Regional Impacts
NB and PEI.. Showers and thunderstorms possibly giving 25mm, small hail.
NS.. Showers and thunderstorms, possibly intensifying tonight, 15- 25mm today. Possibly exceeding 25 mm tonight.
NL.. Possible isolated thunderstorm over southwest Labrador.
Convective Discussion
A low pressure system will slowly make its way across the Maritimes today, passing over southern Newfoundland tonight. Instability aloft will trigger deeper convection across mainland NS today and overnight. This system is expected to move with enough speed that a prolonged period of heavy downpours are not expected, however shorter lived periods of heavier rain perhaps lasting over an hour could bring upwards of 25mm, with rainfall rates of up to 40mm per hour possible.
Over NB most of the potential for intense thunderstorms will be associated with thunderstorms that will initiate over Maine and Southern Quebec today. Surface CAPE values over 1500 J/kg are expected across Maine and some intense storms could move over western NB later in the day. Dynamics are somewhat favourable for organised convection with approximately 35 knots of deep shear. The outlook maybe slightly conservative with the risk, however watches could be issued if organised thunderstorms form in Maine, with the expectation that some stronger cells could track over NB.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Mel Lemmon