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Aviation WeatherAviation Weather
Warm-Up QuestionsWarm-Up Questions
CPS Questions 1-2 CPS Questions 1-2
Chapter 2, Lesson 3
Lesson OverviewLesson Overview
Causes of atmospheric instabilityCauses of atmospheric instability Types and causes of turbulenceTypes and causes of turbulence How types of severe weather affect How types of severe weather affect
aviationaviation
Chapter 2, Lesson 3
Quick WriteQuick WriteColonel Duckworth was an expert in Colonel Duckworth was an expert in instrument flying. Why was this skill instrument flying. Why was this skill
important when flying through a hurricane?important when flying through a hurricane? (Note to teacher: Use “Pick a Student” button in CPS) (Note to teacher: Use “Pick a Student” button in CPS)
Chapter 2, Lesson 3Courtesy of the National Museum of the USAF
Causes of Atmospheric Causes of Atmospheric InstabilityInstability
Small vertical movements grow until they Small vertical movements grow until they produce turbulent airflow and air circulationproduce turbulent airflow and air circulation
Adiabatic process takes place inAdiabatic process takes place in upward and downward moving airupward and downward moving air
When air rises, pressure When air rises, pressure decreases, volume increases, and decreases, volume increases, and temperaturetemperature decreasesdecreases When air descends the opposite is trueWhen air descends the opposite is true
Chapter 2, Lesson 3Chapter 2, Lesson 3Reproduced from NOAA/National Weather Service
Causes of Atmospheric Causes of Atmospheric Instability, cont.Instability, cont.
Water vapor is less dense than airWater vapor is less dense than air Moisture decreases air density, causes air to riseMoisture decreases air density, causes air to rise Decrease in moisture makes air denser and causes Decrease in moisture makes air denser and causes
it to sinkit to sink Moist air cools at a slower rate than dry airMoist air cools at a slower rate than dry air Combination of moisture and temperature Combination of moisture and temperature
determines air stability and weatherdetermines air stability and weather
Chapter 2, Lesson 3Chapter 2, Lesson 3
Activity 1: Air Lapse RatesActivity 1: Air Lapse Rates
Convert Celsius temperatures to Convert Celsius temperatures to Fahrenheit temperaturesFahrenheit temperatures
Review the examples and then complete Review the examples and then complete the temperature conversion problemsthe temperature conversion problems
Chapter 2, Lesson 3
Learning Check QuestionsLearning Check Questions
CPS Questions 3-4CPS Questions 3-4
Chapter 2, Lesson 3
Thermal TurbulenceThermal Turbulence Rise of warm air, taking place on a local scaleRise of warm air, taking place on a local scale Plowed ground, rocks, sand, and Plowed ground, rocks, sand, and
barren land emit a large amountbarren land emit a large amount of heatof heat Water, trees, and other Water, trees, and other growing things absorb heatgrowing things absorb heat These reactions to sun’s energyThese reactions to sun’s energyresults in uneven heating of the air, creates small areas results in uneven heating of the air, creates small areas
called convective currentscalled convective currents
Chapter 2, Lesson 3Reproduced from NOAA/Earth System Research Laboratory
Convective CurrentsConvective Currents Create bumpy, turbulent airCreate bumpy, turbulent air On low-altitude flight, pilots may run into On low-altitude flight, pilots may run into
updrafts over pavement or barren places, and updrafts over pavement or barren places, and downdrafts over water or forestsdowndrafts over water or forests
To avoid these turbulent conditions, they can fly To avoid these turbulent conditions, they can fly at higher altitude, even above cumulus cloudsat higher altitude, even above cumulus clouds
Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration
Mechanical TurbulenceMechanical Turbulence
Generated by resistance of one object moving over Generated by resistance of one object moving over another another
As air moves over Earth’s surface, friction that As air moves over Earth’s surface, friction that develops between air and surface modifies the air’s develops between air and surface modifies the air’s movementmovement
Large objects—mountains to man-made structures Large objects—mountains to man-made structures such as buildings—generate mechanical turbulencesuch as buildings—generate mechanical turbulence
Chapter 2, Lesson 3Reproduced from US Department of Transportation/Federal Aviation Administration
Wind ShearWind Shear
Abrupt, dramatic change in wind Abrupt, dramatic change in wind speed, direction, or bothspeed, direction, or both
Low-level are linked with Low-level are linked with thunderstorms, and temperature thunderstorms, and temperature inversions, with strong upper-inversions, with strong upper-level windslevel winds
High-Level begins around 18,000 High-Level begins around 18,000 feet and can produce clear air feet and can produce clear air turbulenceturbulence
Chapter 2, Lesson 3Reproduced from NASA
Activity 2: Types of TurbulenceActivity 2: Types of Turbulence
Describe the type of turbulence presented and explain its impact on flight using the illustrations provided
Chapter 2, Lesson 3
Chapter 2, Lesson 3
