A powerful low pressure system is still likely to bring stormy weather into the Maritimes beginning on Wednesday and running through Thursday, Christmas Day.

The system will move up and through Ontario into northern Quebec Wednesday through Friday.

This places the Maritimes well on the eastern, warmer side of this storm. The end result will be heavy rain and high winds starting on Wednesday with the brunt arriving on Thursday before clearing out by Friday, Boxing Day, morning.

Now that we're a bit close I can talk about wind strength, rainfall amounts, and timing with more confidence. Let's start with a general timeline for the weather.

By Wednesday evening, periods of rain will have developed in western Nova Scotia and New Brunswick.

In New Brunswick, temperatures will initially be cold enough that this will arrive as a period of widespread freezing rain. Northern areas of New Brunswick may see an initial five to 10 centimetres of snow before the change to freezing rain.

Moving into Wednesday night temperatures will continue to warm in New Brunswick turning the freezing rain over to rain. The turn over should take until the early morning hours of Thursday at the latest.

The rain moves into P.E.I. and across all of Nova Scotia Wednesday night. Rain, heavy at times, will continue to fall across the Maritimes on Thursday before easing late in the day. From there the last of the rain will have moved out by sunrise on Friday.

A lot of rain on the way

Total rainfall amounts will reach 30 to 50 millimetres across much of New Brunswick (higher local amounts of 60 to 80 millimetres will be possible along the Bay of Fundy coastline) and P.E.I.

Nova Scotia is expected to see general rainfall amounts of 40 to 60 millimetres with some local amounts up to 100 millimetres — most likely around the South Shore.

There is potential for localized flooding. The flooding risk may be enhanced along parts of the coast due to a cycle of higher tides this week. It may also be enhanced in New Brunswick due to the mild temperatures causing melting of the snowpack.

Standing water on the roads is a given, and that will create the potential for hydroplaning. Don't forget that initially in New Brunswick on Wednesday that this will start as freezing rain creating icy spots.

As for the winds. An east-southeast wind will develop Wednesday night into Thursday morning with gusts reaching the range of 50 to 80 km/h. Strongest along and just inland of the coast. I would also expect that some gusts in Inverness County of Cape Breton will exceed 100 km/h due to the topography of the Highlands.

The winds will turn south and southwest on Thursday itself. This is also when stronger gusts may develop reaching 70 to 90 km/h. With gusts that strong scattered power outages are a possibility.

In summary:

Freezing rain in place by late Wednesday across New Brunswick may create icy road conditions on that day. The freezing rain turns over to rain by Thursday or very early that morning.

Heavy rain late Wednesday through Thursday will lead to standing water on roads and a risk of localized flooding especially when combined with melting snow and a cycle of high tide levels.

Strong wind gusts will develop both Wednesday night and on Thursday. The strong winds will create a risk of scattered power outages.

The storm is affecting much of eastern Canada and the U.S. Check in with your air service provider for updates on delays and cancellations.



I'll keep you updated through posts via cbc.ca, Facebook.com/kalinCBC, Twitter @kalinCBC, and on our televised news programs.