Thunderstorm Outlook for Today
Regional Impacts
Western Labrador.. Isolated thunderstorms likely producing heavy showers with rates of 10-15 mm/h
Northwestern NB.. Isolated thunderstorms giving a risk of localised heavy showers with rates of 10-20 mm/h, 1 cm hail, and strong wind gusts.
Convective Discussion
There is an upper level low centered near LG4 with a thermal trough extending southward, ahead of this feature there is thermal ridging along the Labrador coast and NF. At the surface, there is a cold front extending from west of Shefferville to southwestern Quebec. This feature will continue to be the focus for convection this afternoon. A few GLM and CLDN lightning flashes are detected and will become more widespread during the next few hours. The more robust convection will likely occur near the St. Lawrence Valley where low level moisture will combine with better upper dynamics including a 100+kt southwesterly jet and some pos pva advection. Diurnal heating will boost mixed-layer cape values to 500-800 J/kg resulting in strong enough instability to help form CB’s with tops/equilibrium level reaching the tropopause which will lower from 45hft to 35hft as the colder air advances over the region. Deep layer shears of 35 to 45 knots will help to sustain these storms longer and some will likely produce heavy showers/hail/strong wind gusts and could propagate into northern Maine/NB early this evening. Some orographic features could also contribute to the development. For Labrador, while the dynamics may not be as strong, the upper flow is somewhat diffluent and the precipitable water estimates from the morning soundings were around 25-30mm which hints at a treat of heavy showers as reported by YKL earlier.
Thunderstorm Outlook for Friday
