Atlantic Canada Weather Blog: Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today: Non-severe convective showers and thunderstorms ongoing late this morning will continue this afternoon across central and northern mainland Nova Scotia. Only hazard foreseen is possible moderate rainfall. In New Brunswick, thunderstorms are entering the northwest from northern Maine and are expected to bring gusty winds and moderate rainfall. The is also a slight risk of convection in SE Labrador, if can overcome the smoke cap and dry air intrusion.

Tonight, into Sunday morning: In the warm sector of and approaching low, embedded thundershowers are possible along Nova Scotia’s slope waters and Atlantic coast.

Sunday afternoon: Clearing trend – no thunderstorms expected.

Monday: Building ridge – no thunderstorms forecast.

Convective Discussion

Smoke is continuing to mix into boundary layer from the northeast sfc flow, but the flow aloft has veered across the Maritimes to Westerly. A low is churning near the Avalon this morning with a trof hanging back over the Gulf waters. Another stronger trof is hanging back over the St Lawrence river valley, and the next Low with associated fronts is cutting thru New England. As such, the forcings amount to the grey risk areas depicted today and tonight. Tonight’s weather will not be discrete cells like yesterday in NS, or the day before in NB. But rather, embedded TS in a broader synoptic rain field. The triple point is expected to pass very close to Halifax. 0-6k shear off this morning’s soundings is near 32kts, but ML CAPE is low and skinny again. This allows most hazards to easily be ruled out. G70 and rainfall max 30mm in slowest moving storms is the “storm of the day” solution. Ridge builds on backside of low mid-day Sunday. Monday is stable and dry in a weak N flow. Nil sig weather expected to start the work-week.

Thunderstorm Outlook for TODAY