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Grandma Says, “Say it ain’t ‘thundersnow’!”

Say it so, thundersnow!
Say it so, thundersnow! - 123RF Illustration

One minute you’re reaching for your sunglasses, and the next minute it looks like you’re trapped in a snow globe! Thursday’s weather was very changeable because the air mass overhead was unsettled. In meteorological terms, “unsettled” means the air is buoyant. The cloud type is usually a good indication air mass instability. This morning, the clouds looked like giant pieces of cauliflower.

If you happened to be out at the height of the flurries, you might have heard some rumbling! Yes, there was enough convection in the air this morning to trigger “thundersnow”! I didn’t hear it, but quite a few people did!

Thunderstorms are most common in the summer, but they do develop during the colder months too!

The nor’easter that rolled in Tuesday has stalled over the Gaspe Peninsula. A closed circulation has developed around the low. On one side of the system you have a stiff southerly breeze pulling warm air into the region, while the other side of the low is caught up in a northerly circulation and a pull of colder air. Cold air from the north, displacing warm air from the south, forms an unstable atmosphere that can create perfect conditions for thundersnow!

While you might like the explanation you might not be so pleased with what Grandma has to say about it: “if you hear thunder in the winter, you’re in for a snowstorm in about seven days.”

There is something brewing off the California coast … stay tuned.

Cindy Day is chief meteorologist for SaltWire Network. Get your regional forecast at weatherbyday.ca.

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