Chief Meteorologist: Could Arthur surprise the Maritimes?
Friday, July 4, 2014, 10:21 PM -
The forecast is now very solid. Arthur will impact the Maritimes as a post-tropical storm on Saturday. The storm’s tropical core will have largely given way to a more nor’easter type storm. However, this will be a large storm with a significant impact.
STORM WATCH: The Weather Network will be LIVE on location in Atlantic Canada this weekend as Arthur takes aim at the region. Find out more about our extended active weather coverage.
Don't focus on the track: Arthur is acting like a nor'easter
The track becomes less important as the storm becomes less tropical. This is because a pure hurricane or tropical storm has its strongest winds very close to the storm centre. Arthur will be more like a nor’easter, where there is a large area of strong winds that extends well away from the storm centre. People in Charlottetown looking only at the track might think winds will be worse for them than in Halifax. In fact, it will likely be the opposite. The track alone can be misleading. This storm will have a large area of strong winds that won’t necessarily follow along the centre of the low pressure track.
The rain could end up being a bigger story than the wind
Wind often grabs the initial headlines with this type of storm, but it may be the rain that makes the bigger news in the end. Winds will certainly be strong, and there will likely be power outages from fallen tree limbs across the region, particularly from central Nova Scotia and the HRM through the Annapolis Valley and the south shore. However, this doesn’t look like a wind event that will do widespread structural damage. The one exception to this may be the south shore of Nova Scotia up through Digby county where strong winds off the Gulf of Maine/Bay of Fundy could cause some minor structural damage.
It’s the rain that could lead to the greatest damage if forecast amounts materialize. Our team is forecasting 100-150 mm of over a large area of New Brunswick, with the target zone being Fredericton, Woodstock and St. Stephen… with just slightly less in Saint John. The area closest to the Maine border could be hardest hit. We’ve seen recently what this type of rain can do with the flooding in Saskatchewan and Manitoba. Road washouts are a possibility. Power outages are also possible. While winds will not be as strong as in Nova Scotia, some trees could come down in New Brunswick due to strong winds and saturated soil.
Saturday is a largely dry day in Halifax
This will likely surprise some people prepared for a tropical soaking through Saturday across the HRM. Heavy showers are likely Friday night, but most of Saturday looks dry with the exception of some quick passing showers. The sun may even make a few appearances. Wind will be the biggest story. It looks like gusts could reach 100 km/h – strong enough to break some tree branches and cause some power outages. However, winds will not likely be strong enough for any widespread heavy damage; certainly nothing like what was seen with Hurricane Juan.
A memorable storm?
While our forecast team is very confident about the overall forecast, there is a very fine line in meteorology between a storm that is forgotten in a week to a storm that is remembered for years. Saturday will be a stormy day in the Maritimes. There will be power outages. The focus is on Nova Scotia for wind and New Brunswick for rain. But there is always a bit of mystery as to how the fine details will pan out and exactly how bad the impact from a storm like this will be.
At this point, it looks substantial, but not epic – not something that will go down in history like a Juan or Igor. The one exception to this could be the rainfall in New Brunswick. There is a big difference between 100 and 175 mm of rain. One is bad, the other is disastrous. Our forecast amounts are on that edge between bad and disastrous – let’s hope we’re not still talking about Arthur in a week.