Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
5.1.3.2 Analysis Symbols ........................................................................................................................................... 5- 12
Figure 5-15. OPC and WFO HNL Surface Analysis Chart Symbols5-12
Figure 5-16. WFO HNL Surface Analysis Chart – North Pacific Example5-13
5.1.3.3 Wave Information ........................................................................................................................................... 5- 13
5.1.3.4 Analyses ......................................................................................................................................................... 5- 13
Isobars5-14
Pressure Systems5-14
Fronts5-14
5.1.4 TPC Surface Analysis Charts5-14
5.1.4.1 Issuance .......................................................................................................................................................... 5- 14
Table 5-3. TPC Surface Analysis Charts Issuance Schedule5-14
5.1.4.2 Analysis Symbols ........................................................................................................................................... 5- 14 Figure 5-17. TPC Surface Analysis Chart Symbols ............................................................................ 5- 15
Figure 5-18. TPC Tropical Surface Analysis Chart Example5-15
Wind5-15
Figure 5-19. TPC Surface Analysis Chart Wind Plotting Model5-16
5.1.4.3 Analyses ......................................................................................................................................................... 5- 16
Isobars5-16
Pressure Systems5-16
Fronts5-17
5.1.5 Unified Surface Analysis Chart5-17
5.1.5.1 Issuance .......................................................................................................................................................... 5- 17
Table 5-4. Unified Surface Analysis Chart Issuance Schedule5-17
Figure 5-20. Unified Surface Analysis Chart Example....................................................................... 5- 17
5.1.5.2 Analysis Symbols ........................................................................................................................................... 5- 17 Figure 5-21. Unified Surface Analysis Chart Symbols ....................................................................... 5- 18
5.1.5.3 Analyses ......................................................................................................................................................... 5- 18
Isobars5-18
Pressure Systems5-18
Fronts5-18
5.1.6 AAWU Surface Charts5-19
5.1.6.1 Issuance .......................................................................................................................................................... 5- 19 Table 5-5. AAWU Surface Analysis Issuance Schedule ..................................................................... 5- 19
5.1.6.2 Analysis Symbols ........................................................................................................................................... 5- 19 Figure 5-22. AAWU Surface Analysis Chart Symbols ....................................................................... 5- 19 Figure 5-23. AAWU Alaskan Surface Chart Example ....................................................................... 5- 20
5.1.6.3 Station Plot Models ........................................................................................................................................ 5- 20
Figure 5-24. AAWU Surface Analysis Chart Station Plot Model5-20
Figure 5-25. AAWU Surface Analysis Chart Ship/Buoy Plot Model5-21
Station Identifier5-21
Temperature5-21
Dew Point5-21
Wind5-21
Figure 5-26. AAWU Surface Analysis Chart Wind Plotting Model5-22
Ceiling5-22
Visibility5-22
Pressure5-22
Pressure Trend5-22
Figure 5-27 AAWU Surface Analysis Chart Pressure Trends5-23
Sky Cover5-23
Figure 5-28. AAWU Surface Analysis Chart Sky Cover Symbols5-23
Water Temperature5-23
Swell Information5-24
Wave Information5-24
5.1.6.4 Analyses ......................................................................................................................................................... 5- 24
Isobars5-24
Pressure Systems5-25
Fronts5-25
5.2 CONSTANT PRESSURE CHARTS5-26
Figure 5-29. Constant Pressure Chart Example ................................................................................. 5- 26
5.2.1 Issuance5-26
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5.2.2 Observational Data5-26
Figure 5-30. U.S. Radiosonde Network ............................................................................................... 5- 27 Table 5-6. Features of Constant Pressure Charts ............................................................................... 5- 28 Table 5-7. Constant Pressure Chart Plotting Models ......................................................................... 5- 28 Table 5-8. Radiosonde Plotting Model Examples ............................................................................... 5- 29
