Regional Impacts
Labrador… Risk of thunderstorms with downpours and small hail possible, today and tomorrow.
Newfoundland, PEI, NS… No Risk of thunderstorms.
New Brunswick… Risk of thunderstorms just north of province.
Convective Discussion
A ridge of high pressure over eastern Atlantic Canada will suppress convection across much of the region. Over the next couple of days, this ridge will gradually shift east, allowing an area of low pressure to move slowly across the remainder of the region. There is some potential for deeper convection just ahead of the low and its associated surface trough over Labrador, both today and tomorrow.
For Labrador, surface-based CAPE values between 500 and 1000 J/kg today and tomorrow will provide sufficient instability for thunderstorm development. Today, however, the triggering mechanism will be subtle. By tomorrow, a surface trough will provide a more focused trigger along with slightly higher low-level moisture. As a result, locally heavy downpours and small hail will become somewhat more likely ahead of this feature. Deep-layer shear is moderate, while low-level shear of around 20 knots may be sufficient to organize convection into a line or possibly support training thunderstorms.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Mel Lemmon