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

Regional Impacts

Today:

LAB: Risk of isolated thunderstorms giving locally heavy downpours and strong wind gusts.

NB: Risk of isolated thundershowers.

NS/PEI/NL: No thunderstorms forecast.

Tonight:

LAB: Risk of isolated thunderstorms.

NS/NB/PEI/NL: No thunderstorms forecast.

Tomorrow:

LAB: Risk of isolated thunderstorms giving locally heavy downpours and strong wind gusts.

NB/NL: Risk of an isolated thundershower.

NS/PEI: No thunderstorms forecast.

Convective Discussion

A ridge of high pressure is slowly sinking southeastward into the southern Maritime waters today and a trough moves eastward into northern Quebec and across northern Labrador. Ahead and along the trough, scattered showers and risk of thundershowers are expected, mainly across southern to central Labrador where CAPE values could exceed 500 J/kg. Shear is generally weak to moderate, so expecting single to multicell potential with brief winds gusts and with precipitable water in of 35 mm, so locally heavy downpours are also possible. Weak troughing also reaches northwestern New Brunswick, where there is a slight risk of showers or thundershowers in the afternoon but conditions are still fairly dry and with some residual smoke aloft, this may cap convection.

Tomorrow, troughing lingers over Newfoundland while another trough quickly moves across central northern Quebec, affecting southwestern Labrador by the evening. With moderate shear or 30 kts and high precipitable water reaching 40 mm, there is more potential for organization into lines into western Labrador but timing may be too late for any severe potential to maintain in the evening. Some isolated showers with a small risk of a thundershower is possible over the higher terrain in northern New Brunswick and Newfoundland but again the lingering smoke aloft could cap convection.

Thunderstorm Outlook for Today