5.2.3 Analyses5-29
5.2.3.1 Height ............................................................................................................................................................. 5- 29
5.2.3.2 Temperature ................................................................................................................................................... 5- 29
5.2.3.3 Wind Speed .................................................................................................................................................... 5- 30
5.2.3.4 Use ................................................................................................................................................................. 5- 30
Table 5-9. Reconnaissance Aircraft (RECCO) Plotting Model Examples5-30
Table 5-10. Aircraft Report (AIREP) Plotting Model Examples5-31
Table 5-11. Satellite Wind Estimate Plotting Model Examples5-31
Figure 5-31. 850MB Analysis Chart Example .................................................................................... 5- 32 Figure 5-32. 700MB Analysis Chart Example .................................................................................... 5- 32 Figure 5-33. 500MB Analysis Chart Example .................................................................................... 5- 33 Figure 5-34. 300MB Analysis Chart Example .................................................................................... 5- 33 Figure 5-35. 200MB Analysis Chart Example .................................................................................... 5- 34
5.3 FREEZING-LEVEL GRAPHICS5-35
5.3.1 Issuance5-35
5.3.2 Observational Data5-35
5.3.3 Format5-36
Figure 5-36. RUC 00-Hour Freezing Level Graphic Example5-37
5.3.4 Use5-38
Figure 5-37. A DDS Freezing Level Graphic Example ........................................................................ 5- 38
5.4 WEATHER DEPICTION CHART5-39
Figure 5-39. Weather Depiction Chart Example ................................................................................ 5- 39
5.4.1 Issuance5-39
Table 5-13. Weather Depiction Charts Issuance Schedule ................................................................. 5- 39
5.4.2 Station Plot Model5-39
Figure 5-40. Weather Depiction Chart Station Plot Model ................................................................ 5- 40
5.4.2.1 Visibility ......................................................................................................................................................... 5- 40
5.4.2.2 Present Weather .............................................................................................................................................. 5- 40
5.4.2.3 Sky Cover ....................................................................................................................................................... 5- 40
5.4.2.4 Ceiling ............................................................................................................................................................ 5- 40
5.4.3 Weather Flying Category Analysis5-41
5.4.4 Use5-41
5.5 ALASKA WEATHER DEPICTION CHARTS5-42
Figure 5-41. AAWU Alaska Weather Depiction Chart Example5-42
Table 5-14. AAWU Alaska Weather Depiction Charts Coverage5-43
5.5.1 Issuance5-43
5.5.2 Legends5-43
5.5.2.1 Flying Category .............................................................................................................................................. 5- 43
Table 5-15. AAWU Alaska Weather Flying Categories and Criteria5-43
5.5.2.2 Station Plot ..................................................................................................................................................... 5- 43
Figure 5-42. AAWU Alaska Weather Depiction Chart Station Plot Legend5-43
5.5.2.3 Sky Cover ....................................................................................................................................................... 5- 44
5.5.2.4 Station Identifier (STNID) .............................................................................................................................. 5- 44
5.5.2.5 Wind ............................................................................................................................................................... 5- 44
Figure 5-43. A AWU Alaska Weather Depiction Chart Wind Symbols5-44
5.5.2.6 Temperature (TMP deg F) .............................................................................................................................. 5- 44
5.5.2.7 Visibility (VIS) ............................................................................................................................................... 5- 44
5.5.2.8 Dew Point Temperature (DEWPT deg F) ....................................................................................................... 5- 45
