Regional Impacts
Today
LAB: Chance of some scattered thundershowers, some may be capable of producing small hail, strong winds, and locally heavy downpours.
NFLD: Chance of scattered thundershowers in the afternoon capable of producing some strong wind gusts, small hail and locally heavy downpours.
NB: Risk of isolated thunderstorms in the afternoon and early evening which may produce strong wind gusts, small hail, and heavy downpours.
NS/PEI: Risk of an isolated thundershower this afternoon in western PEI and Cape Breton.
Tonight
LAB: Some lingering thunderstorms are possible across southeastern Labrador.
Tomorrow
NS/NL: Risk of scattered thunderstorms in the afternoon and early evening which may produce strong wind gusts, small hail, and heavy downpours.
NB/LAB: Risk of isolated thunderstorms which may produce brief strong wind gusts, small hail and heavy downpours.
Convective Discussion
The environment remains unstable today across much of the Atlantic Provinces as a cold upper trough stretches from Labrador southwestward towards the northern Gulf of St. Lawrence and northern New Brunswick today. Along and east of the trough axis, mainly sunny skies should allow for good daytime heating into this afternoon. One hinderance may be some smoke aloft which is drifting across southern Labrador and into the Gulf from fires in central Quebec. Regardless, with the potential for MLCAPE to reach or exceed 1500J/kg, and increasing effective shear of 20 to 30 kts, as well as low freezing levels, some storms that develop may reach near severe limits. Multicell storms are most likely with small hail, strong wind gusts and heavy downpours possible, especially as storms will not be moving quickly and may train over the same areas. Enhanced lift due to terrain and sea breeze convergence will aid in some pop-up convection developing across central Newfoundland this afternoon. Shear is lower over this area, so heavy downpours and small hail are the main threat with anything that develops. A weak shortwave trough is expected to reach northern New Brunswick and into the Gulf of St. Lawrence but not until later tonight, likely limiting any severe convection to the Gaspe Peninsula, but an isolated risk is possible with this overnight. This upper trough has a history also of cold core funnels which were witnessed in PEI yesterday, and similar conditions may also occur today.
For tomorrow, the troughing continues southeastward with isolated showers across most areas by the afternoon, but the higher threat of thunderstorms shifts to Newfoundland and central to eastern Nova Scotia where precipitable water is increasing. Surface convergence and daytime heating will aid in increasing instability. There is a risk of multicell or a possible isolated supercell along convergence lines in the late afternoon or evening. Over Labrador, the upper forcing diminishes but daytime heating and terrain influences may still allow for pop-up convection in the afternoon but with quite low dew points, brief strong wind gusts are the main threat.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
