Sunday, August 28, 2016

The 5th Anniversary of Hurricane Irene

Torrential rain consumed many villages in central and southern Vermont, including Quechee shown above. (NWS)
August 28th is the 5th anniversary of the multi-billion dollar Hurricane Irene arriving in Quebec. Irene had humble beginnings as a weak area of low pressure off the west coast of Africa. The storm was the 9th tropical system of 2011, becoming the first hurricane of the season. Irene would sweep across the Bahamas as a major Category 3 hurricane before weakening and heading for the east coast. Irene made the first of two landfalls on August 27, 2011 at Cape Lookout, North Carolina, as a high end Category 1 storm.

By the time Irene would rain herself out over Atlantic Canada, nearly eight million east coast homes would be without power, and insurable losses would approach US$10 billion. Irene would cause extensive damage to coastal North Carolina, with a storm surge washing over portions of the Outer Banks. The storm then moved inland southwest of New York City and tracked across Vermont and into the Eastern Townships of southern Quebec. Along her path torrential rain would fall, with as much as 250mm (9 inches) in less than 24 hours. The resulting flash flooding would heavily damage numerous villages and towns across the Catskills of New York and into the Green Mountains of Vermont. The flooding in Vermont would be the worst natural disaster in that state since the flood of 1927. In the end, 49 fatalities were attributed to the storm, including one in Quebec. The raging Yamaska River east of Montreal washed out a section of road, contributing to the drowning of a motorist.

A satellite image from August 28, 2011 shows Hurricane Irene engulfing New England and southern Quebec. (NOAA)
In Quebec, Irene produced as much as 150mm (6 inches) of rain in the Charlevoix region and sections of the Beauce and Townships. In Montreal, 65mm (2.5 inches) of rain fell in less than five hours. Winds gusted over 100km/h in Quebec, including a peak gust of 113km/h on Ile d'Orleans. In Montreal, the highest gust was 90km/h. The wind and rain contributed to power outages, with nearly 250,000 Quebec homes in the dark. The power at my home on l'Ile Perrot was out for over 20 hours. Final damage estimates in Quebec exceeded $130 million.

Irene was one of the first storms that tapped into the wave of social media. The storm threatened a large population along the east coast of the US, and was therefore heavily publicized. New York City was shut down for an entire weekend. In the end, many felt the storm was over-hyped. Unfortunately, this drew attention away from Vermont and upstate New York, where Irene was one of the worst natural disasters on record. Irene proved just how devastating a low-category hurricane can be, especially to inland locations.

Thursday, August 25, 2016

The tropics are heating up

NOAA, National Hurricane Center image of Hurricane Gaston, and Invest 99-L (orange X) in the Atlantic basin. At this time, Invest 99-L has a better-than-even chance of becoming tropical storm Hermine. The storm could then impact south Florida as early as this weekend.
We are entering the most active period in the Atlantic hurricane season, which typically runs from June 1st to November 30th. Most of the storms occur within a six-week period from late August to early October, focused around Labor Day.

Forecasters at the National Hurricane Center in Miami, Florida are currently watching two systems in the Atlantic basin. Hurricane Gaston is a minimal storm with 75mph winds, located over 1000 miles east of the Leeward Islands, and not any threat to land. Gaston is expected to weaken over the next 24 hours as it moves into cooler waters. Of more interest this morning to forecasters and weather nerds alike, is an area of showers and thunderstorms dubbed Invest 99-L, just north of Puerto Rico. Depending on your weather model of choice, this low pressure area could become tropical storm Hermine this weekend and impact south Florida. Beyond that, different models are presenting very different scenarios. If the system develops, and that is still not certain, it could swing northeast out to sea, or impact the waterlogged central Gulf Coast as a strong storm next week.

In any event, I will be monitoring this storm closely, as I have been doing since 1979 when my interest in hurricanes started. Many of these storms impact eastern Canada with heavy rains and strong winds. Case in point: Hurricane Irene, whose 5th anniversary is coming up later this week. Irene generated over $1.5 million dollars in damage and one fatality in Quebec back in 2011. It was also the costliest natural disaster in Vermont state history. I will have much more on Irene later this week.

