Friday will be act as the calm before the storm. A pleasant day with single digit highs, light winds, and some sunshine. Beginning after midnight rain will start in the Windsor area. With a mixed bag of precipitation spreading throughout Southern Ontario during the pre-dawn & morning hours.
A moisture laden system will slide towards the lower Great Lakes late this evening, following along a boundary separating cool air across Southern Ontario with warm air south of Lakes Erie & Ontario. Concurrently, an arctic cold front will be descending southwards heralding the arrival of deepening trough over Ontario & the Great Lakes region for Sunday. Temperatures will be running much below seasonal Sunday, daytime highs will struggle to reach the freezing mark. Additionally, Lake-effect flurries or snow is likely across the northwesterly snow-belts.
The challenging aspect of this system will be determining how the air-masses interact. In forecasting situations like this, thickness (a function of the average virtual temperature between 1000 and 500 millibars; read more: https://bit.ly/2WykrG4) can be useful in determining precipitation types. Anywhere, along and north of the blue line will likely see rain change to wet snow. With a brief period of freezing rain or ice pellets possible. South of the red lines will see mostly rain. These lines will move southwards as we progress through the day Saturday. Meaning areas who see mostly rain near Lake Ontario and Lake Erie, may end as wet snow as the system departs.
OKAY SO WHAT DOES THAT MEAN – SNOW, RAIN, OR FREEZING RAIN?
Simply put, all of the above. Depending where in Southern Ontario or Quebec you reside.
The greatest threat for freezing rain will exist across the Ottawa and Montreal region. There’s potential for several hours of freezing rain for this area. And even a threat for appreciable accretion on untreated surfaces. The winds will be light, with temperatures teetering around freezing – largely mitigating any power outage threat.
Next, the snow. Any snow that falls will be wet, the greatest accumulations will be across the Dundalk and Haliburton highlands/highway 60. 10cm or more expected South of Georgian Bay. 10-20cm+ for the Haliburton Highlands. Across much of Southern Quebec – well north of Montreal. Mont-Tremblant National Park could see accumulations as high as 20-30cm. Highways 117, 309, and 105 will be snow covered and slick through Saturday afternoon and evening.
Finally, the rain. 20-40mm will fall along the lower Great Lakes. Including the GTA, Golden Horseshoe, Southwestern Ontario, & Eastern Ontario.
Our forecasting team is vigilantly monitoring a powerful low-pressure system expected to form North of the Texas Panhandle late this evening. The upper-level disturbance originating out of California, will coincide with a favorable setup for an explosive storm development. Read more about Panhandle Hooks’ here.
Did you know? It was an infamous Panhandle Hook which sank the SS Edmund Fitzgerald on November 10th, 1975.
This storm will feature strong winds, blizzard conditions, heavy rainfall, thunderstorms, and shifting ice-conditions across the Great Lakes. Almost everyone in Eastern Canada will feel the effects of this powerful storm. Read more to gain insight on how this storm may impact you.
BLOCKBUSTER BLIZZARD EAST OF LAKE SUPERIOR
Our forecast team is closely monitoring a soon-to-be rapidly strengthening Panhandle Hook, sagging into the Texas Panhandle. Gathering abundant gulf moisture before trekking towards the Upper Great Lakes. The storm will experience the most intensification while tracking Northeastwards through the Upper Midwest (United States), towards Lake Superior & Northern Ontario. Coinciding with an expanding strong to damaging wind field.
Confidence is considerable for a high-impact Low for regions N and NE of Lake Superior with likely 30cm or more of blowing snow contingent with 60km/h+ wind gusts. The heaviest snowfall will likely be 30-40km inland from the immediate Lake Superior shoreline. This is bad news (or good new depending on your prerogative), when considering how much snow has already fallen across this region. Some are running out of places to even put the snow.
The fiercest winds will not correspond with the heaviest snowfall rates. Still, inland locales such as Timmins & Kapuskasing will still have to contend with extensive blowing & drifting snow. Especially, once the low tracks into Quebec, with colder air and stronger gusts arriving on the backside of the low.
There will be a line of mixing of wintry precipitation likely from Sault Ste. Marie to Sudbury to the QC border. Including a brief period of ice pellets and rain-showers.
