Weather (IFR Updated)

This deck has not only my PPL info, but also IFR information.

Define the Terms – VFR, MVFR, IFR, LIFR.

VFR (+3000’ ceilings, +5SM vis)
MVFR (1000’-3000’ ceilings, 3-5SM vis)

IFR (<1000’ ceilings, 1-3 SM vis)
LIFR (<500’ ceilings, <1 vis).

What 4 elements can change across a front?

Temperature

Humidity

Wind

Pressure

What happens to your True Altitude in the following conditions (Cold Air, Warm Air, Low Pressure, High Pressure)?

Cold/Low = TA is lower than indicated.

Warm/High: TA is higher than indicated.

What are the Cloud Coverage Categories?

Few (1/8-2/8)

Scattered (3/8-4/8)

Broken* (5/8-6/8)

Overcast* (7/8-8/8)

A ceiling can only be identified if there are Broken or Overcast clouds. 

What is a Warm Front? What kind of weather should be expected?

Less dense, moves slowly, replaces cold body of air by rolling over it. 

Light Precipitation

Poor Visibility (fog)

Low Ceilings (stratiform, cirriform)

What is a Cold Front?

More dense, fast moving, wedges under a warm front and pushes it upwards. 

It can leave behind cold temps and turbulent winds, Towering Cumulus and Cirriform Clouds. 

*Creates Instability.

Which reports give you Wind Direction in True North?

Winds aloft

METAR/TAF

In terms of Wind Direction, what information is given in Magnetic North?

Wind report from ATC

PIREP

AWOS/ASOS/ATIS

Name the Basic Cloud Forms.

Stratiform

Nimboform

Cirriform

Cummuliform

Describe the basic Cloud Form: Cirriform.

High level clouds (20,000’)

Thin/White appearance

Ice Crystals present

Describe the basic Cloud Form: Nimbo-Form.

Rain clouds between (7000’-15000’)

Steady precipitation

Clouds bases lower as precipitation begins

Describe the basic Cloud Form: Stratiform.

Low Layer, blanket clouds.

Describe the basic Cloud Form: Cummuliform.

Vertical Motion

Thermal Uplift

Height of clouds depends on humidity of rising air. 

*Bad weather incoming.

What are the elements of Aircraft Performance?

Takeoff/Landing Distance

Rate of Climb/Speed

Ceiling

Weight

Maneuverability/Stability

What factors affect aircraft performance during Takeoff/Landings?

Air Density

Surface winds

Runway Surface/Slope

Aircraft weight

Describe Weather Conditions: High Pressure System.

Stable Conditions

Fair Weather

Clear Skies/Calm Air 

*Can lead to fog/frost due to rapid cooling.

Describe Weather Conditions: Low Pressure System.

Rotate Counter clock wise, warm air rising.

Unstable Air

Clouds/Precipitation (light drizzle to heavy storms)

What is Absolute Altitude?

Your height over the ground directly below you – not sea level.

What is True Altitude?

Your height above Sea Level (not based off instruments or pressure).

What causes Thunderstorms? How far must you fly away from them?

Uplifting force, Unstable Lapse Rate and Moisture. 

*Fly 20 miles away from them. 

Can rise to FL450.

What is the 1st Stage of a Thunderstorm?

Cumulus Stage

Updrafts, Warm moist air rising, no rain yet.

What is the 2nd Stage of a Thunderstorm?

Mature Stage

Rain has begun

Updrafts and Downdrafts

Strongest stage of a thunderstorm

What is the 3rd Stage of a Thunderstorm?

Dissipating Stage

Downdrafts only (Updrafts have stopped)

Anvil Cloud Top

Rain on its way out

How often do these weather reports update - METAR, TAF, AIRMET, SIGMET, Convective SIGMET, Winds Aloft, PIREPS, ASOS/AWOS, ATIS?

METAR (hourly)

TAF (6hrs)

AIRMET (6hrs)

SIGMET (4hrs)

Convective SIGMET (valid for 2hrs)

Winds Aloft (6hrs)

PIREPS (1hr)

ASOS/AWOS (every minute real time)

ATIS (hourly, observation not a forecast).

How does temperature affect air pressure (in the case that you do not set the altimeter properly)?

Warm air means that the pressure levels expand you'll be higher than the altimeter says. 

Cold air means that pressure levels contract and you will be lower than the altimeter says.

How is moisture added to the atmosphere/air?

Evaporation (liquid to gas)

Sublimation (solid to gas)

* More heat = More moisture *

What is Low Level Turbulence?

Turbulence that happens below 15,000’ MSL.

What is Convective Turbulence?

Warm air is rising and can push you up.

What causes the changes in weather (seasons)?

The uneven heating of the earth’s surface.

