Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
6.3 CENTER WEATHER ADVISORY (CWA)6-31
6.3.1 CWA Issuance6-31
Figure 6-12. Center Weather Service Unit (CWSU) Areas of Responsibility, Contiguous U.S. .. 6-31
Figure 6-13. CWSU Anchorage, AK (PAZA) Area of Responsibility6-32
6.3.2 CWA Communications Headers (UCWA / CWA)6-32
6.3.3 CWA Criteria6-32
6.3.4 CWA Format6-33
Figure 6-14. Center Weather Advisory (CWA) Decoding Example6-33
Table 6-7. Decoding a Center Weather Advisory (CWA)6-33
6.3.5 Examples6-34
6.4 ADDITIONAL PRODUCTS FOR CONVECTION6-37
6.4.1 Convective Outlooks (AC)6-37
6.4.1.1 Issuance6-37
Table 6-8. Convective Outlook Issuance Schedule6-37
Figure 6-15. Day 1 Categorical Convective Outlook Graphic Example6-38
6.4.1.2 Format of the Categorical Convective Outlook Narrative6-38
6.4.2 Watch Notification Messages6-39
6.4.2.1 Aviation Watch Notification Message6-39
6.4.2.1.1 Format of an Aviation Watch Notification Message6-39
Figure 6-16. Aviation Watch Notification Message Decoding Example6-40
Table 6-9. Decoding a Severe Weather Watch Bulletin6-40
6.4.2.1.2 Issuance6-41
6.4.3 Public Severe Thunderstorm Watch Notification Message6-41
6.4.3.1 Format of Public Severe Thunderstorm Watch Notification Message6-41
6.4.3.2 Example of a Public Severe Thunderstorm Watch Notification Message6-42
6.4.4 Public Tornado Watch Notification Message6-43
6.4.4.1 Format of a Public Tornado Watch Notification Message6-44
6.4.4.2 Example of a Public Tornado Watch Notification Message6-44
6.5 PRODUCTS FOR TROPICAL CYCLONES6-46
6.5.1 Aviation Tropical Cyclone Advisory (TCA)6-46
6.5.1.1 Issuance6-46
6.5.1.2 Content6-46
6.5.1.3 Format6-46
6.5.1.4 Aviation Tropical Cyclone Advisory (TCA) Example6-47
6.5.2 Tropical Cyclone Public Advisory (TCP)6-47
6.5.2.1 TCP Responsibility6-47
6.5.2.2 TCP Issuance6-48
Table 6-10. Tropical Cyclone Public Advisory Issuance Schedule6-48
6.5.2.2.1 TCP Intermediate Issuances6-49
Table 6-11. Intermediate Tropical Cyclone Public Advisory Issuance Schedule6-49
6.5.2.3 TCP Content6-49
6.5.2.4 TCP Format6-50
6.5.2.5 Tropical Storm Public Advisory (TCP) Example6-51
6.5.2.6 Hurricane/Typhoon Public Advisory Example6-51
6.5.2.7 Intermediate Public Advisory Example6-53
6.5.2.8 Special Public Advisory Example6-55
6.5.2.9 Public Advisory Correction Example6-56
6.6 VOLCANIC ASH ADVISORY PRODUCTS6-57
6.6.1 Volcanic Ash Advisory Center (VAAC)6-57
Figure 6-17. Volcanic Ash Advisory Centers (VAACs) Area of Responsibility6-57
6.6.2 Volcanic Ash Advisory Statement (VAAS)6-58
6.6.2.1 Issuance6-58
6.6.2.2 Format6-58
6.6.2.3 VAAS Issued by the Washington VAAC Example6-58
6.6.3 Volcanic Ash Advisory (VAA)6-59
6.6.3.1 VAA Issuance6-59
6.6.3.2 VAA Format6-59
6.6.3.3 Volcanic Ash Advisory (VAA) Example6-59
7 FORECAST TEXT PRODUCTS7-1
AC 00-45F, CHG 2 Table of Contents Page x
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
7.1 AREA FORECASTS (FA)7-1
7.1.1 Area Forecast Issuance7-1
Figure 7-1. AWC Area Forecast Regions- Contiguous U.S7-2
Figure 7-2. AWC Area Forecast Region and WMO Header - Gulf of Mexico7-2
Figure 7-3. AWC Area Forecast Region and WMO Header - Caribbean7-3
Figure 7-4. WFO Honolulu Area Forecast Region and WMO header - Hawaii7-3
Figure 7-5. AAWU Flight Advisory and Area Forecast Zones - Alaska7-4
Table 7-1. AAWU Area Forecast Zones – Alaska7-4
