Threat of Localized Flooding & Freezing Rain Risk in New Brunswick with the Arrival of a Winter Storm Wednesday
/A Colorado Low is set to move through the Maritimes this week, bringing a mixture of rain, freezing rain, and snow to the region, along with the risk of flooding as temperatures rise.
Brief light snow will begin in Southwestern New Brunswick at around sunrise on Wednesday, spreading northeastward into the province throughout the morning and early afternoon. There is a chance for some freezing drizzle around Saint John mixed with the snow. Meanwhile in Nova Scotia, the precipitation will fall as rain across much of the western half of the province, aside from some light snow expected in Northern Nova Scotia.
Model Image showing the location and intensity of snow (Blue), Rain (Green), Freezing rain (Pink), and Ice pellets (Orange) at 1PM AT Wednesday
By the mid-afternoon, the bulk of the moisture from the system will push eastward into the region, bringing rain to Nova Scotia and Southern New Brunswick while Central and Northern New Brunswick will start to receive snow. The precipitation will reach PEI later in the afternoon as a mix of rain and snow across the Island.
Model Image showing the location and intensity of snow (Blue), Rain (Green), Freezing rain (Pink), and Ice pellets (Orange) at 12AM AT Thursday
Starting in the evening, the warm air and rain will start to push northward, leading to a transition from snow to a few hours of freezing rain across Central and Northern New Brunswick, as well as into PEI and Cape Breton. The freezing rain will continue overnight and into early Thursday morning. Ice accretions of up to 5mm are likely, but buildup will be short-lived as the temperatures will continue to rise and the freezing rain will switch over to rain for the remainder of Thursday.
Ahead of the transition to freezing rain and rain, up to 10cm of snow will fall, with the highest amounts expected in Retigouche County and into the Acadian Peninsula.
Not only will the fresh snowfall melt with the rain and temperatures climbing into the double digits on Thursday, but a considerable amount of pre-existing snowpack, especially across New Brunswick will also melt. Parts of Central and Northern New Brunswick have over 70cm of snow on the ground as of Tuesday evening and that value is expected to drop to below 50cm in some areas by Friday. Similarly, Moncton and Saint John, where 10-20cm is already on the ground, could see most, if not all, of their snow melt.
This rapid melting of the snow, along with some heavy rain expected later in the day on Thursday, has led to a significant flooding threat across New Brunswick. The ground is still frozen and recent frigid temperatures have led to ice buildup on lakes and rivers, which will limit where the water from the snow melt and rain can go.
The situation in Nova Scotia and into PEI is less widespread with lesser snowpack overall. There are some areas in Nova Scotia that have up to 30cm of snow on the ground that will almost completely melt, namely in the Annapolis Valley and in Cumberland and Colchester Counties. Those in Cape Breton can expect to see some of their snowpack melt, but the Highlands will experience very little change. In Prince Edward Island, on the other hand, next to no snow will remain on the Island come Friday aside from pockets of up to 5cm possibly remaining in Prince and/or Kings Counties.
The modelled depth of snow across Atlantic Canada, in centimetres, as of 8pm Tuesday.