5.5.2.9 Ceiling (CIG) .................................................................................................................................................. 5- 45
5.5.2.10 Present Weather (WX) .................................................................................................................................... 5- 45
Table 5-16. Alaska Weather Depiction Charts Precipitation Symbols5-45
Table 5-17. Alaska Weather Depiction Charts Obstruction to Visibility Symbols5-45
Table 5-18. Alaska Weather Depiction Charts Precipitation Intensity Symbols5-46
5.5.3 Use5-47
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Figure 5-44. AAWU Alaska Weather Depiction Chart – South Central Alaska Example5-47
5.6 RADAR SUMMARY CHART5-48
Figure 5-45. Radar Summary Chart Example5-48
5.6.1 Issuance5-48
5.6.2 Format5-48
5.6.2.1 Precipitation Type .......................................................................................................................................... 5- 48
Table 5-19. Radar Summary Chart Precipitation Type Symbols5-49
5.6.2.2 Precipitation Intensity5-49
Figure 5-46. WSR-88D Weather Radar Network5-49
Figure 5-47. Radar Summary Chart Precipitation Intensity5-50
5.6.2.3 Echo Coverage ............................................................................................................................................... 5- 50
5.6.2.4 Line Echoes .................................................................................................................................................... 5- 50
Table 5-20. Radar Summary Chart Echo Configuration Symbols5-50
5.6.2.5 Cell Movement ............................................................................................................................................... 5- 50
Table 5-21. Radar Summary Chart Cell Movement Examples5-51
5.6.2.6 Maximum Top5-51
Figure 5-48. Radar Summary Chart Maximum Top Example5-51
5.6.2.7 Weather Watch Areas5-52
Table 5-22. Radar Summary Chart Weather Watch Area Examples5-52
5.6.2.8 Operational Contractions5-52
Table 5-23. Radar Summary Chart Operational Contractions5-52
5.6.3 Use5-52
Figure 5-49. Radar Summary Chart Example5-53
5.7 ALASKA INITIAL GEOPOTENTIAL HEIGHTS AND WINDS CHARTS5-54
Figure 5-50. Alaskan Initial Geopotential Heights and Winds Chart Example5-54
Table 5-24. Pressure Altitudes of Alaska Initial Geopotential Heights and Winds Charts5-54
5.7.1 Issuance5-54
5.7.2 Analysis5-55
5.7.2.1 Height Contours ............................................................................................................................................. 5- 55
5.7.2.2 Winds5-55
Figure 5-51. Alaskan Initial Geopotential Heights and Winds Chart Wind Plotting Model5-55
5.7.3 Use5-55
Figure 5-52. Alaskan Initial Geopotential Heights and Winds Chart – 200MB Winds and Contours Chart Example ............................................................................................... 5- 56 Figure 5-53. Alaskan Initial Geopotential Heights and Winds Chart – 300MB Winds and Contours Chart Example ............................................................................................... 5- 56 Figure 5-54. Alaskan Initial Geopotential Heights and Winds Chart – 500MB Winds and Contours Chart Example ............................................................................................... 5- 57 Figure 5-55. Alaskan Initial Geopotential Heights and Winds Chart – 700MB Winds and Contours Chart Example ............................................................................................... 5- 57 Figure 5-56. Alaskan Initial Geopotential Heights and Winds Chart – 850MB Winds and Contours Chart Example ............................................................................................... 5- 58
6 PRODUCTS FOR AVIATION HAZARDS6-1
6.1 SIGNIFICANT METEOROLOGICAL INFORMATION (SIGMET)6-1
6.1.1 SIGMET Issuance6-1
Figure 6-1. AWC SIGMET Areas of Responsibility – Conterminous U.S6-2
Figure 6-2. AWC SIGMET Areas of Responsibility – Atlantic Basin6-2
Figure 6-3. SIGMET Areas of Responsibility – Pacific Basin6-3
6.1.1.1 SIGMET Identification6-3
6.1.2 SIGMET Standardization6-4
6.1.3 SIGMET (Non-Convective) – Conterminous U.S6-4
6.1.3.1 SIGMET (Non-Convective) Issuance Criteria – Contiguous U.S6-4
6.1.3.2 SIGMET (Non-Convective) Issuance Time and Valid Period – Conterminous U.S6-5
6.1.3.3 SIGMET (Non-Convective) Format – Conterminous U.S6-5
Figure 6-4. SIGMET for the Conterminous U.S. Decoding Example6-6
Table 6-1. Decoding a SIGMET (Non-Convective) for the Conterminous U.S6-6
6.1.3.4 SIGMET (Non-Convective) Cancellations – Conterminous U.S6-7
6.1.3.5 SIGMET (Non-Convective) Amendments – Conterminous U.S6-7
6.1.3.6 SIGMET (Non-Convective) Corrections – Conterminous U.S6-7
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6.1.3.7 SIGMET (Non-Convective) Example – Conterminous U.S6-7
6.1.4 Convective SIGMET6-7
6.1.4.1 Convective SIGMET – Routine Issuance Criteria6-7
6.1.4.2 Convective SIGMET – Special Issuance Criteria6-8
6.1.4.3 Convective SIGMET Issuance Time and Valid Period6-8
