NEW DELHI, May 30 (Reuters) - Monsoon rains, which delivers about 70 percent of India's annual rainfall, arrived at southern Kerala coast on Tuesday in line with forecast, a weather office source said, brightening the outlook for higher farm output and robust economic growth.

"All the required conditions have been met," a weather office source who did not wish to be named, told Reuters. The official announcement is expected shortly, the source said.

The India Meteorological Department declares the arrival of monsoon rains only after parameters measuring consistency of rainfall over a defined geography, intensity, cloudiness and wind speed are satisfied. (Reporting by Sudarshan Varadhan and Mayank Bhardwaj; Editing by Malini Menon)