7.1.2 Area Forecast Standardization7-4
7.1.3 Area Forecast Issuance Schedule7-5
Table 7-2. Area Forecast (FA) Issuance Schedule7-5
7.1.4 Area Forecast Amendments7-5
7.1.5 Area Forecast Corrections7-6
7.1.6 Area Forecast Format – Conterminous U.S. (CONUS)7-6
Figure 7-6. Area Forecast – CONUS Communication and Product Header Example7-7
Table 7-3. Decoding a CONUS Area Forecast Communication and Product Header7-7
Figure 7-7. Area Forecast - Clouds and Weather Element Example7-8
7.1.6.1 Area Forecast – Conterminous U.S. (CONUS) Examples7-8
7.1.6.1.1 Area Forecast – BOS Example7-8
7.1.6.1.2 Area Forecast – SFO (FA) Example7-10
7.1.7 Area Forecast Format – Gulf of Mexico (FAGX)7-12
7.1.7.1 Area Forecast – Gulf of Mexico (FAGX) Example7-13
7.1.8 Area Forecast Format – Caribbean (FACA)7-13
7.1.8.1 Area Forecast – Caribbean (FACA) Example7-14
7.1.9 Area Forecast Format - Hawaii7-15
7.1.9.1 Area Forecast – Hawaii Example7-15
7.1.10 Area Forecast Format - Alaska7-16
7.1.10.1 Area Forecast – Alaska Example7-17
7.2 TERMINAL AERODROME FORECAST (TAF)7-19
7.2.1 Responsibility7-19
7.2.2 Generic Format of the Forecast Text of a NWS-Prepared TAF7-19
7.2.2.1 Type of Report (TAF or TAF AMD or TAF COR)7-19
7.2.2.2 Location Identifier (CCCC)7-20
7.2.2.3 Date/Time of Forecast Origin Group (YYGGggZ)7-20
7.2.2.4 Valid Period (Y1Y1G1G1/Y2Y2G2G2)7-20
7.2.2.5 Wind Group (dddffGfmfmKT)7-21
7.2.2.6 Visibility Group (VVVV)7-22
7.2.2.7 Significant Weather Group (w'w' or NSW)7-22
7.2.2.7.1 Exception for Encoding Multiple Precipitation Types7-23
7.2.2.7.2 Thunderstorm Descriptor7-24
7.2.2.7.3 Fog Forecast7-24
Table 7-5. TAF Fog Terms7-25
7.2.2.8 Vicinity (VC)7-25
Table 7-6: TAF Use of Vicinity (VC)7-25
7.2.2.9 Cloud and Vertical Obscuration Groups (NsNsNshshshs or VVhshshs or SKC)7-26
7.2.2.9.1 Cloud Group (NsNsNshshshs)7-26
Table 7-7. TAF Sky Cover7-26
7.2.2.9.2 Vertical Obscuration Group (VVhshshs)7-26
7.2.2.9.3 Cloud Type (CB)7-26
7.2.2.10 Non-Convective Low-Level Wind Shear (LLWS) Group (WShwshwshws/dddffKT)7-27
7.2.2.11 Forecast Change Indicator Groups7-28
7.2.2.11.1 From (FM) Group (FMYYGGgg)7-28
7.2.2.11.2 TEMPO (YYGG/YeYeGeGe) Group7-29
7.2.2.11.3 PROB30 (YYGG/YeYeGeGe) Group7-30
7.2.2.12 TAF Examples7-31
7.2.3 Issuance7-33
Table 7-8. TAF Issuance Schedule7-33
7.2.3.1 Minimum Observational Requirements for Routine TAF Issuance and Continuation7-34
7.2.3.2 Sites with Scheduled Part-Time Observations7-34
7.2.3.2.1 Examples of Scheduled Part-Time Observations TAFs7-34
AC 00-45F, CHG 2 Table of Contents Page xi
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
7.2.3.3 Automated Observing Sites Requiring Part-Time Augmentation7-35
7.2.3.4 Non-Augmented Automated Observing Sites7-35
7.3 INTERNATIONAL AVIATION ROUTE FORECASTS (ROFOR)7-36
7.3.1 ROFOR Criteria7-36
7.3.2 Issuance7-36
7.3.2.1 ROFOR Amendments7-36
7.3.2.2 ROFOR Corrections7-36
7.3.3 ROFOR Content7-36
7.3.4 ROFOR Examples7-37
7.3.4.1 Majuro to Kwajalein Route ROFOR Example7-37
7.3.4.2 Tarawa to Majuro Route ROFOR Example7-37
7.3.4.3 Santa Barbara and San Francisco to Honolulu Route ROFOR Example7-37
7.4 WIND AND TEMPERATURE ALOFT FORECAST (FB)7-39
7.4.1 Forecast Altitudes7-39
Table 7-9. Wind and Temperature Aloft Forecast Levels7-39
7.4.2 Format7-39
7.4.2.1 Coding Example7-40
Table 7-10. Wind and Temperature Aloft Forecast Decoding Examples7-41
