UPDATE 1-Olympics-Storms wash away Beijing pollution

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BEIJING, Aug 11 (Reuters) - Beijing woke to a cool but overcast morning on day three of the Olympics on Monday after thunderstorms cleared away the city's notorious smog.

Forecasters say cooler, wet weather will continue, easing fears that heat and humidity would make conditions intolerable for tennis players and others hunting medals outside air-conditioned venues.

But the next bout of heavy rain is not expected until early next week, the official Xinhua news agency said.

"In the coming week, the highest temperature Beijing will experience will probably be 32 degrees Celsius (89 Fahrenheit), and it will not be hot and muggy as it was before."

A third of cyclists dropped out of the men's road race on Saturday saying the suffocating and dirty air, in the mid-30s Celsius, had exhausted them.

Thunderstorms doused the Chinese capital on Sunday and overnight, leaving the women cyclists coping with cold, slippery conditions instead of heat they expected.

Heavy rains hit part of southwest China's mountainous Yunnan province over the weekend, prompting the evacuation of thousands.

In humid Hong Kong, host of the Olympic equestrian events, the forecast was for scattered showers and a few squally thunderstorms.

Monday was another big day of swimming in the futuristic Water Cube pool, with Michael Phelps hoping for a second gold in men's 100m freestyle relay. (Reporting by Nick Macfie and Ben Blanchard)