Convective discussion:
Some isolated thunderstorms expected today and tonight associated with a weakening cold frontal trough that’s slowly crossing the Maritimes and Newfoundland.
Isolated thunderstorms possible for southeastern Labrador this afternoon and evening associated with a fairly strong short wave trough with some PVA.
Technical Discussion:
A weakening cold frontal trough will cross southern New Brunswick and western Newfoundland today to lie from Nova Scotia to southeastern Newfoundland this evening.
Isolated morning convection is occurring along the aforementioned frontal trough and this will likely occur at anytime today and tonight in its vicinity. KGYX 12Z tephi shows about 35 knots of shear with decent low-mid level lapse rates, as well as deep low level moisture. Modifying the profile generates between 500 and 800 CAPE, however the instability is marginal given the weakening state of the front…so just garden-variety pop up cells are expected with a very low threat of severe weather. Locally heavy downpours and some gusty winds can be expected. Freezing levels are quite high posing very little chance for hail.
In behind the front (southeastern Labrador) there is a considerable increase in wind shear, falling 500 mb atmospheric heights, drying at the mid levels, a short wave trough (and associated PVA) and a favorable left exit 250 mb jet. However, what’s lacking is the low-level moisture and instability. Isolated non-severe thunderstorms will possibly develop towards the mid afternoon today.
Regional Impacts:
Southeastern Labrador: Gusty winds.
Jeremy