Temperatures are set to surge near the 30 degree mark today in Southern Manitoba, once the humidity is factored in it will feel closer to 40 degrees celsius. Relief will come in the form of thunderstorms; atmospheric conditions will be primed for severe weather.
A potent system will track eastwards out of Saskatchewan into Manitoba this afternoon acting as a trigger for severe thunderstorms. Strong southwesterly winds aloft will overspread southeasterly winds at the surface; a summer-time signal the atmosphere is primed to produce severe thunderstorms.
Lets play out how storm evolution will likely occur today.
[Valid 4pm] In this model projection, we see ongoing storms in Southeastern Saskatchewan. Manitoba still largely remains thunderstorm free – until the forcing for ascent arrives and the capping inversion erodes.
[Valid 7pm] Explosive thunderstorm development follows around the dinner hour across Southwestern Manitoba; including Brandon, Neepawa, Morden, and Portage. Quickly growing into a large line of severe thunderstorms that will produce damaging winds up to 110km/h, 3-5cm hail, torrential rainfall, frequent lightning, and the risk of a tornado.
[Valid 10pm] an expansive line of windstorms will progress throughout Southeastern Manitoba. Likely clipping the Ontario/Manitoba border. This severe complex could become a powerful, long-track Mesoscale Convective Complex (MCS); as it transverses North Dakota & Minnesota through the overnight hours.
Note the triple-point – an axis of intersection between a warm, cold and occluded front. South of this intersection point (warm front), storm energy will likely build to a very-unstable value nearing 4000J/Kg. This is the region that will be watching for the potential of a tornado. The risk may continue into southeastern Manitoba through the late evening.
Our forecasting team at TransCanada Weather is cautiously watching long range model guidance. Between Tuesday May 28th – Thursday, June 6th, the evolution of a pattern supportive of heavy rain, severe thunderstorms & unsettled conditions will envelop parts of Canada. Read below to find out where.
PRAIRIES: Unsettled Conditions, Risk of Cold Core Funnels, Threat of Thunderstorms
The Prairies will have to contend with unsettled conditions. Including a pattern that may support the risk of cold core funnel clouds & areas of severe thunderstorms between late May to early June. This is be welcomed news for Alberta; contending with out-of-control forest fires.
GREAT LAKES: Heavy Rain & Severe Thunderstorms
A second area we are watching closely: the Great Lakes/Ontario region. A supportive pattern for flooding and/or severe thunderstorms is possible between Tuesday May 28th to Thursday May 30th.
Abnormally, deep troughing, seasonably deep height-falls, strong waves of low-pressure, concurrent with a southeast ridge. Will bring surges of warm moist air along with supportive wind profiles for severe thunderstorms and/or flood risk. A significant severe day will be possible within this regime across Southern or Northeastern Ontario.
Saturday, May 25th: after Thursday, the next threat for severe across Southern Ontario will come Saturday. Risks across Southwestern Ontario include: isolated damaging wind gusts, large hail & torrential downpours.
Additional considerations: drought conditions in the Southeastern US allowing mid-level dry/warm air to migrate north within stronger circulations. Abnormally-wet southern plains, increasing low-level moisture transport/PWAT values in stronger 850mb flows.
Alberta Clippers are synonymous for bringing snowfall lee of the Canadian Rockies, during December and January. These typically moisture-starved systems are fast movers, ejecting quickly out of Alberta, through the Southern Prairies – towards the Great Lakes. Read more about Alberta Clippers here.
A clipper is expected to form
in Northern Alberta Saturday evening. Normally, these systems are more of a
nuisance, accompanied by low snowfall totals and quick forward motion. On the
contrary, this weekends system will flourish. Thanks to clashing temperatures
and abundant Pacific moisture.
Accumulations will vary greatly throughout the Prairies, bearing in mind the heaviest snow will fall along a narrow swath. Current guidance suggests close to 15cm across the northern extent of the darker shaded region (in our forecast map). Including, Northern & Central Alberta. The heaviest snow (~20cm) will fall across Extreme Southwest Manitoba and Southeast Saskatchewan. *Model guidance has increased snowfall totals further into Southwestern Manitoba, where Environment Canada has issued snowfall warnings. Several warnings now stretch across parts of Prairies.
