Convective Discussion.
A few areas of convective activity to note mainly over Newfoundland and Labrador today as a quasi-stationary low over northern Quebec with a trough extending through Labrador, Newfoundland, and eastern Nova Scotia today.
The air mass within the trough extending from Newfoundland towards eastern Nova Scotia is quite moist in the low levels with dew points remaining near 20C. Surface temperatures are already near the daytime highs expected over western areas of Newfoundland despite the current cloud cover. The question will be how much additional surface based heating there will be should the cloud break up more. The inhibitor for this afternoon is a slight warming expected in the mid levels which could cut the potential energy of any convection that develops. Despite this, any showers already on the go and what could develop this afternoon will produce locally heavy downpours given the high pecipitable water values in the area as well as strong wind gusts. There should only be a slight risk of a thundershower over eastern Nova Scotia early this afternoon as the trough is currently moving over the area and some coastal convergence could provide further lift. Dew points will still remain high for a few hours after this trough moves through as the more pronounced change in humidity is still further west over New Brunswick.
For central Labrador, the area remains under an unstable westerly flow. A 500mb cold pool lies over central Quebec to central Labrador providing sufficient lift given daytime temperatures in the upper teens. Air mass type thunderstorms are expected but some further organization is possible given convergence near the trough and low pressure centre that is expected to form over eastern Labrador this evening and push off into the Labrador Sea tomorrow morning. Precipitable water remains moderately high so convection this afternoon will likely produce some heavy downpours. Hail is also a risk with freezing levels dropping below 10,000ft.
Regional Impacts.
Newfoundland: Locally heavy downpours and strong wind gusts.
Labrador: Locally heavy downpours, strong wind gusts, and small hail.
Nova Scotia: An isolated thundershower over eastern sections this afternoon.
New Brunswick and Prince Edward Island: nil
Roberta McArthur