Regional Impacts
Today
NB/Labrador: Scattered thunderstorms with some of them becoming strong, rainfall rates 25 mm/h, hail possible, and gusts 50-80 km/h.
NS/PEI/NL: Isolated thunderstorms giving 15-25mm/h rain and brief strong wind gusts.
Tonight
NL/Labrador: A chance of thunderstorms.
NB/NS/PEI/: None.
Wednesday
NL/Labrador: Isolated thunderstorms with rainfall rates 15-25 mm/h.
NB/NS/PEI: None.
Convective Discussion
An upper disturbance and cold front will approach from Quebec/Western Lab today, continuing to increase moisture and instability. Some high level cloud may inhibit the extent of daytime heating over New Brunswick, Newfoundland and central and southeastern Labrador, but CAPE values could still approach 1000J/kg for southeastern Labrador and Newfoundland. There is weak to moderate shear, so the bigger issue will be some training thunderstorms. Divergence aloft and the left exit of the 250mb jet, and moderate 0-6km shear will also aid in sustaining convection in multicell or possible bow line segments over southern Quebec and Maine. The timing of the incoming trough and warm 850mb temperatures is such that stronger convection may remain capped hold off over New Brunswick until later in the day, but elevated convection may persist overnight aided by a strong low level jet as the trough moves over the Gulf of St. Lawrence and into western Newfoundland tomorrow morning.
On Wednesday, the trough continues eastward over northeastern Newfoundland and southeastern Labrador. A weak feature is expected to move into western Labrador in the afternoon and may trigger non-severe thunderstorms. The humid air mass over the Maritimes will trigger some pop up TCUs but are not expected to breach the warm cap from 700-500mb.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Roberta McArthur