Friday, August 18, 2017

Clear skies forecast for partial eclipse in Montreal

Nearly 60 percent of the surface of the sun over Montreal will be covered by the moon on Monday, August 21 at 2:38pm. (Photo: timeanddate.com)
As the final countdown draws close for the start of the total eclipse on Monday, August 21, attention will be focused on the all important weather forecast. Millions of people around the US and Canada will be eager for clear skies to view, what is for many, a once in a lifetime event. The narrow path of totality, spanning only 70 miles (113km) wide, will be the main focus for viewing on Monday. But interest is high, even here in Montreal, where approximately 60 percent of the sun will be covered by the shadow of the passing moon. The eclipse will begin at 1:21 pm in Montreal, peaking at 2:38pm and ending at 3:12pm. The eclipse will be traveling across North America at approximately 1700 mph (2735 km/h), so pay attention! Totality, or in the case of Montreal the peak period, will only last for 2 to 3 minutes at any given location.

Partial eclipse of the sun; if skies remain clear on Monday, Montreal will be in for a rare celestial treat.
In a summer that has had more clouds than sun, there was a good bet that Monday's weather would impede viewing in Montreal. At the moment, that does not appear to be the case. Sunshine and warm temperatures are expected for southern Quebec. Some clouds are possible, especially along the US border and in eastern Ontario, but at worst, the skies would be partly cloudy. The best viewing weather is expected to be across western regions of the continent, with clear skies forecast across southern Albert and British Columbia south into the Pacific Northwest and the northern Rockies. As the eclipse travels southeast across the US, more clouds, along with showers and thunderstorms are possible from the Midwest into the Southeast. Other regions from the Great Lakes into the Northeast have a 50/50 chance of full on clouds or clear skies. It will likely be a daytime decision as to where some will choose to settle in and view this spectacular event. One guaranteed location for clear, safe and extensive viewing, will be online at the NASA website. Live steaming will occur at Eclipse Live. NASA will draw on the resources of 11 spacecraft, at least three aircraft, more than 50 high-altitude balloons and the astronauts aboard the International Space Station.

Wednesday, August 16, 2017

The tropics are heating up

Hurricane Gert is located in the open waters of the Atlantic, while three other areas of disturbed weather are being closely monitored for development. (Weather Nation)
Hurricane Gert is churning northeast through the Atlantic Ocean this morning, 765km south of Yarmouth, Nova Scotia. Gert is the second hurricane of the 2017 season, and the earliest G named storm dating back to the 2005 season. Gert is forecast to remain well offshore along the east coast, however large swells are being generated by the storm. Wave heights along the Nova Scotia coast are expected to be as high as 2 metres through Thursday. On the south coast of Newfoundland, the waves may reach up to 4 metres and 5 metres in the Grand Banks.

As we head into the thick of the Atlantic hurricane season, the tropics are heating up. No less than three areas of disturbed weather in the far eastern Atlantic Ocean have the potential to become tropical systems. A tropical storm is named when winds reach 39mph. The storm is officially a hurricane at 74mph. Forecasters at the National Hurricane Centre in Miami will be closely monitoring the systems for potential development and to evaluate the risk to the Caribbean and eastern seaboard.

Eclipse Weather
Monday, August 21st will be an historic day, as a full solar eclipse takes place across portions of the United States. Here in Montreal, 60 to 70 percent of the sun will be blocked by the passage of the moon, reaching a peak at 2:38pm. At this time, the weather looks perfect for viewing in Montreal and southern Quebec. High pressure will be in control, with sunshine and warm temperatures in the upper 20s.

Monday, August 14, 2017

Partial eclipse to darken the skies over Montreal

The partial solar eclipse on Monday, August 21st, will darken 60 percent of the sun over Montreal.
On Monday, August 21, 2017, a narrow swath of North America, from southern Oregon to the Carolinas, will be treated to a very rare celestial phenomenon:  A total eclipse of the sun will occur on this date, starting on the Pacific Coast at 9:06AM PDT and exiting the Atlantic Seaboard at 4:06PM EDT. The eclipse will produce total darkness for a period of one to three minutes along a 70 mile (113km) wide path stretching diagonally across the US from Oregon to South Carolina. The percentage of sun covered by the moon will decrease rapidly as you move away from the main path. Here in Montreal, our partial eclipse of the sun will start at 1:21PM, reaching close to 60 percent coverage by 2:38PM and ending by 3:12PM. Across southern Canada, the amount of sun covered will vary from 90 percent in Vancouver, to 70 percent in Toronto and less than 50 percent across Atlantic Canada. 

A narrow path of total darkness will sweep across the US from coast to coast during the solar eclipse.
Residents in cities along the path of totality are preparing for a massive influx of people coming to view the rare event. Gridlock is expected on the more than 20 interstates that crisscross the path. Over 200 million residents live within a day’s drive of the path of totality. Hotels along the path have been booked for well over a year for this date. 

