We are closely tracking a quick moving low-pressure system which is expected to cross Southern Ontario beginning in the early hours on Friday and lasting into Saturday morning, before changing over to some wet snow.
We are expecting the showers to push in the Extreme South (Essex/Chatham/Lake Erie Shores) between midnight and 2am. An isolated thunderstorm can't be ruled out. By the morning hours (4-6am), widespread showers are likely for areas in and west of the GTA as well as areas south of Georgian Bay. Local thunderstorms are possible, especially along the Lake Erie shorelines. By the mid-morning hours (9-11am), the showers will have pushed into Central and Eastern Ontario. At times, the rain will be moderate to heavy intensity. Across the Extreme South, the rain may become lighter at this point. An isolated thunderstorm may be possible along the shores of Lake Ontario and Lake Erie. By the early afternoon (12-2pm), the rain should continue with a light to moderate intensity across Central and Eastern Ontario with some light, scattered showers lingering across Southwestern Ontario, including the GTA. The heaviest rain will continue to fall and remain in place across Central and Eastern Ontario extending from Algonquin through towards the Muskoka/Kawartha Lakes region. In the late evening (7-10pm), locally heavier showers including the risk of thunderstorms will exist from Algonquin Park through to Northumberland County. Into the early morning hours on Saturday, we are expecting to see a changeover from rain to snow across Southern Ontario. Total snowfall amounts will remain less than 5cm. Extending towards Timmins/Hearst/Cochran, snowfall amounts between 10-20cm are possible.
Rainfall
Blue or '1':
Areas in the blue or marked with a '1' can expect less than 15mm of rain. This includes much of Northern Ontario (minus areas near the Quebec Border). This area also includes Tobermory extending towards French River. These areas can expect rainfall totals between 5 and 15mm.
IF the system tracks slightly further north then expected, then each region (green, yellow, and orange) will move north. (I.e. French River would be in the green region)
Green or '2':
Areas in the green or marked with a '2' can expect between 15 and 25mm of rain. This includes three main portions of Southern Ontario. The first region is around Niagara where we are expecting between 15 and 25mm of rain. Local amounts just about 25mm are possible, hence the addition of the 'local 30mm' factor to this region. The second region is in Eastern Ontario. Areas across Prince Edward County can expect around 20mm of rain with amounts as high as 25mm. Further east, areas along the United States-Canada Border including Kingston, Brockville, Cornwall and areas further inland (Hawkesbury, Alexandria, Maxville, etc), these areas can expect between 20 and 25mm of rain. Local amounts, especially from Morrisburg north and east, local rainfall totals may reach between 25 and 35mm. We are not confident that this region will see the enhanced totals in the ‘yellow’ region, therefore, we have went with the more ‘safe’ option and did the lower scale. In the North, we are expecting between 15 and 25mm across much of the Bruce Peninsula extending into the Bayfield Inlet/Britt/West Nipissing areas. In Northern Ontario, this region also includes Gowganda.
Yellow or '3':
Areas in the yellow or marked with a '3' can expect between 20 and 40mm of rain. This includes a few parts of Southern and Northeastern Ontario. The first place around Windsor and Essex County. We are expecting between 25 and 35mm of rain with local amounts towards 40mm in this region. Directly in the City of Windsor, rainfall totals may be as low as 20mm. Towards the north in Sarnia, we expect rainfall totals in the range of 30 to 35mm, locally 40 to 45mm. Further east, we are expecting areas in and between St. Thomas, Woodstock, Cambridge, Mississauga, Toronto, Hamilton, and Long Point to see between 20 and 30mm of rain. Multiple places, especially near Kitchener, London, and Toronto, rainfall totals may peak between 30 and 45mm. In Eastern Ontario, areas in and including Ottawa, Kemptville, Napanee, Belleville, Brighton, Kaladar, Plevna and Cobden can expect between 30 and 40mm of rain with local amounts towards 45 and even 50mm of rain. The best risk at seeing near 50mm will extend from Ottawa and Perth west towards the orange leveled region or the area marked with a '4'. Towards the north, areas between and including Saugeen Shores, Owen Sound, Meaford, Parry Sound, and North Bay can expect between 25 and 35mm of rain, locally 35 to 45mm of rain. In Northern Ontario, areas in and between Temagami, Temiskaming Shores, and Kirkland Lake can expect rainfall totals between 20 and 30mm with local amounts towards 40mm.
Orange or '4':
Areas in the orange or marked with a '4' can expect between 25 and 50mm of rain. We have higher confidence in this region compared to the previous yellow region, hence the addition level on this map. This area includes portions of the shores of Lake Erie near Pelee Island and Rondeau Park extending towards Rodney. In this area, a widespread 30 to 40mm appears likely with local amounts near or over 50mm. Further north including London, Grand Bend, Huron, Dufferin and Perth Counties, Kincardine, Hanover, and Kitchener. Rainfall totals between 25 and 35mm appear likely with local amounts towards 40 or slightly higher seeming possible. Areas throughout the York and Durham regions can expect between 30 and 40mm of rain with local pockets near or slightly over 50mm. In Central and Eastern Ontario, this region includes Pembroke, Bancroft, Bon Echo Park, Peterborough, Orillia, Midland, Huntsville, Burk's Falls, and South River. Most of these listed places should see between 35 and 45mm of rain with local amounts towards 50mm of rain. Areas such as Huntsville or Bancroft may see local amounts between 45 and 55mm of rain.
Red or '5':
Areas in the red or marked with a '5' can expect between 30 and 60mm of rain. This includes a portion of Central and Eastern Ontario which includes Mattawa, Algonquin Park, Madawaska, Dorset, Haliburton, Minden, Gravenhurst, Woodview, and Bracebridge. Most places should see between 35 and 45mm of rain although local amounts between 45 and 60mm are possible.
Flooding
Alongside this heavy rain, we are expecting the already record flooding to continue to worsen.
The Ministry of Natural Resources and Forestry have issued a FLOOD WATCH for Southern and Northeastern Ontario.
Multiple local conservation areas have issued FLOOD WATCHES (brown) and FLOOD WARNINGS (red).
The Ministry of Natural Resources and Forestry including the MOST up-to-date flooding information can be found on their website: here.
Alongside these many flood watches and warnings, multiple municipalities have declared states of emergency due to this flooding. These municipalities include (as of 12am, April 26th):
- Bracebridge
- Huntsville
- Minden Hills
- Ottawa
Update: this list will no longer be updated.