How could Irma's moisture affect Atlantic Canada?

Friday, September 8, 2017, 9:52 AM - There has been a lot of talk about what impacts Hurricane Irma, which reached a category 5 in strength, will have on North America.

The exact forecast track remains uncertain. Recent National Hurricane Center updates put the storm as tracking along the northern coast of Cuba Friday and Saturday.

It seems increasingly unlikely that a direct impact will be made in Canada, but those with interests in Florida up to the Carolinas will need to monitor this powerful hurricane. However, Irma may indirectly impact Canada as discussed below.

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WEATHER HIGHLIGHTS

• Irma is a dangerous Category 4 hurricane with maximum sustained winds of 250 km/h
• Located 95 km northwest of Great Inagua Island in the Bahamas.
• At least 10 dead across several islands in the Lesser Antilles.
• Made landfall on the island of Barbuda early Wednesday morning with successive landfalls on St. Maarten and in the British Virgin Islands
• NHC confirms Irma is one of only five hurricanes ever to achieve peak wind speed of more than 295 km/h, following Allen (1980), Labor Day (1935), Gilbert (1988), and Wilma (2005)
• Mandatory evacuations issued for coastal stretches of South Florida
• Hurricane watches and warnings in effect from Florida, the Bahamas, Cuba and Haiti.
• Some fluctuations in intensity are likely during the next day or two, but Irma is forecast to remain a powerful category 4 or 5 hurricane during the next couple of days.

Tropical influence 

The large-scale features that will ultimately guide Irma on its destructive course through the Caribbean will be a direct influence on our weather in Canada. A massive area of high pressure in the central Atlantic Ocean will continuously build towards the Eastern Seaboard of the United States, setting up a stronger southerly flow from the tropics all the way into the Gulf of the St. Lawrence.

As a result, moisture has been funneling into the East Coast of Canada, bringing soggy conditions to the region where rainfall warnings were issued by Environment Canada.

The system will work its way west to east across Newfoundland through Friday, with periods of heavy rain continuing throughout the weekend. Rainfall amounts could reach 50-100+ mm for southeastern Newfoundland.

After a lengthy stretch of summer warmth, it will come to an abrupt end this weekend, as the trough over Quebec swings in, welcoming the return of autumnal temperatures.

Irma's impact on U.S. and Canada

As previously mentioned, latest model runs are trending towards Irma having a high impact on the Bahamas and Cuba into the weekend, with a possible catastrophic landfall in southern Florida early Sunday as a major hurricane. If Irma remains off the east coast, then the Carolinas will be a landfall candidate next Monday. 

If you wish to learn more about Irma, watch this video from our meteorological team:

In the coming days, the track will continuously be refined, even hours prior to the event. Beyond the U.S. impact, we will then need to track the remnant moisture from Irma, as it may get picked up by the upper level winds and spread into eastern Canada late next week.

Check back for updates as we continue to monitor the forecast.