Forecast for the upcoming storm (April 4) from Connor Mockett - Storm Chaser & Photographer.

There’s a lot going on with this, so strap in and read along. I will preface this post as well with this: This is a full blown ice storm for a large portion of the region. There will likely be power outages from this, as well as some tree damage (I’ll explain the trees later too). Different areas will experience different ice accumulations. It won’t just be freezing rain, there will likely be ice pellets around as well. So with that, let me begin.
Freezing rain and/or ice pellets will start moving into the region around 7:00am tomorrow, starting with the Ottawa Valley. It will then move further to the east, getting to Ottawa around 8:30am, and then the entire region will be experiencing the freezing rain by 10:00am (aside from maybe Kingston, which could escape this event altogether and remain rain).
Right off the bat, any precipitation will be very heavy, which will have freezing rain accumulating quite fast. However, with precipitation coming down as quickly as it will be, that could actually mean it won’t stick to trees as much because some of it won’t have time to stick to branches while it comes down heavily. Nonetheless, tree damage in some areas will happen, as will power outages.
As the day continues, freezing rain along the Seaway will switch to regular rain. While this transition happens, the Ottawa Valley, Ottawa, and along the Ottawa River towards Hawkesbury will continue to be freezing rain in the afternoon. As you can probably tell, the Valley, Ottawa, and Hawkesbury are of the greatest concern for this ice storm.
Around mid-afternoon to early evening, all of the freezing rain left in the region will switch to rain. Beyond this point, there will be multiple rounds of precipitation throughout the rest of the evening, and the night. All of those rounds will include heavy rain, although some of it could be a little bit scattered.
Also, throughout each round of precipitation, including the freezing rain, there is likely to be thunderstorms (or in some cases, the elusive thunder freezing rain). There could actually be some stronger thunderstorms later in the day Wednesday or early Thursday morning, giving some areas a good overnight lightning show, the first lightning show potential of the year.
Thankfully, this ice will not stick around for long, as the temperature overnight on early Thursday morning rises, and then the daytime high close to double digits will help as well.
With all of that said, here’s my forecasted numbers:
Ottawa Valley - 15-25mm of freezing rain, 10-20mm of rain Ottawa - 10-25mm of freezing rain, 10-20mm of rain Carleton Place - 10-20mm of freezing rain, 10-20mm of rain Perth - 7-14mm of freezing rain, 20-30mm of rain Smiths Falls - 7-14mm of freezing rain, 20-30mm of rain Kemptville - 7-14mm of freezing rain, 20-30mm of rain Winchester - 7-14mm of freezing rain, 20-30mm of rain Russell/Embrun - 7-14mm of freezing rain, 20-30mm of rain Casselman - 7-14mm of freezing rain, 20-30mm of rain Moose Creek - 7-14mm of freezing rain, 20-30mm of rain Rockland - 10-25mm of freezing rain, 10-20mm of rain Plantagenet/Alfred - 10-25mm of freezing rain, 10-20mm of rain Hawkesbury - 10-25mm of freezing rain, 10-20mm of rain Alexandria - 7-14mm of freezing rain, 20-30mm of rain Kingston - 30-50mm of rain, but possible 2mm of ice to start Gananoque - 30-50mm of rain, but possible 2mm of ice to start Brockville - 3-8mm of freezing rain, 30-45mm of rain Morrisburg - 3-8mm of freezing rain, 30-45mm of rain Cornwall - 3-8mm of freezing rain, 30-45mm of rain
Believe it or not, there is a chance the hardest hit areas surpass 30mm of freezing rain, like some models seem to think. I can’t see that happening, personally. Regardless, this is a dangerous ice storm for the hardest hit areas. Travel is extremely not recommended tomorrow throughout the morning.
This is almost certainly a bus cancellation event as well, a rare late in the season cancellation.
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Good luck, everyone!