AFMAN15-111 Weather Observation Reporting & Encoding PDF

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...

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. AFMAN15-111 12 MARCH 2019 11 3.1.3. Aviation Selected Local Weather Report (LOCAL). A LOCAL is an unscheduled observation, reported to the nearest minute, not meeting SPECI criteria. LOCALs are only taken when unit leadership determines there is a requirement in support of local operations. 3.1.3.1. LOCALs taken in support of aircraft operations are encoded in METAR format. For LOCALs taken and disseminated to agencies other than ATC, the contents are established locally and documented in base/host unit support plans, local weather support agreements or standard operating procedures. 3.1.3.2. Altimeter setting (ALSTG) LOCALs are single element observations that contain the time and ALSTG. When ATC does not have access to real-time ALSTGs, WFs/Dets will disseminate an ALSTG LOCAL observation at an interval not to exceed 35 minutes when there has been a change of 0.01 inches of mercury (iHg) (0.3 hectopascals [hPa]) or more since the last disseminated ALSTG value. (T-1). Note: A METAR or SPECI taken within the established time interval fulfills this requirement. 3.2. METAR/SPECI Code Format. The METAR/SPECI report has two major sections: the Body and the Remarks. Figure 3.1 contains the METAR/SPECI code, format and contents of the Body and Remarks sections of an observation. Together, the body and remarks make up the complete METAR/SPECI coded report and are encoded in the order shown in Figure 3.1. The underline character "_" indicates a required space between the groups. The actual content of the report depends on the observation program at the individual observing organization. Note: Proper encoding of individual elements can be found in their respective chapters. 12 AFMAN15-111 12 MARCH 2019 Figure 3.1. Automated/Augmented METAR/SPECI Code. _CCCC_YYGGggZ_COR or AUTO_dddff(f)Gfmfm (fm)KT_dndndnVdxdxdx_ VVVVVSM or VVVV_RDRDR[DR]/VRVRVRVRFT, RDRDR[DR]/ METAR VNVNVNVNVVXVXVXVXFT, or RDRDR[DR]/VRVRVRVR, or RDRDR[DR]/VNVNVNVNVVXVXVXVX_w'w'_NsNsNshshshs or VVhshshs or SPECI CLR_T'T'/T'dT'd_APHPHPHPH_RMK_(Automated, Manual, Plain Language)_(Additive Data and Automated Maintenance Indicators) Body of Report (1) Type of Report - METAR or SPECI (2) Station Identifier - CCCC (3) Date and Time of Report - YYGGggZ (4) Report Modifier - COR or AUTO (5) Wind - dddff(f)Gfmfm(fm)KT_dndndnVdxdxdx (6) Visibility - VVVVVSM (or VVVV) (7) Runway Visual Range - RDRDR[DR]//VRVRVRVRFT or RDRDR[DR]/VNVNVNVNVVXVXVXVXFT (or m) (8) Present Weather - w'w' (9) Sky Condition - NsNsNshshshs or VVhshshs or CLR (10) Temperature and Dew Point - T'T'/T'dT'd (11) Altimeter - APHPHPHPH Remarks Section of Report—RMK (1) Automated, Manual and Plain Language (2) Additive and Maintenance Data 3.3. Coding METAR or SPECI Reports. 3.3.1. Type of Report (METAR or SPECI). The type of report, METAR or SPECI, is included in all reports. When SPECI criteria are met during the scheduled time of a routine report, the type of report will be a METAR. (T-0). 3.3.2. Station Identifier (CCCC). The observing location identifier, CCCC, is included in all reports. The observing location identifier consists of four alphanumeric characters typically representative of the airfield identifier according to the ICAO. A list of approved identifiers can be found in the FAA Order JO 7350 Series, Location Identifiers. Temporary and/or supplemental observation identifiers provided by the U.S. military beginning with “KQ” are coordinated IAW this publication. 3.3.3. Date and Time of Report (YYGGggZ). The date, YY, and time, GGgg, are included in all reports. The time is the actual time the report is transmitted longline or when the criteria for a SPECI is met or noted. If the report is a correction (COR) to a previously disseminated report, the time of the corrected report will use the same time as the report being corrected. The date and time group always ends with a "Z", indicating the use of UTC. For example, METAR KGRF 210855Z would be the 0900 scheduled report from KGRF taken at 0855 UTC on the 21st of the month. (T-0). 3.3.4. Report Modifier (AUTO or COR). The observation report modifier can be either COR or AUTO. AFMAN15-111 12 MARCH 2019 13 3.3.4.1. COR is entered into the report modifier group when a corrected METAR or SPECI is transmitted. 