7.4.2.2 Example for the Contiguous US and Alaska7-41
7.4.2.3 Example for Hawaii and the Western Pacific7-41
7.4.3 Issuance7-42
Figure 7-8. Wind and Temperature Aloft Forecast Network - Contiguous US7-42
Figure 7-9. Wind and Temperature Aloft Forecast Network - Alaska7-43
Figure 7-10. Wind and Temperature Aloft Forecast Network - Hawaii7-43
Figure 7-11. Wind and Temperature Aloft Forecast Network - Western Pacific7-44
Table 7-11. Wind and Temperature Aloft Forecast (FB) Periods7-44
7.4.4 Delayed Forecasts7-44
8 FORECAST CHARTS8-1
8.1 SHORT-RANGE SURFACE PROGNOSTIC (PROG) CHARTS8-1
Figure 8-1. Surface Prog Chart Example8-1
8.1.1 Content8-2
Figure 8-2. Surface Prog Chart Symbols8-2
8.1.1.1 Pressure Systems8-2
8.1.1.2 Fronts8-2
8.1.1.3 Squall Lines8-2
8.1.1.4 Precipitation8-2
Figure 8-3. Surface Prog Chart Precipitation Symbols8-3
Figure 8-4. Surface Prog Chart Precipitation Example8-3
Figure 8-5. Surface Prog Chart Precipitation Coverage8-4
8.1.2 Issuance8-4
Table 8-1. Short-Range Surface Prog Charts Schedule8-4
8.1.3 Use8-4
Figure 8-6. 12-hour Surface Prog Chart Example8-5
Figure 8-7. 24-hour Surface Prog Chart Example8-5
Figure 8-8. 36-hour Surface Prog Chart Example8-6
Figure 8-9. 48-hour Surface Prog Chart Example8-7
8.2 LOW-LEVEL SIGNIFICANT WEATHER (SIGWX) CHARTS8-8
Figure 8-10. 12-Hour Low-Level SIGWX Chart Example8-8
8.2.1 Content8-8
Figure 8-11. Low-Level SIGWX Chart Symbols8-9
8.2.1.1 Flying Categories8-9
Figure 8-12. Low-Level SIGWX Chart Flying Categories Example8-9
8.2.1.2 Turbulence8-9
Figure 8-13. Low-Level SIGWX Chart Turbulence Forecast Example8-10
8.2.1.3 Freezing Levels8-10
Figure 8-14. Low-Level SIGWX Chart Freezing Level Forecast Example8-11
Figure 8-15. Low-Level SIGWX Chart Multiple Freezing Levels Example8-11
8.2.2 Issuance8-12
8.2.3 Use8-12
AC 00-45F, CHG 2 Table of Contents Page xii
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 8-16. 12-Hour Low-Level SIGWX Chart Example8-12
Figure 8-17. 24-hour Low-Level SIGWX Chart Example8-13
8.3 MID-LEVEL SIGNIFICANT WEATHER (SIGWX) CHART8-14
Figure 8-18. Mid-Level SIGWX Chart Example8-14
8.3.1 Content8-14
8.3.1.1 Thunderstorms8-14
Table 8-3. Mid-Level SIGWX Chart Cumulonimbus Coverage8-15
Figure 8-19. Mid-Level SIGWX Chart Thunderstorm Examples8-15
8.3.1.2 Surface Frontal Positions and Movements8-16
Figure 8-20. Mid-Level SIGWX Chart Surface Frontal Position and Movement Example8-16
8.3.1.3 Jet Streams8-16
Figure 8-21. Mid-Level SIGWX Chart Jet stream Example8-16
8.3.1.4 Tropopause Heights8-17
Figure 8-22. Mid-Level SIGWX Chart Tropopause Height Examples8-17
8.3.1.5 Tropical Cyclones8-17
Figure 8-23. Mid-Level SIGWX Chart Tropical Cyclone Examples8-17
8.3.1.6 Moderate or Severe Icing8-17
Figure 8-24. Mid-Level SIGWX Chart Icing Examples8-18
8.3.1.7 Moderate or Severe Turbulence (in cloud or in clear air)8-18
Figure 8-25. Mid-Level SIGWX Chart Turbulence Examples8-18
8.3.1.8 Cloud Coverage (non-cumulonimbus)8-19
Table 8-4. Mid-Level SIGWX Chart Cloud Coverage (Non-cumulonimbus)8-19
8.3.1.9 Cloud Type8-19
Table 8-5. Mid-Level SIGWX Chart Cloud Types8-19
Figure 8-26. Mid-Level SIGWX Chart - Example of Moderate or Severe Icing, Moderate or
Severe Turbulence (in cloud or in clear air), Clouds, and Cloud Types8-20
8.3.1.10 Volcanic Eruptions8-20
Figure 8-27. Mid-Level SIGWX Chart Volcanic Eruption Example8-20
