Los Angeles's May Gray phenomenon is a normal presence around this time of year (that's why it's got that nickname), but the way it's been behaving lately is pretty unusual. KPCC notes that the marine layer that creates a foggy May usually comes in from the ocean in the morning, heads inland, and then disappears as the day warms up. Typically, the marine layer clears out of the LA basin area first, while the clouds at the beach linger longer.
But what's happening recently is just the opposite: the marine layer is vanishing near the shore, while further inland, especially around the foothills of the mountains and in valleys, the skies remain cloudy.
It's what's called "reverse clearing," and it's being caused by "an atypical low pressure system" over Southern California that's helping low clouds become thicker and heavier than usual. That means that they're harder to disperse, except at the coast, where the strong breezes make short work of sweeping away the gloom.
Good example of "Reverse Clearing". Clearing at beaches staying cloudy inland. Common with deep marine layer. #cawx pic.twitter.com/hj7IGr3eEd
— NWS Los Angeles (@NWSLosAngeles) May 15, 2016
This tweet from the National Weather Service in Oxnard visualizes the phenomenon of reverse clearing, showing the clouds dissipating along the coast but remaining thick further inland.
The obvious benefit of this reverse clearing is that areas that would normally lose their May Gray first are staying cooler longer. It also makes for clear days at the beach. A rep for the National Weather Service says that reverse clearing is expected to persist throughout this week at least, and maybe into the next, so enjoy it while it lasts—May Gray and June Gloom might not be around that much this year.