3.3.4.2. AUTO identifies the report as a fully automated report with no human intervention. AUTO is automatically included in reports when the weather technician signs off the automated dissemination system (ADS) indicating the observations are no longer being augmented. 3.3.4.3. AUTO and COR will not be seen in the same observation. If the term COR is used, the observation cannot be reported as AUTO, since a weather technician is manually correcting the observation. (T-0). 3.4. Coding Missing Data in METAR and SPECI Reports. When an element does not occur, or cannot be observed, the corresponding group and preceding space are omitted from that particular report. When a FBWOS cannot provide an element due to sensor failure, the software will automatically place a missing data flag (M) in the corresponding data field. The system will also include the maintenance indicator ($) at the end of the observation. Together, these two characters will cue the weather technicians to contact ATC agencies and maintenance personnel and begin back-up procedures. 3.5. Remarks (RMK). Remarks, found in Attachment 3, generally elaborate on parameters reported in the body of the report, and will be included in all METAR and SPECI observations if required. Remarks will be separated from the altimeter group by a space and the contraction RMK. If there are no remarks, the contraction RMK will not be entered. (T-0). 3.5.1. METAR/SPECI remarks fall into 2 major categories: (1) Automated and Augmented; and (2) Additive and Maintenance Data. Attachment 3 gives an overview of remarks and their order of entry. 3.5.2. Remarks will be made IAW the following: (T-0). 3.5.2.1. Use of Contractions and Abbreviations. Where plain language is called for, authorized contractions, abbreviations and symbols will be used to conserve time and space. However, in no case should an essential remark be omitted for the lack of readily available contractions. In such cases, the only requirement is that the remark be clear. For a detailed list of authorized contractions, see the list of abbreviations and acronyms in Attachment 1 and FAA Order JO 7340 Series, Contractions. 3.5.2.2. Time Entries in Remarks. Use UTC minutes past the hour if the time reported occurs during the same hour the observation is taken. UTC hours and minutes are used if the hour is different from the hour of the observation or this manual prescribes the use of hour and minutes. 3.5.2.3. Additive data will be reported at 0000, 0600, 1200, and 1800 UTC. When applicable, augment these reports with snow depth during controlled airfield hours. There is no requirement to augment/back-up additive data outside controlled airfield hours. (T-0). 14 AFMAN15-111 12 MARCH 2019 3.5.2.4. Location Entries. Phenomena encoded in the body of the report as vicinity (VC) may be further described (e.g., direction from the observing location) in the remarks. Phenomena occurring beyond, or thought to be beyond, 10 statute miles (SM) of the point of observation may be reported as distant (DSNT) followed by the direction from the observing location. If known, the distance may be included in the remark. In the case of a tornado, the exact location should be included when possible. 3.5.2.5. Movement Entries. Movement of clouds or weather, if known, will be encoded with respect towards the direction the phenomenon is moving. (T-0). For example, a thunderstorm 9SM north moving toward the northeast would be encoded as “TS 9N MOV NE.” 3.5.2.6. Direction. Directions will use the eight points of the compass encoded in a clockwise order beginning with north. (T-0). In the event that the reported phenomena is north but also extends northwest and northeast, record the phenomena in a clockwise direction (e.g., TS 10NW-NE). 3.6. Observation Methods. 3.6.1. Automated Observations. FBWOSs use time averaging of sensor data. Sky condition is an evaluation of sensor data gathered during the 30-minute period ending at the actual time of the observation. All other elements evaluated are based on sensor data that is within 10 minutes or less of the actual time of the observation. For objective elements such as pressure, temperature, dew point, and wind, automated and augmented observations use a fixed location and time-averaging technique. For subjective elements such as sky condition, visibility, and present weather, a FBWOS uses a fixed location, time-linear technique. Some FBWOSs are capable of generating an observation every minute; the One-Minute Observation (OMO) is encoded in METAR format and