UPDATE 11:20 a.m.
PORTLAND, Ore. (AP) -- Appeals court denies group's request for emergency stay blocking Oregon gay marriage ruling.
At noon, U.S. District Judge Michael McShane is expected to release his ruling on Oregon's same-sex marriage ban. McShane hasn't given any indication if he'll uphold the ban or strike it down, but advocacy groups are planning parties and counties are preparing for marriages.
Oregon United for Marriage will open a "special marriage celebration station" at 11 a.m. at the Melody Ballroom in Portland where couples can be married depending on the outcome of the ruling. The group has also invited supporters to its headquarters at 11:30.
If McShane rules that marriages can start immediately, vows will be exchanged at the "marriage station."
In Eugene, couples can get married at Davis Restaurant from 1 to 7 p.m. And in Bend, supporters of same-sex marriage will gather for celebration at the Peace Plaza at 4:30 p.m., should the judge lift the ban.
Today's ruling comes after four same-sex couples challenged Ballot Measure 36, which amended the Oregon Constitution in 2004 to say "only a marriage between one man and one woman shall be valid or legally recognized as marriage."
Attorney General Ellen Rosenblum said she would not defend the ban in February, prompting a national anti-same-sex marriage group, National Organization for Marriage, to request to intervene. McShane denied the request last week, leaving the ban undefended.
Should McShane strike down the ban, the state registrar will be prepared to issue marriage license forms. However, the judge will be the one to decide when the forms would go into effect, which could be the same day as the ruling or later to give counties time to prepare.
Another roadblock to permitting same-sex marriages after the ruling is that the 9th Circuit Court could issue a stay because the case doesn't have any defendants in the state.
"The 9th Circuit panel could agree with the National Organization for Marriage, that they should have been allowed to intervene as defenders because otherwise no one is defending the law," Lewis and Clark College Law Professor Erin Ryan told KGW in an interview Sunday.
OPB will be following the story online and on-air. At noon, Think Out Loud will have guests both for and against the ban plus legal analysis of the ruling after it's issued.
The Associated Press contributed to this report.
This story originally appeared on Oregon Public Broadcasting.