Regional Impacts
Today
NB/PEI/Les Iles: Isolated thunderstorms giving heavy downpours and gusts near 50 km/h
NS: Scattered thunderstorms over eastern half of the province giving localised heavy downpours, small hail and wind gusts near 70 km/h.
NL&LAB: None
Convective Discussion
An upper low high pressure near the Gaspe peninsula will slowly advance eastward today and tonight, at the surface there are two areas of rain associated with a couple of low pressure systems, one near Anticosti island and a second one south of the Burin peninsula. NF radar estimates for the past 12 hours suggest rainfall amounts of 20 to 40 mm with the highest amounts just off the west coast and south of the burin, however observations from autostations suggests amounts of 10 mm. There will likely be another 10-20 mm to come until tomorrow.
The focus for surface-based convection this afternoon will be over the NErn half of NB, PE, and especially Ern NS. Under a cold pool (-16) associated with the upper low, the cumulus field is already starting to grow and diurnal instability will be on the increase during the afternoon. Surface temperature of 24 or 25 will likely be plenty to bump MLCAPE values to nearly 500 J/kg / LI of -2. There are some interesting upper dynamics combining with these conditions, including 500 mb positive vorticity advection and a slightly cyclonic 80 knots upper jet branch south of NS, placing CB and Cabot strait near a right exit. The Shearwater Hodograph shows about 30 knots of effective deep layer shear. Eastern-most areas of NS mainland and Srn CB could get stronger thunderstorms that could evolve into longer-lasting linear features and produce downpours/small hail/high winds.
A high pressure system will build in from the west tonight and Monday.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Monday
