A potent upper-level system will stall all week across Alberta and Saskatchewan. The unsettled pattern will bring much-needed rainfall, thunderstorms, much below seasonal temperatures, and even accumulating S*** for Banff & Jasper.
Beneficial rainfall will persist all week in Alberta & Saskatchewan as an upper-level system stalls across the region. The heaviest rainfall is anticipated across Central Alberta where 50-75mm+ is expected by Friday. With much of that rain falling between Wednesday and Thursday. Some rainfall is in the forecast for drought-stricken High Level (Northern Alberta) & Moose Jaw (Southwestern Saskatchewan).
The much below seasonal temperatures and a soaking rainfall will make it feel more like the middle of October across the foothills. By Wednesday, temperatures will plummet nearly 10c below seasonal. Continuing through the day Thursday.
DAYS OF THUNDERSTORMS CONTINUE WITH THE THREAT OF SEVERE TUESDAY
Thunderstorms have been an almost daily occurrence over the last several days in the Prairies. The thunderstorm risk is expected to continue this week.
Monday: thunderstorms producing heavy downpours and small hail across Interior British Columbia and Northern Alberta.
Tuesday: better dynamics for potent thunderstorms across Southern Alberta (Calgary to Medicine Hat). Discrete cells or supercells could be capable of producing damaging winds and large hail.
Wednesday: daytime heating thunderstorm risk moves further East into Saskatchewan.
ACCUMULATING SNOW KICKS OFF SUMMER IN BANFF & JASPER
Between Wednesday night through Friday, accumulating up-sloping snow is expected over the high-elevation topography of Banff and Jasper National Parks. Believe or not, Friday is officially the first day of summer.
A sudden surge of warm, summer-like air will herald in the risk of thunderstorms across the Lower Great Lakes. These thunderstorms may turn severe; capable of producing damaging winds & hail across portions of Southern Ontario.
SURGING TEMPERATURES, THUNDERSTORMS & RAIN
An area of low-pressure will transverse through the Midwestern United States towards Ontario, throughout the day Sunday. Ahead of the system, temperatures will surge into the mid-20s and humidity readings into the low-30s. Near the Lake-shore, cooler conditions are expected.
Showers are expected before midnight tonight, lasting into the pre-dawn hours. Persistent rain-showers and embedded thunderstorms are expected for Central Ontario – mainly East of Georgian Bay. Sunny breaks are anticipated through the morning hours, allowing for some instability to build before the arrival of a cold front.
At this point, it appears the setup will feature two potential waves of thunderstorms. The primary wave will consist of a complex of heavy rain showers with embedded thunderstorms impacting Southern Ontario between 4-10 pm. Initiating at approximately 4 pm in Windsor and exiting Eastern Ontario by 11 pm. Risks include: torrential downpours, lighting and isolated damaging winds. A potentially stronger second round of thunderstorms (along an advancing cold front) may happen on Sunday evening/overnight, across Extreme Southwestern Ontario. There is some uncertainty regarding the evolution of thunderstorm development. If thunderstorms do develop, risk factors include: hail and isolated damaging wind gusts.
Across Northern Ontario, a large swath of heavy rainfall is expected. Local rainfall totals nearing 50mm is anticipated.
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.
Heavy showers & thunderstorms beginning this afternoon in Sudbury and Algoma District. Continuing through the overnight.
An area of low pressure will rapidly intensify as it tracks through Northern Ontario towards James Bay. A sharp cold front will trigger heavy rainfall and thunderstorms today and tonight across Northeastern Ontario.
The primary threat will be torrential rainfall leading to minor flooding. Additionally, small hail and locally strong winds are possible in stronger thunderstorms.
Rainfall totals in the range of 30-60mm is expected north of Manitoulin Island & East of Lake Superior.
Alberto has been blamed for flash flooding, mudslides and power outages in parts of the Southern United States. The remnants of Alberto will churn into Michigan this evening – increasing humidity readings and creating unsettled conditions for Southern Ontario, beginning late this evening.
