Today and tomorrow, cold-core thunderstorms will occur with over 1000 j/kg SBCAPE, shortwave energy and a strong upper level-jet streak. Some storms could become severe with large hail. Gusty winds and heavy rain are also possible but will likely not be severe.
In fact, storms could produce significant quantities of hail as WBZ heights slide below 700 mb.
The greatest convective coverage today will be on the Quebec side of the Ottawa Valley towards Montreal and the Eastern Townships. Tomorrow, it will be on the Ontario side of the Ottawa Valley towards Montreal and the Eastern Townships.
Storms are possible during the 1 to 11 pm timeframes on both days.
Forecasted radar reflectivity for 5 pm today from the 12Z 3K NAM. The image is only here to indicate storm coverage, not intensity.