Julio Sanguinetti, leader of the center-right Colorado Party, surged ahead today to a convincing victory as votes were tabulated from yesterday's presidential election, the first in this once model democracy in 13 years.

The Colorados, who won 38.6 percent of the vote, ruled during most of the seven decades of social-welfare democracy initiated by the party's founder, Jose Batlle, in 1903. Their traditional adversary, the currently center-left Blancos, captured 32.9 percent, and the leftist Broad Front coalition 20.5 percent.

Sanguinetti, 48, a former education minister, also came up on top in a complicated simultaneous primary system designed to measure each leader's personal popularity -- besting Blanco candidate Alberto Zumaran, a journalist, and the leftist coalition choice, 76-year-old physician Jose Crottogini.

The Broad Front, widely tipped in opinion polls to win the mayoralty of Montevideo -- the country's second most important political post -- lost it to the Colorados. Nearly half of Uruguay's 3 million people live in the capital.

The front only slightly improved on the 18 percent nationwide vote achieved in the last presidential election, in 1971. A Communist faction within the coalition scored only slightly more than 25 percent of the Broad Front's total votes, dealing a blow to the Moscow-line party.

The Colorados opposed programs of land reform, nationalization of banks, and a full amnesty for political prisoners proposed by both the Broad Front and the Blancos. During the campaign, Sanguinetti ran on a promise of "peaceful change."

Many analysts said Sanguinetti won handily in part because the undisputed leaders of the two other major parties were prohibited by the departing military government from running.

Blanco leader Wilson Ferreira Aldunate, 66, a fiery former senator, has been held in a military jail since he returned from 11 years of exile in June. He was charged with links to a once-powerful leftist guerrilla group. Political sources said today they expected the charges to be dropped.

Sanguinetti was bitterly criticized by the Blancos for entering into an agreement with the military that kept in place a political ban on Ferreira and the Broad Front's leader, retired Gen. Liber Seregni. Sanguinetti defended the accord as the best possible under the circumstances. The Broad Front also accepted it. Inauguration is March 1.

"The vote clearly showed the people approved of the agreement," a tired but happy Sanguinetti told cheering supporters early this morning. Defeated Blanco standard bearer Zumaran mounted the podium to congratulate the president-elect. Zumaran promised the Blancos would provide "men and ideas" for a new democratic government.

However, newly elected Sen. Juan Raul Ferreira, Wilson's son, criticized Sanguinetti, saying that "while we will cooperate with his government . . . we will never consider it legitimate."

Some Blanco politicians suggested that the militant rhetoric and erratic personal behavior of Juan Raul Ferreira, long exiled in Washington, was in part to blame for the size of the party's loss.