Aviation Weather Understand basic facts and general principles of aviation weather. 1. Explain the weather hazards associated with aviation. 2. List the

Aviation WeatherAviation Weather

Understand basic facts and general Understand basic facts and general principles of aviation weather.principles of aviation weather.1. Explain the weather hazards 1. Explain the weather hazards

associated with aviation.associated with aviation.

2. List the types of severe weather that 2. List the types of severe weather that affect aviation.affect aviation.

3. Describe arctic and tropic weather 3. Describe arctic and tropic weather characteristics.characteristics.

OverviewOverview

1. Weather Hazards1. Weather Hazards

2. Severe Weather2. Severe Weather

3. Arctic and Tropic Weather3. Arctic and Tropic Weather

Weather HazardsWeather Hazards

• Reduced VisibilityReduced Visibility• Three miles lateral visibility is Three miles lateral visibility is

acceptable for safe flight under visual acceptable for safe flight under visual flight rules (VFR).flight rules (VFR).

• Possibility for accidents is greatest when Possibility for accidents is greatest when visibility is reduced and the pilot is not visibility is reduced and the pilot is not trained to fly according to instrument trained to fly according to instrument flight rules (IFR).flight rules (IFR).

• Clouds, rain, snow, fog, and Clouds, rain, snow, fog, and obstructions.obstructions.

• Haze and smoke can reduce visibility Haze and smoke can reduce visibility when the wind is calm.when the wind is calm.


• Reduced VisibilityReduced Visibility• Blowing dust, sand, and snowBlowing dust, sand, and snow• WhiteoutsWhiteouts

http://upload.wikimedia.org/wikipedia/en/a/a8/Nearwhiteoutinminnesota.JPG


• IcingIcing• Ice is present in the atmosphere at all Ice is present in the atmosphere at all

times-15,000 feet in summer and as times-15,000 feet in summer and as low as 1,000 feet in winter.low as 1,000 feet in winter.

• Glaze and Rime ice form on an Glaze and Rime ice form on an airplane’s windshield, its propeller, airplane’s windshield, its propeller, and other aerodynamic surfaces.and other aerodynamic surfaces.

• Glaze ice is formed and builds quickly Glaze ice is formed and builds quickly as an airplane flies through super-as an airplane flies through super-cooled rain droplets.cooled rain droplets.


• IcingIcing• Rime ice forms when an Rime ice forms when an

airplane is flying through airplane is flying through super-cooled cloud super-cooled cloud condensation. condensation.

• Frost disturbs airflow to Frost disturbs airflow to reduce lift efficiency.reduce lift efficiency.

• Larger, more sophisticated Larger, more sophisticated aircraft are equipped to aircraft are equipped to break or melt ice as it is break or melt ice as it is formed.formed.

http://bbsnews.net/bbsn_photos/Science/icing?full=1

Severe Weather Severe Weather

Severe Weather Severe Weather

• The NWS severe weather classifications The NWS severe weather classifications are based upon destructive effects with are based upon destructive effects with regard to surface cultural features.regard to surface cultural features.

Severe WeatherSevere Weather

• ThunderstormsThunderstorms• A storm accompanied by thunder and A storm accompanied by thunder and

lightning.lightning.• A Thunderstorm is local in nature and A Thunderstorm is local in nature and

is always produced by the growth of a is always produced by the growth of a cumulus cloud into a cumulonimbus cumulus cloud into a cumulonimbus cloud.cloud.

• Three stagesThree stages•CumulusCumulus•MatureMature•DissipatingDissipating


• Thunderstorms - Cumulus StageThunderstorms - Cumulus Stage


• Thunderstorms - Mature StageThunderstorms - Mature Stage


• Thunderstorms - Dissipating StageThunderstorms - Dissipating Stage


• TornadoesTornadoes • Local storm that focuses destructive Local storm that focuses destructive

forces on a small area.forces on a small area.• Occurs with severe thunderstorms.Occurs with severe thunderstorms.• When it touches the ground its path When it touches the ground its path

may be very erratic.may be very erratic.


• Tornadoes Tornadoes • Destructiveness is caused by high Destructiveness is caused by high

winds.winds.• Very low pressure gives tornadoes Very low pressure gives tornadoes

great suction.great suction.


• Tornadoes Tornadoes • Occur most often in the spring Occur most often in the spring

months and in the afternoon hours.months and in the afternoon hours.• Very difficult to forecast.Very difficult to forecast.


• HurricanesHurricanes• A strong tropical cyclone with winds that A strong tropical cyclone with winds that

surpass 100 mph.surpass 100 mph.• A large revolving storm with a calm center A large revolving storm with a calm center

(eye).(eye).


