Group 9: Temperature/Dew Point

CHAPTER ONE

METEOROLOGY FLIGHT PLANNING

4. When the sky is partially obscured by a surface-based obscuration, the amount of the sky

cover hidden by the weather phenomena will be reported s FEW000, SCT000, or BKN000. A

remark will then also be given to describe these details (see Remarks section).

At manual stations CB (cumulonimbus) or TCU (towering cumulus) will be appended to

the layer if it can be determined.

Examples:

BKN000 -- Partial obscuration of 5/8 to 7/8 (surface-based).

VV008 -- Sky obscured, indefinite ceiling, vertical visibility 800 feet AGL.

SCT020CB -- Scattered clouds (3/8 to 4/8 of the sky) at 2000 feet AGL composed of

FEW011 BKN040 OVC120 -- Few clouds (1/8 to 2/8) at 1100 feet AGL, broken clouds

(5/8 to 7/8) at 4000 AGL, overcast clouds (8/8) at 12,000 feet AGL.

Group 9: Temperature/Dew Point

Temperature and dew point are reported as two 2-digit groups, rounded to the nearest whole

degree Celsius, and separated with a (/) (Figure 1-14). Sub-zero temperatures or dew points will

be prefixed with the letter "M" (for Minus). If the temperature and dew point are not available,

the entire group is omitted. If only dew point is unavailable, then only temperature is coded,

followed by the (/).

METAR KNPA 082255Z 27004KT 7/8SM R04/4500FT DZ FG SCT000 BKN011 OVC380

19/18 A2997 RMK VIS1/2V1 CIG009V013 FG SCT000 BKN TOPS 027

SLP149

Figure 1-14 Temperature and Dew Point in METAR

If necessary, convert between Fahrenheit and Celsius using the following formulas:

F = (C * 9/5) +32

C = (F - 32) * 5/9

(9/5 = 1.8)

or by using the conversion scale on the CR-2 circular slide rule.

Group 10: Altimeter Setting

The altimeter setting will be included in all reports. The altimeter group always starts with the

letter "A", and will be followed with a 4-digit group using the tens, units, tenths, and hundredths

of inches of mercury. For example, A2997 indicates an altimeter setting of 29.97 inches of Hg

(Figure 1-15).

1-12 AVIATION ROUTINE WEATHER REPORTS AND TERMINAL AERODROME

FORECASTS