If crowds aren’t your thing, you can watch the event live on your computer or mobile device, streamed by NASA at www.nasa.gov/eclipselive   NASA also has an entire website devoted to the eclipse, eclipse.gsfc.nasa.gov

The Royal Astronomical Society of Canada has a list of viewing events planned from coast to coast. The list can be accessed on their website, www.rasc.ca/solar-eclipse-2017

 A reminder to those who plan on watching the eclipse live and in person, make certain you use protective eyewear. Staring directly into the sun does damage to your retinas and can result in permanent vision loss. More information on eyewear can be found here www.eclipseglasses.com

 With darkness lasting for up to three minutes at each location along the path of totality, the sudden loss of daylight can drop temperatures by as much as 10 degrees. It can also play havoc with wildlife, creating confusion, albeit for a short period of time. According to NASA, eclipses occur due to the special coincidence of the moon and the sun being the same angular size. The sun is 400 times wider than the moon, but it is also 400 times farther away, so both coincidentally appear to be the same size in our sky. A total solar eclipse occurs when the moon crosses the path between the sun and the earth. This happens, on average, once every 18 months, with locations varying around the world. The last total eclipse visible in Montreal was on February 26, 1979. I was in 7th grade at the time in Verdun and very excited, to say the least. The school chose to keep students indoors, however, and the day was cloudy, limiting the effects in Montreal. The next total eclipse visible in the US and Canada will not occur until April 8, 2024, traveling from Texas northeast to New England. It will pass right over Montreal.  Let’s hope for a sunny day!

Tuesday, August 08, 2017

Montreal's summer weather in one word, unsettled

Damage in Saint-Joseph-de-Beauce from a confirmed EF-1 tornado on Saturday, August 5. (Radio Canada Photo)
If there is a word I have overused this summer, it is unsettled. I don't know how else to describe the days where we have sunshine, clouds and the ever present risk of showers or thunderstorms. There have been many. Since May 1st, Montreal's Trudeau Airport has recorded precipitation of a trace or more, on 65 of 100 days through August 8. On many of the other days, the weather has been overcast and cool, not exactly a summer of champions. Some like the cool weather, I don't. Our summers are too short to begin with, I like them to be warm.

This past weekend was just terrible, more clouds than sun, breezy, cold and at times wet. This followed a very stormy Friday, that had rounds of strong thunderstorms impacting southern Quebec. The wind gusted close to 80km/h at Trudeau Airport along with heavy rain. There were numerous reports in the city of downed trees. Some locations such a Napierville and St Constant reported major flooding as more than 100mm (4 inches) of rain fell on Friday alone. A sate of emergency was declared in Napierville. Thousands were also left without power. On Saturday, more strong storms occurred in Quebec, this time east of Montreal. Environment Canada confirmed the provinces fifth tornado of the season, and EF-1, capable of winds up to 170km/h. The storm struck Saint-Joseph-de-Beauce, south of Quebec City. Widespread damage was reported to trees and homes, along with power outages.

The forecast for the balance of the week into the upcoming weekend does not look great. Following the trend well established this summer, expect unsettled weather at best. Tuesday and Wednesday will be the best days of the week, with more sunshine than clouds and mild highs near 27C (81F). The rest of the week into the weekend will be partly cloudy and humid, with numerous showers and isolated thunderstorms. The best chance for rain will be in the afternoon each day. This trend will last well into next week, with temperatures close to normal. The normal high is 26C (79F) and low 15C (59F).

Solar Eclipse
Expect a rare celestial treat for North Americans on Monday, August 21. A solar eclipse will be visible across a large portion of Canada and the US. I will post details on the timing of the partial eclipse here in Montreal, later this week.

Wednesday, August 02, 2017

More strong thunderstorms possible through Friday

Flooding after Monday's severe thunderstorm under Cote-de-Liesse at Hickmore. Firefighters opened the manhole cover to release the flood waters. (CTV News)
Warm and humid weather is expected to continue Wednesday through Friday across metro Montreal. Montreal has not recorded a 30C plus temperature since June 18, when the mercury hit 32.1C (90F). The 30C free month of July, was only the eighth time in recorded history that this has occurred in Montreal. Weather records at Trudeau date back to 1942. The streak will come to an end today, if the city reaches the forecast high of 31C (88F). Strong thunderstorms are possible this afternoon, and again right through Friday evening, as the warm and humid air remains in place. Several impulses of energy will rotate through the warm air mass, generating the thunderstorms. Any storms that do develop will be possible of producing heavy rain, just like the storm Monday afternoon in central Montreal.

Flood waters gather in the parking lot along the Trans Canada Highway at Cote-Vertu on Monday, July 31. (Valley Weather)

Severe Thunderstorm Produces Flooding
On Monday afternoon, a strong isolated thunderstorm cell moved from Laval across north central Montreal towards Trudeau Airport between 4 and 5pm. The storm brought torrential rain, with between 33mm and 37mm falling in less than one hour in Saint Laurent and Dorval. The result was flooding of several basements and highways. Our parking garage and ramp here at The Suburban flooded rapidly from the torrential rain. Strong wind gusts in excess of 85km/h brought down several trees. Lightning and wind knocked out power to over 17,000 Hydro Quebec customers in metro Montreal. The thunderstorm also produced pea size hail. The storm rapidly dissipated as it swept southeast across the Island of Montreal. The isolated nature of this particular storm produced the heavy rain and flooding in a narrow swath through the city. I measured no rain at all on L'Ile Perrot, just 20 kilomteres to the southwest of Trudeau Airport.