Regional Impacts
There is a risk of thundershowers this afternoon and evening across western and central Labrador. These could advect eastward affecting portions of the LAB coast tonight as well. Brief heavy downpours and gusty winds are possible.
There is a slight risk for a severe thunderstorm across the far northwest of NB. The main threat would be torrential rainfall…however strong wind gusts are also a possibility.
Lastly, there is a risk of isolated thundershowers this afternoon across the valley and northern NS. Torrential rainfall is the main threat.
Convective Discussion
The main focus today will be to see what forms upstream across southern Quebec and northern Maine. What will be a moot point today is a trigger. The KCAR tephi has ~ 25 knots of shear, PWAT of around 40 and MLCAPE of 1000-1200 j/kg. There is a moist tongue near the surface which would add to the buoyancy as the day progresses. The deep layer trough at 500 mb is further upstream at 12Z, but that should propagate eastward today, resulting in an increase in wind shear across NW NB. If cells do make it to the region, torrential downpours and gusts to 70-80 km/h would be expected. Will have to monitor the upstream development this afternoon and the evolution of movement.
For Labrador, where shear is 40-45 knots, and closer to the surface and upper trough, scattered cells are likely. Then only issue would be warm air aloft…however given the dynamics that would be broken fairly easily. Brief heavy downpours and gusty winds are possible with the storms.
There is a risk of isolated non-severe thunderstorms across the valley and northern NS this afternoon. There is very little shear (YQI and GYX showing 20 knots), but the PWAT is 40+. CAPE looks to be in the 500-1000 range. Locally torrential downpours will be the threat.
Thunderstorm Outlook for Day 1
Thunderstorm Outlook for Day 2