includes all of the basic weather parameters found in the body of the METAR plus specific automated remarks. The OMO also accepts augmented elements and remarks. The difference between the OMO and the METAR/SPECI is that the OMO is not normally disseminated. The weather technician can manually disseminate the OMO if required, for example, upon arrival at an AOL. 3.6.2. Augmented Observations. A fixed time, spatial averaging technique is used to evaluate subjective elements (i.e. sky condition, visibility, etc.) in augmented observations. Individual elements entered must reflect conditions existing at the actual time of observation. Observation of elements will be made as close to the scheduled time of the observation as possible to meet filing deadlines, but in no case will these observations be started more than 15 minutes before the scheduled time. (T-1). Supplement elements evaluated instrumentally with visual observations to ensure accuracy. 3.6.2.1. Order of Observing. Elements having the greatest rate of change are evaluated last. When conditions are relatively unchanging, evaluate outdoor elements first, followed by indoor elements with pressure being last. 3.6.2.2. Before taking observations at night, spend as much time as practicable outside to allow your eyes to adjust to lower light conditions. AFMAN15-111 12 MARCH 2019 15 3.7. Magnetic Declination. The local magnetic declination must be determined at each observing location to convert wind direction from magnetic to true. (T-1). Obtain local magnetic declination from the installation’s DoD FLIPs or the Tactical Plotting Chart for your area, whichever is most current, or the National Oceanographic and Atmospheric Administration National Centers for Environmental Information website located at http://www.ngdc.noaa.gov/geomag-web/#declination. Local declination changes by several minutes of arc each year at most locations. Weather leadership must monitor FLIPs or revised charts for changes in local magnetic declination. (T-1). Shifts in declination may affect the orientation of the wind equipment; therefore, keep maintenance personnel informed of changes. 3.7.1. From magnetic to true: add easterly declination to magnetic direction and subtract westerly declination from magnetic direction. 3.7.2. From true to magnetic: add westerly declination to true direction and subtract easterly declination from true direction. 3.8. Unofficial Weather Reports. Unofficial weather reports are defined as a report of one or more weather elements from an individual who is not task certified to take official weather observations (e.g., a pilot or law enforcement official). Unofficial reports can provide additional and supplemental information that may be important to local aviation and public safety. They can also help increase the WFs/Dets situational awareness. Unofficial reports of severe weather from credible sources within 10 SM will be reported by weather personnel in the remarks section of the observation IAW Attachment 3 and disseminated longline and locally during augmentation of an FBWOS. (T-2) 3.9. Modes of Observation. For meteorological observations the ‘point of observation’ is defined as the designated spot where the elements of an observation are viewed and/or sensed. The point of observation is within 5 SM (8000 m) of the airfield and affords as clear a view as possible of the runway complex. If necessary as an exception, the point of observation may be located further than 5 SM from the airfield but will be documented in the weather support plan and FLIP. (T-2). 3.9.1. Automated observations. The point of observation is the location(s) of the primary sensor group and the discontinuity sensor group. If the primary sensor group or the discontinuity sensor group is moved or a site survey shows the reported location information to be in error, the updated latitude, longitude, and elevation are provided in the station information file. 3.9.2. Augmented/Manual observations. The point(s) of observation will be the location of the primary and discontinuity (when available) sensor group(s) for objective elements and the designated point of observation used by WF/Det personnel to evaluate subjective elements and back-up sensed objective elements as needed. (T-2). 