Author: Troy Boone

Ontario

Potent System: Severe Thunderstorms & Pattern Change for Ontario…

[UPDATED] A strong fall-like system will track across Ontario and Quebec Friday, bringing a risk of severe thunderstorms. Heavy rainfall, strong winds and a pattern change is expected. Find out where.

Through the day Thursday, an area of low-pressure will deepen as it tracks from the Midwest into Northeastern Ontario, Friday morning. The low will mature as it tracks into Quebec by Friday afternoon.

A warm front, associated with the seasonably-deep low will push north across Ontario and Quebec Thursday morning into Friday. Concurrently, temperatures will soar into the high-20s Friday afternoon across Southern Ontario and Southern Quebec (near the border). Increasing dew-points will lead to muggy conditions feeling into the mid-30s.

Instability, very-strong upper-level winds, wind-shear, and marginal energy will lead to severe thunderstorms Friday. Ahead of a vigorous cold front, and strong upper-level trough where heights will be falling.

RISK & COVERAGE

The greatest risk for severe thunderstorms in Ontario will stretch from Central Ontario to Eastern Ontario. Coverage will be more isolated in Ontario than Quebec. These thunderstorms will be capable of producing strong wind gusts. Upscale growth into a squall-line bringing straight-line winds, heavy downpours and frequent lightning is possible.

In Quebec, atmospheric energy & cooler temperatures will be less favorable than Southern Ontario, but better forcing, shear, and instability will lead to isolated-severe thunderstorms. Risks include damaging winds, frequent lightning and heavy downpours. This will include the risk of supercells. The strongest risk will largely affect rural, unpopulated municipalities.

WIND & HEAVY RAINFALL

Regardless of thunderstorms, synoptic winds will be strong across Southern Ontario and Southern Quebec with this fall-like system. Widespread gusts between 50-80km is expected across a large swath of Ontario and Quebec, preceding the cold front and after its passage.

UPDATE: latest model guidance is suggesting that localized wind gusts of 90-100km will impact Ontario and much of Quebec.

30-50mm of rainfall is expected along a swath East of Lake Superior through Northeastern Ontario.

PATTERN CHANGE INTO FALL

The passage of the cold front will usher is much cooler and drier conditions by Friday night. Temperatures will struggle to get into the mid-teens by the weekend. A hard freeze is looking probable across Northern Quebec and Northern Ontario.

Alberta

Snowflakes Fly in Alberta Wednesday Morning



Environment Canada issues Snowfall Warnings and Special Weather Statements across Central Alberta Wednesday. 

A cold front decended on the province Tuesday into Wednesday morning, sending temperatures near or below the freezing mark.


An area stretching from Slave Lake to Jasper included in Environment Canada’s snowfall warning, which may see 10-15cm of snow. 

Edmonton was awaken to temperatures near the freezing mark. Barrhead saw temperatures drop below-zero with accumulating snow.

 Several wet centimetres can be expected across the region, draped in Special Weather Statements.

https://twitter.com/_shewanders/status/1039881424558481408?s=21
As you can see clearly, there are mixed feelings about the early snowfall shared by this social media user.

Edmonton will not escape the early taste of winter, with a couple wet centimetres possible. Even Calgary, could experience a few wet flakes Wednesday.   



Alberta

Environment Canada Issues Frost Advisories in the Prairies

Environment Canada has issued a frost advisory for much of Southern Saskatchewan and Central Alberta. 

Damage to sensitive crops is possible tonight.

SASKATCHEWAN:

Frost may damage some crops in frost-prone areas.

A ridge of high pressure building over the prairies will bring clear skies and cold overnight lows to Saskatchewan Tuesday night. Overnight lows are expected to be between 0 and -3 Celsius by Wednesday morning.

Special Weather Statement for Saskatchewan

ALBERTA:

Frost may damage some crops in frost-prone areas.

Overnight lows are expected to reach near the freezing mark. Frost is possible overnight.

Take preventative measures to protect frost-sensitive plants and trees.

Frost advisories are issued when temperatures are expected to reach the freezing mark during the growing season, leading to potential damage and destruction to plants and crops.

Special Weather Statement for Alberta

Newfoundland and Labrador

Powerful Storm to Develop Across Newfoundland & Labrador Tuesday

A seasonably-deep low pressure system will develop rapidly Tuesday; impacting Newfoundland & Labrador.

The central pressure is forecast to deepen an incredible 22mb in 24 hours, almost reaching the criteria to be considered a “weatherbomb”.
#NLwx

Far, and largely unpopulated, Northeastern Labrador will see snow mix-in. Accumulating snow is possible in Greenland.

Expect pounding surf of 3-5m and beach erosion in Labrador. As well as, heavy rainfall and strong winds. Strongest winds to 90km/h will remain well off the coast.

