The Cambridge School Committee is considering three finalists for the superintendent's position, and a coalition appears to be forming for the local candidate of the three, a member said yesterday.

According to veteran School Committee member Alfred B. Fantini, three members are leaning towards interim superintendent Mary Lou McGrath, who has worked for the school department since 1956. He added that a fourth and decisive vote may even be hers in a few days.

The School Committee consists of six elected members and Mayor Alfred E. Vellucci, who automatically serves as chair and voting member of the board.

He also said freshman member James Rafferty formally announced his support for McGrath yesterday, and that Mayor Alfred E. Vellucci "favors the in-house candidate."

However, Fantini cautioned that outside the polarized City Council, "politics in Cambridge really is like the weather--it can change."

He said he personally was leaning towards candidate Gordon A. Bruno, superintendent of schools in Ithaca, N.Y., and was still considering Rudolph F. Crew, deputy superintendent of the Sacramento, Calif. school district. Fantini said Crew was the only minority finalist.

Fantini would not describe members' positions in full, but in the course of an interview, he said five members wanted to hurry the process and pick a superintendent by the next meeting on December 20, while he and member Timothy Toomey preferred putting off the decision until January.

He also said members favoring McGrath were reluctant to spend time in Ithaca or Sacramento on "site visits" to evaluate the other two candidates. And Fantini said Rafferty, Toomey and Vellucci were all reluctant to make site visits.

He and liberal member Frances Cooper were both preparing to visit the out-of-town candidates, he said.

He would not describe the inclinations of Henrietta Davis and Lawrence Weinstein '71, except to say Davis' vote would be unpredictable.

Interviewed earlier yesterday, Davis said, "We're looking for someone who has a commitment to the school system, who is an excellent educational leader, who can make decisions collaboratively with the staff and who has experience in a multi-cultural setting."

She would not comment on the finalists except to say that all three displayed "the best and strongest mixture of these qualities of all the people we interviewed."

McGrath has served as acting superintendent since former superintendent Robert Peterkin resigned July 1 to direct the Milwaukee, Wisc. school system.

A Cambridge school employee since 1956, McGrath first taught elementary school, then served terms as coordinator of primary education, director of elementary education and assistant superintendent of administration before becoming interim superintendent this past summer.

A native Cantabridgian, McGrath said she thought her advantages included a familiarity with the city and its policies.