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.
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.
Rain and thunderstorms expected early Tuesday (May 15, 2018) in Southern Ontario.
A complex of rain and thunderstorms is developing this hour in the Midwestern United States. This weather system is expected to push East late this evening, bringing widespread rain and thunderstorms after midnight.
Ahead of this system, humidity levels will increase – with temperatures into the high teens lingering late this evening and overnight.
Windsor to Goderich – approximately 1am Tuesday.
Port Rowan to K/W to Shelburne – approximately 3am Tuesday.
GTA to Barrie – approximately 4am Tuesday.
Peterborough to Eastern Ontario – after 5am Tuesday.
Kingston to Ottawa – approximately 9am Tuesday.
Heavy rainfall and frequent lightning for communities impacted by the complex of rainfall and thunderstorms tonight. A lessor threat for small hail and gusty winds also exists.
Due to already saturated soil, and rainfall intensity, a Special Weather Statement has been issued north of Lake Erie.
Rainfall totals between 20-40mm is expected north of Lake Erie. Locally, up to 50mm is possible. Elsewhere, expect 15+mm.
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