Projected Wave Heights

NEWFOUNDLAND:

Western sections will see locally-heavy rainfall with this system. The biggest weather story is focused on a sudden change in weather pattern.

Warm & humid conditions dominating the Province will end, at least temporarily, with the passage of a cold front.

A cooler much-drier airmass will move across the province West to East throughout Tuesday.

 

Ontario

Wet & Stormy Tuesday Across the Lower Great Lakes

Heavy thunderstorms expected Tuesday (August 21st, 2018) across Southern Ontario.

Rain-showers or thunderstorms are expected to begin moving into deep Southwestern Ontario overnight Monday into Tuesday. Convection will spread throughout Southern Ontario throughout the morning and afternoon as a maturing-low approaches from the US. Another round is possible by the mid-evening along the shores of Lake Huron.

BRIEF CLEARING? & HEAVY RAINFALL

There may be some brief clearing stretching from the Golden Horseshoe into Southwestern Ontario. This would add more energy and instability, allowing for some isolated severe thunderstorms capable of very-strong winds and short-lived rotation.

Much of the day however, is expected to be dominated by cloud, showers and passing heavy thunderstorms – perhaps several rounds. This could lead to locally significant rainfall-totals. With the threat of localized flooding. Widespread amounts between 30-50mm is expected.

BENEFICIAL RAIN:

East of Georgian Bay stretching into East of Superior will see a beneficial, soaking rainfall from this system. Which will help alleviate forest fire concerns, plaguing the region this summer.

WIND:

This will be an early fall-like system for the Great Lakes. As we move deeper into August we are beginning to enter a transitional period, where low-pressure systems produce synoptic rain and wind over a larger area. Widespread winds gusting between 50-70km/h are expected between Tuesday late-afternoon, and through the evening.

No need for “the end of sunmer blues” quite yet, temperatures by this weekend will be near 30c feeling closer to 40c with the humdity factored in.

Manitoba

One Man Deceased After a Tornado Strikes the Rural…

 

https://twitter.com/justinhobson85/status/1025576138192515072?s=21

Severe thunderstorms, including a tornadic supercell thunderstorm tracked across rural Western Manitoba, Friday.

Current indications suggest the tornado was on the ground for 30-45 minutes. Social media users also reported golf-ball to tennis-ball-sized hail, creating additional property damage – unrelated to the tornado. 

Alonsa, Manitoba was hit particularly hard. Photos and videos circulating across social media have shown significant structural damage to homes, trees and property. The RCMP has confirmed the death of one Alonsa resident, a 77-year-old man found outside his badly damaged home. 

The tornado tracking through Alonsa around 9pm CDT. Bluff Creek and Margaret Bruce Beach were hit particularly hard. 

This photo posted to twitter shows a flipped camper in Margaret Bruce Beach. Located near Silver Ridge. 

 

Alberta

Tornado & Damaging Hail Threatens the Edmonton Region

A potent severe weather setup is expected today (July 20th 2018) in the Western Prairies. 

Thunderstorm risk map for today. The highest severe threat is highlighted in red – which includes Edmonton in a risk for tennis-ball sized hail and an isolated tornado. 

Environment Canada Discussion (PASPC):

ALBERTA 

A low pressure system developing in Alberta with an associated trough swinging through west-central Saskatchewan in the afternoon will trigger scattered severe thunderstorms. The main threat with these storms will be large hail. In the northwest section, there is a potential for supercells to develop with the potential of producing a tornado. The severe potential will last into the evening but thunderstorms are expected to persist into the overnight.

SASKATCHEWAN 

A low pressure system developing in Alberta with an associated trough swinging through west-central Saskatchewan in the afternoon will trigger scattered severe thunderstorms. The main threat with these storms will be large hail. In the northwest section, there is a potential for supercells to develop with the potential of producing a tornado. The severe potential will last into the evening but thunderstorms are expected to persist into the overnight.

Environment Canada’s Thunderstorm Outlook for today July, 20th 2018. Highlighting an extreme risk for severe thunderstorms in the Capital Region.

TECHNICAL DISCUSSION

A low pressure system will form south of Edmonton today with an associated cold front extending southward along the northern foothills and warm front through east-central Alberta and into Saskatchewan. Severe thunderstorms will trigger along the cold front early in the afternoon. They will likely be isolated in nature at first, before becoming a severe line of thunderstorms. The warm front will track through the area in the morning followed by a trough in the afternoon. Severe thunderstorms are expected to trigger along the trough in the afternoon. There is the potential for the right conditions to align near and to the east of Edmonton for a tornado to form, with the potential extending into west-central Saskatchewan, albeit, less likely than the risk in Alberta. MLCAPE values are between 1500 to 2200 J/kg with 0-6 km shear values around 30 kt with values up to 40 kt in and around the Capital region in Alberta. RDPS prog tephis are indicating idealized veering hodographs, conducive to tornado development, however, tornado formation in this area will be highly dependent on a few factors: There is the potential that the low level shear will be too much for the marginal CAPE in some areas, essentially shearing the storms apart. As well, on the Saskatchewan side, LCLs are progged to be around 1500 – 2000 m, which is a little high for tornado development, whereas, on the Alberta side, LCLs are progged to be 1000 m, which is more favourable for the formation of tornadoes. In addition, models are indicating the formation of a dryline that will bulge out into the southwestern corner of the Lloydminster region which may also be an area to watch for a tornado to develop in the later afternoon hours.

