Another round of thunderstorms expected in Ontario & Quebec

I am back to reality after spending the last week on vacation in coastal North Carolina, a trip that was planned long before hurricane Florence. The Outer Banks fared well, there was standing water and sand on roadways, along with some beach erosion, but nothing compared to the historic flooding that continues in the rest of the state and into South Carolina.

Catastrophic damage in Dunrobin, Ontario after the EF-3 tornado last Friday, September 21. (CBC)

EF-3 Ottawa Valley Tornado
While I was away, summer ended and fall started with powerful thunderstorms in the Ottawa Valley. A strong cold front generated tornado producing thunderstorms late Friday afternoon. Environment Canada has confirmed three tornadoes with this extremely rare September outbreak. The strongest was a high end EF-3 tornado that produced wind speeds up to 265km/h. The tornado developed at 4:40pm near Dunrobin, Ontario, and moved east into Gatineau, Quebec. Damage was extensive, with nearly 50 homes destroyed in Dunrobin and over 200 buildings damaged or destroyed in neighboring Gatineau. Cars were flipped over and power poles were snapped like toothpicks, with thousands of trees toppled. An EF-2 tornado affected portions of Ottawa near Arlington Woods, with winds of 220km/h. A third EF-1 tornado, with winds of 175km/h hit the region near Calabogie and White Lake. The cleanup continues in earnest Tuesday, with officials worried about the new threat for rain and thunderstorms.

The outbreak produced at least 30 injuries, 5 of those critical. Power was out to over 250,000 residents in Ontario and Quebec after the storms late Friday. As of Tuesday morning, as many as 10,000 still remain without electricity. The City of Ottawa closed schools on Monday, and asked government employees to work from home, in an effort to relieve pressure on the cities infrastructure. On average, Canada records 60 to 80 tornadoes each year, but EF-3 and EF-4 storms are extremely rare in this country. Only one EF-5 tornado has occurred in Canada, at Elie, Manitoba on June 22, 2007, with winds of 420km/h.

Additional damage occurred from a second tornado near the Arlington Woods suburb of Ottawa (Edith Lalonde).

More strong thunderstorms
Low pressure over the Great Lakes, is forecast to move down the St. Lawrence Valley over the next 24 hours. Rainy, windy and cool weather is expected on Tuesday, as a warm front crosses the region. As much as 25-50 mm of rain may fall in Ottawa and Montreal. On Wednesday, a strong cold front associated with the low will sweep across the region in the afternoon, accompanied by showers and thunderstorms. Some of the storms may be strong, with heavy rain and gusty winds. At this time, it does not look like a repeat of the severe weather from last Friday, but we will need to see how unstable the air mass becomes Wednesday. Conditions will be warmer and more humid on Wednesday, with a high near 21C (70F) forecast for Montreal. Cooler weather returns Thursday into the upcoming weekend.

The calm after the storm on Hatteras Island, North Carolina. (ValleyWeather Photo)

Hurricane Florence inundates coastal North Carolina

First responders patrol the streets of New Bern, North Carolina on Friday morning, after the storm surge from Florence lefts as much as 10 feet of water in the community. (Global)

The center of hurricane Florence barely reached land Friday morning, slowly crossing the coast near Wrightsville Beach, North Carolina at around 6am. The once category 4 hurricane had 90mph winds at landfall, with numerous reports of gusts exceeding 100mph. The big story with Florence so far has been the tremendous amount of water that has accompanied the storm inland. The coast was inundated with a 6 to 10 foot storm surge along with battering waves. Widespread damage was reported to homes and infrastructure, especially in and around Wilmington. Power is out to over 600,000 residents in southeast North Carolina. Power lines and trees were down, with sand and water blocking many coastal roads. At 2pm Florence had 75mph winds and was located 35miles west southwest of Wilmington.

The Atlantic Ocean pours across North Carolina Highway 12 near the Village of Hatteras on the Outer Banks, during hurricane Florence midday Wednesday. (NCDOT Photo)

Torrential rain continues to fall across the coastal plain, with over 600mm reported in Atlantic Beach in the last 24 hours. The heavy rain is forecast to continue as Florence crawls along the coast at 5mph (7km/h). Forecasters estimate as much as 1000mm (40 inches) of rain could fall across the extreme southeast portion of North Carolina and adjacent South Carolina. There is a real concern for fresh water flooding lasting weeks as all that rain makes it into the rivers and streams.