High dew-point values will envelop much of Southern Ontario Wednesday through Thursday. Overnight lows near or above 20C Wednesday night, coupled with dew-points in the high teens, will lead to stifling conditions in doors for residences without air-conditioning or central-air.
High humidity with temperatures in the middle to high teens will act as fuel for Thunderstorms Wednesday night in Southwestern Ontario – with a widespread risk for Thursday morning through evening for the rest of Southern Ontario.
The remnant low of Tropical Storm Alberto will act as a trigger Wednesday night and Thursday. As the remnant low approaches Michigan, bands of showers and thunderstorms will wrap around the low.
What is left of Tropical Storm Alberto as it churns north – towards Michigan. Still displaying well defined circulation and heavy rainfall.
On Thursday, the low will coalesce will a cold front and get absorbed by the Jet-stream. Upper-level energy and a cold front is expected to act as a trigger for widespread thunderstorms, some of which could turn severe. The primary risk with any thunderstorms that develop Thursday will be torrential rainfall and gusty winds. We will be watching Southwestern Ontario where rainfall could be an issue with minor flooding concerns.
A secondary cold front passage is expected Friday – which may act as a trigger for another round of thunderstorms. Again, rainfall will be the primary concern. Small hail is also a possibility.
It’s important to note, the next couple days aren’t expected to be a wash-out for everyone. Some locales may only see a few millimetres of rain. Whereas other locales, who receive several rounds of thunderstorms or training thunderstorms, could see locally 50mm or more.
Some solace from the humidity is expected by Saturday. Temperatures return to normal with brilliant sunshine and no humidity.
A deep-layer of tropical moisture will move well north into Canada. Reaching as far North as James Bay and Northern Quebec. Heavy rainfall is expected along a boundary between Lake Superior and James Bay continuing into Northern Quebec. Totals rainfall amounts between 40-75mm are expected in the next 48 hours in the region.
Daytime highs around 30C – challenge record highs across the Southern Prairies this week. Little reprieve in sight from Extreme fire conditions. Locally heavy thunderstorms expected by mid-week.
EXTREME FIRE CONDITIONS & RECORD HIGHS
The last full week of May will feel more like summer across the Canadian Prairies. Rising fire ratings this week, can be attributed to a large ridge in the Jet-stream – sending temperatures soaring up to 10C above seasonal. This has led to the first issuance of a Heat Warning for 2018 – for Central and Northeastern Alberta.
Hot and dry conditions have led to extreme fire conditions across the Canadian Prairies (Alberta, Saskatchewan & Manitoba).
Current Hotspots being detected by satellite show several brush, grass, and vegetation fires in Southern Manitoba – continuing into Saskatchewan.
Source: Natural Resources Canada. Retrieved May 22nd 2018.
“A hotspot is a satellite image pixel with high infrared intensity, indicating a heat source. Hotspots from known industrial sources are removed; the remaining hotspots represent vegetation fires, which can be in forest, grass, cropland, or logging debris.” – Natural Resources Canada
Fire conditions continue to worsen this week ahead of a threat for thunderstorms.
Fire Danger & Forecast High for Tuesday May 22nd, 2018.
Source: Natural Resources Canada
Fire Danger & Forecast High for Wednesday May 23rd, 2018.
Source: Natural Resources Canada
Fire Danger & Forecast High for Thursday May 24th, 2018.
Source: Natural Resources Canada
If you are a smoker, be mindful of where you throw cigarette butts. Avoid any outdoor burning or use of any source of ignition while outside.
RISK FOR THUNDERSTORMS MID TO LATE WEEK
The threat for thunderstorms develops Wednesday for Southern Saskatchewan. Moving east into Manitoba for Thursday. We are closely watching for a risk of severe thunderstorms for Thursday in Southern Manitoba. Thunderstorm risk retreats further west into Alberta for Friday and Saturday.
With thunderstorms comes the risk of lightning – an ignition source for fires.
Unfortunately, little relief from extreme fire conditions is expected due to the isolated and convective nature of thunderstorms. Conditions are expected to improve some – especially for Southern Saskatchewan – by late week.