8.3.1.11 Release of Radioactive Materials8-20
Figure 8-28. Mid-Level SIGWX Chart Release of Radioactive Materials Example8-20
8.3.2 Issuance8-20
Table 8-6. Mid-Level SIGWX Chart Issuance Schedule8-21
8.3.3 Use8-21
Figure 8-29. Mid-Level SIGWX Chart Example8-22
8.4 HIGH-LEVEL SIGNIFICANT WEATHER (SIGWX) CHARTS8-23
Figure 8-30. High-level SIGWX Chart Example8-23
8.4.1 Content8-24
8.4.1.1 Thunderstorms and Cumulonimbus Clouds8-24
Figure 8-31. High-Level SIGWX Chart Thunderstorm and Cumulonimbus Cloud Examples... 8-24
8.4.1.2 Moderate or Severe Turbulence8-25
Figure 8-32. High-Level SIGWX Chart Turbulence Examples8-25
8.4.1.3 Moderate or Severe Icing8-25
8.4.1.4 Jet Streams8-25
Figure 8-33. High-Level SIGWX Chart Jet stream Example8-26
8.4.1.5 Surface Fronts with Speed and Direction of Movement8-26
Figure 8-34. High Level SIGWX Chart Surface Front with Speed and Direction of Movement
Example8-26
8.4.1.6 Tropopause Heights8-26
Figure 8-35. High-Level SIGWX Chart Tropopause Height Examples8-27
8.4.1.7 Tropical Cyclones8-27
Figure 8-36. High Level SIGWX Chart Tropical Cyclone Examples8-27
8.4.1.8 Severe Squall Lines8-27
Figure 8-37. High-Level SIGWX Chart Severe Squall Line Example8-27
8.4.1.9 Volcanic Eruption Sites8-28
Figure 8-38. High-Level SIGWX Chart Volcanic Eruption Site Example8-28
8.4.1.10 Widespread Sandstorms and Dust storms8-28
Figure 8-39. High-Level SIGWX Chart Widespread Sandstorm and Dust Storm Example8-28
8.4.2 Issuance8-28
Table 8-7. High-Level SIGWX Chart Issuance Schedule – WAFC Washington8-29
8.4.3 Use8-29
Figure 8-40. High-Level SIGWX Chart - ICAO Area A Example8-30
AC 00-45F, CHG 2 Table of Contents Page xiii
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 8-41. High-Level SIGWX Chart - ICAO Area B1 Example8-31
Figure 8-42. High-Level SIGWX Chart - ICAO Area F Example8-31
Figure 8-43. High-Level SIGWX Chart - ICAO Area H Example8-32
Figure 8-44. High-Level SIGWX Chart - ICAO Area I Example8-32
Figure 8-45. High-Level SIGWX Chart - ICAO Area J Example8-33
Figure 8-46. High-Level SIGWX Chart - ICAO Area M Example8-33
9 SUPPLEMENTARY PRODUCTS9-1
9.1 COLLABORATIVE CONVECTIVE FORECAST PRODUCT (CCFP)9-1
Figure 9-1. CCFP Example9-1
9.1.1 Issuance9-2
9.1.2 Collaboration9-2
9.1.3 Content9-2
9.1.3.1 Coverage9-2
Figure 9-2. CCFP Forecast Convective Coverage9-3
9.1.3.2 Confidence9-3
Figure 9-3. CCFP Forecast Confidence9-3
9.1.3.3 Movement9-3
Figure 9-4. CCFP Forecast Convective Movement9-4
9.1.3.4 Data Block9-4
Figure 9-5. CCFP Data Block9-4
Figure 9-6. CCFP Data Block Example9-5
9.1.3.4.1 Tops9-5
Table 9-1. CCFP Tops9-5
9.1.3.4.2 Growth9-5
Table 9-2. CCFP Growth9-5
9.1.3.4.3 Confidence9-5
Table 9-3. CCFP Confidence9-5
9.1.3.4.4 Coverage9-5
Table 9-4. CCFP Coverage9-6
9.1.4 Strengths and Limitations9-6
9.1.5 Use9-6
9.2 NATIONAL CONVECTIVE WEATHER FORECAST (NCWF)9-7
9.2.1 Issuance9-7
9.2.2 Content9-7
Figure 9-7. NCWF Example9-7
9.2.2.1 Current Convective Hazard Fields9-8
Figure 9-8. NCWF Current Convective Hazard Fields Example9-8
9.2.2.1.1 Convective Hazard Field Scale9-8
Figure 9-9. NCWF Hazard Scale9-9
9.2.2.2 One-Hour Extrapolated Forecast Polygons9-9
9.2.2.3 Forecast Speed and Direction9-9
9.2.2.4 Echo Tops9-9
Figure 9-10. NCWF One-Hour Extrapolated Forecast Polygon, Forecast Movement Velocity, and
Echo Tops Example9-10
9.2.2.5 Previous Performance Polygons9-10