The storm surge on Pamlico Sound, pushed the Neuse River over it banks Thursday night flooding New Bern under several feet of water. First Responders were forced to carry out nearly 200 rescues, with hundreds more trapped in their cars and homes. They were assisted by the Cajun Navy, a group of volunteers with private boats who assist in water rescues. The Cajun Navy were made famous after their selfless work in New Orleans after hurricane Katrina in 2005.

Florence is forecast to weaken while slowly drifting into South Carolina by Saturday. The forecast has the remains of Florence moving northward across the Appalachians and towards New York State by mid-week. Eastern Ontario and southern Quebec could possibly see strong winds and heavy rain from Florence by Wednesday. We will have to watch the system closely.

Unseasonable warmth, snow and hurricane Florence

An infra-red satellite image of hurricane Florence approaching the North Carolina coast early Thursday, September 13. (Tropical Tidbits)

It must be September. The weather has turned wild across parts of North America, as the seasons begin to do battle. While Montreal remains warm and humid, cold air has filtered into western Canada, with the first snowflakes of the season across northern Alberta and B.C. At the same time, no less than 5 tropical systems are in the Atlantic basin, including powerful hurricane Florence.

I will start here in Montreal, where high pressure will dominate our weather into the weekend. Sunshine will prevail, with very warm daytime highs of 27 to 29C (80 to 85F). We have a shot at some record highs late this week, especially Saturday, (29.4C, set in 1947, and Sunday, 26.9C, set in 1991). Our next threat for rainfall may actually come from the remains of Florence by next Tuesday. Plenty of weather has to happen before that scenario plays out.

Hurricane Florence
Hurricane Florence remains a formidable storm Thursday morning, despite some signs of weakening. The category 2 storm is located 325 km southeast of Wilmington, North Carolina at 5am, moving northwest at 24 km/h. Wind shear and dry air on the southern flank of the hurricane, has brought wind speeds down to 110 mph (175km/h), but Florence remains a very dangerous storm. Landfall is expected later today near Cape Fear, North Carolina, along with a surge of ocean water 6 to 13 feet high. The storm is expected to meander just off the coast of the Carolinas for as much as 36 hours while slowly drifting southwest. Forecasters expect a catastrophic amount of rainfall, perhaps in excess of 30 inches (750 mm). Widespread flooding is expected well inland. Georgia has been added to the list of regions under a state of emergency, which include Maryland, Virginia, North and South Carolina. While millions have evacuated, many remain behind, with the window of opportunity closing. Winds and seas are rapidly increasing this morning, with the outer bands of Florence already reaching the coast.

A beautiful but somewhat disturbing photo of summer snow taken Wednesday, September 12, in Fort St John, B.C. (Paula MacGregor)

Snow!
Finally, winter has returned to parts of Alberta and B.C., with up to 15cm of snow falling in several locations such as Slave Lake and Fort St. John. The unseasonably cold air mass has dropped temperatures below freezing this morning, including -2C (29F) in Edmonton. They can have it, I will take our hot, humid fall anytime over an early winter. We still have one week left to summer 2018.

Warm weather returns to Montreal - hurricane Florence expected to strengthen

Astronaut Ricky Arnold, from aboard the International Space Station, shared this image of Hurricane Florence on Sept. 10, taken as the orbiting laboratory flew over the massive storm. Tweeting from @astro_ricky, he said "Hurricane #Florence this morning as seen from @Space_Station. A few moments later, Isaac and the outer bands of Helene were also visible." (NASA Image)

Strong high pressure will build back into Montreal this week, after the passage of post topical storm Gordon Monday night. I measured just under 25mm of rain on L'Ile Perrot. The rain came to an end on Tuesday, but skies have been slow to clear. Look for sunshine to return by Wednesday afternoon, along with much warmer temperatures. By the end of the week, we may be looking at record warmth returning, with forecast highs from 27C to 29C (80 to 85F). The normal high for mid-September in Montreal is 20C (68F).

Hurricane Florence
The same high pressure that will provide southern Quebec and Ontario with ideal late summer weather, is also responsible for steering hurricane Florence into the Carolinas. At 2pm Tuesday afternoon, Florence was located 845 miles (1360km) southeast of Cape Fear, North Carolina. The storm was moving northwest at 17mph (28km/h), and was showing signs of strengthening, with category 4 winds of 130mph (215km/h). A hurricane watch is in effect for the North and South Carolina coast.

