Figure 1-8. Visibility Values Reportable in METAR

CHAPTER ONE

METEOROLOGY FLIGHT PLANNING

NOTE:

Other types of visibility are reported in the RMK portion of the

METAR/SPECI (see the remarks section later in this chapter). At

military stations tower visibility will be reported when either

surface or tower visibility is four miles or less. This visibility will

be a remark with the surface visibility remaining in the body of the

report.

Source of Visibility Report

Automated

Manual

M1/4

5/8

1 5/8

1/4

2 1/2

1/16

3/4

1 3/4

1/2

1/8

7/8

1 7/8

3/4

3/16

1/4

1 1/8

2 1/4

1 1/4

5/16

1 1/4

2 1/2

1 1/2

3/8

1 3/8

2 3/4

1 3/4

1/2

1 1/2

35a

a. Further values in increments of 5 statute miles may be reported (i.e., 40, 45, 50, etc.)

Figure 1-8 Visibility Values Reportable in METAR

Group 6: Runway Visual Range (RVR)

The runway visual range (RVR), defined in Chapter Five, is a measure of the horizontal visibility

as determined from instruments (transmissometers) located alongside and about 14 feet higher

than runway centerline. They are calibrated with reference to the sighting of either high-intensity

runway lights or the visual contrasts of other targets, whichever yields the greater visual range.

Only activities with operational equipment are allowed to report RVR.

RVR is reported whenever the prevailing visibility is one statute mile or less and/or the RVR for

the designated instrument runway is 6000 feet or less. RVR is measured in increments of

200 feet through 3000 feet and in 500-foot increments above 3000 feet (Figure 1-9).

1-8 AVIATION ROUTINE WEATHER REPORTS AND TERMINAL AERODROME

FORECASTS