CHAPTER 3
AVIATION WEATHER CODES
INTRODUCTION
In this chapter we will discuss two meteorological
codes routinely encountered by Aerographers,
particularly at shore-based commands. The first code
we will discuss is the Terminal Aerodrome Forecast
(TAF) code. You must be able recognize the various
elements that make up this code because you may be
tasked with preparing a TAF for dissemination. The
second code we will discuss is the Pilot Weather Report
(PIREP) code. This code details in-flight weather
conditions reported directly from aircraft via pilot-to-
metro service (PMSV) radio. The meteorological
information received must then be encoded for
electronic transmission to data collection centers.
TERMINAL AERODROME FORECAST
(TAF) CODE
LEARNING OBJECTIVES: Identify the
primary reference publication concerning the
Terminal Aerodrome Forecast (TAF) code.
Identify when TAFs should be transmitted.
Describe the format, elements, and
abbreviations used in the TAF code. Explain
the requirements for amending TAFs.
The Terminal Aerodrome Forecast (TAF) code
provides information about the expected weather con-
ditions that will occur at your airfield or station control
zone. Only certified forecasters are authorized to write
TAFs. However, as the observer, you will often be
tasked to prepare the latest TAF for transmission locally
and over longline. The TAF code is presented here so
you will be able to recognize the various elements of the
code and be able to spot encoding errors if they occur.
TAF FORMAT
The WMO Meteorological code FM51-X is used
internationally as the standard TAF format.
NAVMETOCCOMINST 3143.1 is the governing
instruction for using the TAF code for all U.S. Navy and
Marine Corps weather activities. It is identical to the
WMO TAF code with only minor differences.
TAFs are transmitted at 6-hour intervals at 0300,
0900, 1500, and 2100 UTC, and have valid periods of
24 hours. The complete TAF format is shown in table
3-1 and is explained in the following sections.
The symbolic indicator CCCC is the ICAO
location identifier followed by "TAF," and then the
valid forecast period day and time (Y1Y1G1G1G2G2).
Example:
KNGU TAF 230909 is the aerodrome
forecast for Norfolk, Virginia, valid for 24 hours from
the 23rd 0900 UTC to the 24th 0900 UTC.
Table 3-1.—TAF Code Format and Sample
CCCC TAF (AMD or COR or RTD) Y1Y1G1G1G2G2 dddffGfmfmKT VVVV
w'w' NsNsNshshshs or SKC or VVhshshs (WSHwshwshws/dddffKT or
WSCONDS) (6IchihihitL) (5BhbhbhbtL) QNHP1P1P1INS (Remarks)
(TTTTT GGGeGe/TTGGGG) (TTFTF/GFGFZ) AMD or COR GGGG)
KNGU TAF 210909 23012KT 4800 -SN BKN005 OVC012 620107
QNH3002INS
TEMPO 0914 0800 +SNRA -BLSN VV002
BECMG 0506 33018KT 510804 QNH3015INS T01/15Z
3-1
