Tropical storm Michael is currently on a NNW trajectory off the Yucatan Peninsula. Michael is expected to strengthen throughout early next week.
Rapid intensification before landfall is possible given key factors:
1. The compact size of the storm. 2. Little shear along the forecast track. 3. 30c Sea Surface Temperatures.
Land fall as a strong Category 2 hurricane is possible near Eastpoint, Florida. Dangerous Flash flooding with 200-350mm of rainfall is possible in the Tallahassee area. Coastal storm surge and wind gusts upwards of 170-200km/h are possible.
Georgia, and unfortunately, South Carolina will also see significant rainfall and winds gusting over 100km/h based on current model guidance.
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.
Tricky driving associated with an early taste of winter across Southern Saskatchewan & Southern Manitoba.
Snow begins today in Saskatchewan and Southwestern Manitoba, persisting into Wednesday across Manitoba and Northwestern Ontario.
A boundary separating cold and warm air will descend Southwards across Southern Saskatchewan & Southern Manitoba through Tuesday allowing temperatures to dip near the freezing mark. A drop in temperatures near freezing or just below is expected along a narrow band of light-moderate snow developing across the Southern Prairies. Concurrently, an area of low pressure will strengthen through Wednesday, as it tracks out of Montana into the Dakotas.
A narrow band of snowfall situated across Western Saskatchewan will increase in coverage and intensity throughout the evening, spreading across all of Southern Saskatchewan and Manitoba tonight. Continuing across a narrow corridor of Manitoba and Northwestern Ontario Wednesday.
This will be wet snow event for southwestern Manitoba (including Brandon). Light tree damage due to heavy-wet snow is possible Wednesday.
5-15cm is expected across a narrow swath from Extreme Southern Saskatchewan through Southern Manitoba.
Winnipeg will see a cold rain, changing over to wet snow. Timing of the changeover to wet snow is leading to uncertainty, regarding accumulation.
Higher elevation in the Parklands Region, may see higher accumulations near, or exceeding 20cm. Including Riding Mountain National Park and the Dauphin area.
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.
[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.
Environment Canada has issued a frost advisory for much of Southern Saskatchewan and Central Alberta.
Damage to sensitive crops is possible tonight.
Frost may damage some crops in frost-prone areas.
A ridge of high pressure building over the prairies will bring clear skies and cold overnight lows to Saskatchewan Tuesday night. Overnight lows are expected to be between 0 and -3 Celsius by Wednesday morning.
Special Weather Statement for Saskatchewan
Frost may damage some crops in frost-prone areas.
Overnight lows are expected to reach near the freezing mark. Frost is possible overnight.
Take preventative measures to protect frost-sensitive plants and trees.
Frost advisories are issued when temperatures are expected to reach the freezing mark during the growing season, leading to potential damage and destruction to plants and crops.