Thunderstorm Outlook for Today
Regional Impacts
Potentially robust thunderstorms approaching severe limits over northernmost NB.. main treat is localised damaging wind gusts and some hail
Isolated elevated CB/ACB’s giving brief heavier showers over eastern Gulf of St. Lawrence, western NF/Lab
Convective Discussion
A frontal wave near Gaspé will continue to move NEwd giving widespread rain from eastern NS to Labrador, some elevated convection is associated with this feature and it should continue throughout the day. CLDN did indicate a few strikes over Nrn NS earlier and it continues over the Lower Quebec North Shore.
The main forecast problem today will be what happens in the wake of this system.. convective initiation is expected from the Beauce region to northern Maine.. a slightly cyclonic jet core is approaching from the Eastern Townships and is providing some extra support on the left-side exit which sits over northern NB/Chaleur region. Satellite imagery is showing the airmass transition currently occurring over northern Maine and western NB, although this new brand of air is more dry it has been historically quite buoyant. Convective temperature around 25 or 26 C, combined with dewpoints of 15 to 17 is enough to push SBCAPE above 500 or 600 J/kg. The drying in the mid-levels will certainly increase the downburst potential with modelled DCAPE values exceeding 700 J/kg. Some of the longer-lived storms could organize into a squall line but the deep layer shears are fairly high (45kt).
Thunderstorm Outlook for Tonight
Decaying thunderstorms over the Gulf of St. Lawrence region
Thunderstorm Outlook for Saturday
Surface / upper trough extending south from Labrador and a somewhat unstable airmass over Atlantic Canada
