Sticky Weather to Continue

What weather forecasters jokingly refer to as Southern California’s “monsoon season”--at least as harsh a combination of heat and humidity as the region is likely to see in a year--is expected to continue today and into the weekend.

A high temperature of 90 degrees is anticipated in downtown Los Angeles today, falling into the mid-80s Saturday and Sunday, according to WeatherData Inc., which provides forecasts for The Times. The San Fernando and San Gabriel valleys can expect highs in the low to mid-90s today and during the weekend.

Beaches will enjoy highs in the mid-70s, with patchy early morning low clouds giving way to sunshine.

Nighttime low temperatures in the region will generally be in the mid-60s, but in the San Fernando and San Gabiel valleys they may be as warm as 72.

Thursday’s Civic Center high reached 90, about 6 degrees warmer than normal, according to the National Weather Service. It was made more irritating by the fact that the relative humidity never dropped below 42%.

Dave Beusterien, a WeatherData forecaster, said the strong inflow of tropical moisture from Mexico and Arizona that brought humidity and thundershowers earlier in the week will gradually diminish during the next few days.

“This is the normal pattern for Arizona and Mexico,” Beusterien said. “It’s not rare for one of those thunderstorms to stray into Los Angeles. But we’re not expecting any rainfall in the Los Angeles Basin or the inland valleys, although there may be a few afternoon and evening thunderstorms in the mountains and deserts” today and during the weekend.

In Northern California, where the mercury reached 88 degrees in San Francisco on Thursday and hit 100 in some East Bay communities, continued sunny and warm weather is forecast for the weekend.