My explanation of Southern California’s June Gloom didn’t shed much sunlight on why it has become the June-July-August Gloom. Last week the National Weather Service released a brief statement explaining why: cooler than usual waters in the Pacific Ocean and a persistent “upper level trough” in the atmosphere above the coastline. That upper level trough — or low pressure system — has helped keep the air cool. Together, our cooler water and cooler air have prompted the formation of the clouds and fog that creep inland overnight. This combo has also kept monsoonal moisture at bay. So while the American Southwest is enjoying afternoon thunderstorms, Southern California’s mountains and deserts have not.
All that was supposed to have changed this weekend. Temps were up inland and slightly higher here at the beach. And this morning’s bright sunrise, among a handful of fogless dawns this summer, promised a scorcher. But by noon today dense fog had tumbled in from the harbor. If you listen, you can hear the ships’ fog horns booming in the distance, heralding the end of the heatwave that wasn’t.