An area of low-pressure sliding out of Colorado will undergo explosive intensification through the day Wednesday. This will be an blockbuster blizzard for portions of the Upper Midwest including South Dakota & Minnesota. 40-60cm+ of snow concurrent with 70-90km/h winds will cripple the region.
BLIZZARD WEAKENS AS IT MOVES INTO NORTHWESTERN ONTARIO
The explosive Colorado Low that will cripple South Dakota, will thankfully be weakening as it approaches Ontario. Snow will move into the Thunder Bay, Nipigon, Atikokan, Upsala area before midnight Thursday. Accumulating snow will combine with gusty winds between 40-55km/h, through Thursday night and Friday. It will be a good day to stay home and off the roads if you can.
Wawa to Timmins will see more ice pellets and wet snow, than rain. A transition to rain showers is expected throughout Friday Afternoon.
Kapuskasing to Hearst will remain as snow, where 15-20cm is expected to fall.
SOUTHERN ONTARIO IMPACTS
Strong wind, a surge of warmer air and rainfall will be the story across Southern Ontario Friday. A cool and partly-cloudy day Thursday, with patchy mixed precipitation. Largely confined to Southwestern Ontario.
Strong wind anticipated across Southwestern Ontario Friday morning. Strong Southeasterly gusts between 70-80km/h is expected north of Lake Erie and East of Lake Huron.
Temperatures in the afternoon will spike into the double digits across Southern Ontario. The Nations Capital Region will see the temperature climb near 9c. The trade-off will be a lousy day with occasional rain or showers Thursday. There is even a risk for localized thunderstorms early in the day Friday.
A risk of freezing rain supersedes an early February warm-up. A temperature roller coaster with a risk of freezing rain will be the story this week across Southwestern Ontario.
Rainfall and above seasonal temperatures are the story this evening into the overnight. Rainfall ends before morning, with temperatures falling throughout the day.
Be mindful around streams and creeks Tuesday morning. As well as, on roadways, where standing water could lead to hydroplaning. Rainfall and snow-melt will lead to higher water levels. Stay tuned to your local Conservation Authority for the latest information.
A freezing rain risk develops by Wednesday morning. This may be an extended period of freezing drizzle & freezing rain for locales north of Lake Erie, including the 401/402 corridor. Local freezing rain accretion may approach or exceed 15mm. Ice pellets and patchy freezing drizzle will be the story for the rest of Southwestern and Central Ontario.
There will be two waves of precipitation. The second translates across the region Thursday along a developing low-pressure system. There is some uncertainty in regards to the evolution of this system. Current model guidance suggests a northerly track, leading to a surge in temperatures (above freezing) across Southern Ontario, Thursday. This would be a big snow maker across Northern Ontario & Quebec.
Sporadic power outages are anticipated across portions of Southwestern Ontario. A stiff northeasterly wind (aiding in low-level cold delivery), will be enhanced over Lake Ontario. Bringing wind gusts to 40km/h downwind of the lake. Sporadic power outages will begin throughout the evening. Peaking between 8pm-12am Wednesday. An extended period of freezing drizzle will succeed the initial wave of convective-driven freezing rain. For regions East of the Escarpment, through South Central Ontario & the Northern GTA this will be a primarily ice pellet event. Briefly beginning as snow, especially stretching from the Bruce Peninsula through Northern sections of Central Ontario.
Heavy thunderstorms expected Tuesday (August 21st, 2018) across Southern Ontario.
Rain-showers or thunderstorms are expected to begin moving into deep Southwestern Ontario overnight Monday into Tuesday. Convection will spread throughout Southern Ontario throughout the morning and afternoon as a maturing-low approaches from the US. Another round is possible by the mid-evening along the shores of Lake Huron.
BRIEF CLEARING? & HEAVY RAINFALL
There may be some brief clearing stretching from the Golden Horseshoe into Southwestern Ontario. This would add more energy and instability, allowing for some isolated severe thunderstorms capable of very-strong winds and short-lived rotation.
Much of the day however, is expected to be dominated by cloud, showers and passing heavy thunderstorms – perhaps several rounds. This could lead to locally significant rainfall-totals. With the threat of localized flooding. Widespread amounts between 30-50mm is expected.
East of Georgian Bay stretching into East of Superior will see a beneficial, soaking rainfall from this system. Which will help alleviate forest fire concerns, plaguing the region this summer.
This will be an early fall-like system for the Great Lakes. As we move deeper into August we are beginning to enter a transitional period, where low-pressure systems produce synoptic rain and wind over a larger area. Widespread winds gusting between 50-70km/h are expected between Tuesday late-afternoon, and through the evening.
No need for “the end of sunmer blues” quite yet, temperatures by this weekend will be near 30c feeling closer to 40c with the humdity factored in.
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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