Open enrollment in Covered California runs through Jan. 15, 2019, making it one of seven marketplaces that has a longer open enrollment period than the federal one, which ends today. Anyone enrolling between Dec. 22 and Jan. 15 will see their coverage start on Feb. 1.

U.S. District Judge Reed O'Connor ruled that the landmark health care law was unconstitutional because Congress earlier this year repealed the tax penalty for people who did not buy health insurance, often referred to as the individual mandate.

U.S. Supreme Court Chief Justice John Roberts had upheld the constitutionality of the law in 2012 in part based on it falling under Congress' power to tax. With the mandate repealed, O'Connor sided with 19 Republican attorneys general and one governor who argued that the law was no longer constitutional.

"For the forseeable future, this ruling has absolutely no effect," Lee told KQED. "If people are thinking about signing up for coverage in 2019, now is the time to do it, and their coverage will go live and apply throughout next year."

The insurance marketplace had already been considering extending the deadline due to a surge in last-minute sign ups. According to Lee, 58,000 people have signed up in the past week, and nearly 180,000 people have enrolled for 2019 coverage overall, in addition to another 1.2 million who have renewed their existing plans for 2019.

But enrollment is down about 10 percent compared to last year, which Lee attributes to some healthy Californians choosing not to buy insurance because Congress repealed the individual mandate.

"I want to be really clear: every one of those people is rolling the dice because some of them are going to end up in the emergency room and walking out with a $150,000 debt," Lee said.

California Attorney General Xavier Becerra, who has led a group of Democratic attorneys general defending the ACA, said in a statement Friday that "our coalition will continue to fight in court" to defend the law, which the White House said will stay in effect pending appeal.

The case is expected to end up in front of the U.S. Supreme Court, a process that could take months. Lee said if the decision is upheld, it would have devastating consequences for Californians covered by all types of insurance: private, Medicare and Medi-Cal.

"This is really a decision which is truly beyond the pale," Lee said.