Stage 2 Lesson 8

Weather Observations Tools

What is Surface Aviation Weather Observation?

Also known as METARs, are a compilation of elements of the current weather at individual ground stations across the United States

Why are Surface Aviation Weather Observation valuable for Pilots?

Provides valuable information about individual airports around the country and can help give a good picture of the weather over a wide are when many reporting stations are viewed together=

What is Upper Air Observation?

What are the different types of upper air observation?

Radiosonde observations, pilot weather reports (PIREPs), Aircraft Meteorological Data Relay (AMDAR) and the Meteorological Data collection and Reporting System (MDCRS)

What is Radiosonde?

Weather balloons, that as it ascends the instrumentation gathers various pieces of data, such as air temperature, moisture and pressure, as well as wind speed and direction

What are PIREPs?

Weather infromation that is gathered and filed by pilots in flight. Pilots provide vital information regarding upper air weather observations and remain the only real-time source of information regarding turbulence, icing, and cloud heights.

What is Aircraft Meteorological Data Relay (AMDAR)?

international program utilizing commercial aircraft to provide automated weather observations

What is The Meteorological Data Collection and Reporting System (MDCRS)?

An automated airborne weather observation program that is used in the U.S. this program collects and disseminates real-time upper-air weather observations from participating airlines

What are the four types of Radar Observation and what do they provide?

The WSR-88D NEXRAD radar (aka Doppler radar), FAA termial Doppler Weather radar (TDWR), FAA airport Surveillance radar, and Airborne radar.

Provides information about precipitation and wind.

Explain The WSR-88D NEXRAD radar (aka Doppler radar), and its two modes.

Provides in-depth observation that informs surrounding communities of impending weather.

Clear air mode: radar is in its most sensitive operational mode, antenna moves slow allows for longer observations. images update every 10 minutes

Precipitation mode: radar moves faster, images update about every 4 to 6 minutes.

What does FAA terminal Doppler Weather radar (TDWR) help Pilots be aware of? 

Terminal radar ensure pilots are aware of wind shear, gust fronts, and heavy precipitation, all of which are dangerous to arriving and departing aircraft

Explain FAA airport surveillance radar.

Primarily used to detect aircraft, but it also detects the location and intensity of precipitation, which is used to route aircraft traffic around severe weather in an airport environment  

Explain Airborne radar.

Equipment carried by aircraft to locate weather disturbances

What is FSS

Flight Service Station is the primary source for preflight wetrath information. 1-800-WXBRIEF

What is Telephone briefing?

Provided by FSS, is a system of automated telephone recordings of meteorological and aeronautical information. Provides area and route briefings, airspace procedures and special announcement

What are the three types of weather Briefings?

Standard, Abbreviated, and outlook

What is a Standard Briefing?

Provides the most complete information and a more complete weather picture. Allowed up to 6 hours prior to flight. Gives information on: Adverse conditions, “VFR flight not recommended”, synopsis, current conditions, en rouge forecast, destination forecast, forecast winds and temperatures aloft, NOTAMs, and ATC Delays. 

What is an Abbreviated Briefing?

A shortened version of the standard briefing, can be requested 2 hours before flight or if flight delay.

What is an Outlook Briefing?

Should be requested when a planned departure is 6 hours or more away. Predicts weather based on weather patterns still need standard briefing.

What is a Routine METAR?

An observation of current surface weather reported in a standard international format. Typically released on regular time intervals

What is a SPECI METAR (SPECI)

A special, unscheduled report issued when weather changes significantly between routine METARs.

What is the order of information that a PIREP will give?

Report type (UA-routine/UUA-urgent), Location (OV): {OV ABC 090025 e.g., 25 NM on 090° from ABC VOR}, Time (TM), Flight level (FL), Aircraft type (TP), Sky cover(SK), Temperature (TA), Wind (WV), Turbeulence (TB), Icing (IC), Remarks (RM)

What is a TAF?

