Assemblywoman Noreen Evans, D-Santa Rosa, announced Monday that she will run next year for the open state Senate seat to represent District 2, the expansive North Bay district that includes Napa County.

The announcement came only one day after state Sen. Pat Wiggins told supporters that she will not seek re-election in 2010 due to unspecified medical problems. Evans will now square off against David Rosas, a Santa Rosa Democrat and school board trustee who filed his intention to run earlier this month.

“First, I want to thank Sen. Wiggins, Pat, for her many years of excellent and dedicated public service to her constituents, her District and to California,” Evans said in a prepared statement. “Pat has been a friend, a leader and a colleague for many years and I know I have my work cut out for me to fill her shoes.”

Evans, who is prevented from running for re-election in the state Assembly due to term limits, originally planned to run for state Senate in 2014.

She said in an interview that it was “a struggle to make the decision to run for senate (in 2010), because I have other options when I’m termed out,” such as seeking a seat on the Sonoma County Superior Court. However, Wiggins’ decision not to seek re-election in 2010 caused Evans to reevaluate her timeline, she said.

“Because the position will be open in 2010, and I don’t want to have to run against an incumbent, and I’m termed out in 2010, timing-wise it just made sense,” Evans said.

Some of California’s top Democratic leaders have already given Evans the nod.

Reps. Mike Thompson and Lynn Woolsey, both of whom represent parts of the 2nd Senate District; state Senate President Darrell Steinberg; Assembly Speaker Karen Bass and Wiggins herself all announced their support for Evans Monday.

“Assemblymember Evans is just the kind of experienced, hard-working problem solver that California needs right now as we work to create jobs, fix our state budget problems and revive our state economy,” Steinberg said in a prepared statement. “Assemblymember Evans is the best choice for District 2.”

Evans is currently serving her third term representing Assembly District 7, which includes all of Napa County and parts of Sonoma and Solano counties. She is chairwoman of the Assembly Budget Committee and the Assembly Select Committee on Wine, and a member of the Committees on Banking and Finance, Governmental Organization, and Judiciary. Evans also serves on the Joint Legislative Audit Committee.

If elected to the state senate, Evans said she hopes to improve California’s foster care system and to reform the budget system.

“The issues facing the state are highly complex and very difficult to solve,” she said, “and I think the experience that I’ve had as an assemblymember for the last six years — and as chair of the budget committee in the Assembly and as a member of leadership in the Assembly — that’s the kind of leadership we’re going to need going forward.

Evans added that Rosas is “a well-respected man in Sonoma County” and that she expects they will both run “good clean campaigns.”

Rosas could not be reached for comment.

Primary elections will be held in June, with general elections in November 2010.