Figure 6-5. AWC Convective SIGMET Areas of Responsibility6-8
6.1.4.4 Convective SIGMET Format6-8
Figure 6-6. Convective SIGMET Decoding Example ......................................................................... 6- 10 Table 6-2. Decoding a Convective SIGMET ....................................................................................... 6- 10
6.1.4.5 Convective SIGMET Outlook ........................................................................................................................ 6- 11
6.1.4.6 Convective SIGMET Cancellations ................................................................................................................ 6- 11
6.1.4.7 Convective SIGMET Amendments ................................................................................................................ 6- 11
6.1.4.8 Convective SIGMET Corrections ................................................................................................................... 6- 11
6.1.4.9 Convective SIGMET Bulletin Examples ........................................................................................................ 6- 11
Convective SIGMET Bulletin – Tropical Cyclone Example6-12
6.1.5 SIGMET – Outside the Conterminous U.S. (O-CONUS)6-14
6.1.5.1 SIGMET Issuance Criteria – Outside the Conterminous U.S. (O-CONUS)6-14
6.1.5.2 SIGMET Issuance Time and Valid Period – Outside the Conterminous U.S. (O-CONUS)6-14
6.1.5.3 SIGMET Format – Outside the Conterminous U.S. (O-CONUS) ................................................................... 6- 14
Figure 6-7. SIGMET Outside the Conterminous U.S. Decoding Example6-16
Table 6-3. Decoding a SIGMET Outside of the Conterminous U.S. (O-CONUS)6-16
6.1.5.4 SIGMETs for Volcanic Ash ........................................................................................................................... 6- 17
6.1.5.5 SIGMETs for Tropical Cyclone ...................................................................................................................... 6- 17
6.1.5.6 SIGMET Cancellation – Outside the Conterminous U.S. (O-CONUS)6-17
6.1.5.7 SIGMET Amendments – Outside the Conterminous U.S. (O-CONUS)6-17
6.1.5.8 SIGMET Corrections – Outside the Conterminous U.S. (O-CONUS)6-17
6.1.5.9 SIGMET Example – Outside the Conterminous U.S. (O-CONUS) ................................................................ 6- 18
SIGMET for Volcanic Ash Example6-18
SIGMET for Tropical Cyclone Example6-18
6.2 AIRMEN’S METEOROLOGICAL INFORMATION (AIRMET)6-20
6.2.1 AIRMET Issuance6-20
Figure 6-8. AWC AIRMET Areas of Responsibility – Conterminous U.S6-21
Figure 6-9. AAWU Flight Advisory and Area Forecast Zones – Alaska6-22
Table 6-4. AAWU Flight Advisory and Area Forecast Zones – Alaska6-22
Figure 6-10. WFO Honolulu AIRMET Areas of Responsibility – Hawaii6-23
6.2.2 AIRMET Issuance Criteria6-23
6.2.3 AIRMET Standardization6-24
6.2.4 AIRMET Bulletins, Issuance Times, and Valid Period6-24
Table 6-5. AIRMET Issuance Schedule............................................................................................... 6- 24
6.2.5 AIRMET Format6-25
Figure 6-11. AIRMET Bulletin Decoding Example ............................................................................ 6- 26 Table 6-6. Decoding an AIRMET Bulletin .......................................................................................... 6- 26
6.2.5.1 AIRMET Updates and Amendments .............................................................................................................. 6- 27
6.2.5.2 AIRMET Corrections ..................................................................................................................................... 6- 27
6.2.6 AIRMET Examples6-27
6.2.6.1 CONUS AIRMET Example ........................................................................................................................... 6- 27
6.2.6.2 Hawaii AIRMET Example ............................................................................................................................. 6- 29
6.2.6.3 Alaska AIRMET Example .............................................................................................................................. 6- 29
6.3 GRAPHICAL AIRMAN’S METEOROLOGICAL ADVISORY (G-AIRMET)6-31
6.3.1 G-AIRMET Issuance6-31
Table 6-7. G-AIRMET Issuance Schedule .......................................................................................... 6- 31
6.3.2 G-AIRMET Content6-31
Figure 6-12. G-AIRMET – Ceiling and Visibility (IFR) Snapshot Example6-32
Figure 6-13. G- AIRMET – Mountain Obscuration Snapshot Example6-33
Figure 6-14. G-AIRMET – Icing Snapshot Example ......................................................................... 6- 34
Figure 6-15. G-AIRMET – Freezing Level Snapshot Example6-35
Figure 6-16. G-AIRMET – Turbulence-High Snapshot Example6-36
Figure 6-17. G-AIRMET – Turbulence-Low Snapshot Example6-37
Figure 6-18. G-AIRMET – Low-Level Wind Shear (LLWS) Snapshot Example6-38
Figure 6-19. G-AIRMET – Strong Surface Winds Snapshot Example6-39
