SAN FRANCISCO — Firefighters in Northern California battled more than a thousand wildfires to a stalemate by yesterday, but forecasters said dangerous conditions would not relent anytime soon.

No new major fires had broken out by yesterday morning as fire crews inched closer to getting some of the largest blazes surrounded, according to the state Office of Emergency Services.

But a “red flag warning” — meaning the most extreme fire danger — was still in effect for Northern California until 5 a.m. this morning. And the coming days and months are expected to bring little relief.

Forecasters predicted more thunderstorms and dry lightning through the weekend, similar to the ones that ignited hundreds of fires a week ago. Meanwhile, a U.S. Forest Service report said the weather would get even drier and hotter as fire season headed toward its traditional peak in late July and August.

Lower-than-average rainfall and record levels of parched vegetation likely mean a long, fiery summer throughout Northern California, according to the Forest Service’s state fire outlook released last week.

The fires burning now could take weeks or months to bring under full control, the report said.

Those blazes were mostly sparked by lightning storms that were unusually intense for so early in the season. But summer storms would probably be even fiercer, according to the Forest Service.

“Our most widespread and/or critical lightning events often occur in late July or August, and we have no reason to deviate from that,” the agency’s report said.

The blazes have scorched more than 550 square miles and destroyed more than 50 buildings, a state emergency services spokesman, Gregory Renick, said.