Search results
Results from the WOW.Com Content Network
Monsoon air masses are moist and unstable. Superior air masses are dry, and rarely reach the ground. They normally reside over maritime tropical air masses, forming a warmer and drier layer over the more moderate moist air mass below, forming what is known as a trade wind inversion over the maritime tropical air mass.
It is a form of fluid instability found in thermally stratified atmospheres in which a colder fluid overlies a warmer one. When an air mass is unstable, the element of the air mass that is displaced upwards is accelerated by the pressure differential between the displaced air and the ambient air at the (higher) altitude to which it was displaced.
Moist air is lighter than the surrounding dry air, creating an unstable situation. When enough moist air has accumulated, all the moist air rises as a single packet, without mixing with the surrounding air. As more moist air forms along the surface, the process repeats, resulting in a series of discrete packets of moist air rising to form ...
Clouds initially form in clear air or become clouds when fog rises above surface level. The genus of a newly formed cloud is determined mainly by air mass characteristics such as stability and moisture content. If these characteristics change over time, the genus tends to change accordingly.
Air mass classifications are indicated by three letters: [3] [4] Fronts separate air masses of different types or origins, and are located along troughs of lower pressure. [5] The first letter describes its moisture properties, with c used for c ontinental air masses (dry) and; m used for m aritime air masses (moist).
Instability results from difference between the adiabatic lapse rate of an air mass and the ambient lapse rate in the atmosphere. [2] If the adiabatic lapse rate is lower than the ambient lapse rate, an air mass displaced upward cools less rapidly than the air in which it is moving. Hence, such an air mass becomes warmer relative to the ...
Moist, unstable air moving north from the Gulf of Mexico converged with unseasonably cool, dry air moving south from Canada," the USGS said. The Great Flood of 1993.
The inability of an air mass to resist vertical motion. In a stable atmosphere vertical movement of air is generally difficult, whereas in an unstable atmosphere vertical disturbances can be quite exaggerated, resulting in turbulent airflow and convective activity that may lead to extensive vertical clouds, storms, and severe weather.