*Please note this maps and discussions are currently experimental and are not currently operational on Environment Canada’s website. 

Please closely monitor Environment Canada alerts today. Take any warnings seriously and seek shelter immediately. 

We will be monitoring the situation attentively. 

British Columbia

British Columbia Prepares for the Wildfire Season

As the sun sets a helicopter prepares to dump water on a blaze near Williams Lake, BC Wednesday, July 12, 2017. Jason Payne – Vancouver Sun

After a devastating forest fire season in 2017, tougher penalties in an effort to reduce wildfire risk, have been made law this year – ahead of the dry season. Read more about new failure to comply measures put into law.

It is common for summer temperatures to peak between 30-35 degrees Celsius during the summer months in the Southern Interior. Coupled with long stretches of dry, sunny weather, and low relative humidity. 

Fire Rating July 17th, 2018. Natural Resources Canada.

Hot and dry weather will be the story through the beginning of this week with the Southern Interior reaching the low 30s. In Kamloops, an air quality statement, together with a heat warning have been issued. A respite from the heat is expected mid-week with the arrival of upper-level trough. 

As early as Thursday & Friday, cooler temperatures will spread across the Interior. A chance of rain and cloudier conditions will be welcomed in some communities – but others who see lightning could see new fires.

Current forest fires burning in British Columbia. 

On Vancouver Island, sunny and pleasant conditions are expected to persistent for many days. Coupled with low-humidity, the Victoria vicinity will see rising fire ratings. 

Unfortunately, high-pressure will return to British Columbia next week. Temperatures will once again soar into the high 20s or 30s. The dry season may persist well into August this year.

Ontario

Isolated Severe Storms Slice Humidity in Ontario & Quebec

Scattered thunderstorms are expected across the lower half of Southern Ontario and Southwestern Quebec today (July 2nd, 2018).

A weak cold front will slowly track across Southern ON/SQUE today acting as a trigger for thunderstorms. The frontal passage is not expected to offer much relief from the heat, but will lower humidity to more comfortable levels tonight and Tuesday.

The primary risk with these thunderstorms will be torrential rainfall. Due to slow movement of the frontal passage some thunderstorms may “train” or, regenerate over the same region bringing locally 30-50mm in a short period of time. Additionally, isolated damaging winds are possible – primarily in Eastern Ontario and Southwest Quebec where the greatest risk for severe exists. Small hail between pea and dime size is possible in the more robust updrafts across the entire isolated severe risk zone.

The timing for storm development today, will be between 11am-6pm. We have highlighted localized municipalities – stretching from the Golden Horseshoe into Eastern Ontario in a isolated severe threat.

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Manitoba

Heavy Thunderstorms Expected in Southeastern Prairies

Widespread heavy to severe thunderstorms likely late this evening – continuing into the overnight hours in Southern Manitoba and Southeastern Saskatchewan. 

 

A stationary front this afternoon in Northern Dakota will separate warm, moist air south of the international border, with warm, drier air in Southern Manitoba. Along this front, there is a risk of isolated severe storms in North Dakota this afternoon – staying stateside. 

A deepening system out of Rockies will trigger severe thunderstorms stateside and a second, more significant/widespread risk of thunderstorms this evening/overnight.

Environment Canada (PASPC) Thunderstorm Outlook. Valid 12pm Thursday to 6am Friday. Highlighting the risk for severe thunderstorms. Note: these forecast maps are still experimental and are not currently operational on Environment Canadas website. 

A second wave which is forecast to develop late in the day, stateside, is the one we are watching closely. Moist and unstable air creeps across the border into Southeastern Saskatchewan and Southern Manitoba this evening. The northern extent of the second wave is expected to cross the international border into Southeast Saskatchewan and Southern Manitoba sometime around midnight. 

There is still some uncertainty regarding evolution and timing of this convective complex. Such complexes also known as MCSs or MCCs – Mesoscale Convective Complex; are notorious for producing intense frequent lightning, flash flooding, and damaging to destructive winds. Large hail is also a possibility, during the initial storm development.

The risk moves out of Southeastern Manitoba into Northwestern Ontario pre-dawn Friday into Friday morning.

We will be monitoring the situation attentively into this evening and overnight.