Temperatures in Kelowna will reach highs of 7 C starting on Saturday, April 9. (Phil McLachlan - Capital News - FILE)

Temperatures in Kelowna will reach highs of 7 C starting on Saturday, April 9. (Phil McLachlan - Capital News - FILE)

‘Instability’ and ‘unpredictability’ cause Okanagan temperatures to drop this weekend

Springtime convection has officially arrived in the region: Environment Canada

When people in the Okanagan wake up on Saturday morning, the weather is expected to be quite different from what it was only 24 hours earlier.

It’s a springtime trend most common in B.C. — unpredictability.

Starting this weekend, however, the seasonal inclination is coming straight for the Okanagan.

“What we’re going to see is a transition from winter weather to summer weather, which is going to lead to unstable air masses coming in and that leads to springtime convection,” said Derek Lee, a meteorologist with Environment Climate Change Canada.

“It’s that unstable weather we should expect to see… a sunny morning, quick shift to a very cloudy afternoon and then it could get much cooler.”

Temperatures across the Okanagan are expected to dip into the single digits on Saturday and Sunday after people in the region were treated to a week of 15 C to 17 C highs.

Although wet flurries and showers are in the Okanagan’s weekend forecast, thunderstorms are not.

With spring convection, though, that can change in a hurry.

“This weekend is a great example of that,” Lee explained.

“We’re going from warmer to cooler temperatures in a hurry, which comes with unstable air masses that are quite unpredictable.”

Meteorologists associate convections with the hail and thunderstorms that usually occur in the summer.

Spring’s convection may be weaker than summer’s but that doesn’t change the level of unpredictability people can expect to experience in April and May.

“The unstable air masses don’t happen every day but they come from time to time during the season,” Lee said. “I would say this is the usual B.C. weather pattern…when we get to the springtime it’s very unstable because of an imbalance in the atmosphere.

“When you get cooler air on top of warmer air, it creates that instability.”

Environment Canada previously predicted springtime in the Okanagan to be “cooler than usual.”

The arrival of spring convection and its erratic shift to below 10 C temperatures, will only back up that claim as the season reaches the midpoint of April.

“We’re going to get some cooler days sandwiched between our normal days and it looks like that trend is starting to take shape,” Lee said.

READ MORE: Meteorologist recaps the ‘wild’ end of winter in the Okanagan


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