Figure 9-11. NCWF Previous Performance Polygons Example9-11
9.2.3 The ADDS and AWC JAVA display9-11
9.2.4 Strengths and Limitations9-11
9.2.5 Uses of the NCWF9-12
9.3 CURRENT ICING PRODUCT (CIP)9-13
9.3.1 Issuance9-13
9.3.2 Content9-13
9.3.2.1 Icing Probability9-14
Figure 9-12. CIP Icing Probability (3,000 feet MSL) Example9-14
9.3.2.2 Icing Probability -- Maximum9-15
Figure 9-13. CIP Icing Probability – Max Example9-15
9.3.2.3 Icing Severity9-16
Figure 9-14. CIP Icing Severity (3,000 feet MSL) Example9-16
9.3.2.4 Icing Severity -- Maximum9-17
AC 00-45F, CHG 2 Table of Contents Page xiv
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 9-15. CIP Icing Severity – Max Example9-17
9.3.2.5 Icing Severity – Probability > 25%9-17
Figure 9-16. CIP Icing Severity Probability >25% Example9-18
9.3.2.6 Icing Severity – Probability > 25% - Maximum9-18
Figure 9-17. CIP Icing Severity Probability >25% Example9-19
9.3.2.7 Icing Severity – Probability > 50%9-19
Figure 9-18. CIP Icing Severity Probability > 50% Example9-20
9.3.2.8 Icing Severity – Probability > 50% - Maximum9-20
Figure 9-19. CIP Icing Severity Probability > 50% - Max Example9-21
9.3.2.9 Icing Severity plus Supercooled Large Droplets (SLD)9-21
Figure 9-20. CIP Icing Severity plus Supercooled Large Droplets (SLD) Example9-22
9.3.2.10 Icing Severity plus Supercooled Large Droplets (SLD) - Maximum9-23
Figure 9-21. CIP Icing Severity plus Supercooled Large Droplets (SLD) – Max Example9-23
9.3.3 Strengths and Limitations9-24
9.3.3.1 Strengths9-24
9.3.3.2 Limitations9-24
9.3.4 Uses9-24
9.4 FORECAST ICING POTENTIAL (FIP)9-25
9.4.1 Issuance9-25
9.4.2 Content9-25
Figure 9-22. FIP Example9-26
9.4.3 Strengths and Limitations9-26
9.4.4 Use9-27
9.5 GRAPHICAL TURBULENCE GUIDANCE (GTG)9-28
9.5.1 Issuance9-28
9.5.2 Content9-28
9.5.2.1 GTG Analysis and Forecast9-28
Figure 9-23. GTG Example9-29
9.5.2.2 GTG Composite Analysis and Forecast9-29
Figure 9-24. GTG Composite Example9-30
9.5.3 Strengths and Limitations9-30
9.5.4 Use9-31
9.6 METEOROLOGICAL IMPACT STATEMENT (MIS)9-32
9.6.1 Valid Period9-32
9.6.2 MIS Criteria9-32
9.6.3 MIS Issuance9-33
9.6.4 Format9-33
Figure 9-25. Meteorological Impact Statement (MIS) Decoding Example9-33
Table 9-5. Meteorological Impact Statement (MIS) – Decoding9-33
9.6.5 Examples9-34
Figure 9-26. Center Weather Service Unit (CWSU) Areas of Responsibility - CONUS9-35
Figure 9-27. CWSU Anchorage, AK (PAZA) Area of Responsibility9-35
10 APPENDIX A: DEFINITION OF COMMON TERMS USED IN EN ROUTE FORECASTS
AND ADVISORIES10-1
11 APPENDIX B: CONTRACTIONS AND ACRONYMS11-1
12 APPENDIX C: STANDARD CONVERSION CHART12-1
Figure C-1. Standard Conversion Chart12-1
13 APPENDIX D: DENSITY ALTITUDE CALCULATION13-1
Figure D-1. Density Altitude Computation Chart13-1
14 APPENDIX E: INTERNET LINKS14-1
Table E-1. Selected National Weather Service (NWS) Links14-1
Table E-2. Selected Federal Aviation Administration (FAA) Links14-1
Table E-3. Selected Links to Aviation Weather Products14-2
AC 00-45F, CHG 2 Table of Contents Page xv
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) AC 00-45F, CHG 2 Table of Contents Page xvi
15 APPENDIX F: AWC ADVISORY PLOTTING CHART15-1
Figure F-1. AWC Advisory Plotting Chart15-1
16 APPENDIX G: WSR-88D WEATHER RADAR NETWORK16-1
Figure G-1. WSR-88D Weather Radar Network Sites16-1
Table G-1. WSR-88D Weather Radar Network16-2
