Regional Impacts
Scattered thunderstorms are forecast over extreme SW-ern NS late today, as well as the potential for isolated marginally severe thunderstorms from Windsor through to Collegeville area today. More organized thunderstorms are forecast over western NB where partial clearing is forecast to occur. The main hazard for the day is heavy rain.
Convective Discussion
Complex “tropical-like” dynamics at play today for 3 main forcings for convection each with individual hazards associated. A front in Labrador may spark a few lightning strikes as it transits through over the next 24-hrs.
1. Western NB: MUCAPE values near 1000 could (with a strong enough forcing) even overcome the cap that exists at 500mb, leading to gusty winds and heavy rain. PWATS in this area with actual dew points near 20 at 45mm today.
2. An area of potential instability exists from Kings county through to Guysborough county late this afternoon. The forcing here would be a sea breeze type front. If this materializes, dew points are near 22 and PWATS close to 50 so rain is the main hazard.
3. A frontal feature streaming up from the U.S. eastern seaboard is feeding in moisture and buoyancy causing non-severe thundershowers – Shelburne area likely to be in this moisture feed this evening. Saturday morning the rain hazard exists again in central NS marked in yellow on the overnight graphic. Models are not in perfect agreement on placement, but there is a consistent signal again for decent rain rates (greater than 30mm/hr). These local areas have a high vulnerability/sensitivity based on rainfall that has fallen in the last week.
The rest of Saturday sees generally improving conditions for NS, with pop-up showers across much of NB, PEI and in eastern areas of Nfld. Sunday’s dynamics as humidity builds back into the Maritimes is not a clear picture at this point.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Tomorrow
Thunderstorm Outlook for Sunday
Forecaster: TIRONE