GO GIRLY

1. The difference between Convective clouds and Stratiform Clouds is a function of what characteristic of their respective air masses?

Stratiform Cloud- form in stable air mass, where air resists the vertical movement, so clouds develop horizontallyresulting in layers of sheets, associated with continuous and light precipitation.

Convective Cloud- form in unstable air masses, where warm air tends to rise rapidly because it is less dense and this rapid vertical movement results in towering puffy clouds associated with thunderstorms.

 

2.  How many unique types of stability do we describe in this chapter?

FOUR unique types of stability

Absolute Stability

      - is the state of a column of air in the atmosphere when its lapse rate of temperature is less than the moist adiabatic lapse rate.

      - air parcel lifted upward would be colder (denser) than the surrounding environmental air and would tend to sink back to its level of origin.

  • Explanation: If an air parcel is lifted, it becomes cooler than the surrounding air and sinks back down. The environmental lapse rate is less than the moist adiabatic lapse rate.

  • Result: Clouds that form are generally stratiform and spread out, not rising tall.


Neutral Stability

       -state of a column of air in the atmosphere in which an ascending (or descending) air parcel always has the same temperature (density) as the surrounding environmental air.

        - Surrounding environmental air (same temperature (density)) Air Parcel temperature and dew point

  • Analogy: Like a ball on a perfectly flat surface—it stays where it is or moves at a steady pace if pushed.

  • Explanation: If an air parcel is lifted, it cools at the same rate as the surrounding air. It will not return to its original position but won’t accelerate away either.

  • Result: Clouds and air movement can occur, but vertical motion is steady, not enhanced or suppressed.


Absolute Instability

          - state of a column of air in the atmosphere when it has a super adiabatic lapse rate of temperature (i.e., greater than the dry adiabatic lapse rate).       

           -An air parcel displaced vertically would be accelerated in the direction of the displacement. The kinetic energy of the parcel would consequently increase with increasing distance from its level of origin.

  • Analogy: Like a rock on a steep hill—if pushed, it rolls away and keeps going.

  • Explanation: When an air parcel is lifted, it stays warmer than the surrounding air and continues to rise. The environmental lapse rate is greater than the dry adiabatic lapse rate.

  • Result: Leads to the formation of convective clouds such as cumulus and cumulonimbus, often associated with strong vertical development and storms.

Conditional Instability

            -the state of a column of unsaturated air in the atmosphere when its lapse rate of temperature is less than the dry adiabatic lapse rate, but greater than the moist adiabatic lapse rate.

  • Analogy: Think of a ball on a flat surface that might roll if given a push strong enough to tip it.

  • Explanation: The stability depends on whether the air parcel is saturated or unsaturated:

    • Unsaturated: The parcel is cooler than the surrounding air and stable.

    • Saturated: The parcel becomes warmer than the surrounding air and unstable.

  • Result: Vertical movement and cloud development occur when the air is moist enough.

3.  What is the characteristic that defines ABSOLUTE Stability?

If an air column has a super adiabatic lapse rate (greater than the dry adiabatic lapse rate), it indicates absolute instability. the air cools more rapidly than the rising air parcels, making the environment conducive to rising air and the formation of convective clouds.

 

4.  In a Neutral state of a column of air, where that column of air is saturated, when does Neutral Stability exist? (When the lapse rate is equal to _______________?)

neutral stability exists when the lapse rate is equal to the moist adiabatic lapse rate.

 

5. The Level of Free Convection (LFC) defines which type of of unstable air?

Conditional instability

 

6.  Absolute Instability is achieved when a column of air has a lapse rate we call ________________.

when a column of air has a lapse rate that is greater than the dry adiabatic lapse rate.

 

7.  How does wind change the stability of a column of air?

-by changing the temperature lapse rate. 

-Stability increases when wind blows colder air into the bottom of the air column (cold air advection) and/or warmer air at the top (warm air advection).

-Conversely, stability decreases when wind blows warmer air into the bottom of the air column and/or colder air at the top.

