Regional Impacts
Today
Lab: Risk of a thundershower over western regions this evening giving locally heavy downpours.
NB/NS/PEI/NL : Nil
Tonight
Lab : Slight chance of an isolated thundershower overnight.
NB/NS/PEI/NL : Nil
Tomorrow
NL : Risk of a thunderstorm near the Avalon Peninsula giving strong winds, small hail and heavy downpours. Risk of a thundershower over the Northern Peninsula.
Lab: Risk of a thundershower giving locally heavy downpours over central and eastern regions.
NB/NS/PEI: Nil
Convective Discussion
As a ridge builds through the Maritimes, 850mb and 700mb Jets orientated relatively north-south will aid in the trigger of some thundershowers over Labrador this evening. Generally, for these thunderstorms values of Mixed Layer CAPE (MLCAPE) will be staying close to the 500-700 J/Kg range with Surface Based CAPE (SBCAPE) being slightly higher nearing the 1,000 J/Kg range. Given these CAPE values along with a relatively weak Effective Shear of around 20Kt any convection that does occur will be isolated in nature and is expected to be short-lived. This is also applicable for the overnight hours into tomorrow morning, generally there is a risk for elevated thundershowers over Labrador, though the forcings in the overnight hours will be weaker hence the area outlined does not have any attributes attached to them.
For tomorrow, the ridge moves further southeast and allows for a higher dewpoints and stronger jets to interact with the land-sea boundaries from Trinity Bay and Placentia Bay, which could give rise to more intense thunderstorms in eastern Newfoundland. Currently there is some discrepancy between the Regional and High-Res model guidance for this event. The High-Res currently has higher dewpoints extending further into the atmosphere along with a slight easterly flow, meanwhile the Regional has slightly drier layer with a complete westerly flow throughout the atmosphere column. This discrepancy is enough to not indicate a risk for tornadoes, but is possible with a High-Res solution. With the High-res solution the main region of concern would be from Clarenville to CBS and extending down to Argentia. Meanwhile up in Labrador and the Northern Peninsula, jet streaks still remain the active triggering mechanism though with slightly lower CAPE values the risk for a severe thunderstorm is low.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Forecaster: Lambert/McArthur