Lopez, 48, a veteran anchor at KEYT-TV, Santa Barbara, spoke to her family about 9:30 a.m. but "has not been seen or heard from since," Santa Barbara sheriff's officials said.
While authorities said it wasn't believed Lopez, who was last seen wearing a black sweat suit and tennis shoes, was the victim of foul play, "her family is concerned about her welfare."
Officers searched around her home with the aid of dogs and a helicopter.
"We have been in touch with her family and know they, as well as local authorities, are doing everything possible to find her safe and sound," KEYT-TV General Manager Mark Danielson said in a statement. "Our thoughts and prayers are extended to Paula as well as her family and those searching to find her. ... We hope for her safe and speedy return."
Lopez started at the station as an intern in 1985 and later spent six years at KCAL-TV, Los Angeles, before returning to KEYT-TV in 1996.
She is married to Santa Barbara County Superior Court Judge Frank Ochoa and they have three children, the Los Angeles Times reported her biography said.