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AIM

10/12/17

7

−1−61

Meteorology

FIG 7

−1−22

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
Pressure in hectoPascals & tenths, as shown: 1004.5 hPa; Temp/dew-
point in tenths  

°C, as shown: temp. 18.2°C, dew-point 15.9°C

RMK SLP045
T01820159

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
0920/0922

TEMPOrary: changes expected for <1 hour and in total, < half of the
period between the 2-digit date and 2-digit hour beginning, and 2-digit
date and 2-digit hour ending time

PROB30
1004/1007

PROBability and 2-digit percent (30 or 40): probable condition in the
period between  the 2-digit date & 2-digit hour beginning time, and the
2-digit date and 2-digit hour ending time

BECMG
1013/1015

BECoMinG: change expected in the period between the 2-digit date and
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.