Fog - A cloud, with its base on the surface, reducing visibility. High Wind Warning - Issued when sustained winds of 40 mph or greater are occurring or expected to persist for an hour or longer or if winds of 58 mph or greater are expected for any duration. High Wind Watch - Issued when conditions are favorable for the development of high winds over all of or part of the forecast area but the occurrence is still uncertain. The criteria of a high wind watch are listed under the high wind warning and should include the area affected, the reason for the watch and the potential impact of the winds. Inversion - A layer of the atmosphere where the temperature increases with height.
Surface based inversions occur during long nights when calm conditions and dry air exist.
Isobar - A line on a weather map that connects points of equal pressure. On a weather map, isobars extend around areas of high and low pressure. Jet Stream - Relatively strong winds that are concentrated in a narrow band in the atmosphere. Jet Streams are usually thousands of kilometers long, hundreds of kilometers wide but only a few kilometers thick. They are usually found between 6 and 10 miles above the surface.