Courtesy of Jessyn Farrell's campaign.

State Representative Jessyn Farrell, a Democrat representing Northeast Seattle, plans to resign her House seat to focus on running for mayor.

Farrell announced her decision in an email to reporters and will hold a formal press conference tomorrow at 1:30 p.m. at the University District Food Bank. Several prominent Democrats, including Lt. Governor Cyrus Habib, State Auditor Pat McCarthy, and State Representative Nicole Macri, plan to stand by her side during the appearance.

"With so many issues facing our city—from transportation and education, to homelessness and housing affordability—Seattle needs a mayor who shares our values and has the expertise to bring results," Farrell said in a separate statement. "That's why I've made the decision to resign my seat and fully commit to winning this race."

Her statement did not make clear exactly when she plans to resign.

Farrell, who is currently serving her third term in the house, is known for her support of public transit. She has pushed for more funding for busses and light rail, campaigned heavily for Sound Transit 3, and was named vice chair of the House Transportation Committee.

The state representative announced her mayoral run just three days after Mayor Ed Murray announced he would not seek re-election amid sexual assault allegations, joining a flurry of new candidates entering the race. Former US Attorney Jenny Durkan, who is gearing up to bring in pro-business voters announced a day before Farrell. State Sen. Bob Hasegawa, meanwhile, announced his run a couple days before Murray's decision to drop out.

By resigning her seat, Farrell frees herself to collect campaign contributions. That's because under Washington law, state lawmakers can't receive donations during a legislative session, and both statehouses are still working on crafting a budget that adequately funds K-12 education.

To replace Farrell in the House, Democrats in her legislative district will select three possible replacements. The King County Council will then appoint one of those three to the seat. In 2018, the seat will be on the ballot for the next two-year term.

Sen. Hasegawa, the only other state legislator running for Seattle mayor, has not given any indication that he plans to step down. "I appreciated that Jessyn has made the decision she fees she needs to in order to win," Hasegawa said in a text message. "My campaign is powered by people, not money, and is the only campaign to prove that people can, and will, defeat money in politics."

UPDATE (6:06 p.m.): This post has been updated with comment from State Rep. Jessyn Farrell.

UPDATE (7:47 p.m.): This post has been updated with comment from State Sen. Bob Hasegawa.