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6.4 CENTER WEATHER ADVISORY (CWA)6-40
6.4.1 CWA Issuance6-40
Figure 6-20. Center Weather Service Unit (CWSU) Areas of Responsibility, Contiguous U.S6-40
Figure 6-21. CWSU Anchorage, AK (PAZA) Area of Responsibility6-41
6.4.2 CWA Criteria6-41
6.4.3 CWA Format6-42
Figure 6-22. Center Weather Advisory (CWA) Decoding Example6-42
Table 6-8. Decoding a Center Weather Advisory (CWA) .................................................................. 6- 42
6.4.4 Examples6-43
6.5 ADDITIONAL PRODUCTS FOR CONVECTION6-45
6.5.1 Convective Outlooks (AC)6-45
6.5.1.1 Issuance .......................................................................................................................................................... 6- 45 Table 6-9. Convective Outlook Issuance Schedule.............................................................................. 6- 45
Figure 6-23. Day 1 Categorical Convective Outlook Graphic Example6-46
6.5.1.2 Format of the Categorical Convective Outlook Narrative ............................................................................... 6- 46
6.5.2 Watch Notification Messages6-47
6.5.2.1 Aviation Watch Notification Message ............................................................................................................ 6- 47
6.5.2.2 Format of an Aviation Watch Notification Message ....................................................................................... 6- 47
Figure 6-24. Aviation Watch Notification Message Decoding Example6-48
Table 6-10. Decoding a Severe Weather Watch Bulletin .................................................................... 6- 48
6.5.2.3 Issuance .......................................................................................................................................................... 6- 49
6.5.3 Public Severe Thunderstorm Watch Notification Message6-49
6.5.3.1 Format of Public Severe Thunderstorm Watch Notification Message6-49
6.5.3.2 Example of a Public Severe Thunderstorm Watch Notification Message6-50
6.5.4 Public Tornado Watch Notification Message6-51
6.5.4.1 F ormat of a Public Tornado Watch Notification Message .............................................................................. 6- 52
6.5.4.2 Example of a Public Tornado Watch Notification Message ............................................................................ 6- 53
6.6 PRODUCTS FOR TROPICAL CYCLONES6-55
6.6.1 Aviation Tropical Cyclone Advisory (TCA)6-55
6.6.1.1 Issuance .......................................................................................................................................................... 6- 55
6.6.1.2 Content ........................................................................................................................................................... 6- 55
6.6.1.3 Format6-55
6.6.1.4 Aviation Tropical Cyclone Advisory (TCA) Example6-56
6.6.1.5 Tropical Cyclone Public Advisory (TCP)6-56
6.6.1.6 TCP Responsibility6-56
6.6.1.7 TCP Issuance6-57
Table 6-11. Tropical Cyclone Public Advisory Issuance Schedule6-58
TCP Intermediate Issuances6-58
Table 6-12. Intermediate Tropical Cyclone Public Advisory Issuance Schedule6-59
6.6.1.8 TCP Content6-59
6.6.1.9 TCP Format .................................................................................................................................................... 6- 60
6.6.1.10 Tropical Storm Public Advisory (TCP) Example ............................................................................................ 6- 60
6.6.1.11 Hurricane/Typhoon Public Advisory Example ............................................................................................... 6- 61
6.6.1.12 Intermediate Public Advisory Example6-63
6.6.1.13 Special Public Advisory Example6-65
6.6.1.14 Public Advisory Correction Example6-66
6.7 VOLCANIC ASH ADVISORY PRODUCTS6-67
6.7.1 Volcanic Ash Advisory Center (VAAC)6-67
Figure 6-25. Volcanic Ash Advisory Centers (VAACs) Area of Responsibility6-67
6.7.2 Volcanic Ash Advisory Statement (VAAS)6-68
6.7.2.1 Issuance .......................................................................................................................................................... 6- 68
6.7.2.2 Format ............................................................................................................................................................ 6- 68
6.7.2.3 VAAS Issued by the Washington VAAC Example ........................................................................................ 6- 68
6.7.3 Volcanic Ash Advisory (VAA)6-69
6.7.3.1 VAA Issuance ................................................................................................................................................ 6- 69
6.7.3.2 VAA Format ................................................................................................................................................... 6- 69
