Regional Impacts
Today
Labrador: Isolated thunderstorms possible giving locally heavy downpours and gusty winds.
New Brunswick: Isolated thunderstorms possible giving locally heavy downpours.
Tonight
None.
Friday
Labrador: Isolated thunderstorms possible in the afternoon giving heavy downpours and gusty winds.
New Brunswick: Isolated severe thunderstorms possible giving locally heavy downpours, small hail and gusty winds.
Convective Discussion
A slow moving upper low will remain over Newfoundland today, while an approaching trough moves eastward into western Labrador this afternoon. There may be some remnant early afternoon convection under the upper low over the Avalon Peninsula and marine areas east of Newfoundland. Dynamics are more favourable over western Labrador with the approach on a trough in central Quebec giving diffluence aloft and a weak 500 mb thermal trough. With a fairly decent temperature and dew point spread, there is the threat of convective gusts.
Over the Maritimes, a weak ridge of high pressure and increased warming in the mid to upper levels should cap any convection. However, convective temperatures are expected to be reached over northern Maine and western New Brunswick. With only weak to moderate wind shear over the area, there should not be much organization of cells that develop. Therefore, locally heavy downpours are the main threat with these. There is an incoming 700mb thermal ridge which should prevent convection in Nova Scotia, but some inland TCUs may develop in the sea breeze in western Nova Scotia and give some locally heavy downpours.
For Friday, a approaching trough from Quebec will trigger convection into Labrador and New Brunswick. With an increasingly hot and humid flow, surface based CAPE values are reaching over 1500 J/kg in New Brunswick but 0-6km shear appears to remain weak to moderate. There is the threat of severe pulse storm are possible for northwestern New Brunswick with heavy downpours being the main threat but strong wind gusts and small hail are also possible. Some inland showers may develop again in the sea breeze in Nova Scotia.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Friday
Forecaster: McArthur