Regional Impacts
Today: Newfoundland and Labrador- Non-severe thunderstorms possible in southern Labrador and central-eastern Newfoundland giving rainfall rates of 10-20mm/h, strong wind gusts and lightning.
Tonight: Labrador- Non-severe thunderstorms for central/southern Labrador
Saturday: Labrador: Near-severe thunderstorms possible in Labrador giving rainfall rates of 20mm/h, strong wind gusts and lightning.
New Brunswick: Near-severe thunderstorms possible with rainfall rates of 20mm/h and lightning Saturday evening.
Nova Scotia: Near-severe thunderstorms possible with rainfall rates of 20mm/h and lightning Saturday evening.
Convective Discussion
A frontal boundary extending eastward over central Quebec into central Labrador and southeastward into northern Newfoundland is slowly sinking southwards today while a stationary ridge of high pressure over New England and the Maritimes slowly weakens. Upper dynamics are somewhat favourable over Labrador today to sustain elevated thunderstorms that develop along the boundary but with little thermodynamics changes, CAPE values of 200-500 J/kg, the main threat will be locally heavy downpours. Over Newfoundland, although there is quite a bit of smoke over the region from wildfires over Quebec, an 850 mb jet and sufficient shear may aid in thunderstorm development on a line from Gander to Terra Nova. A trough of low pressure south of Nova Scotia is also slowly moving eastward. Some embedded thunderstorms are expected for the southern slope waters.
For Saturday, the trough of low pressure will track southeastward over central Labrador with a cold front extending across northern Quebec. With high precipitable water rates, increasing CAPE values exceeding 1000 J/kg and moderate shear, the threat for near-severe thunderstorms increases with more organized squall lines or bow echos. Instability and moisture will also increase over the Maritimes as an upper low slowly moves into the region from New England. Precipitable water values of 40-50 mm and CAPE values exceeding 500 J/kg may lead to increased threat for thunderstorms, but the dynamics are not as favourable, so pulse type storms are more likely at this time with locally heavy downpours in the evening.
Thunderstorm Outlook for Day 1
Thunderstorm Outlook for Day 1 Night
Thunderstorm Outlook for Day 2
