METARs TAFs Navigation Practical Meteorology and Practical Navigation

METARs, TAFs, Navigation Practical Meteorology and Practical Navigation Ref: FTGU Pages 158 -172, AIM MET Section

Review 1. What are the four air masses that affect Canada? 2. What is a Front? 3. What does a thunderstorm need in order to form?

Topics to be covered �Weather services and maps �How to read: �METARs/TAFs �Need to know this as interpretation of weather is crucial to aircraft safety.

METeorological Aviation Reports (METARs)

METARs �Aviation Routine Weather Report �Observation of the actual weather from the ground �Issued on the hour and valid only for the time taken �A SPECI is a special weather report that when a significant change in the weather has occurred �Each METAR and SPECI is composed of several standard groups �METAR CYKZ 202000 Z 33009 KT 15 SM FEW 020 BKN 091 M 01/M 06 A 2993 RMK SC 2 AC 3 SLP 144=

Format of METAR �Report type: �Location type: �Date/Time: �Report modifier: �Wind: �Visibility: �RVR: METAR or SPECI CYYZ (Toronto) 231700 Z -> 23 rd day at 1700 Zulu AUTO or CCA, CCB 00000 KT -> Calm 35009 KT -> 350°T @ 9 kts VRB 03 KT -> Variable @ 3 kts 30015 G 25 KT -> 300°T @ 15 gusting 25 kts 30015 G 25 KT 260 V 340 -> 300°T @ 15 gusting 25 kts, wind is varying from 260 true to 340 true 5/8 SM, 1 ½ SM, P 6 SM, 15 SM R 33/4000 FT/U -> Rwy 33, 4000’ increasing R 24 L/1000 V 1200 FT/D -> ?

Present Weather Codes Intensity or Proximity Descriptor �Precipitation intensity refers to all forms at the time combined �- ->Light (-RA = Light rain) �Moderate (no qualifier) �+ Heavy (+SN = Heavy snow) �VC = In the vicinity (within 5 SM) �MI = Shallow �BC = Patches �PR = Partial �DR = Drifting �BL = Blowing �SH = Showers �TS = Thunderstorms �FZ = Freezing

Present Weather Codes Precipitation Obscuration � DZ � RA � SN � SG � IC �BR = Mist (Vis ≥ 5/8 SM) �FG = Fog (Vis < 5/8 SM) �FU = Smoke (Vis ≤ 6 SM) �DU = Dust (Vis ≤ 6 SM) �SA = Sand (Vis ≤ 6 SM) �HZ = Haze (Vis ≤ 6 SM) �VA = Volcanic ash (Any vis) � PL � GR � GS � UP = Drizzle = Rain = Snow grains = Ice crystals (Vis ≤ 6 SM) = Ice pellets = Hail = Snow pellets = Unknown precipitation

Present Weather Codes Other �PO = Dust/sand whirls (dust devils) �SQ = Squalls �+FC = Tornado or waterspout �FC = Funnel cloud �SS = Sandstorm �DS = Duststorm

Sky Condition �SKC �FEW �SCT �BKN �OVC �CLR - “sky clear” - no cloud present - “few” - >0 to 2/8 oktas - “scattered” - 3/8 to 4/8 oktas - “broken” - 5/8 to <8/8 oktas - “overcast” - 8/8 oktas - “clear” - clear below 10, 000’ as interpreted by an autostation �Significant convective cloud (CB or TCU) are identified with the sky condition group SCT 025 TCU – Scattered TCUs at 2500’ �A ceiling is said to exist at the lowest BKN or OVC layer �All cloud heights are in AGL

�Temperature/Dewpoint: 10/05 – Temp: 10°C, Dewpoint: 05°C 05/M 01 – Temp: 05°C, Dewpoint: -1°C �Altimeter setting: A 2992 – 29. 92” Hg A 3031 – 30. 31” Hg �Recent weather: Significant weather �Wind shear: Low level windshear within 1600’ AGL along t/o or landing path or a specific runway “WS R 33 L”

Remarks �Include: �Cloud layer type and opacity in oktas (SF 5) �General weather remarks �Sea level pressure: SLP 134 = 1013. 4 h. Pa �SPECI CYEL 201958 Z 36010 KT 1 SM -SHSN OVC 008 RMK SF 8 WNDS ESTD= �METAR CYEL 201900 Z 36010 KT 15 SM -SHSN BKN 030 BKN 080 M 05/M 10 A 3003 RMK SC 6 AC 2 WNDS ESTD SLP 190=

Terminal Area Forecasts (TAFs)

Aerodrome Forecast (TAF) �Description of the most probable weather conditions with the most probable time of occurrence �Gives weather within 5 NM of the centre of the runways complex �Uses the same weather coding as the METAR, although forecast times are included �Altitudes in AGL �Degrees are given in True

TAF Format �Report type: TAF or TAF AMD �Location: CYYZ �Issue Date/Time: 281139 Z: 28 th day @ 1139 Zulu �Period of validity: 2812/2918 – Valid from 1200 Zulu on the 28 th to 1800 Zulu on the 29 th �TAF CYYU 201948 Z 2020/2108 30012 KT 3 SM -SN OVC 012 TEMPO 2020/2022 P 6 SM SCT 015 BKN 030 FM 202200 30010 KT P 6 SM SCT 015 BKN 030 TEMPO 2022/2108 4 SM –SHSN BKN 015 RMK NXT FCST BY 210200 Z=

TAF Format – Significant Weather �Uses the same format as the METAR �VC or ‘vicinity’ in a TAF means 5 – 10 NM �A maximum of 3 significant weather groups are allowed per forecast period �If one significant weather groups is forecast to change, all other that will exist will be indicated �CB layers will be identified with cloud groups (i. e. SCT 040 CB)

Change Groups �In all change groups, multiple elements are considered single entities �“SCT 030 BKN 050 OVC 080. . . change indicator. . . BKN 050” would mean that after the change indicator, there would only be a broken layer at 5000’ �FM – Permanent change (rapid) – All forecast conditions are superseded by this. FM 280945 30015 KT P 6 SM BKN 030

Change Groups �BECMG – Permanent change (gradual) – When the conditions evolve over a period of time (one to two hours) BECMG 2808/2809 OVC 030 � Any weather element not indicated as part of the BECMG group remains the same �TEMPO – Transitory change group – Temporary fluctuations in some or all weather elements during a specified period �TEMPO are only used if the condition is expected to last less then an hour, if more, than a time period would be given (i. e. TEMPO 2812/2815 1 SM RA BR) �PROB – Probability group – Probability of alternative weather values occurring (that are considered hazards to aviation) -> PROB 30 2817/2821 +TSRA

�TAF CYTS 201948 Z 2020/2108 33012 KT 11/2 SM -SHSN OVC 015 TEMPO 2020/2022 P 6 SM NSW OVC 020 FM 202200 33012 KT 6 SM -SN FEW 015 OVC 040 TEMPO 2022/2102 2 SM –SN OVC 015 FM 210200 31010 KT P 6 SM SCT 020 BKN 030 TEMPO 2102/2108 4 SM -SHSN BKN 020 RMK NXT FCST BY 210200 Z= �TAF CYTL 201948 Z 2020/2108 33015 KT P 6 SM SCT 015 OVC 025 TEMPO 2020/2108 2 SM -SHSN BKN 015 OVC 030 BECMG 2102/2104 31012 KT RMK FCST BASED ON AUTO OBS. NXT FCST BY 210200 Z=

Summary �Topics covered today: �How to read: � METARs/TAFs �Next class will be Navigation