Convective Discussion
Nothing expected for the Maritimes nor Newfoundland and Labrador land areas.
Basically, there is a large and deep ridge over Atlantic Canada, with a strong subsidence inversion pushing well south over the Scotian Shelf and the Grand Banks. There are other inhibiting factors, including low moisture and very low shear over most regions, but the inversion is the real killer. On Tuesday there is a slight chance of convection along southernmost areas of Newfoundland, and a lesser chance for Cape Breton.
For the marine areas to the south, there is a chance of convection, due to a small low moving up slowly from south of the Scotian Shelf towards southwestern Newfoundland. Currently there is some convection mainly east and south of the low, with some surface based convection near and south of the warm front. As the low moves north over colder water, this will diminish, and there will be occasional embedded convection as it moves up tonight, again near and south of the warm front.
Regional Impacts
Atlantic Provinces: none today or tonight.
Southeastern offshore waters: non-severe thunderstorms over southernmost waters slowly moving north and weakening, mainly for Laurentian Fan and the southwestern Grand Banks. For southernmost waters of Laurentian Fan the Southwestern Grand Banks gusty winds are possible with CAPEs near 500 J/kg for southernmost Laurentian Fan and somewhat higher for the southern half of the Southwestern Grand Banks where it ranges from 500 to 1000+ J/kg. Otherwise local downpours are fairly likely, with precipitable water near 50 mm in the south. Again. Convection will become embedded and weaken as the low moves north.
Doug Mercer
