TP 14371E Transport Canada Aeronautical Information Manual (TC AIM) MET—METEOROLOGY OCTOBER 8, 2020 TC AIM October 8, 2020 TRANSPORT CANADA AERONAUTICAL INFORMATION MANUAL (TC AIM) EXPLANATION OF CHANGES EFFECTIVE—OCTOBER 8, 2020 NOTES: 1. Editorial and format changes were made throughout the TC AIM where necessary and those that were deemed insignificant in nature were not included in the “Explanation of Changes”. 2. Effective March 31, 2016, licence differences with ICAO Annex 1 standards and recommended practices, previously located in LRA 1.8 of the TC AIM, have been removed and can now be found in AIP Canada (ICAO) GEN 1.7. MET (i) MET 4.11 Clouds and Weather Chart Additional text was added to clarify forecasts of cloud layers. (ii) MET 4.11 Clouds and Weather Chart Figure 4.4(e)—Multiple Cloud Layers “AS” was removed from the image since altostratus (AS) is not specified in any chart. (iii) MET 7.2 General A sentence related to significant weather was added. (iv) MET 8.3 Sample Message In (f)(i) Wind gusts, information on wind gusts was improved by specifying the wind gust averaging period. (v) MET 12.1 Mid-Level Charts The title of this subpart was renamed. TC AIM October 8, 2020 Table of Contents MET—METEOROLOGY 127 1.0 GENERAL INFORMATION ............................................................................................................................... 127 1.1 General .......................................................................................................................................................................................................... 127 1.1.1 Meteorological Responsibility ................................................................................................................................................... 127 1.1.2 Meteorological Services Available ............................................................................................................................................ 127 1.1.3 Aviation Weather Services �������������������������������������������������������������������������������������������������������������������������������������������������������� 127 1.1.4 Weather Service Information ����������������������������������������������������������������������������������������������������������������������������������������������������� 128 1.1.5 Weather Information from Air Traffic Service (ATS) �������������������������������������������������������������������������������������������������������������� 128 1.1.6 Pilot Reports ............................................................................................................................................................................... 128 1.1.6.1 Pilot Weather Reports (PIREPs) ................................................................................................................................................ 128 1.1.6.2 Air Reports (AIREPs) ................................................................................................................................................................ 128 1.1.7 Applicable International Civil Aviation Organization (ICAO) and World Meteorological Organization (WMO) Documents .................................................................................................................................................................................. 128 1.1.8 Differences from International Civil Aviation Organization (ICAO) Annex 3 ....................................................................... 129 1.1.9 Pilot Responsibility..................................................................................................................................................................... 129 1.2 Meteorological Observation and Reports ............................................................................................................................................................129 1.2.1 Type and Frequency of Observations ........................................................................................................................................ 129 1.2.2 Flight Weather Documentation ................................................................................................................................................. 129 1.2.3 Weather Services Definitions in Flight Publications ............................................................................................................... 129 1.2.4 Automated Weather Observation Systems (AWOS) .................................................................................................................. 130 1.2.4.1 Overview ..................................................................................................................................................................................... 130 1.2.4.2 Visual Flight Rules (VFR) Weather Stations ����������������������������������������������������������������������������������������������������������������������������� 130 1.2.5 Automatic Aerodrome Routine Meteorological Reports (METAR AUTO) and Limited Weather Information System (LWIS) Reports .............................................................................................................................................................. 130 1.2.5.1 Automatic Aerodrome Routine Meteorological Reports (METAR AUTO) ........................................................................... 130 1.2.5.2 Limited Weather Information System (LWIS) Reports ........................................................................................................... 131 1.2.6 Automatic (AUTO) Reports ....................................................................................................................................................... 131 1.2.7 Weather Services in Support of Approach Unicom (AU) ......................................................................................................... 131 1.2.8 Runway Visibility Assessment ................................................................................................................................................... 131 1.3 Meteorological Forecasts and Charts ........................................................................................................................................................ 131 1.3.1 Flight Information Centre (FIC) Hours of Service and Telephone Numbers ........................................................................... 131 1.3.2 World Area Forecast System (WAFS) Charts .......................................................................................................................... 132 1.3.3 Aerodrome Forecasts (TAFs) .................................................................................................................................................... 132 1.3.4 Aerodrome Advisory Forecasts ................................................................................................................................................. 132 1.3.5 Coastal Weather .......................................................................................................................................................................... 132 1.3.6 Graphic Area Forecasts (GFAs) and AIRMET .......................................................................................................................... 132 1.3.7 Upper Level Wind and Temperature Forecasts (FD) ................................................................................................................ 132 1.3.8 Air Traffic Control (ATC) Weather Assistance ........................................................................................................................ 132 1.3.9 Supplementary Information ...................................................................................................................................................... 133 1.3.9.1 Weather Radar ........................................................................................................................................................................... 133 1.3.9.2 ECCC/DND Weather Radar Network ........................................................................................................................................ 134 1.4 In-Flight Meteorological Information (VOLMET) .................................................................................................................................134 2.0 PILOT WEATHER REPORTS (PIREPs) ............................................................................................................ 134 2.1 General .........................................................................................................................................................................................................134 2.1.1 Pilot Weather Report (PIREP) Example .................................................................................................................................... 135 2.2 Clear Air Turbulence (CAT) ...................................................................................................................................................................... 135 2.2.1 General ........................................................................................................................................................................................ 135 2.2.2 Turbulence Reporting Criteria ..................................................................................................................................................