Severe thunderstorm in Montreal - August 11th, 2020

****I STRONGLY RECOMMEND USING EARPHONES/HEADPHONES (BASS AMPLIFIED) TO HEAR THE MORE NATURAL SOUND OF THE THUNDER/RAIN****

A video compilation highlighting the severe thunderstorms that affected the island of Montreal during the mid- to late-afternoon period. Thunderstorms were largely isolated but became more scattered during the mid-afternoon ahead of a weak North-South-oriented cold front and shortwave trough. Lift ahead of these features was most magnified by mid-afternoon, when convergence at the surface was greatest ahead of the front, along with sufficient positive vorticity advection associated with the trough. The pre-frontal environment was characterized by hot and very humid air, leading to one of the most unstable days in this area this year. Meanwhile, while modest, deep shearing fields were sufficiently strong for organized and somewhat longer-lived (deep) convection. A Severe Thunderstorm Watch was released early, and then eventually a warning was released for the island as thunderstorms began grouping near Huntingdon and St. Anicet before NNE progression (eerily similar to the situation on June 23rd – see video footage for that). The rainfall released from these thunderstorms was incredible (watch the fast moving bands on rain in the distance how they blow ahead of the thunderstorm), much like on June 23rd and August 2nd, but the downbursts of wind were also quite forceful (like on June 23rd), and local gusts reached up to 90 km/h. At the same time, these winds caused some damage, including to trees over the South Shore and portions of the West Island. Several close lightning strikes were observed near Longueuil and towards Greenfield Park. Thunder can also be heard in the video, though the rain does block it substantially. Louder thunder, however can be heard from a second thunderstorm that developed closely to my WNW to NW. The shelf cloud/arcus with the first thunderstorm was astonishing in structure (much like many shelf clouds!), and a rare occasion of iridescence was briefly seen over the developing second thunderstorm (as a colorful patch above the mature congestus). Before all of this, some impressive and intimidating-looking deep convection began to appear during the late-morning to early-afternoon, with the first thunderstorm of this general area affecting the Mascouche area by mid-afternoon.

Footage was taken in SW Pierrefonds, located in Montreal’s West Island. Radar imagery is courtesy of NOAA.

~Trav.~

Видео Severe thunderstorm in Montreal - August 11th, 2020 канала Rain1290