Let's get started with some essential terms!
Glossary of essential terms
Jet stream - a narrow variable band of very strong predominantly westerly air currents encircling the globe several miles above the earth. Wind speeds are as a result in the differences in pressure created by the different densities of warm and cold air masses.
Rossby waves – oscillations in the jet stream flows. Rossby waves help transfer heat from the tropics toward the poles and cold air toward the tropics in an attempt to return atmosphere to balance. They also help locate the jet stream and mark out the track of surface low pressure systems. The slow motion of these waves often results in fairly long, persistent weather patterns. Jet streams and Rossby waves are both heavily impacted by Coriolis force.
Advective cooling – when air masses move horizontally from a cool area into a warmer area, effectively dropping its temperature.
Radiative cooling – when air is cooled on contact with the ground. For example at night when the ground loses heat rapidly, the air in contact with it is also cooled. Moisture in this air often condenses when relative humidity reaches 0°C/32°F and forms dew or even fog at the ground level.
Tropical easterly waves - waves, or oscillations of low pressure that develop in the trade winds and move from east to west across the tropics. Satellite imagery provides the best view of an easterly wave. As low-level winds enter the trough of the wave, they converge, causing convection along the wave axis and to the east. To the west of the line, there is usually a zone of divergence. A few of these systems develop into tropical storms or hurricanes.
Hurricanes – an intense low-pressure system or tropical storm characterized by extremely high winds and torrential rainfall. These form in tropical latitudes over deep ocean waters. Tropical cyclones are like giant engines that use warm, moist air as fuel. The warm, moist air over the ocean rises upward from near the surface. This air moves up and away from the surface, causing an area of lower air pressure below. The accelerated updraughts of air cause thunderstorms to form and the Coriolis force causes the clouds and winds to rotate. |
Click to view the You Tube video below that explains jet streams.
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