Monsoon season is finally ramping up. Here's how it could impact California:

San Francisco Chronicle / August 12, 2023

An erratic monsoon pattern this summer could usher in episodes between fire weather and wet thunderstorms in parts of California this week and through the month.

The North American monsoon requires clockwise winds from mild ridges of high pressure over the Four Corners region to ferry summertime moisture from the Gulf of California to the Southwest. But like a chef adding too much of an ingredient to a recipe, the atmosphere has overcooked its recent ridges of high pressure, charring the first-half of the 2023 monsoon.

Drying grasses, a weak monsoon and isolated thunderstorms fueled recent fire weather in the Mojave desert, said Jonathan O’Brien, a fire meteorologist with the Southern California Geographic Coordination Center’s Predictive Services unit.

But there are growing signs that high pressures are slowly weakening and that this year’s monsoon is set to make a comeback. Surges of moist air will briefly bring some muggy, rainy weather back to a drying California in the coming weeks with some isolated fire risks.

LINK (paywall): https://www.sfchronicle.com/weather/article/california-monsoon-summer-fire-18289836.php

HIGHLIGHTS FROM THE LINK:

• Some moisture will stream into Northern California on Saturday, locking in slight chances of wet and dry thunderstorms to parts of the Central Coast, Sierra Nevada and Southern Cascades through the second half of August.

• Threat of thunderstorms in the valleys of the Sierra Nevada between Tahoe and Yosemite on Saturday -- slight risk of downpours.

• Risk of dry thunderstorms ... periodic lightning events in the Sierra Nevada

• August “might set the stage for a more active fire pattern over the next month or so because now things are really starting to dry out,” said Daniel Swain, a researcher at UCLA and the Nature Conservancy.