Terminal Aerodrome Forecast,  basically a forecast for the airport aerodrome (airport). Valid for 24 or 30 hours time periods and is updated four times a dat at 0000Z, 0600Z, 1200Z, and 1800Z

What is a TEMPO>

 Basically like SPECI, Any report that needs to be made outside the normal time frame

What are Inflight Weather Advisories?

Provided to en route aircraft, and are forecasts that detail potentially hazardous weather

What is an Airmet?

Inflight weather advisories that are issued every 6 hours, Information is of operational interest to all aircraft, but the weather section concerns phenomena considered potentially hazardous to light aircraft and aircraft with limited operational capabilities.

What does The AIRMET include for forecast?

Moderator icing, moderate turbulence, sustained surface winds of 30 knots or greater, widespread areas of ceilings less than 1,000ft and/or visibilities less than three miles, and extensive mountain obscurement. 

What are the three types of Airmets?

Sierra: code used to denote IFR and mountain obscuration

Tango: used to denote turbulence, strong surface winds, and low-level wind shear

Zulu: Freezing

What is a Sigmet?

Inflight advisories concerning non convective weather that is potentially hazardous to all aircraft. SIGMETs are unscheduled forecasts that are valid for 4 hours unless the SIGMET relates to a hurricane, in which cast it is valid for 6

What reporting does a Sigmet include?

Severe icing not associated with thunderstorms, severe or extreme turbulence or clear air turbulence (CAT) not associated with thunderstorms, dust atoms or sandstorms that lower surface  or inflight visibility to below three miles, and volcanic ash.

What is a Convective Sigments?

an inflight weather advisory insured for hazardous convective weather that affect the safety of every flight. Valid for 2 hours.

What weather is Convective Sigments issued for?

Issued for severe thunderstorms with surface winds greater than 50 knots, hail at the surface greater than or equal to ¾ inch in diameter, tornadoes, or embedded thunderstorms

What is a Center Weather Advisory?

A short-term weather warning for pilots and controllers.

• Purpose: Alerts to developing or ongoing hazardous weather (thunderstorms, icing, turbulence, etc.). Weather advisories (center)  see a trend of PIREPs and will make an updated prediction 

• Time frame: Valid for up to 2 hours.

• Use: Helps identify weather that may impact flight operations in real time.

What is winds and Temperature Aloft Forecast?

Provide wind and temperature forecasts for specific locations throughout the United States. The Forecasts are made twice a day based on the radiosonde upper air observations taken at 0000Z and 1200Z.

How do you decode winds aloft, normal winds, high winds, and calm winds?

• When the winds aloft are less than 100 knots, the report shows them normally (e.g., 2406+03 = 240° at 6 knots).

• When the winds are 100 knots or more, the code can’t fit a 3-digit wind speed — so the forecasters use a trick:
  → They add 50 to the direction code to signal “this wind is over 99 knots” and then they subrtract 100 from the knot

• When winds are calm it is forecasted as 9900

What is a surface Analysis Chart

Depict an analysis of the current surface weather. This chart is transmitted every 3 hours. Shows the areas of high and low pressure, fronts, temperature, dew points, wind directions and speeds, local weather, and visual obstructions

What is a Weather Depiction Chart?

Details surface conditions as derived from METAR and other surface observations.  Prepared and transmitted by computer every 3 hours beginning at 0100Z time and is valid data for the forecast period. Designed to be used for flight planning by giving an overall picture of the weather across the United States. 

What is a Significant Weather Prognostic chart?

A forecast chart showing important weather conditions for aviation.

• Purpose: Helps pilots and controllers plan for en-route hazards.

What weather and levels is depicted in a Significant Weather Prognostic chart?

• Weather shown includes:

  • Turbulence (moderate or greater)

  • Icing (light, moderate, severe)

  • Thunderstorms / convective activity

  • Low-level wind shear

  • Jet streams and tropopause heights

  • Cloud coverage / fronts

• Levels: Charts are provided for different flight levels, often FL240–FL630 (upper-level) and below FL240 (low-level).

