Convective Discussion
Another active day for the Atlantic provinces today. A trough stretching from central Labrador to southwestern Nova Scotia will slowly progress eastward this afternoon. Along and ahead of the trough, moisture remains high with dew points in the 18-20 degree range. Along with some solar insolation and a slight increase in 0-6km shear, thunderstorm development will likely initiate this afternoon and continue into the evening. There has already been some elevated convection this morning over Newfoundland that will continue to push to the northeast. There is a thicker cloud band with isolated showers stretching the Gulf of St. Lawrence toward southwest Nova Scotia. Should this cloud break up this afternoon, surface based CAPE values could range from 1500-1800 J/kg over parts of mainland Nova Scotia and central Newfoundland. Surface based convection is expected to initiate early this afternoon over the spine of Nova Scotia and central Newfoundland. The main risk with these storms will be heavy downpours (25-50mm), especially over Nova Scotia and central to northeastern Newfoundland where some training of thunderstorms may occur. There is also the risk of hail (1-2cm) and strong wind gusts.
Central Labrador will also continue to see come elevated embedded convection associated with an upper level low over northern Quebec. Locally heavy downpours and small hail are possible.
For southern marine areas, there are a couple of low pressure centers that are tracking from West Scotian Slope to the southern Grand Banks. Some isolated convection is expected to continue today. Some strong wind gusts to 30KT are possible under thunderstorms.
Regional Impacts
New Brunswick… Mainly southern New Brunswick could see lightning and locally heavy downpours.
Nova Scotia…Lightning, heavy downpours (25-50mm where training may occur), small hail and strong wind gusts.
PEI…Lightning, heavy downpours , small hail and strong wind gusts are possible.
Newfoundland…Lightning, heavy downpours (25-50mm where training may occur), small hail and strong wind gusts.
Labrador… Lightning, heavy downpours , small hail and strong wind gusts are possible.
Roberta McArthur