17 APPENDIX H: AWC GEOGRAPHICAL AREA DESIGNATOR MAP17-1
Figure H-1: AWC Geographical Area Designator Map17-1
18 APPENDIX I: PRESENT WEATHER SYMBOLS18-1
Figure I-1. Present Weather Symbols with Text Explanation18-1
Figure I-2. Present Weather Symbols with Corresponding METAR/SPECI Present Weather Code
.18-2
19 APPENDIX J: TURBULENCE AND ICING INTENSITY DEPICTIONS19-1
Table J-1. Turbulence Intensity19-1
Table J-2. Icing Intensity19-1
NOTE: CLICK ON ANY ENTRY IN THE OF THE TABLE OF CONTENTS TO JUMP DIRECTLY TO THAT SECTION.
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) 1 AVIATION WEATHER SERVICE PROGRAM The aviation weather service program is a joint effort of the National Weather Service (NWS), the Federal Aviation Administration (FAA), the Department of Defense (DOD), and other aviation-oriented groups and individuals. This section discusses the civilian agencies of the U.S. Government and their observation, communication and forecast services to the aviation community.
1.1 National Oceanic and Atmospheric Administration (NOAA) The National Oceanic and Atmospheric Administration (NOAA) is an agency of the Department of Commerce (DOC). NOAA conducts research and gathers data about the global oceans, atmosphere, space, and sun, and applies this knowledge to science and service which touches the lives of all Americans. Among its six major divisions are the National Environmental Satellite Data and Information Service (NESDIS) and the NWS.
1.1.1 National Environmental Satellite Data and Information Service (NESDIS) The National Environmental Satellite Data and Information Service (NESDIS) manages the U.S.
civil operational remote-sensing satellite systems, as well as other global information for meteorology, oceanography, solid-earth geophysics, and solar-terrestrial sciences. NESDIS provides this data to NWS meteorologists and a wide range of other users for operational weather forecasting.
1.1.1.1 Satellite Analysis Branch (SAB) NESDIS' Satellite Analysis Branch (SAB) serves as the operational focal point for real-time imagery products and multi-disciplinary environmental analyses. The SAB’s primary mission is to support disaster mitigation and warning services for U.S. Federal agencies and the international community. Routine environmental analyses are provided to forecasters and other environmental users and used in the numerical models of the NWS. The SAB schedules and distributes real-time satellite imagery products from global geostationary and polar-orbiting satellites to environmental users. The SAB coordinates the satellite and other information for the NOAA Volcanic Hazards Alert program under an agreement with the FAA and works with the NWS as part of the Washington, D.C. Volcanic Ash Advisory Center (VAAC).
1.1.2 National Weather Service (NWS) The National Weather Service (NWS) provides weather data, forecasts and warnings for the United States, its territories, adjacent waters and ocean areas for the protection of life and property and the enhancement of the national economy. NWS data and products form a national information database and infrastructure that can be used by other government agencies, the private sector, the public and the global community. The following is a description of NWS offices associated with aviation weather.
