When will heat wave break in the Maritimes?

CTV Atlantic meteorologist Kalin Mitchell shares the forecast and impacts for the Oldfield fire in New Brunswick amid scorching days across the Maritimes.

Hot and dry weather is making for arduous conditions for combating the Oldfield wildfire burning just north of Miramichi, N.B. Heat warnings will extend into mid-week before a cold front breaks the heat wave with a round of showers Thursday.

Scorching summer temperatures are in the forecast for the Maritimes through Wednesday.

The high temperature for the Miramichi area is likely to approach 35 C on Monday, Tuesday and Wednesday.

Relative humidity has increased from last week and is expected to maintain just above 40 per cent through the day. That decreases the risk of crossover conditions, a condition where air temperature exceeds relative humidity while wind speeds are near 30 km/h. Crossover conditions increase the risk of explosive growth of a wildfire.

Surface winds will maintain from the southwest through the day. Sustained 10-to-15 km/h with occasional gusts near 20 km/h, not particularly strong but not the preferred still winds for combating a wildfire either. Wind speed is forecast to diminish into a range of five-to-10 km/h between 10 p.m. and midnight.

The wind is initially directing the smoke to the east of the fire before turning southerly as it rises into a more northerly wind present aloft. Environment Canada cautions of an air quality health index of 6, or moderate risk, in the vicinity of any surface smoke from the fire.

Sizzling weather

A ridge, or plume, of hot air extends from the southeastern U.S. through Ontario, Quebec, and Atlantic Canada.

Aside from some direct coastal areas, daytime highs in the Maritimes are expected to be mostly in the low-to-mid 30’s through Wednesday. Heat warnings issued by Environment Canada caution on humidex values making it “feel” 33 C to 43 C through that period.

Nights will be warm and stuffy. Low temperatures won’t fall much below the high-teens and low-twenties with many communities still feeling in the mid-to-high 20’s even during the coolest hours of the night and morning.

Looking to beat the heat during the day? Beaches on the Atlantic coastline of Nova Scotia and the Bay of Fundy coastline in New Brunswick will be your best bet for cooler ocean breezes. The prevailing wind will be mostly from the southwest through Wednesday and is more onshore for those areas.

Heat breaks with showers

A cold front associated with a low-pressure system moving from Hudson Bay to Labrador is expected to arrive in the Maritimes Thursday.

The front will bring the region scattered showers with a risk of thunderstorms. This won’t be the long duration, soaking rainfall the region needs to help with developing drought conditions. The showery weather is only likely to produce rain amounts of a few to several millimetres in most cases.

Locally high rain totals will be possible in the event of thunderstorms accompanying the showers. The next chance of showers after that will be Sunday into Monday.

The Thursday cold front will bring temperatures down in the Maritimes for the end of the week. High temperatures on Friday are expected to be mostly in the low-to-mid 20’s.