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

Regional Impacts

Today: risk of an embedded thundershower for eastern NS giving torrential downpours. Isolated thunderstorms possible for northwestern NB and parts of Labrador giving heavy downpours and gusty winds.

Tonight: continuing with the risk of an embedded thundershower for eastern NS and a portion of NL giving torrential downpours.

Tuesday: once again a risk of an embedded thundershower across southeastern NL giving heavy downpours. Scattered thunderstorms likely for most of Labrador and northern areas of NB giving heavy downpours, gusty winds and small hail.

Convective Discussion

A couple areas to watch today through to Tuesday. The first is an approaching frontal trough and associated thickness ridge moving up south of Nova Scotia that will move eastward into NL tonight and Tuesday. The PWATs with this feature could be in excess of 50 mm so torrential rainfall is a definite concern. But there looks to be a very limited chance in seeing lightning due to the warming aloft creating a stable, nimbostratus-type profile. The instability seems to get good just in behind the thermal trough, basically when the precipitation is ending from west to east. But no doubt some embedded deep layer TCUs capable of dropping copious amounts of rain over a short period of time.

The second feature is an upper-level trough that will give bouts of non-severe thunderstorms to north/northwestern NB today and Tuesday as well as a good chunk of Labrador, as short wave troughs move up along the base of the long wave trough. As freezing levels lower on Tuesday, some small hail is possible in some of the stronger cells.

Thunderstorm Outlook for Today