Regional Impacts
Today
NB: Scattered thunderstorms, slight risk of severe in multi-clusters/features in the north. Rainfall rates in excess of 25mm/h, gusts 60km/h, small hail and frequent lightning.
NF&LAB: Frequent thunderstorms over central and southern Labrador. Rainfall rates in excess of 15mm/h, gusts 70km/h, small hail and frequent lightning.
NS: Risk of thunderstorms producing downpours
PEI: None
Tonight
NB: Isolated thunderstorms possible giving localized downpours.
Sunday
NB and Lab: Thunderstorms possibly giving strong wind gusts, heavy downpours, and frequent lightning.
Convective Discussion
At 12z the two large scales features of interest are an upper low on the western shores of Hudson’s Bay and a ridge along the NF coast. The thermal ridge is holding strong over NF where fair conditions continue to prevail. Convective temperatures for interior regions is 30+ which will likely not be reached however Cu/Tcu should develop. Over Labrador, a weak area of convergence will advance over central regions/Churchill Valley and become the focus for surface-based convection. If the extend of the cloud cover currently over the lower Churchill valley diminishes, warm temperatures will yield increase instability with cape values ranging from 500-800 J/kg, LI -3, but deep layer shear are less than 20 kt. The main threat would be downpours and high wind gusts.
Over the Maritimes, the tropical air mass continues to prevail with VIL values for today between 40-50 mm (up to 65 mm over New England). Some of the clusters of thunderstorms have produced significant amounts of rainfall even during the night and that will continue today with the focus for the afternoon over northern NB. The steering flow will be southwest around 20kt.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
