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Aeronautical Information Manual (AIM), page 503

Index   502 -- Page 503 -- 504

5/26/16
12/10/15                                                                                                        AIM


FIG 7-1-20 Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR) (Back) Key to Aerodrome Forecast (TAF) and Aviation Routine Weather Report (METAR) (Back) In METAR, ReMarK indicator & remarks. For example: Sea- Level RMK SLP045 Pressure in hectoPascals & tenths, as shown: 1004.5 hPa; Temp/dew- T01820159 point in tenths °C, as shown: temp. 18.2°C, dew-point 15.9°C FM091930 FroM: changes are expected at: 2-digit date, 2-digit hour, and 2-digit minute beginning time: indicates significant change. Each FM starts on a new line, indented 5 spaces TEMPO TEMPOrary: changes expected for <1 hour and in total, < half of the 0920/0922 period between the 2-digit date and 2-digit hour beginning, and 2-digit date and 2-digit hour ending time PROB30 PROBability and 2-digit percent (30 or 40): probable condition in the 1004/1007 period between the 2-digit date & 2-digit hour beginning time, and the 2-digit date and 2-digit hour ending time BECMG BECoMinG: change expected in the period between the 2-digit date and 1013/1015 2-digit hour beginning time, and the 2-digit date and 2-digit hour ending time Table of Significant Present, Forecast and Recent Weather - Grouped in categories and used in the order listed below; or as needed in TAF, No Significant Weather. Qualifiers Intensity or Proximity "-" = Light No sign = Moderate "+" = Heavy "VC" = Vicinity, but not at aerodrome. In the US METAR, 5 to 10 SM from the point of observation. In the US TAF, 5 to 10 SM from the center of the runway complex. Elsewhere, within 8000m. Descriptor BC – Patches BL – Blowing DR – Drifting FZ – Freezing MI – Shallow PR – Partial SH – Showers TS – Thunderstorm Weather Phenomena Precipitation DZ – Drizzle GR – Hail GS – Small Hail/Snow Pellets IC – Ice Crystals PL – Ice Pellets RA – Rain SG – Snow Grains SN – Snow UP – Unknown Precipitation in automated observations Obscuration BR – Mist (≥5/8SM) DU – Widespread Dust FG – Fog (<5/8SM) FU – Smoke HZ – Haze PY – Spray SA – Sand VA – Volcanic Ash Other DS – Dust Storm FC – Funnel Cloud +FC – Tornado or Waterspout PO – Well developed dust or sand whirls SQ – Squall SS – Sandstorm - Explanations in parentheses "()" indicate different worldwide practices. - Ceiling is not specified; defined as the lowest broken or overcast layer, or the vertical visibility. - NWS TAFs exclude BECMG groups and temperature forecasts, NWS TAFS do not use PROB in the first 9 hours of a TAF; NWS METARs exclude trend forecasts. US Military TAFs include Turbulence and Icing groups. Meteorology 7-1-59

Page 503 of the Aeronautical Information Manual (AIM.pdf)
AIM: Official Guide to Basic Flight Information and ATC Procedures

Index   502 -- Page 503 -- 504