Tuesday morning’s positioning of the Pacific High, shaded in reds and oranges, and the dying low pressure system in the lighter shadings to its north.

Today’s forecast from Newsroom Meteorologist Gerry Díaz :

A weak low-pressure system to the north of the Pacific High is dying off this morning. Its remnant moisture is being soaked up by the marine layer.

Think of the marine layer like a sponge that’s filled to the brim with water. On this Tuesday morning, the Pacific High pressure system is squeezing this water out — any moisture that escapes will immediately condense and fall to the ground as precipitation. And because this kind of precipitation came out of a quiet weather system and not a raging thunderstorm, it gets the label of “non-convective” attached to it.

Drizzle will quickly precipitate out of the fog bank this morning, churning out totals between one hundredth to five hundredths of an inch (greys). Some isolated pockets could see totals up to one tenth of an inch (greens and blues) in some of the coastal ranges of Northern California and the Bay Area.

Residents waking up under the wall of clouds on the Pacific side of the Peninsula and the west side of San Francisco can look for a slight chance of drizzle coming down this morning. These patchy fog banks will mean residents in the Marin Headlands and the East Bay hills can also expect a chance for some drizzle after dawn. And based on what the latest weather models are casting, we could end up tallying anywhere from a few hundredths to a tenth of an inch before all is said and done.

The Pacific High continues to compress cool marine clouds to the immediate coast, promoting hot and hazy weather across most of the wider Bay Area today.

A shallow layer of marine clouds will hug much of the Peninsula, the west side of San Francisco and parts of the Marin Headlands (shaded in blue) this morning. This layer will cover most of the northern California coast.

Northern winds from this high are also moving traces of soot and ash down from the Six Rivers Lightning Complex fire into the Napa, San Ramon and Livermore valleys today. The Bay Area Air District has issued an air quality advisory for hazy skies and the smell of smoke wafting into higher terrains. The good news is the district doesn’t expect the air quality to be unhealthy from this upcoming round of smoke.

At least we’re getting some precipitation out of this otherwise hot and hazy environment.

• San Francisco: Plenty of marine clouds in the Presidio, Richmond and Sunset districts will keep temps in the upper 60s for most of the day. Several of the weather models are aligning toward a chance for brief bursts of drizzle before drier air clears most of them out by noon.

The strong high-pressure influence over the city will promote sunnier skies and drier air for residents east of Diamond Heights, where temperatures will climb into the lower 70s. Look for the fog to return around 5-6 p.m., with potential for another round of scattered drizzle this evening.

• The Pacific Coast: A misty day is in store for Highway 1 along the San Mateo Coast. More of the same this week, with temperatures in the upper 60s as patchy fog churns into Half Moon Bay and Pacifica with a slight chance for some scattered drizzle during the day.

• East Bay: Not much in the way of marine layer support for Oakland, Hayward and Fremont today. Weather models show highs into the upper 70s by the afternoon. The exception will be parts of the Oakland Hills where patchy fog could keep temps closer to the lower 70s. Weather models also don’t rule out the chance for some brief bursts of drizzle at some of the higher peaks.

Residents east of the Caldecott Tunnel can expect light winds, haze and afternoon temps in the mid 90s in the San Ramon and Livermore valleys. The good news is that both the North American (NAM) and hi-res rapid refresh (HRRR) weather models agree that just enough of a sea breeze around 6-7 p.m. could remove pollutants and drive temps down to the more comfortable lower 80s around dinnertime. After sunset, temps will begin plummeting to the 50s.

• South Bay: A warm day is on tap for the Santa Cruz Mountains, where temps will climb into the upper 70s today. This warm air will spread into San Jose and much of the Santa Clara Valley, thanks to the Pacific High’s influence, while the Santa Cruz Mountains will act as a shield for downstream residents, helping to keep heat and haze out of the city of Santa Cruz. Residents on the coast can expect light winds and comfortable temperatures in the lower 70s.

We’re connecting Californians to the science of weather, explaining the how and why behind heat waves, fires and storms through forecasts, news stories and deep data dives. Through judicious science-forward reporting our team aims to become California's go-to destination for weather coverage.

Reach out to us at weatherwonks@sfchronicle.com

Gerry Díaz is The San Francisco Chronicle's first ever Newsroom Meteorologist.

He previously served as a meteorologist for the National Weather Service Bay Area, working from the agency's Monterey office. In that position he led an initiative aimed at increasing outreach to Spanish speaking communities during extreme weather events.

Most recently he worked as a meteorology specialist for utility Southern California Edison.

Díaz enjoys hiking through California's national parks and shooting panoramic photography, including of the Central Coast.