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Lesson 2-4 Weather Forecasting

Lesson 2-4 Weather Forecasting. Lesson Overview. The history of weather forecasting The types of instruments used in weather forecasting The various types of communication methods used to provide weather information. The First Aviation Weather Forecast -- 1918.

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Lesson 2-4 Weather Forecasting

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  1. Lesson 2-4Weather Forecasting

  2. Lesson Overview • The history of weather forecasting • The types of instruments used in weather forecasting • The various types of communication methods used to provide weather information Chapter 2, Lesson 4

  3. The First Aviation Weather Forecast -- 1918 • Weather forecasts done by US Weather Bureau • Now called NOAA’s National Weather Service • Early meteorologists used primitive methods • Attached instruments to kites and tethered balloons • Only data on temperature and wind direction • First reports were used by pilots carrying mail between New York and Chicago • Mostly only provided local conditions -- not forecasts

  4. Weather Reports Address Safety Issues • By 1920, half of airmail service pilots died on the job • Congress passed Air Commerce Act on 20 May 1926 • Directed US Weather Bureau to0 make air travel safer • Focus on safety also boosted commercial passenger business • Today U.S. has one of world’s most advanced aviation weather forecasting systems • Produces 4 million aviation weather forecasts each year Courtesy of USAF

  5. Air Force Weather Agency • Army set up its first military weather service in 1917 • AFWA partners with NOAA’s National Weather Service to improve weather science • AFWA provides worldwide coverage today • Since WWII, AFWA has provided hurricane reconnaissance

  6. The Types of Instruments Used in Weather Forecasting—Surface • 4 types of observations: • Surface • Upper Air • Radar • Satellite • Surface observations are generally in an area within a 5-mile radius from an airport • Data collected on wind, visibility, pressure, temperature, dew point, sky conditions (cloud cover

  7. Instruments Used to Study Surface Weather • Thermometers -- Temperature • Barometers -- Pressure • Aneroids -- flexible metal bellows that respond to changes in atmospheric pressure • Psychrometer -- Relative Humidity • Anemometer -- Wind Speed

  8. Surface Weather -- ASOS • Automated Surface Observing System • Joint program of NWS, FAA, and DoD • Our main surface weather observing network • Provides surface observations non-stop, every minute, 24 hours a day, 365 days a year • Computer-generated voice broadcasts • Can also provide broadcasts in print and over-the-phone • Limitations – can’t report weather: • Over the horizon • Above 12,000 feet • Tornadoes • Freezing Drizzle • Snow Depth Chapter 2, Lesson 4

  9. Upper Air • More challenging than surface observations • Data collected in two ways: • 1. Radiosondes • Small instruments suspended from weather balloons • Collect data such as air temperature, pressure, wind speed, and wind direction • 2. Pilots • Only real-time source of information regarding turbulence, icing, and cloud heights • Some aircraft also equipped with instruments that can report weather data to dispatchers on the ground

  10. VIDEOWeather Balloon Radiosonde

  11. Radar • An instrument that sends out and receives radio waves (invisible electromagnetic waves) • Reflectivity is the strength of a returned signal—to gauge a storm’s intensity • On moving and fixed objects, radar can identify: • Distance • Strength • Direction • Speed

  12. Four Types of Radar • 1. Doppler—common name : WSR-88D NEXRAD • Two modes of operation: Clear Air and Precipitation • More than 160 Doppler radars are scattered throughout the United States and overseas • Max Range of each radar is 250 miles • Data is converted into brightly colored maps giving info on distance, strength and velocity of weather fronts • Can provide info on tornados to 13 minutes in advance • Run by the US Department of Commerce, DoD, and DOT • The heart of the Doppler operation is the Radar Operations Center in Norman, Oklahoma

  13. Doppler Radar

  14. Four Types of Radar • 2. FAA terminal Doppler -- found at major airports • Provides severe weather alerts and warnings to air traffic controllers • Warns pilots of wind shear, gust fronts. Amd heavy precipitation near airports (for takeoff and landing) • 3. FAA airport surveillance • Main purpose is to detect aircraft • Air Traffic Controllers also use it to know location and strength of precipitation so they can divert aircraft around severe weather

  15. Four Types of Radar • 4. Aircraft airborne radar -- flown on aircraft • Radar can spot a big thunderstorm as well as detect light rainfall • Can also tell how big a storm is

  16. VIDEOUsing Airborne Radar

  17. Satellites • The Geostationary Operational Environmental Satellite (GOES) • Launched in 1975 by NASA for NOAA • Currently 4 satellites operate in geostationary orbits • Satellites remain over the same part of the earth all the time • Used to track: • Thunderstorms • Tornados • Fog • Mud Slides • Dust Storms, volcanoes, wild fires

