Posting this to give you an idea of how uncommon Thunderstorms are for the entire West Coast of North America due to the Marine influence of the Ocean. For Vancouver, BC we average only 6 Thunderstorms per year. Usually those 6 are very weak, very short lived counting down to mere minutes, and only impact a very localized area. What we saw yesterday around our area was an MCS Thunderstorm Outbreak. A Mesoscale Convective System. A term that has no business being anywhere within 400km of Vancouver, BC normally. Seriously, we hadn't seen one in over 29 years before yesterday. What it means, is that it is not a Supercell Thunderstorm. But it is a group of Thunderstorm Clouds that organize into what you saw last night. It was made up of numerous seperate Thunderstorm cells within its complex. Each cell would blow up into a Thunderstorm, spark 10-20 Lightning Bolts, then dissipate. But remember that it was organized. Once over the Strait, as one Thunderstorm would die out, another would blow up right beside it, and so on and so on over an area of over 100km in a straight line. The factors that allowed it: 1. Extreme Instability for our area 2. Exceptionally high humidity 3. Abnormally high Convective Available Potential Energy 4. Daytime Heating 5. Warm Ocean Water in the Strait 6. Monsoonal Moisture feeding into the low 7. A negatively tilted Upper Level Low sliding in 8. Very cold air aloft 9. The Mountains acting as a guide to keep the Storms locked over the Strait 10. Earlier Thunderstorms feeding into the Instability 11. Abundant Thunderstorms along VI and S2S regions as the setup reached the Strait 12. A long open stretch of water from Comox to Tsawwassen Available for the MCS setup See where I am going with this? This was not a run of the mill setup for Thunderstorms yesterday and early this morning. As soon as all those steps came together to prime a Severe Thunderstorm outbreak. As the main energy of the Storms hit the Strait, the incoming and slow moving Upper Level Low lit the match, then Boom! I believe this has a return period of once every 20-30 years for our area. Super, super rare weather event to see for this area. The conditions and result are at the absolute peak of what is Geographically Possible for our area. We may never see something like this again for our area. An MCS is something you see on the Prairies in Canada, or along the Plains and Southern States of the USA. To see one occur in Vancouver, BC, is downright shocking to the Weather community. Severe Thunderstorms Warnings are almost non-existent in the Lower Mainland of BC as a whole. We can go years without seeing one issued for our area. But for Richmond/YVR we can go decades without seeing one issued. That's how truly insane this was... #bcstorm – at Coquitlam, British Columbia