If warm moist air rises, it will expand and cool. As it cools, the relative humidity will increase and water will condense. It can then fall back to the earth as precipitation. The boundaries between warm, moist air and cold, dry air is where storms frequently occur.

When two large air masses of different temperature meet, the warmer and hence lighter air is lifted above the cooler air. The warm air then rises, cools and condenses to form rain. The boundary that separates the cold air and the warm air is called a Front.

Water at the Earth’s surface evaporates into water vapor which rises up into the sky to become part of a cloud which will float off with the winds, eventually releasing water back to Earth as precipitation.

As air rises over a mountain it cools and loses moisture, then warms by compression on the leeward side. The resulting warm and dry winds are Chinook winds. The leeward side of the mountain experiences rainshadow effect.

Answer. Answer: It will happen is precipitation falls as the air rises over the mountains, the air will be dry as it sinks on the leeward size. This dry, sinking air causes a rainshadow effect , which creates many of the world’s deserts.

As an air parcel sinks the pressure of the surround air around it increases. Therefore as the pressure increases the temperature increase. Since there is no addition of water to a sinking parcel of air, meaning the dew point is going to remain constant, the relative humidity will drop.

Atmosphere Interactions As air rises, air pressure at the surface is lowered. Rising air expands and cools (adiabatic cooling: that is, it cools due to change in volume as opposed to adding or taking away of heat). The result is condensation/precipitation. Cold air sinks.

The air parcel expands as it rises and this expansion, or work, causes the temperature of the air parcel to decrease. As the parcel rises, its humidity increases until it reaches 100%. When this occurs, cloud droplets begin forming as the excess water vapor condenses on the largest aerosol particles.

Air is warmest at the bottom of the troposphere near ground level. Air gets colder as one rises through the troposphere. That’s why the peaks of tall mountains can be snow-covered even in the summertime. Air pressure and the density of the air also decrease with altitude.

The degree of stability or instability of an atmospheric layer is determined by comparing its temperature lapse rate, as shown by a sounding, with the appropriate adiabatic rate. A temperature lapse rate less than the dry adiabatic rate of 5.5°F.

The atmosphere is said to be absolutely unstable if the environmental lapse rate is greater than the dry adiabatic lapse rate. This means that a rising air parcel will always cool at a slower rate than the environment, even when it is unsaturated.

What are the characteristics of stable air? A—Good visibility; steady precipitation; stratus clouds. B—Poor visibility; steady precipitation; stratus clouds. C—Poor visibility; intermittent precipitation; cumulus clouds.

Air is considered unstable, in the lowest layers of an air mass when the air is warmer and or more humid than the surrounding air. When this occurs the air will rise, as that air parcel is warmer than the air surrounding it. In an unstable environment, the weather can change suddenly and can be violent.

To be “unstable”, the lowest layers of an air mass must be so warm and/or humid that, if some of the air rises, then that air parcel is warmer than its environment, and so it continues to rise. This condensation releases heat, which warms the air parcel, which can cause the parcel to rise higher still.

Expansion

The state of a layer of unsaturated air when its lapse rate of temperature is less than the dry-adiabatic lapse rate but greater than the moist-adiabatic lapse rate. This definition does not require that such a parcel be obtained by adiabatic displacement from any level. …

Terms in this set (7)

• What are three types of lifting? Convectional lifting, Orographic lifting, and Frontal Lifting.
• Air mass. Huge volumes of air that can cover entire continents or oceans.
• Warm front.
• Cold front.
• Stationary front.
• Occluded front.
• Formation of fronts.

– There are four lifting mechanisms that form clouds: Orographic Lifting, Convection, Convergence, and Updraft. – Orographic lifting is when air cannot go through a mountain, and so it flows over it. – Frontal Lifting is when less dense warm air is forced to rise over cooler, denser air as a weather fronts move.

Lake-effect snow typically forms on the downward side of a lake. Lake Erie and Lake Ontario are positioned in such a way that prevailing winds from the west blow the entire length of the lakes often generating huge amounts of snow that fall on the east end (downwind side) of the lakes and surrounding land.

Warmer, less dense air rises upward, creating lift. As the air lifts higher and higher, it causes a storm cloud to grow taller and taller. Thunderstorm clouds can rise up to 10 miles into the air!

A thunderstorm is classified as “severe” when it contains one or more of the following: hail one inch or greater, winds gusting in excess of 50 knots (57.5 mph), or a tornado.

Sources of Lift (upward)

• Fronts are the boundary between two air masses of different temperatures and therefore different air densities.
• Dry Lines are the boundary between two air masses of different moisture content and divides warm, moist air from hot, dry air.

Concepts: 1. Students will discover that three main ingredients are needed for clouds to form: moisture, condensation, and temperature. 2. Evaporation and condensation are part of how a cloud forms.

Lifting of Air As air rises it expands because pressure decreases with altitude. Kinetic energy is converted to potential energy and the parcel temperature decreases, and the relative humidity increases. The two main large scale lifting processes that result in cloud formation are convection and advection of air.

Lift is necessary to overcome a capping inversion on the most dynamic days as well. Usually, lift is associated with an upper level storm system aloft and with surface boundaries where winds converge down low. Atmospheric lift is achieved in other ways as well.