MONTGOMERY, Ala. — Alabama voters will head to the polls next week for party primaries in the race to fill Attorney General Jeff Sessions’ old Senate seat, but despite a crowded Republican field, turnout is expected to be slim, a state official said Monday.

Alabama Secretary of State John Merrill said he is projecting that 20 percent to 25 percent of voters will go to the polls on Aug. 15. Merrill said a typical primary brings turnout of 30-32 percent.

The closely watched race features crowded fields and heated matchups, particularly on the Republican side. However, the late summer special election comes at a time that state voters aren’t accustomed to going to the polls, Merrill said. The Senate election is the only race on the ballot on Aug. 15, meaning there will be no other elections to help drive voters to the poll.

Appointed Sen. Luther Strange, a Republican, faces a slate of aggressive challengers, including former Chief Justice Roy Moore, U.S. Rep. Mo Brooks, state Sen. Trip Pittman and Christian Coalition leader Randy Brinson.

A Sept. 26 primary runoff between the top two finishers is anticipated. The state requires a primary runoff unless a candidate tops 50 percent of the vote in the first round of voting.

The dynamic of a special election with low turnout has upped the pressure on candidates to get their supporters to the polls.

Strange has run a high-dollar race and is backed by a super political action committee which is trying to fight off his challengers. The super PAC is tied to Senate Majority Leader Mitch McConnell.

Moore has built up a loyal following among some evangelical voters after being twice removed from chief justice duties for defying courts over same-sex marriage and the public display of the Ten Commandments. Brooks is a member of the conservative House Freedom Caucus and has been the target of several super PAC ads highlighting his past criticisms of President Donald Trump.

Former U.S. Attorney Doug Jones, environmentalist Michael Hansen and Naval Academy graduate Robert Kennedy, Jr., are among the contenders in the Democratic primary.

The Republican and Democratic nominees will face off in a December election.