The higher the dew point, the greater the moisture content of air. High pressure systems, usually associated with widespread fair weather, will on rare occasions bring extensive, persistent cloudiness. The flow of the wind resulting in a horizontal outflow of air from a region. Divergence at ground level requires that air immediately above the diverging layer must descend. The incident resulted in this country s first meaningful air pollution laws, culminating in the federal Clean Air Act of 1970.
Drafts often consist of cold air moving across a floor and, as such, are unpleasant.
Unlike fog, drizzle falls to the ground. Dry lightning is the leading natural cause of forest fires in the western states. In the Great Plains within a few hundred miles of the Rocky Mountains, a dry line is a boundary separating warm, dry air to the west from warm, moist air to the east. In climates in which the seasonal variation of precipitation is a major feature, the dry season is the annually recurring period of a few months during which precipitation is absent or nearly so for that region. Colloquially, an interval of abnormally dry weather less extensive and less severe than a drought.