21.   A thick cloud cover is expected over this region with light snow likely from eastern Minnesota to central Michigan.

22.   Abundant cloud cover will continue from the continental divide to the Atlantic Seaboard.

23.   Brisk breezes from the north will combine with patches of rain and thick cloud cover to enhance the chill in Iowa and eastern South Dakota.

24.   But although they knew that factors such as cloud cover were important, they are difficult to include in such calculations.

25.   But several of them are now in almost continuous use over Afghanistan, providing surveillance images even at night or through cloud cover.

26.   But the scandals and near-scandals form a permanent cloud cover that this administration can never rise above.

27.   But Walkinshaw said a low cloud cover was keeping some helicopters away.

28.   But Walkinshaw said low cloud cover was keeping some helicopters away.

29.   Cloud cover and haze may obscure some sites.

30.   Cloud cover prevented him from seeing where he was going, and when he dropped down, he almost hit the Empire State Building.