Atmospheric river brings extreme rainfall to parts of the Maritimes

Digital Writers
·4 min read
Atmospheric river brings extreme rainfall to parts of the Maritimes
Atmospheric river brings extreme rainfall to parts of the Maritimes

An incoming system, packed to the brim with Gulf moisture, is serving as an atmospheric river, set to bring extreme levels of rainfall over parts of Atlantic Canada, beginning Thursday and lasting through much of the weekend. In all, some 50-100 mm of rain is possible over the course of the system, a serious flood threat on its own before considering the already heightened risk for some areas. Worsening matters, a blocking pattern will drastically slow its passage, hence the heightened amounts lasting for several days. More on the timing and impact, below, plus a look at a second system that threatens a 'white Easter' for parts of the region this weekend.

WEATHER HIGHLIGHTS:

  • Prolonged period of heavy rain for the Maritimes begins Thursday and continues into the weekend

  • 50-100 mm for parts of Nova Scotia, some freezing rain risk for parts of New Brunswick

  • Threat for unsettled weather for the eastern Maritimes and into Newfoundland during the weekend and through early next week

THURSDAY INTO SATURDAY: CONVEYOR BELT OF MOISTURE THREATENS DAYS OF HEAVY RAIN

A scant few days after an early week storm brought heavy rain, snow and damaging winds to Atlantic Canada, the next major weather maker is set to fall upon the region, beginning Thursday.

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Though largely a rainfall event, there are two factors that will make it a very significant one for the region. The first is the fact that the storm will be completely laden with moisture, funnelling it into the region from the Gulf of Mexico like a conveyor belt. The second will be a blocking pattern that will cause the low to all but stall for multiple days – plenty of opportunity for that moisture to be unleashed.

ATLMoisture (1)
ATLMoisture (1)

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The first swath of heavy rain will pick up in the Maritimes later Thursday, remaining pretty persistent for multiple days. The heaviest rain will fall from Thursday into Friday, though with periods of rain still continuing into the weekend as well.

There will be many areas in Nova Scotia and the Lower North Shore of Quebec where 50-100 mm of rain will be possible throughout the duration of this event.

ATLRain (12)
ATLRain (12)

Meanwhile, a widespread 20-40 mm of rain is likely to fall across New Brunswick, with locally heavier amounts for northern sections as well.

Special weather statements and rainfall warnings are in effect, warning of the threat for flash floods and water pooling on roads.

One additional complication: A temperature differential that will raise the risk of freezing rain or ice pellets for parts of northern and western New Brunswick later Thursday, tapering to scattered flurries by early Friday morning.

ATLIce (2)
ATLIce (2)

HEIGHTENED FLOOD THREAT IN ALREADY VULNERABLE AREAS

This rain comes on the heels of an ice jam in the Perth-Andover area of New Brunswick, where water levels were already about 1 metre from flood levels earlier this week.

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NBFlood
NBFlood

"As some areas in northern New Brunswick still have snow on the ground, the combination of snow melt along with the heavy rain is going to increase water levels over the coming days," warns Weather Network meteorologist Matt Grinter.

Residents along the Saint John River are being advised to stay up to date on any advisories or alerts for the risk of flooding through the weekend.

PLAN AHEAD: RESIDENTS URGED TO STAY ALERT TO FLOOD ADVISORIES

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WATCHING THE THREAT FOR A WHITE EASTER

Forecasters are watching for another area of low pressure that will develop over the Atlantic and track north into the region, bringing additional rainfall through the weekend and into early next week.

Some wet snow is also expected for New Brunswick on Easter with widespread totals of 5-10 cm possible. The precipitation looks to stay as rain elsewhere, with totals of 25-50+ mm likely, but locally 50-100+ mm for parts of central and eastern Nova Scotia, PEI and eastern Quebec.

Be sure to check back for updates on the moisture-filled system for Atlantic Canada.