Task C: Weather Information

Here are the key topics you should know:

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PA.I.C.K1 Sources of weather data

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You need to understand where to get official weather data for flight planning.

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Approved sources include the Federal Government (FAA and National Weather Service (NWS)).

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Flight Service Stations (FSS) provide pilot briefings. You can call 1-800-WX-BRIEF or use www.1800wxbrief.com.

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Automated resources such as Automated Surface Observing Systems (ASOS) and Automated Weather Observing Systems (AWOS) provide airport weather observations.

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Commercial weather information providers contracted by the FAA are also approved sources.

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PA.I.C.K2 Acceptable weather products and resources

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You must know how to obtain, understand, and apply current and forecast weather information for departure, en route, and arrival phases of flight.

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a. Airport Observations (METAR and SPECI) and Pilot Observations (PIREP)

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METARs (Aviation Routine Weather Reports) and SPECIs (Special Aviation Weather Reports) report current weather conditions at an airport. You need to be able to decode these reports, including elements like wind, visibility, sky condition (ceiling), temperature/dew point, and altimeter setting.

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PIREPs (Pilot Weather Reports) provide valuable information about actual conditions encountered in flight, such as cloud bases/tops, turbulence, wind shear, and icing. PIREPs are considered among the most accurate resources. ATC or FSS facilities are required to solicit PIREPs when ceilings are below 5,000 feet or visibility is at or below five miles. You should know how to file a PIREP.

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b. Surface Analysis Chart, Ceiling and Visibility Chart (CVA)

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These charts provide graphical depictions of surface weather features and conditions across a wide area. The CVA specifically shows ceiling and visibility.

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c. Terminal Aerodrome Forecasts (TAF)

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TAFs are forecasts for the area within 5 statute miles of an airport. They are typically issued for larger airports and are usually valid for 24 or 30 hours, updated four times a day. You need to understand how to decode the forecast elements like wind, visibility, weather, and sky condition.

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d. Graphical Forecasts for Aviation (GFA)

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The GFA website provides graphical weather information for the continental U.S., including forecasts for thunderstorms, clouds, flight category, precipitation, icing, turbulence, and wind. It shows forecasts from 14 hours prior to 15 hours into the future.

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e. Wind and Temperature Aloft Forecast (FB)

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This forecast provides wind direction, speed, and temperature at various altitudes. This is crucial for calculating true airspeed, groundspeed, and wind correction angle during flight planning. Winds aloft are given in true course and knots.

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f. Convective Outlook (AC)

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This product forecasts the potential for convective activity, such as thunderstorms.

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g. Inflight Aviation Weather Advisories including Airmen's Meteorological Information (AIRMET), Significant Meteorological Information (SIGMET), and Convective SIGMET

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These advisories alert pilots to potentially hazardous weather conditions.

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AIRMETs concern weather phenomena of operational interest to all pilots, especially those in aircraft not approved for flight in icing conditions, and cover conditions of lesser severity than SIGMETs or Convective SIGMETs. They can include advisories for moderate icing or turbulence. Graphical AIRMETs highlight hazardous weather like IFR conditions, mountain obscuration, moderate icing/turbulence, freezing levels, and low-level wind shear.

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SIGMETs are issued for weather significant to the safety of all aircraft, covering severe and extreme turbulence, severe icing, and widespread dust or sandstorms reducing visibility to less than 3 miles.

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Convective SIGMETs specifically concern convective weather like thunderstorms, hail, and tornadoes, significant to the safety of all aircraft.

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PA.I.C.K3 Meteorology applicable to VFR in VMC

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You must understand basic weather theory and how different meteorological phenomena affect VFR flight and the maintenance of Visual Meteorological Conditions (VMC). VFR weather minimums vary by airspace class.

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a. Atmospheric composition and stability: Understanding atmospheric stability helps determine the type of clouds and precipitation expected.

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b. Wind (e.g., windshear, mountain wave, factors affecting wind, etc.): Wind affects takeoff, landing, en route navigation (wind correction angle, groundspeed), and can cause turbulence. Wind shear is a significant hazard, especially at low altitudes.

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c. Temperature and heat exchange: Temperature affects aircraft performance (density altitude) and the potential for icing.

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d. Moisture/precipitation: Moisture leads to clouds, fog, and precipitation (rain, snow, etc.). Precipitation intensity is reported in METARs. Rain, snow, or freezing rain can affect visibility and cause icing.

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e. Weather system formation, including air masses and fronts: Understanding air masses and fronts helps in anticipating changing weather conditions along your route.

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f. Clouds: Knowledge of cloud types, bases, and tops is essential for VFR flight to maintain VMC and remain clear of clouds as required by VFR minimums. A ceiling is the lowest broken or overcast layer, or vertical visibility into an obscuration.

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g. Turbulence: Turbulence is irregular motion of the air. Pilots should know how to identify and avoid areas of turbulence using forecasts and PIREPs. Moderate turbulence is included in AIRMETs, and severe/extreme turbulence in SIGMETs.

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h. Thunderstorms and microbursts: Thunderstorms contain severe hazards like extreme turbulence, lightning, hail, and microbursts. Microbursts are severe, localized downdrafts. You should know how to avoid thunderstorms. Thunderstorms are forecast in TAFs (as TS) and covered by Convective SIGMETs.

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i. Icing and freezing level information: Structural icing can significantly degrade aircraft performance and is a serious hazard. Pilots must understand icing types (e.g., clear ice, rime ice, mixed ice), the conditions conducive to icing (visible moisture and temperatures at or below freezing), and how to interpret icing forecasts (e.g., AIRMETs for moderate icing, SIGMETs for severe icing). Freezing level information is also critical.

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j. Fog/mist: Fog and mist are obstructions to visibility that can prevent VFR flight. Fog is common when the temperature and dew point are close.

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k. Frost: Frost is ice crystals formed on surfaces at or below freezing with dew point below freezing. Frost can disrupt airflow over the wing and must be removed before flight.

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l. Obstructions to visibility (e.g., smoke, haze, volcanic ash, etc.): Various phenomena can reduce visibility, impacting VMC. Volcanic ash is a significant hazard and covered by PIREPs.

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PA.I.C.K4 Flight deck instrument displays of digital weather and aeronautical information

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You should be familiar with how flight deck displays (e.g., Electronic Flight Bags (EFB) or installed systems) can present digital weather and aeronautical information.

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These displays can provide near-real-time information like METARs, TAFs, SIGMETs, AIRMETs, PIREPs, and TFRs.

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However, it's important to understand the limitations of these systems and that they do not replace a thorough preflight briefing. You should not rely only on FIS-B or similar services for weather or aeronautical information.

For your private pilot exam, be prepared to explain these concepts, interpret weather reports and forecasts, determine if weather conditions are suitable for VFR flight, and explain how different weather phenomena could impact your planned flight. You should be able to use available resources to obtain an adequate weather briefing. This includes knowing the procedures for obtaining a standard, abbreviated, or outlook briefing.

**I'm not a CFI, don't forget to verify the information as times change. Email me for any updates that I might have missed.