Cirriform clouds composed of ice crystals with a base above around 20000 feet.

Winds that shift in an anticlockwise direction with time at a given location (e.g. from southerly to south-easterly), or change direction in an anticlockwise sense with height (e.g. easterly at the surface and becoming more northerly aloft). The opposite of veering winds. In storm spotting, a backing wind usually refers to the turning of a south or [..]

The latitude belt between 30° and 0° North and South.

Large-scale atmospheric flow in which the east-west component (i.e., latitudinal) is dominant. The accompanying meridional (north-south) component often is weaker than normal. Compare with meridional flow. Weather systems tend to move past quickly in a zonal flow regime.

A local wind that flows up the side of valleys due to increased heating along the valley walls. Often the anabatic wind results in cumulus clouds along the ridges either side of the valley. See also Katabatic winds.

The mixture of gases and particles surrounding the Earth where weather occurs.

[Slang] A penetration into the heavy precipitation core of a thunderstorm. Core punching is not a recommended procedure for storm spotting or chasing.

(or cyclonic rotation) Circulation (or rotation) which is in the same sense as the Earth's rotation, i.e., clockwise (in the Southern Hemisphere) as seen from above. Winds around synoptic-scale low pressure systems circulate cyclonically. Nearly all mesocyclones and strong or violent tornadoes exhibit cyclonic rotation, but some smaller vortic [..]

An idealised description of the way wind-driven ocean currents vary with depth. In the atmosphere, it represents the way the wind varies from the surface upwards in the planetary boundary layer. Ekman transport is the net water transport due to the Ekman spiral. In the southern hemisphere, net mass transport is 90° to the left of the surface wind d [..]

The zone of relatively low pressure, which lies between the subtropical anticyclones of the two hemispheres.