3.10. Rounding of Figures and Values. Except where otherwise directed in this AFMAN, round figures and values to the nearest reportable value as follows (round half up method): If the fractional part of a positive number to be dropped is equal to or greater than one-half, the preceding digit shall be increased by one. If the fractional part of a negative number to be dropped is greater than one-half, the preceding digit shall be decreased by one. In all other cases, the preceding digit shall remain unchanged. Example: 1.5 becomes 2, -1.4 becomes -1, 1.3 becomes 1, and -2.6 becomes -3. 16 AFMAN15-111 12 MARCH 2019 3.10.1. When cloud height and visibility values are less than or equal to halfway between two reportable values, report the lower value; otherwise, report the next higher value. Example: cloud heights of 2,549 feet (ft) and 2,550 ft are reported as 2,500 ft and visibility values of 5 1/4 SM (8250 m) and 5 1/2 SM (8500 m) are reported as 5 SM (8000 m). 3.10.2. When computations of pressure values require that a number be rounded to comply with standards of reportable values, the number is always rounded down to the next reportable value. Example: A station pressure reading of 29.249 is rounded down to 29.245 and 29.244 is rounded down to 29.240. An ALSTG of 29.249 and 29.244 are both truncated to 29.24. 3.10.3. ALSTGs provided for international aviation purposes and reported in hPa are always rounded down and reported as whole numbers. Example: 1009.9 hPa and 1009.1 hPa are both truncated to 1009 hPa. 3.11. Dissemination. Most WFs/Dets use an ADS as the primary local and longline dissemination system. During periods when the ADS is unavailable use AF Weather-Web Service (AFW-WEBS), the OWS or another WF/Det to disseminate observations longline. Figure 3.2 contains example METAR/SPECI augmented observations. 3.11.1. Pressure altitude (PA) and density altitude (DA) are disseminated locally. When required, disseminate PA (e.g., PA +130) or DA (e.g., DA +3680) following the last element or remark in the observation, with the exception of runway condition remarks which are reported last. 3.11.2. Corrections (COR) to Transmitted Data. Disseminate CORs in the same manner as the observation being corrected as soon as possible whenever an error is detected in a transmitted report. However, if the erroneous data has been corrected or superseded by a later report (with the same or more complete dissemination), do not transmit the corrected observation. Transmitted corrections will consist of the entire corrected observation. Use the original date and time of the observation as the date and time in the COR'd observation. See Attachment 3. (T-0). AFMAN15-111 12 MARCH 2019 17 Figure 3.2. Examples of Augmented Longline Dissemination of METARs/SPECIs. Augmented METAR Observations METAR ETAR 010756Z VRB06KT 1400 R09/1220 -RA BR FEW000 SCT008 OVC012 01/M01 A2938 RMK AO2A TWR VIS 1600 VIS N 3200 CIG 010V015 BR FEW000 SLPNO ALSTG ESTMD; METAR ETAR 011058Z COR 02010G17KT 1400 R36/4000 HZ SCT007 BKN020 OVC070 20/17 A3019 RMK AO2A SLP015 ALSTG/SLP ESTMD COR 1104; METAR KHLN 011158Z 27004KT 3/4SM R32/P6000FT -RA BR FEW000 SCT005 OVC020 00/M01 A2992 RMK AO2A TWR VIS 2 BR FEW000 SLP982 ALSTG/SLP ESTMD 60010 70100 4/002 10010 21002 52010; METAR EOIN 011157Z 30003KT 9999 CLR M04/M10 A3003 RMK AO2A SLP985 70010 4/002; METAR RKTG 010358Z 00000KT 0800 FG VV011 24/24 A2998 RMK AO2A TWR VIS 1000 SLP982 RVRNO; METAR ETAB 010655Z 24010G18KT 9999 TS SCT020CB BKN035 30/27 A2993 RMK AO2A TS 4SW MOV NE SLPNO; METAR KGRF 011157Z 24012KT 10SM -TSRA FEW008 FEW025TCU SCT030CB 25/17 A2992 RMK AO2A PK WND 28045/10 TS 2NE MOV SE FU FEW008 SCT030 V BKN TCU SE-S SLPNO 60010 70010 52010; Augmented SPECI Observations SPECI ETAR 010731Z 25003KT 1600 BR BKN006 10/06 A3002 RMK AO2A CIG 004V008 RVRNO; SPECI RJFA 011614Z 02005KT 0600 R36/2400 -DZ FG SCT000 SCT006 SCT016 02/M03 A2981 RMK AO2A TWR VIS 1000 VIS 0400V0800 FG SCT000; SPECI KFAW 010812Z 24020G40KT 1 1/2SM +FC +TSRAGR SQ FEW030CB SCT040 BKN050 25/22 A2992 RMK TORNADO 3SW MOV NE FUNNEL CLOUD B02E09 3W MOV NE AO2A TWR VIS 2 1/2 VIS SW 2 TSB59 TS 5S-3W MOV NE GR 1/2 PRESFR; 3.11.3. Local Dissemination. During ADS outages or if ADS is not available, disseminate observations to ATC first. For further dissemination, establish procedures locally in an order of priority that is consistent with local requirements and scheduled file times for longline transmission. Coordinate local dissemination procedures to include code form, format and content with local customers and document in the local weather documentation. Locations without an ADS should disseminate observations locally as follows: 3.11.3.1. Disseminate wind direction in degrees magnetic (unless otherwise specified, see Chapter 7) using three digits. 