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

Regional Impacts

Today:

NB/PEI/NS: Risk of severe thunderstorms with torrential downpours and strong wind gusts.

NL: Risk of thunderstorms with locally heavy downpours and strong wind gusts.

LAB: Risk of an isolated thundershower.

Tonight:

NS/PEI/NL: Isolated embedded thunderstorms giving locally heavy downpours.

Tomorrow:

NL/LAB: Risk of isolated thunderstorms giving locally heavy downpours.

Martimes: None

Convective Discussion

This morning, a trough is moving through northern New Brunswick giving some heavy downpours (15-25mm/h rates), while a trailing cold front will sweep through the Maritimes and Newfoundland this afternoon and overnight. The main area of interest exists across central to southern New Brunswick, Prince Edward Island and northern Nova Scotia, where clearing of cloud is more likely along with adequate daytime heating ahead of the cold front and allow MLCAPE values to exceed 1000 J/kg. With effective shear increasing to 45 knots ahead of the front and advection of precipitable water above 50 mm, there could be an isolated supercells early in the afternoon but mainly expecting cells to organize into line segments by late afternoon over southern New Brunswick and Prince Edward Island and continue southeastward in the evening before they lose surface instability. With these ingredients, the main threats with these storm will be very strong wind gusts and torrential downpours. Isolated thunderstorms are also possible in the trough over Labrador this afternoon with brief wind gusts.

For tomorrow the cold front continues eastward across the Maritimes waters into Newfoundland while a low pressure system develops over Newfoundland into the trough in the morning and tracks into the Labrador Seas by Sunday. Isolated thunderstorms are possible along the front and in the troughing behind the low as colder air moves in aloft and behind the low over eastern Labrador and central Newfoundland.

Thunderstorm Outlook for TODAY