 

8. Convective Instability, associated with Thunderstorms, is because one part of the column of air becomes saturated first and slows its lapse rate.  This is convective instability, and occurs when the Bottom or the Top begins cooling at the Moist Adiabatic Lapse Rate.  Which part, bottom or top of the column causes this convective instability by saturating first?  

-occurs when the bottom of the column becomes saturated first

-This causes it to cool at the moist adiabatic lapse rate (which is slower than the dry adiabatic lapse rate).

 

9.  What effect does an Inversion or an ISOTHERMAL layer have on instability?

  • An inversion (where temperature increases with height) or an isothermal layer (where temperature remains constant with height) acts as a stabilizing force.

  • These layers can cap convection, trapping pollutants and moisture below, but if lifted or eroded, they can release significant instability.

10. What is C.A.P.E.?

Convective Available Potential Energy. It's the maximum amount of energy available to an ascending air parcel for convection.

CAPE is directly related to the maximum potential vertical speed within an updraft; thus, higher values indicate the potential for stronger updrafts.

1 joule per



1. As an air parcel ascends, what happens?

  • The parcel expands due to lower pressure at higher altitudes and cools as it rises.

2. Why does the air cool as it rises?

  • Expansion causes cooling. As the air parcel rises, it moves into areas with lower pressure, expanding and using its energy for expansion, which lowers its temperature.

3. If the Dry Adiabatic Lapse Rate of an air parcel is 3°C per 1,000 feet, what is the Lapse Rate of the Dew Point within that parcel of air?

  • The Dew Point Lapse Rate typically decreases by about 0.5°C per 1,000 feet as the air parcel rises.

4. What do we call the level at which a parcel of moist air lifted dry adiabatically becomes saturated?

  • This is called the Lifted Condensation Level (LCL).

5. What happens when we continue ascending past the level referred to in Question 4?

  • The air parcel cools at the moist adiabatic lapse rate, which is slower than the dry rate, and clouds form as moisture condenses.

6. What is happening to the RELATIVE humidity of an ascending parcel of air?

  • The relative humidity of the parcel increases as it rises because the air cools and can hold less moisture. It reaches 100% at the LCL, where condensation begins.

7. Among the sources of vertical motion, one of them is the presence of Mountains and Valleys, which effects are called:

  • These are called orographic lifting or orographic effects.

8. What happens to a parcel of air (temp-wise) as it descends on the leeward side of a mountain?

  • The parcel warms up due to compression as it descends, following the dry adiabatic lapse rate. This process often leads to drier, warmer conditions known as a rain shadow effect.

9. What are the four basic cloud types (appearances) observed in our atmosphere?

  • The four basic types are:

    1. Cumulus (puffy, cotton-like)

    2. Stratus (layered, blanket-like)

    3. Cirrus (wispy, high-altitude)

    4. Nimbus (rain-producing)

10. At what altitude does our definition of MIDDLE clouds begin?

  • Middle clouds start at altitudes of approximately 6,500 feet (2,000 meters) and extend up to about 20,000 feet (6,000 meters).

    1. Source Regions: where an Air Mass originates. There are 5. What are they

  • Continental Arctic (cA)—Cold, dry.

  • Continental Polar (cP)—Cold, dry.

  • Continental Tropical (cT)—Hot, dry.

  • Maritime Polar (mP)—Cool, moist.

  • Maritime Tropical (mT)—Warm, moist.

  1. Is the United States a favorable source region?

Given its geographic location and closeness to several bodies of water (the Atlantic, Pacific, and Gulf of Mexico) as well as large land areas, the United States can be considered as a favorable source region for a number of air masses.

3. A warm moist air mass moving over a cold surface produces stable air, stratiform clouds, drizzle, and what is referred to as Advection Fog. Where, in the USA, is this Common?

warm, moist air mass moving over a cold surface produces stable air, stratiform

●  Pacific Northwest (Washington, Oregon, Northern California)

●  Northeast U.S. (New England, Mid-Atlantic)

●  Great Lakes Region I

4. How are fronts classified? What gives them their NAME?

  • ●  Fronts are classified according to the temperature differen ces between the air masses and their movement direction (cold, warm, stationary, or occluded).