There will be another swath of snow tracking down the Rockies, bringing 10-20cm. It looks like Calgary will be limited to less than 5cm through Friday. By Saturday, a steep contrast in temperature envelopes the Prairies. Calgary will see a high of 9c and sunshine. Whereas, Eastern Saskatchewan will still be below freezing.
STRONG WINDS & BLOWING SNOW
Winds pickup between the
Grande Prairie – Whitecourt corridor early Saturday evening. Winds sustained at
or over 30km/h, gusting 60-80km/h. Gusty winds will overspread much of Alberta and
Southern Saskatchewan overnight Saturday into Sunday morning. The strongest
wind gusts aren’t expected to coincide with the heaviest swath of snow. Still,
freshly fallen snowfall, which is dry and light – will combine with gusty winds.
Bringing local blowing and drifting snow. Stay tuned to weather advisories, or
statements pertaining to any potential road closures.
An area of low pressure will strengthen as it tracks through the Upper Midwestern United States. Bringing accumulating snow and gusty winds across Northwestern Ontario. Summer-like heat & humdity returns to Southern Ontario.
TIMING & ACCUMULATIONS
Snow flurries will begin mixing in along Highway 17 late Wednesday evening. With wet snow falling by Thursday morning. By Thursday afternoon, anywhere along and south of Highway 11 will likely be seeing rain.
North of Lake Superior, precipitation will fall as a cold rain with gusty winds. Including the Thunder Bay area, where cold rain and gusty winds will lead to a miserable day.
By Wednesday afternoon or late evening, cold air will wrap around the deepening system. Heavy snowfall will begin accumulating in a line from Kenora to Dryden to Sioux Lookout to Pickle Lake. Continuing into extreme Southeastern Manitoba. Moderate to heavy snowfall and gusty winds will persist, increasing in coverage across Northwestern Ontario through the day Thursday.
Projected amounts are subject to change based on the track & timing of the low + Hurricane Michael. Current guidance suggests a large swath of 20-30cm. 30-40cm could fall locally.
Actual accumulations will be largely dependant upon key factors: track of the low, temperature, and snowfall ratios. Moisture won’t be an issue with tropical moisture from Hurricane Michael.
While Northwestern Ontario deals with heavy snow, Northeastern Ontario will be dealing with heavy rainfall. A large swath of 50-75mm is expected East of Lake Superior.
THE TALE OF TWO SEASONS
As Northern Ontario deals with heavy rain and snow, Southern Ontario will get one last blast of summer. Temperatures Wednesday will likely be soaring into the mid or high-20s. With abundant humidity making it feel into the 30s. Forecast temperature & humidity readings will challenge all-time October records Tuesday and Wednesday.
Tricky driving associated with an early taste of winter across Southern Saskatchewan & Southern Manitoba.
Snow begins today in Saskatchewan and Southwestern Manitoba, persisting into Wednesday across Manitoba and Northwestern Ontario.
A boundary separating cold and warm air will descend Southwards across Southern Saskatchewan & Southern Manitoba through Tuesday allowing temperatures to dip near the freezing mark. A drop in temperatures near freezing or just below is expected along a narrow band of light-moderate snow developing across the Southern Prairies. Concurrently, an area of low pressure will strengthen through Wednesday, as it tracks out of Montana into the Dakotas.
A narrow band of snowfall situated across Western Saskatchewan will increase in coverage and intensity throughout the evening, spreading across all of Southern Saskatchewan and Manitoba tonight. Continuing across a narrow corridor of Manitoba and Northwestern Ontario Wednesday.
This will be wet snow event for southwestern Manitoba (including Brandon). Light tree damage due to heavy-wet snow is possible Wednesday.
5-15cm is expected across a narrow swath from Extreme Southern Saskatchewan through Southern Manitoba.
Winnipeg will see a cold rain, changing over to wet snow. Timing of the changeover to wet snow is leading to uncertainty, regarding accumulation.
Higher elevation in the Parklands Region, may see higher accumulations near, or exceeding 20cm. Including Riding Mountain National Park and the Dauphin area.
