JPATS Weather - NETC

JPATS AVIATION WEATHER BOOKLET
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
Group 3: Date Time Group and Report Modifier
Figure 6-4 — Station Identifier in METAR
The time of observation will be included in all reports, using the standard date time group (DTG)
format. Times are always given in Universal Coordinated Time (UTC) and therefore will end in
“Z,” indicating Zulu, or UTC, time. The first two numbers are the date, and the second four are
the time of the report (Figure 6-5).
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 6-5 — DTG in METAR
Manual METAR observations are required to be started no earlier than 15 minutes prior to the
reporting time, which is a window between 55 and 59 minutes past the hour. Additionally,
elements having the greatest rate of change are evaluated last. At automated stations, evaluations
are based on sensor data taken within 10 minutes of the report time (although sky cover data is
gathered over the preceding 30 minutes). Therefore, as an aviator, you can be assured you have
the most up-to-date information available, assuming you’re checking the weather at the top of
the hour.
Of course, report times given for SPECI observations are the time at which the event requiring
the SPECI report occurred.
Reports may also contain one of two modifiers, “COR,” or “AUTO,” which will appear after the
DTG:
COR — Indicates a CORrected report, which is transmitted as soon as possible whenever an
error is detected in a METAR or SPECI report. In this case, the DTG will be the same time used
in the report being corrected.
AUTO — Indicates a routine scheduled observation was sent from a fully AUTOmated station
with no human intervention. In the remarks section, either “AO1” or “AO2” will be present
indicating the type of automatic precipitation measuring equipment. Sometimes, manual
observations are reported using data gathered from automatic devices, in which case an “AO1”
or “AO2” will be present in the remarks without an “AUTO” following the DTG.
Group 4: Wind
Winds are a 2-minute average speed and direction report in knots and degrees true from which
direction the wind is blowing. The wind direction is first and will be in tens of degrees, using
three digits. Directions less than 100 degrees are preceded by a zero to supply three digits. Speed
is in whole knots, using two or three digits after the direction, without spaces, and speeds of less
than 10 knots are preceded with a zero. The wind group will always end with the letters “KT” to
indicate knots. Other countries may use different units of measurement, such as KM
(kilometers), MPH (miles per hour), or MPS (meters per second) (Figure 6-6).
6-4 Version 3.2/Dec 08