National Code Groups
All data in section 5 after the 555 indicator is in
National code forms. In WMO Region IV, U.S.
National Weather Service stations report certain
information in this section on record temperatures,
coastal tides, and coastal or lake water temperatures.
The specific codes used are contained in FMH-2. Navy
and Marine Corps stations do not use these codes.
Canada and Mexico report different national codes, as
may each country in Region V. Now let’s look at the
ship synoptic code.
REVIEW QUESTIONS
Q44. What information follows the 333 indicator
group?
Q45. When should the 24-hour maximum and
minimum temperatures be reported in WMO
region IV?
Q46. When is the 58p24p24p24 group used?
Q47. What information follows the 555 indicator
group?
SHIP SYNOPTIC CODE
The ship Synoptic code (WMO code FM 13-XI
SHIP) is used aboard U.S. Naval ships to report weather
as observed and recorded in the METAR/SPECI code.
The ship synoptic report is encoded on the bottom
portion of the ship observation form. Internationally,
the code is used to disseminate meteorological data
from nearly all ships that observe weather conditions.
Table 3-7 shows the symbolic format of the ship
Synoptic code. Many of the data groups are the same as
the land Synoptic code, especially in data section 1. The
ship Synoptic code uses different environmental data in
data section 2, "Maritime Data," not generally used by
shore stations. While some countries may use selected
groups from data section 3 as identified in the land
synoptic report, U.S. Naval vessels currently do not
carry the equipment required to take the appropriate
measurements, and likewise, do not report total
precipitation (6RRRtR).
Identification Data
The identification data in the ship Synoptic code
contains the message type identifier BBXX, the ship’s
International Radio Call Sign, the date-time group, and
the latitude and longitude of the ship.
INTERNATIONAL RADIO CALL SIGN.—
DDDD. The ship’s four-letter International Radio Call
Sign (IRCS) is used as identification for the station.
Converting the IRCS to the ship’s name and country of
registration may be done by using Allied
Communication Publication 100 (ACP-100), Allied
Call Sign and Address Group System - Instructions and
Assignments. The group may consist of as few as three
or as many as six letters or letter-number combinations,
or may use the word SHIP for any ship, or RIGG for a
stationary (oil) platform.
DATE-TIME GROUP.—YYGGiW. Same as for
land Synoptic code.
LATITUDE/LONGITUDE.— 9 9 La La La a n d
QCLOLOLOLO. The 99 is an indicator for latitude, and
LaLaLa is the latitude in degrees and tenths of a degree
(the minutes divided by 60 yields tenths of a degree).
The first value in the longitude group, QC, is the
quadrant of the globe (WMO code table 3333). (In
relation to the equator and the prime meridian, quadrant
1 is north and east, 3 is south and east, 5 is south and
west, and 7 is north and west.) And LOLOLOLO is the
hundreds, tens, units, and tenths of degrees longitude.
International Data Section
All of the data in the International Data Section,
Section 1 of the code, is exactly the same as the land
Synoptic code. However, since most ships do not carry
rain-measuring equipment, the rainfall group, 6RRRtR,
is normally omitted from reports, and the associated
indicator, iR, is reported as 4.
Table 3-7.—Symbolic Format of Ship Synoptic Weather Observation Report (WMO Code FM 13-XI SHIP)
BBXX DDDD YYGGiW 99LaLaLa QCLOLOLOLO iRiXhVV Nddff (00fff) 1SnTTT 2SnTdTdTd
4PPPP 5appp (6RRRtR) 7wwW1W2 8NhCLCMCH 9GGgg 222DSvS 0SSTWTWTW
(1PwaPwaHwaHwa) 2PWPWHWHW 3dw1dw1dw2dw2 4Pw1Pw1Hw1Hw1 5Pw2Pw2Hw2Hw2 (70HwaHwa)Hwa) 6IsEsEsRs
8SwTbTbTb ICE ciSibiDiZi (or plain language);
3-16
