Convective Discussion
The focus for severe weather today will be regions adjacent to southeastern Maine, and also inland portions of western Nova Scotia where hot and humid conditions prevail. Strong thunderstorms have migrated from Quebec over Maine this morning and are now entering Charlotte county in southwestern NB. These clusters of thunderstorms have a history of producing hail the size of a ping pong ball. The latest radar presentation suggests that these clusters are becoming better organized and are beginning to look more like early stages of squall lines. One of these features extends from Oromocto Lake to St. Stephen, and another one stretches NE-SW upstream from Bangor.
Convection should initiate during the first half of the afternoon over inland areas of Nova Scotia. The best forcing is expected over western regions but any storms that form could migrate to other regions of the province during the later part of the day. Buoyancy will increase throughout the afternoon and some of the forcing mechanisms will become better aligned. Using a Ts of 34 and Td of 24 is enough generate CAPE values in excess of 1500 J/kg pushing the lifted index to -5 or less. These large cumulonimbus would then become long-lived in this moisture-rich environment where deep layer shear of 30-40 knots are expected.
Regional Impacts
New Brunswick…For southernmost regions, strong thunderstorms with clusters of frequent lightning, widespread downpours, hail and locally severe winds.
Nova Scotia…For western regions, strong thunderstorms with clusters of frequent lightning, widespread downpours, hail and locally severe winds.
Newfoundland and Labrador…Isolated non-severe thunderstorms over southeastern regions.
PEI…None