WIDESPREAD DAMAGING WINDS ACROSS SOUTHERN ONTARIO
Temperatures will begin to surge above freezing across Southwestern Ontario, as early as, late Saturday evening. Double-digit temperatures & strong Southwesterly winds will advance throughout the Southern half of the Province throughout the morning & afternoon. Rain-showers and even a risk of elevated thunderstorms is expected. Proceeded by, a sharp cold front & plummeting temperatures.
We anticipate extensive blowing snow and poor-visibility East of Lake Huron late Sunday evening through Monday. Avoid all unnecessary travel in the red highlighted area on our wind impact map.
The supportive track and strength of the low will herald in a significant damaging wind threat across Southern Ontario. The strongest winds could peak as high as hurricane force (120km/h), along the Northeast shore of Lake Erie. We anticipate wind gusts over 100km/h across Prince Edward County, and East of Lake Huron. Peak wind gusts will likely reach or exceed 90km/h across the rest of Southern Ontario.
The sudden onset of warm air, rainfall, and extreme wind gusts will bring treacherous ice conditions across the Great Lakes. Ice shoves may be damaging to infrastructure along exposed shorelines. If you participate in winter activities such as, ice fishing or snowmobiling, it would be a good idea to remove your ice hut from the Great Lakes. Avoid snowmobiling until ice conditions improve.
A NEW COASTAL LOW BOMBS OUT AS IT TRACKS THROUGH THE MARITIMES
The powerful storm sweeps through Quebec on Sunday, and will subsequently phase into a strong ‘weather bomb’ south of Yarmouth. Potentially, deepening below 970mb (967-969mb).
While the exact phasing & extend of warm air advection is not entirely set-in-stone, it appears the heaviest swaths of snowfall will likely be off the Gaspe Peninsula shoreline and into the North Atlantic, thereby mitigating what could have been 2 or more feet of snow.
Southern New Brunswick will likely experience a rain/snow/wintry mix. With amounts totaling near 10cm. Amounts increasing to 20-30cm across the Northern extent of the Province. Pockets of heavier enhancement, accompanied by similar conditions is expected across Extreme Southern Newfoundland
Timing Western New Brunswick – Late Afternoon Sunday Most of New Brunswick – Sunday Evening Nova Scotia – Sunday Mid Evening PEI – Sunday Overnight Newfoundland – Monday
Hardest Hit Gaspe (35-45cm) Bathurst (25-35cm) Edmundston (30-35cm) Campbellton (30-35cm) Extreme Southern Shoreline of Newfoundland (25-40cm)
DANGEROUS BLIZZARD CONDITIONS STRETCH FROM JAMES BAY THROUGH NORTHERN QUEBEC
A major blizzard is on-tap for much of Northern Quebec. The worst of the treacherous conditions will be felt across the mouth of the Rupert River, Southeast of James Bay. Where rural communities can expect winds over 90km/h combined with 15-25cm of freshly fallen snow. Extensive blowing/drifting snow & near-zero visibility is expected. Isolated communities across Central & Northern Quebec may become cut-off, briefly.
Winter returns to the Great Lakes, after an extended lull in activity and cold air between December and early January. Find out where, and, how bad the ‘next one’ will be.
An area of low-pressure tracks through Illinois late this evening. Tracking through Michigan & Northeast Ontario by Wednesday afternoon & evening. Precipitation begins as snow across Central, Northeastern, and much of Southwestern Ontario Tuesday evening.
Freezing rain and ice pellets begin after 9pm across the Windsor – Sarnia corridor. Changing to rain, with little impact. Freezing rain spreads north of Lake Erie through the overnight. 3-6 hours of freezing rain is expected before changing over to rain.
continues across much of Central, Southwestern, and Eastern Ontario overnight
into Wednesday morning. A lull in snow develops across the 400 corridor near
7am. Lowering snowfall totals across Southern Simcoe county; risk of freezing
South of the 401/402 changes over to all rain during the early morning. Freezing rain continues along the escarpment (West of Lake Ontario). A changeover to rain continues North & East throughout the afternoon, proceeded by brief freezing rain.
