Regional Impacts
Today: Isolated risk of a thunderstorm in extreme northwestern New Brunswick late this evening. Heavy downpours are the main risk.
Tonight: Some isolated thunderstorms possible over northern and central New Brunswick tonight. Heavy downpours are the main risk.
Tomorrow: Scattered strong thunderstorms expected across southern New Brunswick tomorrow afternoon. Strong wind gusts and torrential downpours are the main risk.
Convective Discussion…
A quiet day is in store for the Maritimes today as a ridge of high pressure sits off the Atlantic coast. Late this evening, a trough expected to bring widespread severe weather to Ontario today will slowly make its way into New Brunswick. With much of the region largely capped (evident on the 12Z Caribou and Maniwaki soundings), only extreme northwestern New Brunswick will see the potential for any thunderstorm activity late this evening. By this time, daytime heating will have dropped off, so storms are not expected to be severe as they cross northern New Brunswick tonight. Weak lapse rates out ahead of the trough will also diminish the severe potential here tonight, so the main hazard will be heavy downpours.
Tomorrow looks to be more interesting, as an intense cold front will sweep across New Brunswick during the day, which will likely trigger some marginally severe thunderstorms. The main area of interest exists across the southern half of New Brunswick, where adequate daytime heating ahead of the cold front could help increase MLCAPE values upwards of 1000 J/kg. Dynamics look really good as well out ahead of the front, but once again lapse rates remain fairly weak so hail is not likely. A few discrete cells might fire early in the afternoon ahead of the cold front, but things are expected to line out fairly quickly as upwards of 60 knots of bulk shear crosses the region late in the afternoon with the passage of the cold front. An abundance of moisture will also be fed into this system, with PWATs expected to rise above 50 mm over southern New Brunswick tomorrow, increasing the potential for torrential downpours. As such, the main threats with these storm will be very strong wind gusts, and torrential downpours.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Forecaster: Copp