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Study: Longer and more frequent heatwaves expected for Southern California

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Posted at 5:37 PM, Aug 13, 2020
and last updated 2020-08-13 20:37:41-04

SAN DIEGO (KGTV) — Temperatures are forecasted to climb in Southern California and surrounding areas through the next week and as this heat persists, there are other factors in play as well.

Moisture entering the region will increase humidity, and humidity overnight will lead to overnight lows staying warmer, which means an extended period of heat with less overnight relief can be expected.

This is a trend that is becoming more and more common. Climate researchers from Scripps Institution of Oceanography studied the history of these warmer, prolonged and humid stretches in the San Diego area, and found that periods similar to this are on the rise.

“What we found is that heatwaves in Southern California, and I would say California more broadly, have been increasing over time in their frequency and tendency,” said researcher Dan Cayan.

The lack of overnight cooling means no break from the heat at night, so the long stretch of days of increased temperatures combined with a lack of overnight relief could lead to dangerous conditions.

“It’s a lot easier to contend with a heatwave that lasts a day or two than one that lasts four days,” said Cayan.

Cayan said this is part of a larger picture of climate change impact, and this trend will likely continue in the years to come.

Humidity can make temperatures feel worse. A Heat Index chart from the National Weather Service shows how the two climb simultaneously: