Dowell, 63, has been exploring a candidacy for weeks and has scheduled a formal announcement for Wednesday. An alderman since 2007, her diverse 3rd Ward includes the South Loop and Bronzeville.

More recently, Dowell has served as chair of the City Council’s budget committee in dealing with the city’s strained financial situation.

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Dowell will enter a race with several other announced contenders, including former state Treasurer Alexi Giannoulias, Chicago City Clerk Anna Valencia and state Sen. Michael Hastings of Frankfort. Cook County Clerk Karen Yarbrough also is considering a bid.

Giannoulias on Monday said he had raised $2.1 million from January through March for his campaign. His last run for public office was in a losing bid for the U.S. Senate to one-term Republican Sen. Mark Kirk in 2010.

White, 86, is the state’s longest serving secretary of state and has been in the post since 1999.