Regional Impacts
Today
New Brunswick: Isolated to scattered severe thunderstorms possible giving torrential downpours (25 to 50 mm per hour rates), small hail and gusty winds in central to northern regions.
Labrador: Isolated non-severe thunderstorms possible in the afternoon giving heavy downpours and gusty winds.
Tonight
New Brunswick: Isolated non-severe thunderstorms giving locally heavy downpours and gusty winds.
Saturday
New Brunswick: Isolated severe thunderstorms possible giving locally heavy downpours and gusty winds.
Newfoundland and Labrador: Isolated non-severe thunderstorms possible giving locally heavy downpours.
Convective Discussion
An approaching trough from central Quebec combined with daytime heating will trigger convection into Labrador and New Brunswick this afternoon and evening. The air mass continues to be hot and humid (20-22C dewpoints this morning over New Brunswick and 19C into southwestern Labrador) and surface based CAPE values are expected to exceed 1500 J/kg in New Brunswick. There will be further destabilization in the upper levels as a 500 mb thermal ridge currently over the Maritimes tracks further east but there is only weak to moderate 0-6km shear of 20 to 30 kts. Therefore, there is the threat of slow moving severe pulse or multicell storms for central to northern New Brunswick with torrential downpours being the main threat with 25 to 50 mm per hour rates likely, although strong wind gusts and small hail are also possible. This could especially be a concern for areas of northwestern New Brunswick that received substantial rainfall from last week.
Early morning elevated thundershowers over Prince Edward Island and northern and eastern Nova Scotia may continue into early this afternoon. Upper level troughing over eastern Newfoundland will keep the environment cool and unstable but some elevated convection may persist in the waters east of Newfoundland.
For Saturday, the main threat of showers and thunderstorms will be over New Brunswick under a hot and humid air mass and central Labrador as the trough slowly progresses eastward. Isolated convection under an upper trough in central Newfoundland is also possible.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Saturday
Forecaster: McArthur