    ●  Their names are determined by the type of air mass that is advancing forward (warm or cold) and how the front is acting (whether it is stationary, occluded, cold or warm).

    ●  Cold Front: Cold air advances, replacing warm air

    ●  Warm Front: Warm air advances, replacing cold air.

    ●  Stationary Front: Neither air mass moves significantly.

    ●  Occluded Front: Cold front overtakes a warm front, lifting the warm air.

5. Which has a more shallow slope: a Cold Front or a Warm Front
● A Warm Front has a more shallow slope compared to a Cold Front.

6. What is the wind direction you would typically find behind a Warm Front? How about what wind direction would you find behind a Cold Front?

  • ●  Behind a Warm Front: Winds are typically from the south or southwest.

  • ●  Behind a Cold Front: Winds are typically from the northwest or west.




    7. Which type of front can produce Squall Lines of Thunderstorms?

● Cold fronts are the type of front that is most commonly associated with the formation of squall lines of thunderstorms.

8. Is there weather associated with a Stationary Front? What kind?

● Yes, there is weather associated with a stationary front, although it usually lasts longer and isn't as severe as other front kinds.Cloudy sky, light to moderate precipitation, and consistent, long-lasting weather that may last for many days.

9. Which creates more SEVERE Weather: A Warm Front Occlusion or a Cold Front Occlusion?

● A Cold Front Occlusion creates more severe weather than a Warm Front Occlusion. Severe weather, including heavy rain, thunderstorms, and occasionally tornadoes, can result from the strong lifting of warm, moist air by the cold front.

10. Which type of Front is a sign that a Wave Cyclone is going to soon begin gradually dissipating?

● A Stationary Front is typically a sign that a Wave Cyclone (a developing low-pressure system) is beginning to dissipate or weaken.

1. What THREE things affect the flow of wind?

  •  Pressure Gradient Force (PGF)

  • Coriolis force

  • Friction

    2. What is a Pressure Gradient Force (PGF)?

- The PGF is the force formed from change in atmospheric pressure over distance. When the pressure changes, a gradient, or slope, is created, which initiates air movement.

3. In the NORTHERN Hemisphere, what direction does Coriolis Force cause wind to turn?

- The Coriolis Force deflects the wind to the right.

4. Does FRICTION FORCE vary with the magnitude of the Wind Speed?

- The magnitude of the friction force and wind speed are directly proportional. That means that if the wind speed doubles, the friction force acting against it doubles as well.

5. Does CORIOLIS FORCE vary with the magnitude of the Wind Speed?

- Coriolis force magnitude is directly proportional to wind speed; therefore, as wind speed increases, the Coriolis force also increases.

6. Within the Boundary Layer, wind speeds are lower. This can have an effect on the strength of Coriolis Force. This causes Wind Direction to vary within the Boundary Layer. As we Ascend in the atmosphere out of the boundary layer, what "clock direction" does Wind Direction move?

- In the Northern Hemisphere, wind direction often turns clockwise when one ascends out of the boundary layer because of the combined effects of the Coriolis force and the pressure gradient force.

7. Do Local Winds experience Coriolis Force?

- All winds are affected by the Coriolis force, but because local wind systems typically cover less than 100 miles, their scale and duration make the Coriolis Force effects insignificant.

8. Why are the COASTS of Florida cooler than the inland portions of that state?

- Due to the effect of the sea breeze, the high specific heat of the water, humidity levels, and variations, Florida's coasts experience colder temperatures.

9. What direction does air circulate around an Anti-Cyclone?

- Winds around an anticyclone in the Northern Hemisphere rotate clockwise, while winds around an anticyclone in the Southern Hemisphere rotate counterclockwise.

10. What is the opposite of a RIDGE in the Atmosphere? - Trough, it represents a low pressure area.