3.11.3.2. Disseminate all other plain language remarks as required by local agencies after the last element of the observation. 3.11.3.3. Maintain a copy of all observations disseminated locally. 18 AFMAN15-111 12 MARCH 2019 3.11.4. Voice Dissemination. Maintain instructions outlining priorities and procedures to follow for local dissemination of observations by voice relay (e.g., read back by the person receiving the data). Disseminate all observations immediately to local ATC agencies (e.g., tower, Radar Approach Control, Ground Control Approach), then to other users as established locally. Also maintain a record (written or recording) of all the following when voice is used to disseminate locally during outages of the primary system: 3.11.4.1. Actual time of observation (UTC). 3.11.4.2. Time (in minutes past the hour) the observation was transmitted to the tower and other local ATC agencies. 3.11.4.3. Single element LOCALs for Altimeter setting, PA or DA (where required). 3.11.4.4. Initials of the weather technician making the dissemination and the initials of the receiver at the supported agency. 3.11.5. Supplementary Identification of Observations. At limited-duty manual WFs/Dets and gunnery ranges, identify the last observation of the day (METAR or SPECI) by adding the term "LAST" following the last element in the observation text (e.g., TCU SE LAST), and include the remark on the AF Form 3803/JET Form 3813, as applicable. 3.11.6. Delayed Reports. Transmit the contraction NIL at the standard time when it is evident that a weather report will not be completed in time for scheduled transmission. (T-0). (Example: METAR KDYS NIL.) 3.11.7. Reports Filed But not Transmitted. When an augmented observation is not able to be transmitted longline before the next METAR or SPECI is required, transmit only the latest observation longline. Enter "FIBI" (contraction for Filed But Impractical to Transmit) in parenthesis in column 13 (FIBI). Include FIBI in a METAR only if a later observation containing all elements of a METAR is available for transmission. 3.11.8. When a SPECI is not transmitted longline, transmit subsequent SPECI only when the change between the last transmitted report and the current report meets the criteria for a SPECI. Otherwise, enter (FIBI) in remarks for the current report and only disseminate it locally. 3.12. Longline Dissemination by other WFs/Dets. Enter a record of longline dissemination by another WF/Det in parentheses in column 13 of AF Form 3803/JET Form 3813. Identify the WF/Det that transmitted the observation longline and the initials of the individual that received the data (e.g., [BY KGRF/DR], [BY 25 OWS/MS]). 3.13. Reports of a Volcanic Eruption. Reports of a Volcanic Eruption are disseminated regardless of the delay. Use any reasonable means to disseminate the report. AFMAN15-111 12 MARCH 2019 19 Chapter 4 GENERAL OBSERVING INFORMATION 4.1. General. This chapter contains general procedures pertaining to all AF weather organizations responsible for producing surface weather observations. 4.2. FBWOS. The following requirements apply to all primary meteorological equipment used in the generation of surface weather observations at both automated and manual weather observing locations. 4.2.1. FBWOSs operate in automated mode at AF and Army controlled airfields to provide the official METAR and SPECI observations with augmentation when required. 4.2.2. Siting and Exposure. As best as practical, FBWOS sensor groups are sited in accordance with the Unified Facilities Criteria 3-260-1 (UFC 3-260-1), Airfield and Heliport Planning and Design. Previously installed sensors may be operated at their present locations; however, if they are relocated, siting will be in accordance with the federal standard. (T-1) 4.2.3. FBWOSs procured for operation on AF and Army locations must be certified as conforming with the station certification requirements contained in FCM-H1 as part of an operational evaluation and a fielding decision. Each site will conform to the site acceptance procedures and commission their FBWOS. (T-1). 4.2.3.1. At locations with assigned AF weather personnel, site acceptance and commissioning will be accomplished by the host-installation AF weather organization. 