

So what can we expect Thursday? More of the same, isolated strong to severe thunderstorms. This time, they may be a little closer to Montreal or even north of the city. The high for Montréal is forecast at 33C (92F). Overnight lows will be warm and muggy in the middle 20s. 

More heat is expected on Friday, up to 34C (94F). Some relief is forecast for Saturday in southwestern Quebec, as a weak cold front arrives with lower dew points behind it thus slightly less-humid. Warm temperatures however are expected to remain into next week.

Elevated heat and thunderstorms for southern Ontario and Quebec

Temperatures are forecasting to soar into the middle 30s across many locations in Ontario and Quebec on Wednesday. If you have outdoor plans on this Canada Day, do so carefully.

Happy Canada Day! Stay cool, stay hydrated.

Heat warning in effect for eastern Ontario and southern Quebec, including metro Montreal.

The heat is on! Numerous forms of weather warnings and advisories are in place for extreme heat, impacting millions of residents across the eastern United States and Canada, as high heat and humidity levels prevail. If that were not enough, we are contending with strong to severe thunderstorms as well.

Starting with the forecast, we are already warm Wednesday morning in Montreal, despite persistent cloud cover and even a few showers around. Temperatures are already in the middle 20s, with humidex values over 30C. Wednesday will be warm and humid, with a high near 33C (92F). There is a risk of strong thunderstorms late in the day. Overnight will remain very warm and muggy, with temperatures around 25C (77F). Thursday will be a repeat of today.

As far as thunderstorms are concerned, the risk remains high, but the exact location of the storms is not so clear. On Tuesday, several strong clusters of storms moved around the edge of the high pressure producing all this heat, sliding southeast across Ontario, between Cornwall and Kingston. The storms occurred in waves, prompting tornado warnings and resulting in damage. Widespread power outages occurred along with significant tree damage and flooding. Winds gusted in excess of 100km/h at sveral locations, and there were thousands of lightning strikes.

Similar storms are possible later Wednesday and again Thursday afternoon, stay alert if you have outdoor plans, especially across our western locations towards the Ontario border.

Wednesday will be hot. Some locations in Ontario and upstate New York, less likely in Québec, may flirt with the 100F mark Wednesday. On Tuesday, Windsor, Ontario reached 35C (95F), they are forecasting 37C (98.6F) on Wednesday. 

Montreal's warmest temperature occurred on August 1, 1975, when Trudeau Airport reached 37.6C (99F). Unofficially several downtown locations exceeded the 100F mark during the 1975 heatwave, however officially, the city has never hit the century mark. That record has come close to falling, but still stands after 51 years, and should remain safe this week.

Montreal heatwave to last through Saturday

Elevated heat and humidity is expected in Montreal through at least Saturday. Daytime high temperatures will range from 32C to 34C (90 to 95F), with humidex values well over 40C (104F).

A yellow weather warning for extreme heat is in effect for metro Montreal.

In fact, heat warnings and advisories of some form stretch across southern Ontario, southwestern Quebec and a large portion the Untied States, east of the Mississippi River.

Strong high pressure over the southern US is pushing a very warm and moist air mass into our region. Temperatures will rise into the low and middle 30s for some locations, with elevated humidity levels, especially Wednesday and Thursday resulting in humidex (real feel) temperatures over 40C (104F).

The reminders are the same with this kind of heat, drink plenty of water, refrain form strenuous outdoor activities, especially during the afternoon hours. Try to spend some time in air conditioned spaces if possible. The most simple advice is often the most difficult for some to follow, under no circumstances, none, do you leave pets or children unattended in vehicles.

Extreme heat can be a killer. Watch for heat exhaustion and heat stroke. Know the difference and most importantly know how to respond. Always stay hydrated. (NWS)

If you have plans to move on July 1st, as many do in Montreal, plan for very uncomfortable and at times dangerous conditions. Drink plenty of water, avoid alcohol, pizza is ok :) and take frequent breaks.

Little relief is expected overnight, with temperatures remaining very warm in Montreal, in the middle 20s (70s F). The cumulative effect of a few days of extreme heat is often what leads to health issues.

There is a chance of some strong thunderstorms late each day as disturbances in the atmosphere ride along the northern edge of the high pressure ridge. The first risk arrives Tuesday afternoon. Some of the storms may be severe, with high wind gusts and torrential rainfall.

Relief may arrive by Saturday as a cold front moves southeast from western Canada. The timing is not clear at the moment, but temperatures should cool slightly by Sunday.