Severe Thunderstorm in Montreal - May 16th, 2012

A video of a severe thunderstorm advancing towards the island of Montreal from the WNW. This storm grazed our area to the North and NE as it moved toward the ESE, consequently affecting the greater Montreal area and areas farther East/ESE. The main threats associated with these storms were damaging winds and small hail. Prolonged daytime heating, coupled with marginally moderate moisture levels, supported surface-based CAPE values near 1000 J/kg while significantly weakening convective inhibition early. Daytime heating also allowed for steep low level lapse rates during the early afternoon hours, which was a large part of the reason as to why many of these storms produced strong downbursts of wind. Bulk shear additionally favored organized thunderstorm development, but no tornadoes had been reported, likely because of weak low level jet winds. The principal driver for these storms was a prevalent upper level trough to the West, which supported strong surface convergence along and ahead of a cold frontal wave.

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