I am very familiar with the Outer Banks of North Carolina, having vacationed there since 1991. The 200 mile long chain of barrier islands is beyond beautiful, but also very fragile. The region is no stranger to hurricanes and powerful ocean storms, but Florence has many concerned. Hatteras Island, my location of choice, was the first to be evacuated, starting at 12pm on Monday. Evacuations have since been expanded to cover the region from coastal Maryland south into South Carolina. Millions of residents and tourists are heading inland today.

Florence is taking an unusual path westward towards the coastline, being blocked by the aforementioned strong high pressure centered north of Bermuda. Typically storms at this latitude move northeast out to sea. Florence is expected to approach the coast in the watch area by late Thursday, and then meander around coastal North Carolina through the upcoming weekend. A storm of this magnitude is capable of catastrophic damage. A storm surge of ocean water from 6 to 12 feet is possible as the center of Florence makes landfall. As much as 10 to 20 inches (250-500mm) of rain is forecast from the Carolinas into Virginia as the storm stalls inland. Significant coastal flooding and inland fresh water and river flooding is likely.

Mandatory evacuations ordered for the Outer Banks in advance of Hurricane Florence

Visible satellite image of a strengthening hurricane Florence early Monday morning. (NOAA)

1:00PM: Florence has exploded into a Category 4 hurricane with 130mph winds as of 12:30pm.

Dare County Emergency Management announced at 10am Monday, September 10, that a mandatory evacuation has been ordered for Hatteras Island effective at noon today. The evacuation will be expanded to the northern beaches including Nags Head and Kitty Hawk on Tuesday at 7am. All tourists and residents are urged to evacuate immediately in advance of a strengthening hurricane Florence. Tropical storm force winds and dangerous surf may arrive as early as Wednesday afternoon. Pounding surf is already lapping at the dunes along the Outer Banks.

Early Monday morning, Florence was located 625 miles southeast of Bermuda, moving northwest at 9 mph. The storm is rapidly deepening at this time, with winds of 105mph. Forecasters anticipate tht Florence will become a category 4 storm prior to landfall somewhere along the North Carolina coast by Thursday. There is still some uncertainty in the track and strength of Florence, but it is becoming more certain that the Carolinas will have significant impacts from this storm.

Gordon to bring heavy rain to Montreal - Florence takes run at east coast

Tropical activity has increased significantly over the last week. (NHC)

Hurricane season is well underway with 4 systems creating a stir in the Atlantic basin. The Atlantic hurricane season runs from June 1 to November 30, but September has always produced the most activity. Forecasters are tracking the remnants of tropical storm Gordon over Arkansas, tropical storm Florence, newly formed tropical storm Helene and soon to be Isaac.

The remnants of tropical storm Gordon are dumping heavy rain over the Midwest US. Amounts have been impressive, with 100 to 200 mm in several locations. Widespread flood warnings are in effect, as far north as Pennsylvania. A special weather statement has been posted for the St. Lawrence Valley and locations along the shoreline of the Great Lakes, for 30 to 60mm of rain on Monday. What is left of Gordon should pass fairly close to Montreal late Monday, with gusty winds and heavy rain expected.

Florence is expected to strengthen into a major hurricane this week while threatening the US east coast. (NHC) 

Florence
Our attention will then focus on tropical storm Florence. Forecasters at the National Hurricane Center are entering uncharted waters with Florence. This storm has been difficult to pin down, not following any rules, with numerous different scenarios at play. One thing is certain this morning, Florence will strengthen and become a major hurricane as it approaches the southeast US coast by the middle of the upcoming week. Models have the storm reaching at least a Category 4 status by Wednesday, with 140 mph winds. What the models can't seem to nail down is a track. While Florence could still turn northeast out to sea, that window of opportunity appears to be closing. A likely target appears to be somewhere along the Carolina coast. I fear for my beloved Outer Banks. Landfall, if any, is still 5 to 6 days out, so a lot can change, especially with fickle tropical systems. Stay tuned! In the meantime stay dry on Monday in Montreal.

Fall-like weekend for Montreal followed by tropical troubles

An AP photo of heavy rain and flash flooding in coastal Alabama on Wednesday, as tropical storm Gordon moved inland. The remains of Gordon will sweep into Ontario and Quebec early next week.