Monday, August 22, 2016

Autumn-like start to the week

Another spectacular warm and humid morning sky on L'Ile Perrot this past Friday, August 19. Summer will take a brief break today before returning Tuesday.
A wet and windy cold front on Sunday afternoon ushered in a brief taste of fall for southern Quebec. This morning temperatures are as cool as they have been at any time this month. It was 14C (56F) at 7am on L'Ile Perrot. The front also added to our quickly-recovering summer rainfall totals, with another 15 to 25mm falling on Sunday, 21.6mm here on L'Ile Perrot. That actually lifts us to close to normal precipitation since June 1st, with over 125mm (5 inches) falling in just the last week.

Today will be partly cloudy and fall-like, with a high temperature near 20C (68F) and very comfortable humidity levels. Clear skies tonight will allow for cool lows between 10C and 14C (50 to 55F) in southern Quebec. On Tuesday, warm southwest winds will return, along with high temperatures rising rapidly to 27C (81F). The balance of the week will see a return to warm and humid weather, with highs approaching 30C (86F) once again. The warm weather will last through Friday, before another cold front arrives with showers and thunderstorms. At this time next weekend looks sunny, warm and dry.

Wednesday, August 17, 2016

Record rainfall for Montreal

Torrential rain slowed the evening commute in Montreal. A record-setting 67mm fell on the city in less than five hours Tuesday night. (ValleyWX Photo)

Tropical rains fell across southern Quebec and Ontario late on Tuesday, with a record 67mm at Trudeau Airport in Dorval, most of that falling between 2pm and 9pm. That amount shattered the previous 24-hour record for August 16 of 49.5mm, established in 1966. It also rapidly brought the August total for the city from nothing to 119mm in just four days. The average August rainfall for Montreal is 94.1mm. Heavy rain and strong winds created widespread power outages across the region. As of early Wednesday morning, nearly 100,000 Hydro Quebec customers were in the dark. That number has since fallen to around 35,000 as of noon, August 17. Hydro Quebec has not specifically mentioned the cause, but a substation in Mercier-Hochelaga-Maisonneuve was flooded and knocked offline last evening.

The rain and poor visibility may have also contributed to accidents in which two pedestrians were struck by cars, in different parts of the city. Some underpasses were also flooded, but for the most part the water drained well. The ground has been parched lately and water levels have been very low, so the runoff was quick.

Other amounts of rain reported last evening included 58mm at my home on L'Ile Perrot, 77.8mm downtown at the McTavish recording station, 75mm at Oka, 90mm in Wiarton, Ontario, 58mm in Kemptville, Ontario and 26mm in Ottawa. South of the border in Vermont, heavy localized rain from thunderstorms washed out a section of Route 100 in Duxbury.

Warm and humid weather will now be with us through the weekend, with highs from 28 to 30C (83 to 86F) and warm lows near 20C (68F). The humidex readings will climb from the low to middle 30s by the weekend. Scattered thunderstorm activity is possible over the weekend, in the soupy air mass.

Tuesday, August 16, 2016

Heavy rain warning for Montreal

Heavy rain warnings have been posted for Ontario and Quebec. 
( map)

Widespread heavy rainfall warnings have been issued by Environment Canada for southern and eastern Ontario and southern Quebec. The same system that has created the devastating flooding in Louisiana will lift northeast across the Great Lakes and towards Quebec. The good news is that the system will be moving fairly quickly through our region. Rain will spread west to east across Ontario this morning and into Montreal later this afternoon. The rain will be heavy at times tonight, along with thunderstorms.

The death toll has risen to nine in Louisiana after nearly 25 inches of rain. Widespread historic flooding is occurring. The photo above is from Prairieville, Louisiana. (Photo via Twitter @presleygroupmk)

At this time, we can expect 40 to 60mm of rain across the region, with as much as 70mm locally. The heavy rain comes on the heels of the 50 to 100mm that fell over the weekend, however we are not expecting any major flooding. Southern Quebec and Ontario were bone dry for the past six weeks and water levels are very low. We should be able to absorb the new precipitation without incident. There may be some minor ponding of water in low-lying areas and on roadways. Temperatures will be rather warm and muggy, with a high of 25C (77F) today and 27C (81F) Wednesday. Overnight lows will be near 20C (68F). Skies will slowly clear in Montreal on Wednesday.

