Page 10 - AFMAN 15-111, 12 MAR 2019

10 AFMAN15-111 12 MARCH 2019

Chapter 3

REPORTING AND ENCODING WEATHER OBSERVATIONS

3.1. Aviation Weather Code Forms. This chapter contains information and directive guidance
on reporting and encoding weather observations. In addition to prescribing basic observing
fundamentals and terms, this chapter establishes aviation code forms for recording and
disseminating METAR, SPECI, and LOCAL weather observations.
3.1.1. Aviation Routine Weather Report (METAR). A METAR is a routine scheduled
observation as well as the primary observation code used by the United States to satisfy
requirements for reporting surface meteorological data. METARs contain a complete report of
wind, visibility, runway visual range (RVR), present weather, sky condition, temperature, dew
point and altimeter setting collectively referred to as "the body of the observation." In addition,
encoded and/or plain language information that elaborates on data in the body of the
observation is appended in the METAR remarks (RMK) section. The contents of the remarks
vary according to the mode of operation (e.g., automated or augmented), and are defined in
each part of this manual.

3.1.1.1. WFs/Dets will operate with established METAR file times between 55 to 59
minutes past the hour. (T-2). When augmenting an FBWOS, the time ascribed to the
observation is based on the last observed element to the nearest minute.

3.1.1.2. METAR observations taken at 0000, 0600, 1200, and 1800 Coordinated Universal
Time (UTC) include additional data and are known as “6-hourly observations.” The
METAR observations taken at 0300, 0900, 1500, and 2100 UTC also contain additional
information and are known as “3-hourly observations.”
3.1.2. Aviation Selected Special Weather Report (SPECI). A SPECI is an unscheduled
observation completed and transmitted when any of the special criteria listed in Attachment
2 are observed or sensed. SPECIs contain all data elements found in a METAR plus additional
remarks that elaborate on data in the body of the observation. All SPECI reports will be
prepared and transmitted as soon as possible after the relevant criteria are observed. (T-2). The
time ascribed to a SPECI reflects the time, to the nearest minute, that the SPECI criteria are
first met or observed. For a METAR with SPECI criteria, the actual time ascribed to the
observation is +55 to +59 minutes past the hour (standard time of a METAR observation) when
the last element of an observation is recorded.

3.1.2.1. Base SPECI criteria on published take-off, landing, and circling airfield minima
(e.g., Instrument Landing System [ILS], Tactical Air Navigation system [TACAN]) and
other AF, higher headquarters, MAJCOM, Army and installation directives for all
approaches. (T-2).
3.1.2.2. Range criteria may take the place of the criteria in Attachment 2.

3.1.2.3. Units may supplement the criteria values in Attachment 2 with values from
Combatant Commander Instructions, manuals, or supplement relating to minima for take-
off, landing, visual flight rules (VFR), instrument flight rules (IFR) and alternates.