Regional Impacts
Today
NB: Risk of thunderstorms this afternoon and evening with strong wind gusts, small hail, and heavy downpours.
NS/PEI: Risk of thunderstorms this afternoon and evening with strong wind gusts, small hail, and heavy downpours.
NFLD: Risk of thunderstorms across parts of western, central, and northern Newfoundland this afternoon and evening with strong wind gusts, small hail, and heavy downpours.
LAB: Risk of isolated thunderstorms across southern Labrador this afternoon and evening with strong wind gusts, small hail, and heavy downpours.
Tonight
PEI, NS and NFLD.. A chance of thunderstorms giving locally heavy downpours.
Tomorrow..
PEI, NS and NFLD.. A chance of thunderstorms giving locally heavy downpours.
Convective Discussion
An upper-level trough will remain nearly stationary through most of today before gradually progressing across the Atlantic Region on Saturday and Sunday. Ahead of this feature, a warm and moist airmass will remain in place, with deep-layer shear around 40 kt and modest mixed-layer CAPE of 750–1500 J/kg. Upper-level flow will remain largely zonal from the west.
Several active thunderstorm complexes over Gulf waters may aid convective initiation over Cape Breton and Newfoundland later today. Across New Brunswick, initiation may be more subtle, but storms are expected to intensify once again as they approach the Acadian coastline.
Yesterday produced several supercell thunderstorms, including reports of damage and a likely waterspout over the Northumberland Strait. While the airmass is not expected to be quite as unstable today, similar storm modes remain possible. In addition, very high low-level moisture, with dew points near 20°C and precipitable water values approaching 40 mm, will support efficient rainfall production and high rainfall rates across all regions, including Labrador.
Thunderstorms may persist into the overnight period and continue to affect portions of the region. The greatest risk appears to be across Cape Breton and eastern Nova Scotia; however, as has been the case with recent nocturnal convective events, the exact location and extent of overnight activity remain difficult to determine.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Mel Lemmon