Convective Discussion
The main feature today is an intensifying low pressure system southwest of Nova Scotia which is expected to track just south along the Atlantic coast of Nova Scotia today and stall east of Cape Breton Island Saturday morning. Heavy rain with embedded thunderstorms has moved and are continuing to affect parts of southern Nova Scotia this morning as the warm front continues to push eastward. Embedded thunderstorms are expected to continue mainly for Nova Scotia and southern marine waters for today and overnight, leading to locally heavier rainfall amounts (Kejimkujik has already received over 50 mm since rain began early this morning). The Yarmouth sounding verifies this with precipitable water values of 45 mm. Rainfall warnings are in effect for Southern New Brunswick, most of mainland Nova Scotia, and Prince Edward Island where 50 to 75 mm is forecast. These rainfall warnings also extend into western and central Newfoundland as heavy rain fills in for them this evening. Convection however, is expected to remain offshore south of Newfoundland.
There is also an area of instability associated with an upper level low spinning over western Labrador. Convection has already initiated south of Churchill Falls where areas remained more cloud free this morning. An area over northwestern Labrador where some positive vorticity advection will help to trigger some afternoon convection.
Regional Impacts
Nova Scotia: Embedded thunderstorms will give lightning and periods of enhanced heavy rainfall today.
New Brunswick and Prince Edward Island: Mainly heavy downpours today for southern New Brunswick and Prince Edward Island.
Newfoundland and Labrador: Lightning and brief downpours for parts of western Labrador. Heavy downpours for marine areas south of Newfoundland overnight and into Saturday morning.
Roberta McArthur