PRECIPITATION TOTAL.6RRRtR. The
RRR is the liquid equivalent of the precipitation amount
reported in hundreds, tens and units of millimeters
(exception: 990 is a trace, and codes 991 to 999 are used
to report tenths of a millimeter total precipitation from
0.1 to 0.9 respectively). And tR is the duration of the
reference period ending at the reporting time (WMO
code table 4019). Precipitation amounts observed in
inches may be converted to millimeters by multiplying
25.4 mm/inch. In WMO Regions IV and V, this group is
normally used to report 6-hour precipitation at each
synoptic observation with tR encoded 1, except the
0000Z report from U.S. stations in Region V reports 24-
hour precipitation with TV encoded 4.
WEATHER.7wwW1W2. The ww is the present
weather code (WMO code table 4677), and W1 and W2
are past weather codes (WMO code table 4561). See
PREDOMINANT CLOUD TYPE.
8NhCLCMCH. The Nh is the summation coverage of all
low etage clouds present, or, if no low clouds are
present, the summation of all the mid-etage cloud
coverage, in oktas of the sky covered (WMO code table
2700). CL is the predominant low-etage cloud type
(WMO code table 0513). CM is the predominant mid-
etage cloud type (WMO code table 0515). And CH is
the predominant high-etage cloud type (WMO code
OBSERVATION TIME.9GGgg. This group is
only encoded when the actual observation time (time
the last element in the observation was observed) differs
from the standard observation time (the synoptic or
intermediate synoptic hour) by 10 minutes or more. The
GG is the UTC hour, while the gg is the minutes of the
actual observation time.
What is the purpose of the Synoptic code?
What are the intermediate synoptic hours?
What is the primary reference manual used for
encoding land synoptic observations in the
What groups are included in the identification
section of a land synoptic observation?
How would iRiXhVV be encoded for a manned
station with no precipitation or significant
weather in the past 6 hours, a low overcast cloud
deck at 3,500 feet, and visibility at 7 miles?
How would a station with 6/8 total sky coverage
and a wind direction of 240° and a wind speed of
103 knots be encoded?
What do the sections 1SnTTT and 2SnTdTdTd
What do the sections 3POPOPOPO and 4PPPP
If the station pressure at 0300Z was 1020.6 hPa,
then increased to a high of 1021.5 hPa at 0400Z,
and is now 1019.8 hPa at 0600Z, how should the
group 5appp be encoded?
If a station received 1.2 mm of precipitation
between 0000Z and 0600Z, how should 6RRRtr
If a station had heavy snow showers at the time of
observation and rain showers and overcast
conditions in the previous 2 hours, how should
the group 7wwW1W2 be encoded?
If a station has no low clouds, 2/8 altocumulus
castellanus, 3/8 thin altostratus, and 3/8
cirrostratus not covering the whole sky and not
invading the celestial dome, how should the
group 8NhCLCH be encoded?
Regional Data Section
The regional data section, following the group 333,
includes both internationally established codes and
codes unique to each region.
WMO REGION IV STATE OF THE SKY IN
THE TROPICS.0CSDLDMDH. The CS is the cloud
state from FMH-2, table 6-4; while DL, DM, and DH are
the direction from which the low-, mid-, and high-etage
clouds, respectively, are moving (using the 8-point
compass, 1 = NE, 2 = E, and so forth; 0 is no movement,
and 9 is unknown). This group is only reported by
stations in the southern portion of WMO Region IV
within 310 statute miles of the seacoast during the
The TXTXTX is the maximum temperature in tens, units
and tenths of a degree Celsius. The time period is
specified by regional agreement; see table 3-6 for
WMO Region IV and V conventions.
The TnTnTn is the minimum temperature in tens, units,
and tenths of a degree Celsius.