The winter across Canada for many this season is expected to be cold, particularly for Saskatchewan, Manitoba, Ontario, and Quebec.
Through careful analysis of meteorological data, we have compiled a preliminary forecast for the winter across Canada for this winter. We will issue an updated version, should the situation warrant, in December.
For many places, we expect an early start to winter. Some places in Manitoba have already received accumulating snow. For Southern Ontario, we expect accumulating snow perhaps as early as late October.
Key Highlights – Frigid & Snowy Winter for Saskatchewan and Manitoba – Cold & Stormy for Ontario and Quebec – Potentially Historic Squalls for Great Lakes (NW and W Flow) – Several Winter Storms for Maritimes and NL but Not All Snow
British Columbia For this winter BC is expected to receive a relatively typical winter season. Normal precipitation amounts with normal temperatures will be present in the region. While a few colder outbreaks are certainly likely with some snow getting into the mainland, we expect nothing out of the ordinary.
Prairies From Alberta to Saskatchewan to Manitoba, we expect a frigid winter overall. While Alberta is expected to receive moderating temperatures throughout the winter from Pacific air flows, Saskatchewan and Manitoba are expected to be exceptionally cold, and at times, record-breaking with several rounds of ‘deep-freezes’. Precipitation is expected to be slightly above normal for Alberta, and above normal for Saskatchewan and Manitoba.
Ontario & Quebec Ontario is expected to be overall, cold this winter. Northwestern and Northern Ontario are expected to parallel the frigid air likewise to the Prairies. With the set-up of the storm track this winter, we expect more rounds of Colorado and Texas lows to infiltrate the Great Lakes and Southern Quebec for the first time in what has seemed to be a number of years. The cold air from Manitoba and Saskatchewan will provide flourishing variables to allow a well-above and significantly active lake-effect season in an NW to W flow. Preliminary indications represent a repeat of December 2010 across the region.
Quebec is expected to receive above-normal snowfall this year as several storms track through the interior NE of the USA this year. Temperatures will become vastly more frigid through Northern regions of the province.
Maritimes and Newfoundland & Labrador While the Maritimes and NL are expected to be active this year, it is expected at times, slightly milder air will target the regions, therefore, not all systems this year will be snow-makers. The regions will certainly be stormy this year, but several storms may end up more of a ‘wintry-mix’, rather than snowstorms. Temperatures will be slightly more moderated at times, although at times, cold bouts are certainly likely.
Territories The Yukon is expected to receive slight benefits from Pacific air and a slight ridge at times over Western Canada/Western USA, providing relief at times relative to the typical winter in the region. Conversely, NWT and Nunavut are expected to receive normal precipitation
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.
This photo posted to twitter shows a flipped camper in Margaret Bruce Beach. Located near Silver Ridge.
This is the reason why we tell you not to take shelter in a trailer and your car during a tornado pics taken by Vanessa Whyte at Margaret Bruce Beach Campground near Silver Ridge MB last night #mbstormpic.twitter.com/B8ckD7fLxz
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.
Isolated severe thunderstorms are possible today (Monday June 25th, 2018) and tomorrow (Tuesday June 26th, 2018) in the Prairies.
A cold front will act as a trigger for severe thunderstorms today in Alberta.
The greatest risk for severe will center itself north of highway 43 and along and west of highway 63. Much of the severe activity looks to be staying south of Fort McMurray.
Environment Canada (PASPC) has placed this region in a “severe” risk on their map. Highlighting the risk for 3-6cm hail. Other threats include damaging winds in excess of 90km/h, and frequent lightning.
Environment Canada forecast map for today – highlighting the severe risk in Alberta. Please note: these maps are still in the experimental stage and are not currently operational.
A disturbance and associated cold front will move Eastwards out of Alberta tonight into Saskatchewan. The disturbance is expected to deepen as it centres itself over Central Saskatchewan Tuesday Afternoon.
The cold front will act as a trigger for thunderstorms in Eastern Saskatchewan and Southwestern Manitoba between 2pm and 8pm – West to East.
Some of these storms could turn severe with frequent lightning, large hail, torrential rainfall and strong winds.
Environment Canadas Convective Discussion for Tuesday, June 26th.