Regional Impacts
NB and NS: Risk of an embedded thunderstorm, bands of heavier showers giving 10 to 20 mm today
Lab: occasional rain spreading over western Lab, amounts less than 10mm today
Rest of NF and PEI: none
Convective Discussion
Surface low over south-central Ontario with inverted trough extending towards northern Quebec. Surface warm front extends from the Low to southern Quebec-southern Maine-South shore of NS. A high pressure area now sits east of NF. The biggest change in the past 24 hours is the northward and eastward propagation of the increasingly moist air mass that has been sitting over the Maritimes. A strong southerly low-level-jet 30kt will maintain the supply of moisture with calculated precip. water from the upper air soundings indicating values in the 35-45 mm range.. this trend is expected to spread into NF&Lab today and tonight. The cloud deck mostly consists of overcast layers from near or at the surface extending up above 9-10km. While the extensive cloud cover will make it difficult to get enough surface heating to initiate convection, in their current state, soundings from YQI and YAW show plenty of instability (MUCAPE of 300 or 400 J/Kg) for embedded CB’s with tops up to 7-9 km. Deep layer shear values are a solid 35kt which might help sustain the convection over the Gulf of Maine until the clusters reaches the Fundy region later today. A few public forecast regions have been identified with the greatest potential for high rainfall rates/amounts during the next 48H, some of the forecast guidance is indicating amounts as high as ~100 mm.. but an average of the main deterministic models indicates a medium probability of 40 to 60. Regardless of the numbers, the maximum amounts will be driven by convective bands and it would be fairly difficult to identify which location/county will receive the most.
Thunderstorm Outlook for Today
Thunderstorm Outlook for Tonight
Thunderstorm Outlook for Wednesday