1.1.2.1 National Centers for Environmental Prediction (NCEP) The National Centers for Environmental Prediction (NCEP) is where virtually all global meteorological data is collected and analyzed. NCEP then provides a wide variety of national and international weather guidance products to NWS field offices, government agencies, emergency managers, private sector meteorologists, and meteorological organizations and AC 00-45F, CHG 2 Section 1: Aviation Weather Service Program Page 1-1
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) societies throughout the world. NCEP is a critical resource in national and global weather prediction and is the starting point for nearly all weather forecasts in the U. S.
NCEP is comprised of nine distinct centers and the Office of the Director. Each center has its own specific mission. The following NCEP centers provide aviation weather products and services:
1.1.2.1.1 NCEP Central Operations (NCO) NCEP’s Central Operations (NCO) in Camp Springs, Maryland, sustains and executes the operational suite of the numerical analysis and forecast models and prepares NCEP products for dissemination. It also links all nine of the national centers together via computer and communications-related services.
1.1.2.1.2 Aviation Weather Center (AWC) The Aviation Weather Center (AWC), a Meteorological Watch Office (MWO) for the International Civil Aviation Organization (ICAO), is located in Kansas City, Missouri. The AWC issues the following products in support of FAA air traffic controllers and the National Airspace System (NAS): Airman’s Meteorological Information (AIRMETs), Significant Meteorological Information (SIGMETs), Convective SIGMETs, Area Forecasts (FAs), Significant Weather Prognostic Charts (low, middle, and high), Collaborative Convective Forecast Product (CCFP), National Convective Weather Forecast (NCWF), Current Icing Product (CIP), and Forecast Icing Potential (FIP).
1.1.2.1.3 Hydrometeorological Prediction Center (HPC) The Hydrometeorological Prediction Center (HPC) in Camp Springs, Maryland, provides analysis and forecast products specializing in quantitative precipitation forecasts to five days, weather forecast guidance to seven days, real-time weather model diagnostics discussions and surface pressure and frontal analyses.
1.1.2.1.4 Storm Prediction Center (SPC) The Storm Prediction Center (SPC) in Norman, Oklahoma, provides tornado and severe weather watches for the contiguous U. S. along with a suite of hazardous weather forecasts including the Alert Severe Weather Watch Bulletins and mesoscale guidance products
1.1.2.1.5 Tropical Prediction Center (TPC) The Tropical Prediction Center (TPC) in Miami, Florida, provides official NWS forecasts of the movement and strength of tropical weather systems and issues the appropriate watches and warnings for the contiguous U.S. and surrounding areas. It also issues a suite of marine products covering the tropical Atlantic, Caribbean, Gulf of Mexico, and tropical eastern Pacific.
1.1.2.2 Alaskan Aviation Weather Unit (AAWU) The Alaskan Aviation Weather Unit (AAWU), located in Anchorage, Alaska, is a MWO for the ICAO. The AAWU is responsible for the entire Anchorage Flight Information Region (FIR). They issue the following products for the airspace over Alaska and adjacent coastal waters:
AIRMETs, SIGMETs, FAs, Graphic Area Forecasts, and Significant Weather Prognostic Charts (Low- and Mid-level – below flight level (FL) 250).
The AAWU is also designated as the Anchorage Volcanic Ash Advisory Center (VAAC). The VAAC area of responsibility includes the Anchorage FIR and Far Eastern Russia and is responsible for the issuance of Volcanic Ash Advisories (FVs).
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Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
1.1.2.3 Center Weather Service Unit (CWSU) Center Weather Service Units (CWSUs) are units of NWS meteorologists under contract with the FAA that are stationed at and support the FAA’s Air Route Traffic Control Centers (ARTCC).
CWSUs provide timely weather consultation, forecasts, and advice to managers within ARTCCs and to other supported FAA facilities. This information is based on monitoring, analysis, and interpretation of real-time weather data at the ARTCC through the use of all available data sources including radar, satellite, Pilot Weather Reports (PIREPs), and various NWS products such as Terminal Aerodrome Forecasts (TAFs), FAs, and inflight advisories.
Special emphasis is given to those weather conditions hazardous to aviation or which would impede the flow of air traffic within the NAS. Rerouting of aircraft around hazardous weather is based largely on forecasts provided by the CWSU meteorologist. They issue the following products in support of their respective ARTCC: Center Weather Advisories (CWA) and Meteorological Impact Statements (MIS).
1.1.2.4 Weather Forecast Office (WFO) A NWS Weather Forecast Office (WFO) is a multi-purpose, local weather forecast center that produces, among its suite of services, aviation-related products. In support of aviation, WFOs issue Terminal Aerodrome Forecasts (TAFs), Transcribed Weather En Route Broadcasts (TWEBs) forecasts, with some offices issuing Airport Weather Warnings, and Soaring Forecasts.
