Regional Impacts
Today
NS/PEI: Isolated embedded thunderstorms giving lightning, heavy downpours with up to 50 mm/h rates and strong wind gusts
NB: Isolated embedded thunderstorms giving lightning, heavy downpours, small hail and strong wind gusts
NL&LAB: None
Tonight
NS: Isolated embedded thunderstorms giving lightning, heavy downpours and strong wind gusts over Cape Breton
NL: Isolated embedded thunderstorms giving lightning and heavy downpours.
Sunday
NB/PEI/NS: Scattered thunderstorms giving lightning, heavy downpours, small hail and strong wind gusts.
Convective Discussion
A warm and moist air mass continues to spread north and eastward across the Maritimes today ahead of a trough from a quasi-stationary low over central Quebec. The trough becomes oriented northwest/southeast today as the low centre slowly shifts southeastward across the Gulf of St. Lawrence and south of Newfoundland Sunday night. A thin stream of 40-50 mm precipitable water values is being fed northward across Nova Scotia, allowing for very high rainfall rates where 50 mm/h has been seen in parts of the HRM this morning with training thunderstorms. Areas of upper level rotation have also been evident with some wind gusts reaching 60 km/h in the stronger cells. Although lightning activity has diminished, the heavier band continues slowly north and eastward today, exiting east of Cape Breton tonight and the threat of heavy rainfall continues. A increasingly heavier rain band over southeastern New Brunswick will give high rainfall rates today which will affect parts of northern Nova Scotia and Prince Edward Island this afternoon and evening.
With expected clearing behind the trough today over western New Brunswick, convection is possible in the afternoon and late evening. With an increase in CAPE values exceeding 1000 J/kg, lower freezing levels, and weak to moderate 0-6km shear, there is the threat for small hail, strong wind gusts and locally heavy downpours.
There is the risk of waterspouts tonight into Sunday morning mainly in the Northumberland Strait and southern Gulf of St. Lawrence, where the highest SST’s above 20C and cooler 850mb temps are located, along with weak to moderate deep shear.
On Sunday, convection is possible again for the Maritimes in the afternoon still under the influence of the upper low which will move east of Newfoundland by Monday. With cooler air aloft, CAPE values approaching 1000 J/kg and weak to moderate shear of 20-30Kt, there is the threat of pulse or multicells over central and eastern New Brunswick towards Prince Edward Island and northern Nova Scotia.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Sunday
