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

Regional Impacts

NS… Scattered thunderstorms today with heavy downpours of 20 to 30 mm/h.

NB… Slight chance of an isolated thundershower over northern New Brunswick this afternoon, with downpours of 10 to 20 mm/h.

NL… Slight chance of an isolated thundershower this afternoon over extreme southern Labrador, with downpours of 10 to 20 mm/h.

PEI… None.

Convective Discussion…

The upper low that brought severe thunderstorms to parts of the Maritimes yesterday will move east over Nova Scotia today. This once again brings the risk for some scattered thunderstorms that will be capable of producing heavy downpours. MLCAPE values over 1000 J/kg will provide ample instability to get convection going under the upper low this afternoon, weaker bulk shear and lower PWAT values over central mainland NS keeps the risk slightly lower here. Higher PWAT values of 30-35 mm over eastern mainland NS and parts of Cape Breton increase the potential for severe thunderstorms here, with rainfall rates of 20 to 30 mm/h possible. Localized flooding will also be a risk under storms that remain slow moving today.

There also exists a very slight risk for an isolated non-severe thundershower in northern New Brunswick and extreme southern Labrador this afternoon. Smoke aloft over Labrador in addition to a thermal ridge above 700 mb may inhibit convection here today as storms will struggle to get going.

Thunderstorm Outlook for Today