What is a  low-level prognostic chart?

A forecast of aviation weather hazards, primarily intended to be used as a guidance produced for briefing the VFR pilot. issued 4 times a day. 

Explain ATC Radar Weather Basics

• How it works: Sends out radio beam → reflects off precipitation (rain, hail, snow).

• Intensity: Stronger return = larger/denser object → measured in dBZ.

• Limits:

  • Cannot detect clouds.

  • Cannot determine precipitation type (all displayed as “precipitation”).

  • Cannot detect turbulence.

• Precipitation intensity levels (dBZ):

  • LIGHT <30 dBZ

  • MODERATE 30–40 dBZ

  • HEAVY 40–50 dBZ

  • EXTREME >50 dBZ

Explain ATC Radar and Turbulence

• Turbulence: Not detected by radar.

• General rule:

  • Higher precipitation intensity → more likely/severe turbulence.

  • Convective activity (e.g., thunderstorms) → severe turbulence even in clear air.

• Thunderstorms:

  • Extreme caution within 20 miles.

  • Turbulence may be greater than precipitation intensity suggests.

What is the best way to Avoidance Weather?

Best way to avoid weather is to get the whole picture

• Build the biggest picture you can with all the tools you can

• Look for Convective activities

• ATC can help if you request vectors and or turn around or change in altitude 

Electronic Flight Displays (EFD)/ Multifunction Display (MFD)

Many aircraft manufacturers now include data link weather services with new electronic flight display (EFD) systems. EFDs give a pilot access to many of the data link weather services available

What is Wind Shear?

Sudden change in wind speed and directions. Turbulent , violent, sudden increase or decrease in air speeds and groundspeed

What doe 91.103 require?

That you as a pilot understand and go over weather forecast prior to flights.

What are some way to find or indicators of wind shear?

Metars, tafs, PIREPs, sigmets for low-level wind advisories

When might you encounter wind shear?

Might see them after sunset, or low level temp advisers

What does 91.155 talk about?

Basic VFR minimums

What are the different kinds of surface weather observations?

METARs, Automated Weather Observing Systems (AWOS), Automated Surface Observing Systems (ASOS), and Automatic Terminal Information Service (ATIS)

Explain what a METAR is.

• Type: Routine weather report (updated hourly)

• Source: Issued by airports / weather stations

• Includes: Wind, visibility, sky condition, temperature, dew point, altimeter, weather phenomena

• Use: For flight planning and weather observation

Explain what a AWOS is.

• Meaning: Automated Weather Observing System

• Type: Automated weather station (updates every minute or so)

• Operated by: Typically local airports or state aviation agencies

• Provides: Continuous, automated reports — wind, visibility, temperature, dew point, altimeter

• Limitations: May not include cloud layers or weather types unless equipped depends on AWOS type:

  • Alpha: altimeter 

  • 1: measures wind speed, direction, gust and dew point

  • 2: Has winds direction, gust, dew point and adds in viz

  • 3.: adds in clouds ceiling, and is basically equivalent to a ASOS

Explain what a ASOS is.

• Meaning: Automated Surface Observing System

• Type: More advanced automated weather system

• Operated by: National Weather Service (NWS), FAA, and Department of Defense

• Provides: Detailed, official weather observations for METARs (includes sky cover, precipitation type, intensity)

• Frequency: Hourly (or special reports if conditions change)

• Diffrent levels:

  • A: Used for bravo airports

  • B: has human to verify

  • C: part time airports like Class D

  • D: smaller airports

Explain what a ATIS is.

• Meaning: Automatic Terminal Information Service

• Type: Continuous recorded broadcast at airports

• Contains: Weather, runways in use, approaches, NOTAMs, altimeter, remarks

• Updates: When significant change occurs (new “Information” letter issued: Alpha, Bravo, etc.)

• Purpose: Reduces radio congestion and gives pilots the latest airport info before contacting ATC