What is Clear Air Turbulence? What is the best way to find these areas?

Sudden/Severe High-Altitude Turbulence (15000’) that forms in cloudless regions between Jet Stream and surrounding air. 

Best info can be found in PIREPs.

What is Verga?

Visible precipitation along the horizon that evaporates before reaching the ground.

What are different weather observations?

METAR

PIREP

ATIS/ASOS/AWOS

What are the four kinds of AFSS/FSS Briefings?

Standard

Abbreviated

Outlook

Inflight

What is a TAF?

Terminal Aerodrome Forecast

Issued every 6 hours. 

Predicts future weather conditions of a single airport within a 5 SM radius. 

Can last up to 24 hours.

Which is more stable: Cold Front or Warm Front?

Cold = instability

Warm = more stable

What is Convection?

The transfer of heat (warm air rises, cold air falls).

While en-route, how can a Pilot obtain updated weather information?

ATIS/AWOS/ASOS

ATC

Sigmets

FSS

PIREPs

What is SVFR?

What do you need to be able to fly SVFR at night?

Special VFR – remain clear of clouds and 1SM visibility. 

Need an Instrument Rating/Equipment to fly SVFR at night (sunset to sunrise).

How long will Radar for weather be delayed by?

7 minutes.

What are Convective SIGMETs?

Issued hourly for Thunderstorms, embedded Thunderstorms and Thunderstorms affecting more than 40% of an area.

What weather conditions should you expect when flying near Cumulus Clouds?

Turbulence

What are Rotor Clouds?

Turbulent clouds that form in lower levels caused by airflow hitting against a mountain range.

Explain what Density Altitude is.

Pressure Altitude corrected for Non-Standard Temperature. 

Tells you how high the plane feels like it’s flying.

High DA = thinner air

Low DA = thicker air

What is Standard Temperature Lapse Rate? What is Standard Pressure Lapse Rate?

Temperature = 3.5°F/2°C degrees up to 1000’ 

Pressure = 1inHg per 1000’ up to 10000’

The amount of Moisture in the air is dependent on what factor?

The temperature of the air. 

Warmer air holds more moisture; colder air holds less moisture.

How is Fog Classified? What conditions produce it?

It is classified by how it forms. 

Small temperature to dew point spread, moisture in the air leads to fog.

What are the kinds of Optical Illusions?

Rain – horizon looks lower, so you feel high which makes you fly low. 

Haze – runway looks further away so you feel high which makes you fly low. 

Fog – can give you a false pitch up attitude which makes you steepen your approach.

Where should you look for the first sign that you’re picking up ice?

Pitot Tube

What takes longer to cool – Water or Ground?

Water

What does 9999 mean for visibility on a METAR?

Indicates visibility is 10KM or more

What is a Temperature Inversion & Signs?

When Temperature increases as altitude increases. 

Warmer air is sitting on top of cooler air which suppresses vertical motion. 

Signs: Turbulence and Poor Visibility.

What is Radiation Fog?

Forms over low laying flat surfaces on calm/clear nights.

The ground cools quickly, cooling the air above it to its dew point and the moisture condenses into fog.

What is Frontal Precipitation Induced Fog?

When warm rain falls through colder air and evaporates before reaching the ground.

Low visibility and poor flying conditions.

What is Advection Fog?

When warm air moves over cooler areas, coastlines, this makes warm air cool to its dew point. 

Needs air to form. 

*Advection means horizontal movement.

What is Upslope Fog?

When warm air is pushed up sloping terrain where it rises and cools. Requires wind and can reduce visibility.

What is Steam Fog? What is this an Indication of?

When cold/dry air moves over warm water (lakes and oceans). 

This indicates Unstable Air.

What Weather Reports help you determine freezing levels?

0° Celsius / 32° Fahrenheit. 

Freezing level charts - CIPs/FIPs

PIREP 

AIRMET

SIGMET 

Surface/Upper-Level Weather Charts

What clouds have the greatest turbulence?

Cumulonimbus

What factors increase Density Altitude?

Altitude (higher = less dense air).

Temperature (hot air expands = less dense). 

Humidity (the more water vapor is in the air it replaces heavier gas molecules in air). 

Hot + Humid + High = High Density Altitude

The atmosphere is denser when Pressure is ___ and Temperature/Humidity are ___?

Pressure is High and Temperature/Humidity are Low.

At which temperature do these types of Ice form (Clear, Rime, Mixed)?

Clear = forms first at 0° to -10° Celsius. 

Rime = forms at -10° to -20° Celsius. 

Mixed = Unpredictable at -5° to -15° Celsius.

Where can more stable air be found in an air mass?

More Stable in the center of the air mass.

How do you know if you have a tailwind or a headwind?

