Maritime weather: Potential for heavy rain, snow later this week

A pedestrian shields themselves from rain and wind during a rainfall warning in Halifax on Thursday, January 26, 2023. (Source: THE CANADIAN PRESS/Darren Calabrese)

There will be a very fair weather start to the week for the Maritimes.

High pressure in place Monday allowed for a mostly sunny day with afternoon temperatures rising into the low-to-high single digits for large areas of Nova Scotia and New Brunswick. A northerly wind kept it cooler for Prince Edward Island and eastern Nova Scotia with high temperatures closer to zero.

For context, the normal high for Fredericton is +1 C, for Halifax +2 C, and for Charlottetown -1 C.

Tuesday night-Wednesday rain, showers

A low pressure system travelling up the eastern U.S. seaboard returns rain and showers to the Maritimes late Tuesday into Wednesday. The rain will develop Tuesday evening into early Wednesday morning. Patchy showers and drizzle will linger for Wednesday afternoon and evening.

The rain through Wednesday night is expected to generally total 10-to 20 mm for most of the Maritimes. Lower rainfall totals look possible for parts of Nova Scotia moving towards the Atlantic coastal counties.

A light-to-moderate rainfall for the Maritimes Tuesday evening through Wednesday. (Source: CTV News Atlantic)

Thursday-Friday heavy snow, rain

A more impactful storm system is possible Thursday into Friday for the Maritimes.

This would be a stronger eastern seaboard low pressure system that could meet up with cold air being pushed down from northern Quebec and Labrador. The result would be a heavy mix of snow and rain for the region with a risk of freezing rain and ice pellets as well.

Rain, heavy at times, possible for Nova Scotia on Thursday. A risk of a mix of snow and freezing rain for New Brunswick and Prince Edward Island. (Source: CTV News Atlantic)

Heavy rain during the day Thursday is a risk for Nova Scotia. There are indications it could total as much as 30-to-70 mm for some areas. That amount of rain could lead to localized flooding and hydroplaning conditions on roadways.

As the rain meets up with colder air positioned around southern New Brunswick, northern Nova Scotia, and Prince Edward Island, it could turn over to an area of heavy snow with a risk of freezing rain. That could be most intense Thursday evening and night. While how much snow is possible will depend on the nature of that mix, I can’t rule out a range of 10-to-30 cm.

Heavy snow could accumulate in southern New Brunswick, northern Nova Scotia, and Prince Edward Island Thursday afternoon and evening. (Source: CTV News Atlantic)

To further complicate the forecast, the colder air may push further into Nova Scotia Thursday night into Friday morning. That would turn the remaining areas of Nova Scotia receiving rain over to a mix of snow, ice pellets, and freezing rain. That snowy, icy mix may linger long enough into Friday to produce some significant accumulation as well. It is too early to put a range on that possible accumulation.

The remainder of Nova Scotia could turn from rain over to snow and freezing rain Thursday night into Friday morning. (Source: CTV News Atlantic)

Summary

The period of weather Thursday through Friday looks to be the most impactful of the week. The combination of rain turning to snow could make for challenging travel conditions, especially on the roads. Snowy, icy road conditions could develop through the day on Thursday for central/southern New Brunswick and Prince Edward Island. Nova Scotia could follow with snowy, icy conditions developing Thursday night into Friday morning.

It is not possible to rule out significant change in the timing or amounts of snow and rain expected at this time. I strongly advise monitoring the forecast for Thursday and Friday moving through the week. I’ll have updates here and on our CTV News Atlantic programming at 5 p.m., 6 p.m., and 11:30 p.m.