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

Regional Impacts

Today:

Labrador: Risk of a thundershower this afternoon with strong wind gusts and small hail.

Northern New Brunswick: slight risk of a pop-up thundershower.

Tomorrow: Risk of near-severe thunderstorms giving strong wind gusts and small hail for parts of New Brunswick, Prince Edward Island, and northern Nova Scotia. Risk of thundershowers for southeastern Labrador.

Convective Discussion

A low pressure system over northern Quebec will slowly drift eastward across northern Labrador today. Period of moderate to heavy rain associated with a trough extending from the low move across Newfoundland. Cooler air aloft behind the low along with surface heating will lead to destabilization this afternoon with the risk of some pop-up thundershowers mainly across central and western Labrador southward towards northern New Brunswick. Winds over Labrador will be increasing with the low throughout the day, but there could be enhanced wind gusts in any convection that develops but with low freezing levels there is also the possibility of small hail.

For Thursday, another trough that will be over the Great Lakes today will make its way into Atlantic Canada by tomorrow morning. This will aid in triggering thunderstorms by early afternoon along the trough line from southeastern Labrador towards New Brunswick. For the Maritimes, mixed CAPE values are expected to reach 500 J/kg, and although the overall 0-6km layer shear is high >60kt, the effective shear into the afternoon over New Brunswick will be closer to 40 kt, and more conducive to maintaining convection or organizing into lines. The main threat will be strong wind gusts and small hail as freezing levels decrease as storms that develop are expected to move quickly and precipitable water around 25 mm.

Thunderstorm Outlook for Today