• HurricanesHurricanes• Born over the tropical water of the Atlantic and Born over the tropical water of the Atlantic and

Pacific Oceans, the Gulf of Mexico and the Pacific Oceans, the Gulf of Mexico and the Caribbean Sea.Caribbean Sea.

• Energy gained from heat given off by warm air.Energy gained from heat given off by warm air.


• HurricanesHurricanes• Tropical depressionTropical depression• Tropical stormTropical storm• HurricaneHurricane


• HailHail• May be within a strong cumulus cloud May be within a strong cumulus cloud

before any type of precipitation falls to the before any type of precipitation falls to the surface.surface.

• The combined velocity of an aircraft and The combined velocity of an aircraft and hail gives these small pellets a hail gives these small pellets a tremendous amount of energy. tremendous amount of energy.

• If the pellets are “hard” because of If the pellets are “hard” because of exceptionally cold temperatures at their exceptionally cold temperatures at their level, aircraft will experience damage.level, aircraft will experience damage.

HailHail

Orlando, Florida…1992


• HailHail• Encounters with larger hail are even Encounters with larger hail are even

more damaging. Hail having the size, more damaging. Hail having the size, weight, (baseball size), and velocities weight, (baseball size), and velocities produced by thunderstorms in the produced by thunderstorms in the western and mountain areas could rip western and mountain areas could rip a small plane apart.a small plane apart.

• Hail and rain pulled into an aircraft Hail and rain pulled into an aircraft engine can cause the engines to stall engine can cause the engines to stall and flame out, as well as cause and flame out, as well as cause internal damage.internal damage.

Arctic and Tropic WeatherArctic and Tropic Weather

• Arctic WeatherArctic Weather• Mountains around Arctic Circle holds in Mountains around Arctic Circle holds in

cold aircold air• Precipitation is lightPrecipitation is light• Strong winds occur in fall and winterStrong winds occur in fall and winter• Visibility is a major problemVisibility is a major problem


• Tropic Weather-fronts are rare and there Tropic Weather-fronts are rare and there is more moisture in the air, especially in is more moisture in the air, especially in the oceanic and coastal regions.the oceanic and coastal regions.• Oceanic WeatherOceanic Weather

•Clouds cover about half the sky over the tropical Clouds cover about half the sky over the tropical oceans.oceans.

•Northeast and southeast trade winds converge.Northeast and southeast trade winds converge.

•When the wind convergence gets strong, When the wind convergence gets strong, thunderstorms develop that may produce winds up to thunderstorms develop that may produce winds up to 70 mph.70 mph.


• Tropic WeatherTropic Weather• Continental WeatherContinental Weather

•Subject to extreme variations because of Subject to extreme variations because of land features.land features.

•Weather ranges from hot and humid in the Weather ranges from hot and humid in the lower Congo River to arid Libyan Desert to lower Congo River to arid Libyan Desert to snow-capped mountains of Kenya.snow-capped mountains of Kenya.

•Day time temperatures may exceed 100Day time temperatures may exceed 100o o F.F.

•Precipitation often evaporates before it Precipitation often evaporates before it reaches the ground.reaches the ground.

•Thick early morning steam fog often forms in Thick early morning steam fog often forms in the jungles.the jungles.


• Tropic WeatherTropic Weather• Island and Coastal WeatherIsland and Coastal Weather

•Weather similar along coastal areas and Weather similar along coastal areas and mountainous islands.mountainous islands.

•During the day, large cumuliform clouds During the day, large cumuliform clouds develop.develop.

•Clouds seen from long distances indicating Clouds seen from long distances indicating presence of islands.presence of islands.

•Trade winds result in onshore winds on Trade winds result in onshore winds on one side of island and offshore winds on one side of island and offshore winds on the other.the other.


• Tropic WeatherTropic Weather• Island and Coastal WeatherIsland and Coastal Weather

•When approaching a coastal area or an When approaching a coastal area or an island, the aviator should be prepared for island, the aviator should be prepared for instrument conditions.instrument conditions.

•Precipitation and cloudiness are heavier on Precipitation and cloudiness are heavier on windward side.windward side.

•One of the major factors influencing tropical One of the major factors influencing tropical weather is the easterly wave.weather is the easterly wave.

•As the wave line approaches, the pressure As the wave line approaches, the pressure falls and the wind shifts to the east as the falls and the wind shifts to the east as the line passes. line passes.

SummarySummary

1. Weather Hazards1. Weather Hazards

2. Severe Weather2. Severe Weather

3. Arctic and Tropic Weather 3. Arctic and Tropic Weather

Documents

Aviation Weather Understand basic facts and general principles of aviation weather. 1. Explain the weather hazards associated with aviation. 2. List the