6.7.3.3 Volcanic Ash Advisory (VAA) Example ........................................................................................................ 6- 70 Table of Contents xi
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7 FORECAST TEXT PRODUCTS7-1
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 Header7-8
Figure 7-7. Area Forecast – Clouds and Weather Element Example7-8
7.1.6.1 Area Forecast – Conterminous U.S. (CONUS) Examples7-9
Area Forecast – BOS Example7-9
Area Forecast – SFO (FA) Example ....................................................................................................... 7- 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)7-14
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
Table 7-4. Generic Format of NWS TAFs ........................................................................................... 7- 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 Exception for Encoding Multiple Precipitation Types ............................................................................ 7- 23 Thunderstorm Descriptor ........................................................................................................................ 7- 24 Fog Forecast ........................................................................................................................................... 7- 24 Table 7-5. TAF Fog Terms ................................................................................................................... 7- 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)7-25
Cloud Group (NsNsNshshshs) ................................................................................................................ 7- 26 Table 7-7. TAF Sky Cover.................................................................................................................... 7- 26
Vertical Obscuration Group (VVhshshs)7-26
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
From (FM) Group (FMYYGGgg)7-28
TEMPO (YYGG/YeYeGeGe) Group7-29
PROB30 (YYGG/YeYeGeGe) Group7-30
7.2.2.12 TAF Examples7-30
7.2.3 Issuance7-33
Table 7-8. TAF Issuance Schedule ....................................................................................................... 7- 33
7.2.3.1 Minimum Observational Requirements for Routine TAF Issuance and Continuation7-33
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7.2.3.2 Sites with Scheduled Part-Time Observations7-33
Examples of Scheduled Part-Time Observations TAFs7-34
7.2.3.3 Automated Observing Sites Requiring Part-Time Augmentation7-34
7.2.3.4 Non-Augmented Automated Observing Sites7-35
7.3 INTERNATIONAL AVIATION ROUTE FORECASTS (ROFOR)7-37
7.3.1 ROFOR Criteria7-37
7.3.2 Issuance7-37
7.3.2.1 ROFOR Amendments7-37
7.3.2.2 ROFOR Corrections7-37
7.3.3 ROFOR Content7-37
7.3.4 ROFOR Examples7-38
7.3.4.1 Santa Barbara and San Francisco to Honolulu Route ROFOR Example
7.4 WIND AND TEMPERATURE ALOFT FORECAST (FB)7-39
7.4.1 Forecast Altitudes7-39
Table 7-9. Wind and Temperature Aloft Forecast Levels .................................................................. 7- 39
7.4.2 Format7-39
7.4.2.1 Coding Example7-39
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 U.S7-42
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 Example8-6
8.2 LOW-LEVEL SIGNIFICANT WEATHER (SIGWX) CHARTS8-7
Figure 8-10. 12-Hour Low-Level SIGWX Chart Example8-7
8.2.1 Content8-7
Figure 8-11. Low-Level SIGWX Chart Symbols8-8
8.2.1.1 F lying Categories8-8
Figure 8-12. Low-Level SIGWX Chart Flying Categories Example8-8
8.2.1.2 Turbulence8-8
Figure 8-13. Low-Level SIGWX Chart Turbulence Forecast Example8-9
8.2.1.3 Freezing Levels .............................................................................................................................................. 8- 10
Figure 8-14. Low-Level SIGWX Chart Freezing Level Forecast Example8-10
Figure 8-15. Low-Level SIGWX Chart Multiple Freezing Levels Example8-10
8.2.2 Issuance8-11
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Table 8-2. Low-Level SIGWX Chart Issuance Schedule8-11
8.2.3 Use8-11
Figure 8-16. 12-Hour Low-Level SIGWX Chart Example8-11
Figure 8-17. 24-Hour Low-Level SIGWX Chart Example8-12
8.3 MID-LEVEL SIGNIFICANT WEATHER (SIGWX) CHART8-13
Figure 8-18. Mid-Level SIGWX Chart Example8-13
8.3.1 Content8-13
8.3.1.1 Thunderstorms8-13
Table 8-3. Mid-Level SIGWX Chart Cumulonimbus Coverage8-14
Figure 8-19. Mid-Level SIGWX Chart Thunderstorm Examples8-14
8.3.1.2 Jet Streams8-15
Figure 8-21. Mid-Level SIGWX Chart Jet stream Example8-15
8.3.1.3 Tropopause Heights8-15
Figure 8-22. Mid-Level SIGWX Chart Tropopause Height Examples8-15
8.3.1.4 Tropical Cyclones8-16
Figure 8-23. Mid-Level SIGWX Chart Tropical Cyclone Examples8-16
8.3.1.5 Moderate or Severe Icing8-16
Figure 8-24. Mid-Level SIGWX Chart Icing Examples8-16
8.3.1.6 Moderate or Severe Turbulence (in cloud or in clear air)8-16
Figure 8-25. Mid-Level SIGWX Chart Turbulence Examples8-17
8.3.1.7 Cloud Coverage (non-cumulonimbus)8-17
Table 8-4. M id-Level SIGWX Chart Cloud Coverage (Non-Cumulonimbus)8-17
