JPATS Weather - NETC

JPATS AVIATION WEATHER BOOKLET
Examples:
1 ⅛ SM — Visibility one and one-eighth statute miles.
5SM — Visibility five statute miles.
M1/4 — Visibility from an automated station less than one-quarter statute mile.
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 4 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 2 9 0 5/8 1 5/8 4 12
1/4 2 1/2 10 1/16 ¾ 1 3/4 5 13
1/2 3 1/8 7/8 1 7/8 6 14
3/4 4 3/16 1 2 7 15
1 5 1/4 1 1/8 2 1/4 8 20
1 1/4 6 5/16 1 1/4 2 1/2 9 25
1 1/2 7 3/8 1 3/8 2 3/4 10 30
1 3/4 8 1/2 1 1/2 3 11 35 a
a. Further values in increments of 5 statute miles may be reported (i.e., 40, 45, 50, etc.)
Table 6-1 — Visibility Values Reportable in METAR
Group 6: Runway Visual Range
The runway visual range (RVR), defined in Chapter 5, 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 1 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 6-8).
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 6-8 — RVR in METAR
RVR is encoded with an “R” indicating runway, followed by a 2-digit group denoting runway
number, and may be followed by an “R,” “L,” or “C,” denoting right, left, or center runway.
Next is a forward slash followed by the constant reportable value in four digits and ending with
the letters “FT” for feet.
6-6 Version 3.2/Dec 08