If a wall cloud rotates, it might precede tornado development. Commonly Used Weather Terminology Advisory - Issued when hazardous weather or hydrologic conditions exist, are imminent or are likely tc occur. Advisories are issued for conditions that may cause major inconvenience and could lead to situations that may threaten life or property. Anticyclone - An area of high pressure. Winds blow in a clockwise direction in the Northern Hemisphere and in a counter clockwise direction in the Southern Hemisphere.
Fair weather is associated with an anticyclone.
Backdoor Front - A front that moves east to west in direction rather than the normal west to east movement. Backing Wind - A wind that changes its direction in a counter clockwise motion. An example would be a Northwest wind changing to a West wind. Beaufort Wind Scale - A scale classifying wind strength in terms of observable effects both on the sea and over land. Copies of the Beaufort Wind Scale for both land and water are included with this terminology guide.