Thunderstorm Outlook for Day 1
Regional Impacts
New Brunswick: strong wind gusts likely and near severe possible, possibly small hail, and some brief heavy downpours.
Nova Scotia and Prince Edward Island: chance for weak thundershowers, with some gusty winds and brief downpours.
Labrador: strong wind gusts likely and near severe possible, possibly small hail, and some brief heavy downpours.
Convective Discussion
The situation is roughly similar to yesterday, with an occluded low southeast of James Bay and a trough extending from it east to the Great Northern Peninsula of Newfoundland. A weak low has developed northeast of the Island, with yesterday’s cold front extending south. The low is moving away and will no longer be of concern. For the Maritimes there is a deep cold north-south trough near western Maine which will slowly drift east, destabilising mid to upper levels. The associated upper jet over New Brunswick is not aligned to help with lift, however. There is a moderate but no generous amount of moisture, with PWAT in the 20-30 mm range, and mainly between 700-900mb, with surface dewpoints near 15 C being advected in from the southwest. So the main lift mechanism is daytime heating, a bit of PVA from the trough near west and northwest New Brunswick, and enough moisture to make things interesting. With the dry mid to upper layers, strong downdrafts are possible. With the freezing level near 10,00 ft, there is a chance for small hail. For Nova Scotia there is less dynamic lift, so marginal thundershowers are possible. For Labrador, condifitons are similar to New Brunswick, but with the freezing level higher and some weak PVA associated with the east-west trough.
Thunderstorm Outlook for Day 2
For the Maritimes basically a repeat from yesterday, with the area of highest threat moved southeast into parts of Nova Scotia. The low freezing levels from yesterday persist, so there is a chance of small hail, and gusty winds are also likely.