Learning Check QuestionsLearning Check Questions
CPS Questions 5-6CPS Questions 5-6
How Types of Severe Weather Affect Aviation—Thunderstorms
Convection triggers Convection triggers thunderstormsthunderstorms
Water vapors rising with warm Water vapors rising with warm air condense into cloudsair condense into clouds
Convection process then Convection process then continues within the cloudscontinues within the clouds
At the tropopause the At the tropopause the unstable atmosphere stabilizesunstable atmosphere stabilizes
Chapter 2, Lesson 3Reproduced from NOAA/Earth System Research Laboratory
Thunderstorms—Thunderstorms—Air Mass and Steady-State Air Mass and Steady-State
Air mass occur in unstable air, last only an hour or twoAir mass occur in unstable air, last only an hour or two Warm surface temperatures cause this type of stormWarm surface temperatures cause this type of storm
Steady-state often form into narrow band of active Steady-state often form into narrow band of active thunderstorms called squall linesthunderstorms called squall lines Updrafts grow stronger and last much longer than in Updrafts grow stronger and last much longer than in
an air mass storman air mass storm
Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration
Hazardous Flying ConditionsHazardous Flying Conditions Look for squall lines, tornadoes, turbulence, Look for squall lines, tornadoes, turbulence,
icing, hail, lightning, and poor visibilityicing, hail, lightning, and poor visibility Light aircraft won’t be able to fly over Light aircraft won’t be able to fly over
thunderstormsthunderstorms Air Force instructs pilots to fly 20 miles from the Air Force instructs pilots to fly 20 miles from the
storm’s edgestorm’s edge
Chapter 2, Lesson 3Courtesy of NOAA Photo Library; OAR/ERL/NSSL
Squall LinesSquall Lines Develop in moist, unstable air, Develop in moist, unstable air,
on or in advance of a cold fronton or in advance of a cold front Often contain steady-state Often contain steady-state
thunderstormsthunderstorms Form quickly, are strongest in Form quickly, are strongest in
the late afternoon and early the late afternoon and early eveningevening
Chapter 2, Lesson 3Courtesy of NOAA/National Weather Service
TornadoesTornadoes Materialize out of the most violent thunderstormsMaterialize out of the most violent thunderstorms Can sharpen into a powerful vortex that reaches Can sharpen into a powerful vortex that reaches
from the ground into the cloudsfrom the ground into the clouds Funnel-shaped cloud that stretches earthward Funnel-shaped cloud that stretches earthward
from a cumulonimbus basefrom a cumulonimbus base
Chapter 2, Lesson 3Courtesy of NOAA/National Weather Service
TurbulenceTurbulence Inside a cloud, pilots encounter the strongest Inside a cloud, pilots encounter the strongest
turbulence turbulence Outside of clouds, as much as several Outside of clouds, as much as several
thousand feet above and 20 miles sidewaysthousand feet above and 20 miles sideways Gust front may stir up trouble as far as 15 Gust front may stir up trouble as far as 15
miles ahead of any stormmiles ahead of any storm
Chapter 2, Lesson 3 Courtesy of NOAA/National Weather Service.
Icing—HailIcing—Hail
Icing, is a product of updrafts In a thunderstorm, the updraft lifts water vapor
above freezing level,, the water supercools Hail, another form of supercooled water
Can be just as dangerous to aircraft as turbulence
Chapter 2, Lesson 3 Reproduced from US Department of Transportation/Federal Aviation Administration.
Lightning—Poor VisibilityLightning—Poor Visibility
Lightning—hazard that’s most closely associated with thunderstorms Can puncture an aircraft’s skin, damage its
communications and navigational equipment Poor Visibility— generally visibility is near zero within a
thunderstorm cloud
Chapter 2, Lesson 3Courtesy of NOAA.
Activity 3: AtmosModeler Activity 3: AtmosModeler Lab—Temperature and AltitudeLab—Temperature and Altitude
Use the AtmosModeler interactive simulation Use the AtmosModeler interactive simulation software to investigate how changes in software to investigate how changes in altitude affect temperaturealtitude affect temperature
Gather and record data on temperature and Gather and record data on temperature and altitude then use that information to make altitude then use that information to make calculationscalculations
Chapter 2, Lesson 3
Chapter 2, Lesson 3
Learning Check QuestionsLearning Check Questions
CPS Questions 7-8CPS Questions 7-8
Activity 4: Severe Weather Activity 4: Severe Weather InvestigationInvestigation
Create a presentation on one of the Create a presentation on one of the severe weather eventssevere weather events
Conduct and investigate research using Conduct and investigate research using the sources identifiedthe sources identified
Chapter 2, Lesson 3
SummarySummary
Chapter 2, Lesson 3
Causes of atmospheric instabilityCauses of atmospheric instability Types and causes of turbulenceTypes and causes of turbulence How types of severe weather affect aviationHow types of severe weather affect aviation
Chapter 2, Lesson 3
Review QuestionsReview Questions
CPS Questions 9-10CPS Questions 9-10
Next….Next….
Done – Done – aviation aviation weatherweather
Next – weather Next – weather forecastingforecasting
Chapter 2, Lesson 3 Courtesy of NASA/George Shelton