Snow continues North of Lake Simcoe and North of Ottawa through the afternoon. A extended period (5-8 hours) of freezing rain develops Wednesday afternoon in Montreal, after a period of snow. Conditions will be hazardous in the City.
A primarily snow event
stretching from Bruce and Huron county’s through Georgian Bay. Also, putting
parts of Eastern and Northeastern Ontario in a swath of 15-25cm. Little
accumulation north of Lake Erie, but watch for icing with the potential of
5-8mm of accretion before the changeover to rain. 2-4cm of snow across the GTA,
with brief freezing rain. A larger swath of 5-10cm of snow is expected across
the light blue shaded area on our forecast map.
A system developing in the Southeastern United States will track up the Eastern Seaboard this weekend, becoming a weather story across Eastern Canada.
A developing coastal system will bring a wintery mix across Southern Ontario, Quebec, and Northern New Brunswick.
A boundary will form in Southern Ontario between a cold & dry high-pressure system, and moist air arriving from the Southeast. Colder air will overspread Southern Ontario and Southern Quebec Saturday, owing to a cold Northeasterly wind. Concurrently, a large area of precipitation will push north into Southern Quebec and Southern Ontario.
Snow, mixing, rain and freezing rain is expected from Saturday morning to Sunday evening. Flurries will continue through Monday.
Across, Nova Scotia, PEI and much of New Brunswick will see primarily rain. Although, Northern New Brunswick could remain as a mix or snow depending on the track of the developing system.
Many residents East of Highway 6 and across the GTA have started the day with moderate wet snow.
A cold northeasterly wind will reinforce colder air by Saturday evening. Mixing or rain-showers will transition into a wintery mix of wet snow & ice pellets east of Highway 6, along/north of highway 407/7. Continuing through much of Central and Eastern Ontario (away from the lake shore). A few wet centimetres is possible. Especially for municipalities at higher elevation South and East of Georgian Bay. Please plan accordingly, as conditions will deteriorate through the day Saturday.
MARITIMES: Strong Winds & Heavy Rainfall
This system will be a rain and wind story across much of the Maritimes. The strongest winds, with gusts between 80-90km/h, will be located across the Bay of Fundy. Elsewhere winds across much of Nova Scotia, PEI and New Brunswick are expected to be gusting between 50-70km/h Sunday morning. Total rainfall amounts between 20-50mm is expected by Sunday afternoon. The heaviest rain falling in Southern New Brunswick and coastal Nova Scotia. Across Northern New Brunswick, a period of snow and mixing may persist into the overnight.
Flurries will begin north of the St. Lawrence Saturday evening. Montreal, and the Eastern Townships will likely changeover to rain late Saturday evening/overnight, with the arrival of warmer air.
For regions north of the St. Lawrence, this will be a snow and ice story. Stay tuned to further forecasts Saturday night through Sunday morning, this region could see a 5-8 hour window for freezing rain.
A strong cold front will act as a trigger for isolated severe thunderstorms across the Eastern Townships and Southeastern Quebec Wednesday. Damaging winds, torrential rainfall giving 25-50mm of rain in a short duration, frequent lightning and isolated supercell(s) are risk factors with these storms.
Thunderstorms may track into Northern New Brunswick bringing heavy rainfall and lightning as they begin to weaken and become elevated.
A developing area of low-pressure will track out of Northeastern Ontario into Quebec Wednesday, deepening rapidly. An area of height-falls & falling atmospheric pressure will overspread the warm sector, ahead of a seasonably sharp cold front. Temperatures will rise into the mid-20s with dew-points nearing 20c. Pockets of 1500J/kg of CAPE should develop across the warm sector. Largely unfavourable lapse rates will be compensated by a strong tendency for ascent. 65 knot, 500mb flow will overspread the Eastern Townships & Southeastern Quebec – ahead of an amplified, positively tilted trough. A modest low-level jet should be sufficient for moisture transport across the warm sector, and a damaging wind threat. Speed-shear and wind shear will be sufficient enough to sustain long-lived updrafts – well-tilted updrafts capable of rotating. A threat for stronger bowing-linear segments or super-cells exists between 1-5pm. Additional risks, include torrential downpours, frequent lightning and hail in the stronger updrafts.