Monday, August 15, 2016

Heavy rain from Louisiana to Quebec and Ontario

Historic flooding across Louisiana has resulted in at least four fatalities and thousands of evacuations and water rescues. (Photo via Twitter @cbcnews)
What a difference a few hours can make when it comes to the weather. In less than 48 hours, many portions of southern Quebec and eastern Ontario recorded more rain than in the previous six weeks. Heavy tropical rains, along with embedded thunderstorms, swept along the edge of a large Bermuda high to our southeast. Southern Quebec reported 50 to 100mm (2 to 4 inches) of rain over the weekend, the heaviest along the Ottawa Valley, through Montreal and into the Townships. Here on L'Ile Perrot, I measured 78mm from late Friday to early Sunday. That included nearly 27mm in just a couple of hours, during a thunderstorm early Sunday morning. The normal monthly rainfall in August is 94.1mm for Montreal. Some severe weather was also observed, with tree damage in the eastern Townships, as well as minor flooding being reported. In Ontario, at least two tornadoes were confirmed on Saturday, including an EF-1 (150 to 175km/h winds) along the shores of Lake Simcoe.

The soupy weather across eastern North America is the result of a large Bermuda high sitting off the east coast of the US. This system is pumping extremely warm and humid air north and west. Searing heat has been gripping the large east-coast cities of the US, as well as southern Ontario. We had a break on Saturday, as clouds and rain managed to keep the temperatures down here in Montreal. Along the edge of the high is a conveyor belt of moisture running from the Gulf of Mexico into Quebec. Therefore the closer to the Gulf, the more rainfall. Unprecedented historic flooding is occurring in Louisiana, with a least four fatalities reported. Thousands of water rescues have occurred, in addition to tens of thousands more evacuated. The flooding was the result of nearly 2 feet of rain in less than 48 hours. Damage is widespread across the state, including the closure of Interstate 10.

After the severe drought conditions of the last month, more rain is expected in southern Quebec late Tuesday and Wednesday, with perhaps another 25 to 50mm. Temperatures will warm up again for Monday, reaching 28C (83F) this afternoon in Montreal.

Thursday, August 11, 2016

Much needed rain this weekend

Tropical moisture may help alleviate some of the drought conditions in Ontario and Quebec this weekend. ( Map)
7AM Friday Morning Update: A few weak thunderstorms this morning deposited a few millimetres of rain on L'Ile Perrot and Montreal. This was the first precipitation in 18 days. More rain is expected this weekend, possibly heavy at times. A flood watch is in effect for northern New York and Vermont. The same conditions prompting that watch state side, will exist in southern Quebec, with 25 to 75mm (1 to 3 inches) of rain possible through Sunday. Temperatures will be warm all weekend, in the middle 20s, and it will be very muggy.

Previous post below:
It remains hot and humid across eastern Canada this week, but with no rain here in southern Quebec. The last rainfall in Montreal was way back on July 25th. Hot weather has returned this week, with daytime high temperatures well into the 30s on Wednesday. Montreal fell just shy of the 1944 record of 32.8C (91F), with a high of 32.5C (91F) recorded at Trudeau Airport. Ottawa reached 35C (95F), and Toronto a scorching 36C (97F).

Thursday will feature the exact same weather, but more oppressive, as humidity levels rise. Overnight temperatures in Montreal remained uncomfortable, in the low-to-middle 20s, with highs today expected to reach the low-to-middle 30s. Combined with the humidity, the humidex or real feel temperatures will reach 40C (104F). Starting Friday, deep tropical moisture will lift north from the Gulf of Mexico. As it interacts with a front over eastern Canada, heavy rainfall is possible. The rain will come in waves, along with very muggy temperatures. Expect showers and thunderstorms from Friday through Sunday. It will not rain all the time, but when it does, it could be rather heavy at times, with some local flooding. The possibility exists for 25mm to as much as 75mm of rainfall in some locations across eastern Ontario, southern Quebec and New England. The rain will be beneficial to the moisture-starved vegetation. Temperatures will remain warm, but not as warm as we have experienced, due to thick cloud cover. Highs in Montreal will range in the middle 20s, with lows in the upper teens.