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

Regional Impacts

Newfoundland and Labrador… slight risk of isolated thunderstorm over western Labrador

New Brunswick… low risk of severe thunderstorms over northwestern areas early this evening. Gusty winds and heavy downpours possible.

PEI and NS… No thunderstorms expected.

Convective Discussion

Although the synoptic ingredients are not fully aligned for severe thunderstorms, there is a risk that lingering severe storms could move in from Quebec into northern New Brunswick early this evening. A drier-than-normal airmass will persist today, with surface dew point temperatures reaching the mid-teens over New Brunswick and slightly lower across Labrador, where thunderstorms are also possible.

The surface trough expected to trigger thunderstorm activity will cross Labrador today but is forecast to move only slowly toward New Brunswick. The upper-level jet may play a limited role, with its axis extending from central Labrador toward the Saint Lawrence River by this evening.

Surface-based CAPE values exceeding 1000 J/kg, combined with moderate wind shear over eastern Quebec and into northern New Brunswick, could support the development of a mesoscale convective system (MCS) along the trough through the day. If organized thunderstorms do develop, there will be an elevated risk of strong wind gusts and heavier downpours.

Thunderstorm Outlook for Today