00000nas 2200000za 4500 9.838231 CaOODSP 20221107151330 cr ||||||||||| 170614d20172019qucgr p o||||f0 a0eng|d 2291-2886 CaOODSP eng n-cn--- En58-20E-PDF Observer circular [electronic resource]. [Gatineau, QC] : Environment and Climate Change Canada, [2017]-[2019] Twice a year Began with: OBS 2-2017 (April 27, 2017); ceased with OBS4-2018. Issued also in French under title: Circulaire d’observation. "Effective February 2019, coinciding with the publication of MANOBS 8th Edition, Observer Circulars are no longer issued by Environment and Climate Change Canada" -- https://www.canada.ca/en/environment-climate-change/services/weather-manuals-documentation.html#Cir . Observer circulars provide instructions concerning new or revised observing procedures and/or new equipment and provide temporary interim instructions. Observer circulars supplement the current edition and amendment of the Manual of Surface Weather Observations (MANOBS) and are incorporated in subsequent editions or amendments. https://www.ec.gc.ca/meteo-weather/default.asp?lang=En&n=A85A01B3-1 gccst Civil aviation gccst Weather forcasts Canada. Environment and Climate Change Canada. Circulaire d’observation (CaOODSP)9.838233