A Montgomery County school board member charged yesterday that the board has set a pattern in its decisions on school closings that could be viewed as discriminatory and that could be subject to legal challenge.

Blair Ewing, a dissenting voice on the board, said at a public meeting that the board "is on very serious ground" because of decisions to close two predominantly minority schools and to change the recommended assignment of students from threepredominantly white elementary schools.

Ewing's criticism reflects the concerns of many liberals and minority group members in the county who are troubled by the direction the school board has taken in recent months. But his views have been repeatedly rejected by a majority of the board.

Board members interviewed yesterday disputed Ewing's latest assertions and said actions by the board actually will improve racial balance in some school areas. Ewing, they said, is isolated on the board and his views have been overpublicized.

"I believe the actions by the board thus far already present a pattern of decisions which could be interpreted as discriminatory in intent," Ewing said. "I am not an attorney, but I have read the cases, and I believe the board is bringing this school system toward de jure segregation through its actions."

De jure segregation is segregation that is established by specific actions of a legislative body. The board has no legal obligation to ensure racial balance in the schools, but actions that result in racial segregation can be challenged in court.

The board voted yesterday to hold a special meeting in December to look at the overall effects of the closings. The board's attorney has reviewed the superintendent's master plan for school closings, which the board has adhered to in most cases, and will review other decisions as they are made.

Several board members responding to Ewing's charges said that racial balance is being considered but that it is one of many factors in a complicated process of picking schools to close.

"We are closing many schools, some are low minority and some are higher minority," explained board member Marian L. Greenblatt. "It is a process of trying to address declining enrollment in the schools and a fiscal crisis. The net result will demonstrate that the board has considered racial balance . . . and it will improve integration."

The issue of integration arose frequently when community groups presented testimony during public hearings last month. When the board began voting on schools last week, Ewing warned several times that the issue was being ignored.

As evidence he cited the board's decision to turn aside a recommendation from Superintendent Edward Andrews that would have improved racial balance at Montgomery Blair High School in Silver Spring, which has the largest minority population of any high school in the county.

Board member Joseph R. Barse said it is not the school board's intent to segregate schools, but he noted that the board majority's vote last week to close Takoma Park Junior High "could be misinterpreted by observers."

"I think the board ought to reconsider that decision," said Barse, who voted to keep Takoma Park open. The school has a minority enrollment that exceeds 60 percent.

Barse said he will urge his colleagues to reconsider boundary changes affecting Blair High School.

Board member Eleanor Zappone said the board is making its decisions on school closings "piece by piece" and is taking into consideration a variety of factors.

Zappone and Greenblatt emphasized that racial balance will be improved in the Springbrook High School area as a result of the board's decisions. They said that two elementary schools below the beltway, Brookview and Broad Acres, are now included in the Springbrook boundary area and that more minority students will enroll at the high school because of the board's changes. The Brookview area has a student population that is roughly 40 percent minority, while Broad Acres is 68 percent minority.

Those two schools were formerly in the Blair boundary area but fed into Key Junior High above the beltway, a school closed by the board during last week's voting.

Zappone said she believed Ewing made his remarks yesterday "to be the catalyst for a liberal opinion that points out his perspective of whatever decision is being made." She surmised that Ewing "feels uncomfortable" on the seven-member board because, as of the election in 1978, he no longer shares the views of the majority.

Ewing urged his colleagues to reconsider two of their decisions, involving Parkwood and Larchmont schools, to avoid worsening the racial balance in the Bethesda-Chevy Chase area.