Tailwind = GS is higher than IAS (indicated air speed). 

Headwind = GS is lower than IAS (indicated air speed).

What are different pressure areas?

High, Low, Ridge, Trough, Col.

What is a Stable Atmosphere?

Has little to no vertical movement.

This can lead to a possibly poor environment because air isn’t moving.

What is a Stationary Front?

When two air masses meet (warm or cold).

The air isn’t moving and on a map they have arrows (blue/red) pointed in opposite directions.

What is CIP and FIP?

CIP = Current Ice Potential (updated in real time as well as hourly). 

FIP = Future Icing Potential (up to 15-18 hours).

How often do these weather reports update, METAR, TAF, WINDS ALOFT?

METAR = hourly

TAF = 4x a day

Winds Aloft = 6 hours

What primarily determines the type of vertical extent of clouds?

The stability of the atmosphere.

What do these acronyms mean, PRESFR and PRESRR?

Pressure Falling Rapidly and Pressure Rising Rapidly.

What do these acronyms mean BR, UA/UUA, RAE04B24?

BR = Mist

UA = Regular PIREP

UUA = Urgent PIREP

Rain Ended 4 minutes past the hour and began again 24 minutes past the hour.

METARs have a four-letter identified. What is this letter?

K (example: KCDW).

What service does the FAA provide pilots to obtain weather briefings?

FSS

1-800-WX-BRIEF

1800WXBRIEF.COM

What Level do Weather Charts Show?

Up to FL024 because not many weather disturbances happen above this height.

What is a TAF?

Terminal Aerodrome Forecast

Updates 4x a day and each forecast can last for up to 24-30 hours. 

AMD = amended TAF (unusual time of release).

Covers a 5NM radius from where the forecast is taken.

What are three different kinds of AIRMET?

Sierra, Tango, Zulu.

What is AIRMET Sierra?

IFR Conditions 

Ceiling = < 1000’ 

Visibility = < 3SM

What is AIRMET Tango?

Turbulence of Surface Winds with 30kts or greater.

What is AIRMET Zulu?

Moderate icing/Freezing Level.

What are the three primary causes of turbulence?

Convective Currents - rising of warm and fall of cooler air.

Mechanical Turbulence - Obstructions to wind flow.

Wind Shear - sudden change in wind speed/direction.

What causes wind?

Pressure differences: Pressure Gradient Force

Coriolis Force

Frictional Force 

What do Surface Analysis Charts show?

Pressure and Fronts.

What is needed for a Thunderstorm to form?

Moisture, Unstable Lapse Rate, Uplifting Force.

When is Indicated Altitude the same as True Altitude?

At sea level under standard conditions.

Define VFR, MVFR, IFR, LIFR.

VFR: ceiling greater than 3000’ and visibility greater than 5SM. 

MVFR: ceiling 1000ft-3000 and visibility 3-5SM. 

IFR: ceiling less than 1000ft visibility 1-3SM. 

LIFR: ceiling less than 500ft and visibility less than 1SM.

What are AIRMETS?

How often do they update?

What are types of AIRMETS?

Airmen’s Meteorological Information. 

They alert pilots (general aviation) to hazardous conditions (IFR conditions, moderate icing/freezing/turbulence, LLWS alerts) that updates every 6 hours. 

Sierra, Tango, Zulu 

What are SIGMETS?

How long are they valid for?

Severe Meteorological Information.

They alert all pilots to severe weather conditions. 

Valid for up to 4 hours.

When you fly from an area of High Pressure to an area of Low Pressure your altimeter will read…

Higher than your actual altitude above sea level.

What is a Lapse Rate?

It is the rate at which temperature decreases as altitude increases. 

*Standard Temperature Lapse Rate is 2°C or 3.5°F degrees per 1000ft.

To condense, water vapor needs…

High atmospheric pressure.

Pressure Altitude and Density Altitude are the same value at…

Standard Temperature.

What are the size of rain drops?

.08 inches or 2mm

What is the difference between vertical air movement in high and low pressure systems?

High = Clockwise, falling 

Low Pressure = Counter clockwise, Warm Air rising

What kind of weather can you expect flying into Low-Pressure and High-Pressure areas?

Low Pressure: Warm air is rising, rain, bad weather. 

High Pressure: Clear Skies, sinking air, leads to good weather.

What is Freezing Level (in degrees)?

32° F

0° C

Where can you get weather information?

FSS

1-800-WXBRIEF

Aviation Weather Center

Foreflight

If you are flying and the temperature/dew point are getting closer together, what weather phenomenon could that mean?

Fog.

Can you takeoff with frost on your wings?

No.

What kind of pressure system do you think we have right now?

Check your weather the day of.

What is standard temperature at sea level?

15°C

59°F