WASHINGTON — In another forecast of continued economic growth, the index of leading economic indicators rose a strong 0.5% in June, the Conference Board said.

The index’s rise was its fifth in a row, including a 0.3% gain in April and a 0.2% gain in May. Three consecutive increases usually signal that the economy is expanding.

"The economy is on the move again, but the speed of the expansion is uncertain," said Robert Dederick, chief economist at Northern Trust Co. in Chicago.

The index of leading indicators is intended to predict economic activity six to nine months ahead, but many economists say it …