WFO Honolulu is also designated as a Meteorological Watch Office (MWO) for ICAO. As a result of this unique designation, WFO Honolulu is the only WFO to issue the following text products: AIRMETs, SIGMETs, FAs, and Route Forecasts (ROFOR). WFO Honolulu serves as the Central Pacific Hurricane Center (CPHC). CPHC provides official NWS forecast of the movement and strength of tropical weather systems and issues the appropriate watches and warnings for the central Pacific including the State of Hawaii. WFO Honolulu also issues a suite of marine products covering a large portion of the Pacific Ocean.
1.1.2.5 NWS Office at the FAA Academy The mission of the National Weather Service (NWS) Office at the FAA Academy is to provide weather training for Federal Aviation Administration (FAA) Air Traffic Controllers, write reference materials, and administer NWS certification examinations for FAA Pilot Weather Briefers and Tower Visibility Observers.
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Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
1.2 Federal Aviation Administration (FAA) The FAA, a part of the Department of Transportation (DOT), provides a safe, secure, and efficient aerospace system that contributes to national security and the promotion of U.S.
aerospace safety. As the leading authority in the international aerospace community, the FAA is responsive to the dynamic nature of user needs, economic conditions, and environmental concerns.
The FAA provides a wide range of services to the aviation community. The following is a description of those FAA facilities which are involved with aviation weather and pilot services.
1.2.1 Air Traffic Control System Command Center (ATCSCC) The Air Traffic Control System Command Center (ATCSCC) is located in Herndon, Virginia.
ATCSCC has the mission of balancing air traffic demand with system capacity. This ensures maximum safety and efficiency for the NAS while minimizing delays. The ATCSCC utilizes the Traffic Management System, aircraft situation display, monitor alert, the follow-on functions, and direct contact with ARTCC and terminal radar approach control facility (TRACON) traffic management units to manage flow on a national level.
Because weather is the most common reason for air traffic delays and re-routings, the ATCSCC is supported by Air Traffic Control System Command Center Weather Unit Specialists (ATCSCCWUS). These flight service specialists are responsible for the dissemination of meteorological information as it pertains to national air traffic flow management.
1.2.2 Air Route Traffic Control Center (ARTCC) An ARTCC is a facility established to provide air traffic control service to aircraft operating on Instrument Flight Rules (IFR) flight plans within controlled airspace and principally during the en route phase of flight. When equipment capabilities and controller workload permit, certain advisory/assistance services may be provided to Visual Flight Rules (VFR) aircraft.
En route controllers become familiar with pertinent weather information and stay aware of current weather information needed to perform air traffic control duties. En route controllers advise pilots of hazardous weather that may impact operations within 150 NM of the controller’s assigned sector(s).
1.2.3 Air Traffic Control Tower (ATCT) and Terminal Radar Approach Control (TRACON) An ATCT is a terminal facility that uses air/ground communications, visual signaling, and other devices to provide ATC services to aircraft operating in the vicinity of an airport or on the movement area. It authorizes aircraft to land or take off at the airport controlled by the tower or to transit the Class D airspace area regardless of flight plan or weather conditions (IFR or VFR).
A tower may also provide approach control services.
TRACONs manage the airspace from 10 to 40 miles outside of selected airports and below 13,000 feet. They also coordinate aircraft spacing as they approach and depart these airports.
Terminal controllers become familiar with pertinent weather information and stay aware of current weather information needed to perform air traffic control duties. Terminal controllers advise pilots of hazardous weather that may impact operations within 150 NM of the controller’s AC 00-45F, CHG 2 Section 1: Aviation Weather Service Program Page 1-4
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) assigned sector or area of jurisdiction. ATCTs and TRACONs may opt to broadcast hazardous weather information alerts only when any part of the area described is within 50 NM of the airspace under the ATCT’s jurisdiction.
The tower controllers are also properly certified and act as official weather observers as required.
An Automatic Terminal Information Service (ATIS) is a continuous broadcast of recorded information in selected terminal areas. Its purpose is to improve controller effectiveness and to relieve frequency congestion by automating the repetitive transmission of non-controlled airport/terminal area and meteorological information.
1.2.4 Flight Service Station (FSS) / Automated Flight Service Station (AFSS) Flight Service Stations (FSSs) and Automated Flight Service Stations (AFSSs) provide pilot weather briefings, en route weather, receive and process IFR and VFR flight plans, relay ATC clearances, and issue Notices to Airmen (NOTAMs). They also provide assistance to lost aircraft and aircraft in emergency situations, and conduct VFR search and rescue services.
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