The nation's balance of payments, the broadest measure of its foreign trade position, ballooned to a record $32.9 billion deficit in the third quarter and headed toward a record high of more than $100 billion for the year, the Commerce Department reported yesterday.

"The deficit will exceed $100 billion for 1984, more than double last year's $41.6 billion, and it probably will rise again next year," Commerce Secretary Malcolm Baldrige said. He blamed the growing current account deficit on the strong dollar, which cuts the price of imports to Americans and increases the price of U.S. merchandise overseas. The merchandise trade deficit also is running at record levels, and Baldrige pointed out that "a 10.2 percent increase in imports swamped a modest 1.7 percent gain in exports.

"The strength of the dollar is seriously hurting our industry," he said. "To bring down the dollar and stem the trade deficit, we must lower the budget deficit."

A major factor in the rising balance-of-payments deficit has been the shrinking surplus in services -- which includes overseas earnings from industries such as banking, insurance, accounting and advertising, as well as overseas investments and tourism. One analyst called the decline in the services surplus "a very big structural change."

The balance-of-payments deficit has increased every quarter this year and last, and, based on third-quarter figures, is running on an annual basis at more than $130 billion -- the same total as the projected 1984 merchandise trade deficit.

In the past, the United States' overseas income on services -- especially interest payments on American investments abroad -- had kept the balance of payments on an even keel. As recently as 1981, for instance, the current account balance was running $4.5 billion in the black despite a merchandise trade deficit.

The surplus in services dropped to a record low of $3 billion during the third quarter. The decline was $200 million from the second-quarter level, but it was far less than the $5 billion fall in the services surplus between the first and second quarters.

"The traditional U.S. surplus on services has almost evaporated," said C. Fred Bergsten, director of the Institute for International Economics, who described the shift as a significant structural change and "a dramatic reversal.

"We are becoming a debtor nation," he added. "Instead of earning dollars on our foreign investment, we are paying. Already we are at a point where we can no longer cover any merchandise trade deficit with service earnings. Soon we will need a merchandise surplus to pay foreign holders" of American securities.

The surplus between what Americans earned on investments overseas and what they paid to foreigners who invested in this country narrowed to $24.4 million during the first three quarters of this year from $27.8 million in the same period last year.

High interest rates have pulled in foreign investments, which have helped to finance America's budget deficits and have been a major contributer to the overvalued dollar.

In a speech late last month, Federal Reserve Board Chairman Paul A. Volcker said the United States "is importing capital so fast that the largest and richest country in the world is well on its way to becoming the largest international debtor as well.

"When we import more goods and services than we export, we must pay for it the only way we can, by borrowing capital from abroad in the same amount," he continued.

Also contributing to the third-quarter current account deficit was the record number of American tourists traveling abroad during the months of July, August and September.