Convective Discussion:
A slight chance of thundershowers over northern Labrador and for the southern border between Labrador and the Quebec border. Over southernmost sections of the Scotian Shelf and the southern Grand Banks occasional thundershowers.
Today a broad trough will be moving into Labrador from the west as a trigger, with some associated cooling aloft and weak destabilisation. The main inhibitor is again a lack of moisture. From 850 mb and higher there is precious little moisture, and at the surface the dew points are near 10 C or less. PWATs over and upstream of Labrador are only near 17 mm. Now there is some low to mid level cloud moving in , which may supply the necessary moisture. Topographic forcing may help a little north and south, as previously mentioned. Impacts will be mainly some gusty winds , followed by some brief heavy showers, Freezing levels are again below 9000 ft, so there is a slight chance for small hail.
For the Maritimes there is little upper forcing, low shear near 20-25 kts, PWAT less than 20 mm, and low to moderate dew points. For Newfoundland the shear is higher as is the PWAT in the southeast, but upper forcing is again limited. Finally , Stephenville and St. John’s tephis, show a moderate cap in the west and a strong cap in the east.
For offshore waters, high SSTs near the North Wall of the Gulf Stream will trigger some thunderstorms, further north isolated embedded convection is possible,
Regional Impacts:
Maritimes and Newfoundland: none.
Labrador: low chance for non-severe convection for northern Labrador and the southern border.
Marine areas: occasional non-severe thunderstorms over the southern Scotian Shelf, as well as the southern Grand Banks.
Doug Mercer