A refreshingly cool air mass is in place Friday morning across southern Quebec, with some of the coolest temperatures since early June. Temperatures across the region are in the single digits, including 8C (48F) at St Anicet and 9C (49F) across the West Island of Montreal. High pressure will crest across the region today into the weekend, with nothing but sunshine. High temperatures will be either side of 20C (68F), with overnight lows around 10C (50F). Abundant sunshine and light winds, will make it a perfect weekend for anything outdoors.

Tropical Update
The remains of tropical storm Gordon, which made landfall in Mississippi earlier this week, are meandering across Arkansas early Friday morning. The system has produced very heavy rainfall between 100 and 200 mm (4 to 8 inches) along its path inland. Widespread flooding has occurred, with warnings stretching northeast into the Ohio Valley. Gordon will continue slowly moving off to the northeast over the weekend, arriving in southern Ontario and Quebec by Monday. We can expect a decent swath of rain across our region, with perhaps 25 to 50 mm (1-2 inches) falling into Tuesday. As Gordon becomes extra-tropical, winds will increase, with gusts up to 50km/h possible in the St. Lawrence Valley. The exact track of Gordon through Quebec will determine where the heaviest rain and strongest winds will occur. I am not expecting any flooding issues locally, as it has been very dry of late. We need the rain in extreme southern Quebec.

Hurricane Florence weakened to a tropical storm early Friday morning, located 955 miles southeast of Bermuda in the open waters of the Atlantic. The once powerful storm has encountered some shear, but this will be temporary. All indications are that Florence will restrengthen over the weekend and perhaps take a run at the Eastern Seaboard. It is very rare for a storm in this location to impact the east coast. Typically they will curve out to sea. However, Florence is being blocked by unusually strong high pressure to the north, the same high pressure that has been giving Montreal our hot summer. Computer models have been all over the place with the eventual track of Florence, but recent runs seem to be leaning on a potential impact to the middle Atlantic region and perhaps eastern Canada. It is way too soon to determine the impacts, if any to the east coast.

I have been tracking tropical systems since hurricane David in 1979, so I will be closely watching Florence over the weekend, and posting updates.

Tropical weather from Montreal to Florida

The National Hurricane Center is watching three areas of disturbed weather in the Atlantic basin this Labour Day. (NHC)

6 PM Update: Tropical storm Gordon has formed in the Gulf of Mexico, 50 miles southwest of Fort Myers, Florida. A hurricane warning is now in effect for the central Gulf Coast. Landfall is forecast by late Tuesday close to the mouth of the Mississippi River.

Previous post: Summer does not want to let go on this Labour Day weekend in southern Quebec. A warm and humid air mass is dominating the weather across the eastern portion of North America. The pattern is very similar to that of July and August in Montreal, with steamy humidity levels and warm temperatures. Montreal remains on the northern periphery of high pressure located near Bermuda. As a result, the weekend has been partly cloudy with numerous showers and thunderstorms.

On Sunday, some heavier storms put down a quick 17mm of rain on L'Ile Perrot. Trudeau Airport recorded 10.4mm. Some parts of north end Montreal had between 30 and 50mm or rain. More strong thunderstorms and heavier showers are possible Labour Day Monday. Temperatures were capped in the middle 20s on Sunday due to the clouds and showers, but should be in the upper 20s Monday and Tuesday. Wednesday will likely be the warmest day of the week, perhaps even the month, with high temperatures into the lower 30s and more oppressive humidity. Overnight lows to start the week at least, will remain warmer than the average daytime high for early September of 22C (72F). A cooler, drier air mass will arrive by Thursday.

NHC forecast track for tropical storm Gordon.

Tropical Atlantic Update
September is the peak period of tropical development in the Atlantic basin. So it is no surprise that we are looking at three systems today. The first is Florence, a 60 mph tropical storm located in the far eastern Atlantic, 900 miles west of the Cabo Verde Islands. At this time Florence is no threat to land.

Of more concern this week, is the tropical depression located in the Florida keys early Monday morning. This system is forecast to become tropical storm Gordon on Monday afternoon. A tropical storm warning is already in place for the central Gulf Coast from Florida to Louisiana. The biggest threat from Gordon will be heavy rainfall and the potential for life threatening flash flooding. The Gulf Coast was soaked with heavy rain last week, and any additional rainfall will cause flooding. Gusty winds and a 2 to 4 foot storm surge are also expected as the storms approaches the coast late Tuesday.

The third area of concern is located off the coast of Africa. This area of disturbed weather will be watch closely by the National Hurricane Center for any signs of development over the next few days.