Tag: Flooding


Powerful Line of Storms Threaten Damaging Winds in Manitoba

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.

Environment Canada Thunderstorm Outlook valid today. Noting an ‘Extreme Risk’ for Severe Thunderstorms. Navigate to their forecast here.

Severe Thunderstorm Risk; Brief Cool-Down; Another Blast of Heat…

Conditions will become favourable for the development of severe thunderstorms for a large area across Southwestern, Southern, Central and Eastern Ontario for Thursday, July 5th.

What to Expect
With continued rising temperatures, high dew-points, and daytime heating, a weak front will slice through the aforementioned regions and provide enough instability to bring-about some severe thunderstorms later in the day on Thursday.

While the dynamics are not entirely conducive to significant supercell development, a lack of shear, ultimately, will mitigate rapid intensification and development. The primary risk therefore, with these thunderstorms, will be quick flooding rains (25-50mm).

The greatest threat for severe thunderstorms will likely occur just east of Lake Huron, but likely 15-20km west of the major 401 corridor. The GTA and QEW should remain non-severe (overall) and regions around Cottage Country should receive rain showers.

1 or 2 severe thunderstorms on the northern edge of Lake Ontario cannot be ruled out.

A brief / slight cool-down (24-27C; less humid; and drier conditions), will arrive for the aforementioned regions on/for Friday, Saturday and Sunday.

What’s Next?
From te brief cool-down outlined above, temperatures are expected to rebound back into the upper 20s and low 30s for the next severel weeks (avg: 29-32C). This time around however, conditions will be less humid than the more recent surge of warmth.

As outlined in our summer prediction, isolated severe thunderstorms will continue across Ontario and Quebec for much of the summer.

Long-Range Outlook: Manitoba, Ontario and Quebec.
Continued above normal temperatures and relatively dry conditions are still expected for Manitoba, Ontario and Quebec. There is some potential for record-breaking heat once again somewhere in the last few days of July into early August for about a week.

Remember, summer thunderstorm forecasts  – severe and/or non-severe – represent a plausible scenario based on extensive weather calculations, parameters and up-to-date atmospheric data. Nothing is for certain, but outlines a possible or likely scenario based on the aforementioned points.

Please stay tuned, as we at TCW are monitoring this situation attentively.

Drive safe and always be alert during hazardous conditions.

For hourly and live storm updates around the clock, follow us on Twitter.


Evacuation Ordered for Brantford, ON

A parade of weather systems in combination with several factors, including record warmth, frozen ground/snowmelt, and ice-jams, have led to flooding along riverside watersheds across Southern Ontario.

The City of Brantford has been hit especially hard this morning, where a State of Emergency has been issued.

Evacuation Order

City officials have issued Evacuation Orders for any street identified in the following floodplain: Foster, Cayuga, Aberdeen, Strathcona, Pontiac, Tecumseh, Ontario, Port, Eagle Ave, Robertson, Dover and Baldwin.

Residents are urged to evacuate these areas of the city until water levels recede and the Evacuation Order is lifted.

High Water Levels Across Much Of Southern Ontario

All communities along river-side watersheds and their tributaries throughout Southern Ontario, are urged to monitor local watches, warnings and statements from their local Conservation Authority. Flood warnings remain in affect for many watersheds who are dealing with flood conditions.

Flood Statements: https://www.ontario.ca/law-and-safety/flood-forecasting-and-warning-program

The flood concern is expected to peak early this afternoon (Wednesday), when cooler temperatures and drier air arrives. A brief period of freezing rain north of the GTA, will make efforts challenging for cleanup crews who are working tirelessly pumping water to ease residential flooding.

What Caused The Flooding?

A persistent High pressure ridge off the coast of Bermuda is responsible for channeling Gulf moisture and record warmth that led to this early “spring like” flooding event across Southern Ontario.


Soaking Rain For Ontario and Quebec

A series of moisture-laden impulse waves that will provide a strangle-hold through the Southern and Central USA states will push Northeastwards across Southern Ontario, Eastern Ontario and Southern Quebec beginning Monday and lingering into Thursday.

Several days of moderate rainfall will tally up the precipitation totals to respectable amounts; ranging from 20-80mm based on the location as depicted on our map.

Due to many regions still having a more than measurable snow depth, localized flooding will be a widespread concern, particularly across ‘Cottage Country’, Eastern Ontario and Southern Quebec.
For regions across Southern Ontario, many regions are still dealing with isolated and ‘patchy’ ice from last weekends ice accretion: watch for localized pooling.

While some models are suggesting 100-125mm is possible over a ~60 hour interval for some regions near Lake Huron and Lake Erie, this is likely a slight over-achievement and we expect the upper threshold of totals to be more in-line with 80mm, with many populated locales receiving 40-65mm.

Is it all bad news? Absolutely not! Warm temperatures will surge through much of the aforementioned regions and potentially ‘tickle’ record-breaking on Tuesday as temperatures surpass the teens.

What’s to come afterwards? Temperatures will cool off, however, there is no significant frigid or arctic air in the forecast until at-least March, and confidence and certainty is somewhat low at this time.

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