4.2.3.2. At locations with an DAF-owned FBWOS, but no DAF weather personnel assigned, the sponsoring MAJCOM, Lead Command and the Program Managers Office will coordinate site acceptance and commissioning with appropriate technical experts and mission owners utilizing the appropriate host service or agency as needed. 4.2.4. AN/TMQ-53s are used for tactical airfields, or as long-term backup (72-hours or greater) for fixed meteorological sensors (when sited appropriately) at AF and Army controlled airfields. AN/TMQ-53s will not be used as standalone weather sensors outside the local aerodrome, without prior approval from their parent MAJCOM. (T-1). 4.2.5. MAJCOMs must approve the use of FBWOS at locations other than controlled airfields (or local aerodromes). 4.2.6. In the automated mode, the FBWOS system continually senses, reports and measures the atmosphere for the following weather elements: wind speed and direction, visibility, thunderstorms, precipitation, obscurations to visibility, sky cover, cloud height, temperature, dew point and altimeter setting on all observations. 4.2.7. Locations with an FBWOS installed IAW section 4.4 below, are always designated as automated locations, even during periods of time when a weather technician augments an observation. 4.3. Automated Dissemination System (ADS). Any AF, Army, or National Weather Service accredited system capable of disseminating observations for use by operational customers is an ADS. At the majority of AF Weather operating locations the primary ADS is the Joint Environmental Toolkit (JET) platform. 20 AFMAN15-111 12 MARCH 2019 4.4. FBWOS Certification Requirements. 4.4.1. FBWOS Commissioning Process. The process consists of four phases: installation, acceptance, activation, and operational capability. Certification of the weather flights concludes with the weather certification official declaring their weather flight is ready to operate using the FBWOS and the designated commander declaring initial operating capability (IOC). Commissioning occurs after all certification and commissioning requirements have been met to include ensuring open write-ups are addressed and closed on the AFTO 747, Cyberspace Infrastructure System Acceptance. 4.4.1.1. Installation. This phase includes all the activities at the site prior to the acceptance phase (e.g., site preparation, hardware installation, checkout, and calibration). WFs/Dets continue to use existing weather equipment to produce observations. 4.4.1.2. Acceptance. Acceptance testing, acceptance of the system from the contractor by the acquisition agency, and turnover of the system from the acquisition agency to base or post agencies. 4.4.1.3. Activation. Includes the act of placing the system into pre-operational use and includes training and a determination of operational readiness. 4.4.1.4. Operational Capability. Consists of two declarations: 4.4.1.5. Declaration of IOC. The weather certification official attests the system is ready for IOC and the WF/Det submits a memo recommending FBWOS be certified to operate as the official observation for that location. The memo will be sent to leadership of supported units, base operations, 14th Weather Squadron (WS) and the unit’s parent MAJCOM. The designated commander for Air Force units’ is the OSS/CC or equivalent. The designated commander for Army support units that fall under a WS is the WS/CC and MAJCOM weather functional for Army support units that fall directly under that command. The weather certification official must be sufficiently satisfied with system performance, level of proficiency of flight personnel, and the maintenance support capability to declare the assets operational and capable of performing the assigned mission. IOC is based solely on the judgment of the commander, and will not be schedule-driven. (T-1). 4.4.1.6. IOC signifies the weather flight has transformed from the existing system to the newly installed automated system. From this point forward, the newly installed system will generate the official surface weather observation. Units may declare portions of the system IOC [i.e. temperature, pressure, wind; but may have issues with ceilometer]. Units doing this identify which portions of data they are willing to use and which they will backup/augment. (T-1). 