Hurricane Lee moving northwest, poses weekend risk to Atlantic Canada

As of Monday afternoon, Lee is a category three hurricane with maximum sustained winds near the eye of the storm at 195 km/h.

As of Monday afternoon, Lee is a Category 3 hurricane with maximum sustained winds near the eye of the storm at 195 km/h. The hurricane is moving northwest at near 13 km/h, starting to make a turn around the southern edge of a high pressure system that sits to the east of it.

In the latest forecast cone from the National Hurricane Center, which extends out five days, the storm does not yet reach land areas of Atlantic Canada, but does encompass the southern marine districts of Georges Bank and West Scotian Slope. The intensity of the storm at that time, Saturday, is currently forecast to be a category one hurricane with maximum sustained winds near 130 km/h. A further expansion of the forecast cone northward over the next 24 hours, which looks likely, would start to reach into Nova Scotia and New Brunswick.

The forecast cone is the area in which the centre of the storm is expected to take a path through and it has been found to historically be accurate about 70 per cent of the time. The cone does not represent the entirety of the area that could experience impacts from the storm. The cone broadens in size considerably the further out in time it goes due to increased uncertainty in the forecast.

The current timing of Lee, of which there is uncertainty in as well, would pose a weather threat to the Maritimes for the upcoming weekend. Stormy conditions are a risk for both Saturday and Sunday, the inclement weather arriving ahead of the centre of the storm may be on the slower side to progress through the region. It is still too early to determine a more precise path the storm could take through the Maritimes. Specific weather impacts and their intensity will be determined by that track. A higher confidence in those details will emerge through the week, particularly as we get about three days out from the storms possible approach which would be the Wednesday/Thursday of this week.

One aspect of these weather systems to keep in mind is that they see a notable increase in size as they move northward. Weather impacts such as the rain and wind become more diffused from the centre of the storm, but cover a larger area.