8.3.1.8 Cloud Type8-17
Table 8-5. Mid-Level SIGWX Chart Cloud Types8-18
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 Types8-18
8.3.1.9 Volcanic Eruptions ......................................................................................................................................... 8- 18
Figure 8-27. Mid-Level SIGWX Chart Volcanic Eruption Example8-18
8.3.1.10 Release of Radioactive Materials .................................................................................................................... 8- 19
Figure 8-28. Mid-Level SIGWX Chart Release of Radioactive Materials Example8-19
8.3.2 Issuance8-19
Table 8-6. Mid-Level SIGWX Chart Issuance Schedule .................................................................... 8- 19
8.3.3 Use8-19
Figure 8-29. Mid-Level SIGWX Chart Example8-20
8.4 HIGH-LEVEL SIGNIFICANT WEATHER (SIGWX) CHARTS8-21
Figure 8-30. High-Level SIGWX Chart Example8-21
8.4.1 Content8-22
8.4.1.1 Thunderstorms and Cumulonimbus Clouds8-22
Figure 8-31. High-Level SIGWX Chart Thunderstorm and Cumulonimbus Cloud Examples8-22
8.4.1.2 Moderate or Severe Turbulence8-23
Figure 8-32. High-Level SIGWX Chart Turbulence Examples8-23
8.4.1.3 Moderate or Severe Icing8-23
8.4.1.4 Jet Streams8-23
Figure 8-33. High-Level SIGWX Chart Jet stream Example8-24
8.4.1.5 T ropopause Heights8-24
Figure 8-35. High-Level SIGWX Chart Tropopause Height Examples8-24
8.4.1.6 Tropical Cyclones8-24
Figure 8-36. High Level SIGWX Chart Tropical Cyclone Examples8-25
8.4.1.7 Severe Squall Lines8-25
Figure 8-37. High-Level SIGWX Chart Severe Squall Line Example8-25
8.4.1.8 Volcanic Eruption Sites8-25
Figure 8-38. High-Level SIGWX Chart Volcanic Eruption Site Example8-26
8.4.1.9 Widespread Sandstorms and Dust storms8-26
Figure 8-39. High-Level SIGWX Chart Widespread Sandstorm and Dust Storm Example8-26
8.4.2 Issuance8-26
Table 8-7. High-Level SIGWX Chart Issuance Schedule – WAFC Washington8-27
8.4.3 Use8-28
Figure 8-40. High-Level SIGWX Chart – ICAO Area A Example8-28
Figure 8-41. High-Level SIGWX Chart – ICAO Area B1 Example8-29
Figure 8-42. High-Level SIGWX Chart – ICAO Area F Example8-29
Figure 8-43. High-Level SIGWX Chart – ICAO Area H Example8-30
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Figure 8-44. High-Level SIGWX Chart – ICAO Area I Example8-30
Figure 8-45. High-Level SIGWX Chart – ICAO Area J Example8-31
Figure 8-46. High-Level SIGWX Chart – ICAO Area M Example8-31
9 NEW GENERATION WEATHER 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
9.1.3.3 Movement ........................................................................................................................................................ 9.3
Figure 9-3. CCFP Forecast Convective Movement9-3
9.1.3.4 Data Block9-4
Figure 9-4. CCFP Data Block9-4
Figure 9-5. CCFP Data Block Example9-4
TOPS9-4
Table 9-1. CCFP Tops9-4
Growth9-5
Table 9-2. CCFP Growth9-5
Confidence9-5
Table 9-3. CCFP Confidence9-5
Coverage9-5
Table 9-4. CCFP Coverage9-5
9.1.4 Strengths and Limitations9-5
9.1.5 Use9-6
9.2 EXTENDED CONVECTIVE FORECAST PRODUCT (ECFP)9-6
9.2.1 Issuance9-6
Figure 9-6. ECFP Example9-7
9.2.2 Content9-7
9.2.3 Use9-8
9.2.4 Frequency9-8
9.3 NATIONAL CONVECTIVE WEATHER FORECAST (NCWF)9-9
9.3.1 Issuance9-9
9.3.2 Content9-9
Figure 9-7. NCWF Example9-9
9.3.2.1 Current Convective Hazard Fields9-9
Figure 9-8. NCWF Current Convective Hazard Fields Example9-9
Convective Hazard Field Scale ............................................................................................................... 9- 10
Figure 9-9. NCW F Hazard Scale9-10
9.3.2.2 One-Hour Extrapolated Forecast Polygons ..................................................................................................... 9- 10
9.3.2.3 Forecast Speed and Direction ......................................................................................................................... 9- 10
9.3.2.4 Echo Tops....................................................................................................................................................... 9- 10 Figure 9-10. NCWF One-Hour Extrapolated Forecast Polygon, Forecast Movement Velocity,
and Echo Tops Example9-11
9.3.2.5 Previous Performance Polygons ..................................................................................................................... 9- 11
Figure 9-11. NCWF Previous Performance Polygons Example9-12
9.3.3 Strengths and Limitations9-12
9.3.4 Uses of the NCWF9-13
9.4 CURRENT AND FORECAST ICING PRODUCTS (CIP/FIP)9-13
9.4.1 Issuance9-13
9.4.2 Content9-13
9.4.2.1 Icing Probability9-14
Figure 9-12. CIP/FIP Icing Probability (3,000 feet MSL) Example9-15
9.4.2.2 Icing Probability – Maximum ......................................................................................................................... 9- 15
Figure 9-13. CIP/FIP Icing Probability – Max Example9-16
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9.4.2.3 Icing Severity ................................................................................................................................................. 9- 16