Timing of the cold front and pre-frontal clearing will be important determining factors considering how severe thunderstorms will be.
Monday will be a pleasant seasonal day, dominated by high pressure and brilliant sunshine – across Southern Ontario & Quebec.
Wet, humid and stormy conditions start the week, with a risk of thunderstorms. Find out when and where.
Cloud, spotty showers, steady rainfall and humidity will make a return to Southwestern Ontario as early as tonight, with a warm front pushing northwards. Overspreading, the rest of Southern Ontario and Extreme Southern Quebec by Tuesday Morning.
Concurrently, an area of low pressure will strengthen along the Manitoba/Ontario border as it tracks towards Hudson Bay. 15-30mm of rainfall is expected in Northwestern Ontario. With wet snow mixing in across far Northern sections.
2 WAVES OF PRECIPITATION
The first wave of precipitation will arrive overnight tonight into Tuesday morning across Southern Ontario, moving into Quebec by the morning – ending early afternoon. Some embedded heavy-downpours is expended in a swath from the shores of Lake Erie to Niagara. Elsewhere, expect light to moderate rainfall and predominantly cloudy, warm and humid conditions. Dry slot arrives in the late morning to afternoon.
We will be watching Southwestern Ontario closely Tuesday, as any clearing could further destabilize the atmosphere increasing the risk of evening thunderstorms ahead of the cold front.
SECOND WAVE; RISK OF ISOLATED SEVERE THUNDERSTORMS
Associated with a sharp cold front – along a developing strong area of low-pressure forecast to deepen as it tracks through Northeastern Ontario and Quebec.
Thunderstorms will develop ahead of a cold front Tuesday night, persisting into Wednesday morning from East of Georgian Bay through Southwest Ontario. Isolated severe storms are possible. Bringing isolated strong wind gusts and heavy downpours.
A risk of isolated severe thunderstorms develops for Extreme Eastern Ontario and Southeastern Quebec late Wednesday morning or early afternoon, ahead of a sharp cold front. The primary risk will be damaging winds and heavy downpours. Isolated supercell(s) cannot be ruled out in Southeastern Quebec, but the risk will largely depend on timing & clearing.
Gusty southwesterly winds of 40-60km/h will overspread the risk area Tuesday. Becoming northwesterly through Wednesday. The strongest wind gusts of 60-70km/h will remain draped across Central Quebec and Nova Scotia.
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
[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.
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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2018 Canada Summer Outlook and Higlights Depicted Below —- July and August
– Heat Builds for Northern, Southwestern, Southern, Central and Eastern Ontario and Southern Quebec Beginning June 29th.
– Many Canadians are Expected to Receive a Warm or Hot July 1st (Canada Day!).
– Unusually Dry for Ontario and Quebec.
– Intermittent Rounds of Isolated Severe Thunderstorms for MB, ON, and QC.
– Decently Warm for SK and AB; Some Periods of Very Warm to Hot Weather.
– Wet BC Coast; Warmer and Drier Interior.
– Newfoundland and Labrador Likely to be Disappointed this Summer Due to Cooler and Wetter Conditions.
– ‘Bone-Dry’ for the Yukon, NWT, and Nunavut.
*Some Potential for Record-Breaking Heat (the Upper 30s) for Parts of ON and Parts of QC for the Last Week of July or 1st Week of August.
We at TCW are expecting overall, the country to be slightly above seasonal for the majority of the two months. We expect consistent heat to surge into Manitoba, Ontario and Quebec. While the heat will be slightly less humid as is typical, the heat will be quite consistent for the months of July and August.
It is expected that Manitoba, Ontario and Quebec will be quite dry for these two months, but, become inundated with intermittent days of isolated severe thunderstorms as a result of day-time heating.
The Maritimes are expected to warm-up as the summer progresses, while Newfoundland and Labrador is expected to remain cool and somewhat wet.
Saskatchewan and Alberta will have a few periods of hot weather (especially Saskatchewan), however temperatures will overall, be more warm to very-warm than hot.
British Columbia will remain seasonal and wet near the immediate coast, with the interior being drier and a few degrees above seasonal.
The Yukon, NWT and Nunavut will be slightly above seasonal and very dry.