Convective Discussion
A short wave trough is approaching New Brunswick from central Quebec today. An increasingly more hot and humid air mass is also approaching the region this afternoon over western New Brunswick as winds begin to shift to the southwest on the backside of a ridge of high pressure. This trough is expected to bring showers and thundershowers to northern New Brunswick this afternoon and continue to track eastward towards Nova Scotia and western Labrador by tomorrow morning.
The air mass will become increasingly warmer in the low levels which will lead to further instability this afternoon. As the trough approaches northwestern New Brunswick, 0-6km wind shear will increase somewhat but remain moderate, with divergence aloft and the approach of a strong 250mb jet to help maintain convection. Only modest CAPE values of 200-500 J/kg are expected, except perhaps for extreme northwestern New Brunswick which could exceed 500 J/kg. It is expected that multicellular storms will be the dominant type of convection with brief heavy downpours and strong wind gusts possible with some cells possibly developing stronger lines of convection over northwestern New Brunswick this evening. Freezing levels remain high enough that hail is not expected to be a main threat with cells that develop today.
Regional Impacts
New Brunswick…Lightning, locally heavy rainfall amounts, and brief strong wind gusts are possible for northern and central New Brunswick this afternoon and evening.
PEI and Nova Scotia…Scattered showers with the slight risk of a thundershower maintaining into the late evening possible.
Newfoundland and Labrador…None
Roberta McArthur