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

Regional Impacts

Today:

NB: Risk of thundershowers with heavy downpours and strong wind gusts.

NS/southwestern marine waters: Risk of embedded thundershowers.

Tonight:

NB: Risk of thundershowers with heavy downpours.

NS/southern marine waters: Risk of embedded thundershowers.

Tomorrow:

NB: Risk of thundershowers with heavy downpours, small hail and strong wind gusts.

NS/PEI/southern marine waters: Risk of embedded thundershowers.

Convective Discussion

A slow moving trough over southern Quebec along with daytime heating and increasing shear will aid in the development of thunderstorms for southern Quebec and Maine this afternoon and this area will slowly move into northwestern New Brunswick tonight and tomorrow. Ahead of the trough, daytime heating will aid in destabilization with mainly non-severe pop-up thundershowers in north central New Brunswick and southwestern Labrador this afternoon. The main threat this evening and overnight will be heavy downpours if cells redevelops over one area with moderate precipitable water with this air mass. Meanwhile, embedded thundershowers are possible along a boundary off New England that will move into the southern Maritime marine waters and across southwestern Nova Scotia this evening and overnight into tomorrow. With precipitable water increasing over southwestern Nova Scotia into the 40s overnight and early tomorrow morning, there is a risk of heavy downpours.

For Friday, the trough will lie over New Brunswick and there is a possibility of moderate rain, small hail and strong wind gusts and the upper levels cool and freezing levels lower. With CAPE values above 500 J/kg and increasing shear towards 35 kts into the afternoon, some storms could form into lines or possible supercells. A low pressure system that develops south of Nova Scotia will aid in thundershower development across central and eastern Nova Scotia and eastern Prince Edward Island towards southern Newfoundland by the evening.

Thunderstorm Outlook for TODAY