California has very slow vote counts, and the late vote strongly tends to favor Democrats, who usually send in their ballots later than Republicans.
John Wildermuth at the San Francisco Chronicle:
In Orange County, home to four of the seven targeted congressional races, the early voting numbers tell the story.
The week before the primary, about 24,000 more Republican ballots had been received, Avila said. But a surge of Democratic ballots over the pre-election weekend slashed the GOP edge to just 34, a lead that vanished over the next two days.
The effect of that late rush of Democratic votes in Orange County shows up in the results. Democratic Rep. Katie Porter of Irvine picked up more than three percentage points after election night, moving from 48% to 51%. Rep. Harley Rouda of Laguna Beach was lifted to a double-digit lead over GOP Orange County Supervisor Michelle Steel, and Rep. Mike Levin of San Juan Capistrano bumped his margin over Republican Brian Mayott from six percentage points on election night to 13 by Friday.
While Republican Young Kim of Fullerton kept her election night lead over Democratic Rep. Gil Cisneros, she saw it cut by five percentage points, leaving her with a 48% to 47% lead.
Closer to the Bay Area, Democratic Rep. Josh Harder of Turlock (Stanislaus County) picked up nearly seven percentage points after election night, giving him a nine-point lead over Republican Ted Howze. In the Cox-Valadao rematch, the Democrat moved from 17 points down to 12.
Personal gatherings? Supervisor — OC residents should stay home. Period.— Harley Rouda (@HarleyRouda) March 28, 2020
Last week, I wrote a letter asking to clarify your confusing shelter-in-place order to our constituents. It seems that you didn’t get the message.
This misleading info puts OC families at risk. https://t.co/UUTHIfmCFT