  18. GOESSatellites

  19. VIDEOGOES-R Satellite

  20. Satellite Weather Products • SIGMETs (Significant Meteorological Information • Can cover areas of at least 3000 square miles • Provides data on weather that reduces visibility to less than 3 miles • Severe and extreme turbulence • Severe icing • Widespread dust or sandstorms Chapter 2, Lesson 4

  21. Satellite Weather Products • AIRMETs (Airman’s Meterological Information) • Weather advisories issued to modify earlier forecasts and reports • Especially vital to pilots of smaller aircraft or pilots with limited experience • Does not cover severe weather events like SIGMETS • Reports include: • Moderate icing and turbulence • Winds of 30 knots or more • Ceilings of less than 1,000 feet • Visibility less than 3 miles

  22. VIDEONASA’s A-TRAIN

  23. Weather Outlets • Purpose: Get the latest weather data to pilots • Who: FAA, NOAA, NWS, Private Groups • Outlets: • AFSS: Automated Flight Service Station • Main source for preflight weather reports • Briefing available 24 hours by phone • Tailors info for pilot’s route, type of aircraft, type of flight (VFR or IFR), altitude, etc • Can also provide in-flight weather data

  24. Weather Outlets • Outlets (continued): • TIBS: Transcribed Information Briefing Service • Briefings are prerecorded, quick rundown of weather • Includes special announcement • Does not replace fuller pre-flight briefings • EFAS: En Route Flight Advisory Service • Also called “Flight Watch” • Used once the pilot is airborne • One of best sources for current weather along a route • Limitation: Not available 24 hours a day

  25. Weather Outlets • Outlets (continued): • HIWAS: Hazardous Inflight Weather Advisory Service • Broadcasts bad weather alerts 24 hours a day • Broadcasts are just summaries • Pilots would use other services if they want more detailed info

  26. Types of Briefings • Standard • Most complete report used before departure • Provides an overall weather picture • Adverse conditions; airport closings • Recommendation regarding VFR or IFR • Fronts and other major weather systems in area • Ceilings, winds, temperatures • Enroute weather forecasts • Destination weather at time of landing • NOTAMS: Notices to Airmen => airport closings and restricted flight space (e.g., around DC area)

  27. VIDEOStandard Pilot Weather Brief

  28. Types of Briefings • Abbreviated • Shortened version of the standard • Used to update a standard brief you already have • Add one or two weather items you don’t yet have • Outlook • At least 6 hours in advance of your planned departure time • Can influence route, altitude, departure time, etc

  29. Current Weather Reports • METARs: Aviation Routine Weather Reports • Hourly reports of current surface weather • Wind direction and speed, visibility, strength and location of precipitation and funnel clouds • PIREPs: Pilot Weather Reports • Current upper air conditions such as icing • RAREPs: Radar Weather Reports • Also known as SDs (Storm Detections) • Current readings of precip and thunderstorms

  30. Forecast Weather Reports • TAFs: Terminal Aerodrome Forecasts • —cover a five-mile radius around airports • FAS: Area Forecasts • Give picture of clouds, general weather, and visual conditions over large area (several states) • SIGMETs and AIRMETs • See earlier slides • FDs: Winds and Temperature Aloft Forecasts • Predict winds and temperatures for specific spots based on upper air readings from radiosondes

  31. WeatherCharts • Surface analysis chart: • Assesses current surface weather • Shows areas of high and low pressure, fronts, temps, dew points, wind directions/speed, visual obstructions

  32. WeatherCharts • Radar summary chart: • Marks precipitation cells only; published every hour • Marks areas of severe weather (tornadoes, thunderstorms) with heavy dashed lines

  33. WeatherCharts • Significant weather prognostic charts: • Forecast weather—does not provide current weather • Predicts turbulence, freezing levels, and IFR weather

  34. Standard UniformAltimeterSetting • How does an altimeter work? • It’s a simple barometer set to convert to pressure reading to the atmospheric altitude • Average sea-level pressure is 29.92 • Above 18,000 feet, all planes set altimeter to have sea-level pressure at 29.92 • This ensures aircraft will know what altitude they are in relation to other aircraft • What would happen if an aircraft used something different than 29.92, say 28.86 when they took off?

  35. AtmosphericPressure and TemperatureTable • Atmospheric Pressure Table

  36. Next…. • Done – weather forecasting • Next – the effects of weather on aircraft Chapter 2, Lesson 4 Courtesy of AP Photo.

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