Figure 9-14. CIP/FIP Icing Severity (3,000 feet MSL) Example9-17
9.4.2.4 Icing Severity – Maximum ............................................................................................................................. 9- 17
Figure 9-15. CIP/FIP Icing Severity – Max Example9-18
9.4.2.5 Icing Severity – Probability > 25 Percent ....................................................................................................... 9- 18
Figure 9-16. CIP/FIP Icing Severity Probability >25 Percent Example9-19
9.4.2.6 Icing Severity – Probability > 25 Percent – Maximum ................................................................................... 9- 19
Figure 9-17. CIP/FIP Icing Severity Probability >25 Percent Example9-20
9.4.2.7 Icing Severity – Probability > 50 Percent ....................................................................................................... 9- 20
Figure 9-18. CIP/FIP Icing Severity Probability > 50 Percent Example9-21
9.4.2.8 Icing Severity – Probability > 50 Percent – Maximum ................................................................................... 9- 21
Figure 9-19. CIP/FIP Icing Severity Probability > 50 Percent - Max Example9-22
9.4.2.9 Icing Severity Plus Supercooled Large Drops (SLD) ...................................................................................... 9- 22
Figure 9-20. CIP/FIP Icing Severity Plus Supercooled Large Drops (SLD) Example9-23
9.4.2.10 Icing Severity Plus Supercooled Large Drops (SLD) – Maximum ................................................................ 9- 23
Figure 9-21. CIP/FIP Icing Severity Plus Supercooled Large Droplets (SLD) – Max Example9-24
9.4.3 Strengths and Limitations9-25
9.4.3.1 Strengths9-25
9.4.3.2 Limitations9-25
9.4.4 Uses9-25
9.5 GRAPHICAL TURBULENCE GUIDANCE (GTG2)9-26
9.5.1 Issuance9-26
9.5.2 Content9-26
9.5.2.1 GTG Analysis and Forecast9-26
Figure 9-22. GTG Example9-27
9.5.2.2 GTG Composite Analysis and Forecast .......................................................................................................... 9- 27
Figure 9-23. GTG Composite Example9-28
9.5.3 Strengths and Limitations9-28
9.5.3.1 Strengths9-28
9.5.3.2 Limitations9-29
9.5.4 Use9-29
9.6 METEOROLOGICAL IMPACT STATEMENT (MIS)9-30
9.6.1 Valid Period9-30
9.6.2 MIS Criteria9-30
9.6.3 MIS Issuance9-31
9.6.4 Format9-31
Figure 9-24. Meteorological Impact Statement (MIS) Decoding Example9-31
Table 9-5. Meteorological Impact Statement (MIS) – Decoding9-31
9.6.5 Examples9-32
Figure 9-25. Center Weather Service Unit (CWSU) Areas of Responsibility – CONUS9-33
Figure 9-26. CWSU Anchorage, AK (PAZA) Area of Responsibility9-33
9.7 CEILING AND VISIBILITY ANALYSIS (CVA)9-35
9.7.1 Issuance9-35
9.7.2 Content9-35
9.7.2.1 CVA Ceiling Analysis9-35
Figure 9-27. CONUS Display of CVA Ceiling Analysis9-36
Figure 9-28. Regional Display of CVA Ceiling Analysis9-36
9.7.2.2 CVA Visibility Analysis9-37
Figure 9-29. Regional Display of CVA Visibility Analysis ................................................................. 9- 37
9.7.2.3 CVA Flight Category Analysis ....................................................................................................................... 9- 37
Figure 9-30. Regional Display of CVA Flight Category Analysis9-38
9.7.3 Strengths and Limitations9-38
9.7.3.1 CVA Strengths9-38
9.7.3.2 CVA Limitations9-39
9.7.4 Use9-39
APPENDIX A: DEFINITION OF COMMON TERMS USED IN EN ROUTE FORECASTS AND
ADVISORIES10-1
Table A-1. Definition of Common Terms Used in En route Forecasts and Advisories10-1
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APPENDIX B: CONTRACTIONS AND ACRONYMS11-1
APPENDIX C: STANDARD CONVERSION CHART12-1
Figure C-1. Standard Conversion Chart12-1
APPENDIX D: DENSITY ALTITUDE CALCULATION13-1
Figure D-1. Density Altitude Computation Chart13-1
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
APPENDIX F: AWC ADVISORY PLOTTING CHART15-1
Figure F-1. AWC Advisory Plotting Chart15-1
Table F-1. AWC Advisory Plotting Chart Reference Points15-2
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
APPENDIX H: AWC GEOGRAPHICAL AREA DESIGNATOR MAP17-1
Figure H-1. AWC Geographical Area Designator Map17-1
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 Code18-2
APPENDIX J: TURBULENCE AND ICING INTENSITY DEPICTIONS19-1
Table J-1. Turbulence Intensity19-1
Table J-2. Icing Intensity19-1
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Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) 1 AVIATION WEATHER SER VICE 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) 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 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' 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) 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) 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 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 United States.
Section 1: Aviation Weather Service Program Page 1-1