4.4.1.7. Declaration of Full Operating Capability (FOC). The weather certification official will declare FOC once all requirements for weather flight certification and system commissioning has occurred. This will include the closure of any open write-ups recorded on the AFTO 747. The declaration of FOC may occur simultaneously with IOC. The weather certification official will prepare the certification and commissioning documents for submission. (T-1). AFMAN15-111 12 MARCH 2019 21 4.4.1.8. The weather certification official will prepare a memo for the designated commander’s signature recommending commissioning of the FBWOS. Attach the new station information file to the commissioning document. The weather flight will mail the signed commissioning document and attachments to 14 WS/DOD and 2 SYOS/SYSD and retain a copy of the document package in the flight's permanent historical file. (T-1). 4.5. Position Qualification Requirements. Weather personnel are trained, task certified, and position qualified IAW applicable Career Field Education and Training Plan, Talent Management Framework and local training requirements and plans. Additionally, weather personnel task-certify ATC personnel to evaluate tower visibility values from the control tower. When required, weather personnel also ensure DAF ATC personnel can operate applicable weather equipment located inside DAF ATC facilities. Log DAF ATC task certification on ATC provided AF Form 3622, Air Traffic Control/Weather Certification and Rating Record. 4.6. Station Information File. E-mail information to the 14 WS ([email protected]) and 2 SYOS ([email protected]) or mail it to: 14WS/WXD, 151 Patton Avenue, Asheville, NC 28801-5002. See Attachment 4 for a list of information required. 4.7. Accuracy of Time. The accuracy of the time ascribed to weather observations is of the utmost importance, especially in aviation safety investigations. The standard clock is a standalone clock zeroed with the US Naval Observatory time (DSN: 312-762-1401). A computer network clock may be used as the standard clock if it is verified that the Base/Post network time is synchronized on a daily basis with a Global Positioning System (GPS) or Naval Observatory clock. Annotate time checks in Column 90 on either AF Form 3803/JET Form 3813, as applicable. 4.8. Alternate Operating Location (AOL). Allows a quick, safe, and seamless transition during an evacuation suitable for WFs/Dets to continue their full spectrum of normal operations. WFs/Dets work with the local command to establish an AOL and outline what is needed from various agencies on the installation to support operations at the location. 4.8.1. At a minimum, during evacuated procedures, WFs/Dets must be able to take/augment and disseminate an observation containing the minimum required elements (i.e., wind speed and direction, prevailing visibility, present weather and obscurations, sky condition, temperature, dew point and altimeter setting). (T-1). 4.8.2. When the capability exists, WFs/Dets will continue to augment observations following normal procedures. (T-2). 4.8.3. WFs/Dets will disseminate an observation within 15 minutes of arrival at the AOL and then resume normal operations to the fullest extent possible. (T-2). Exception: An observation is not required at automated locations when the FBWOS is working properly and no mandatory supplementary criteria are occurring. 4.8.4. Resume normal observing operations (i.e., automated, augmented) upon return to the primary observing location. If supplemental criteria are occurring or if the FBWOS is not working properly, disseminate an observation within 15 minutes of return to primary observing location. (T-2). 22 AFMAN15-111 12 MARCH 2019 4.9. Cooperative Weather Watch. Encompasses the report of tower visibility, local pilot reports (PIREPs), and any occurrence of previously unreported conditions from ATC that are critical to the safety or efficiency of local operations and resources. At a minimum, the cooperative weather watch documents: 4.9.1. Procedures for task certified ATC personnel to report changes in tower visibility when it is less than 4 SM (6000 m) and differs from the prevailing visibility by at least one reportable value. 4.9.2. Procedures for ATC personnel to relay PIREPs as soon as practical, within ATC established duty priorities. 4.9.3. As part of the cooperative weather watch, if continuous RVR reporting is needed outside controlled airfield hours, WFs/Dets notify airfield leadership that the RVR system requires the runway lights to be left on to work properly. This practice supports the possibility that an aircraft may divert into the location in an emergency. 4.10. Control Tower Observations 4.10.1. ATC Personnel. ATC directives (e.g., AFMAN 13-204v3, Air Traffic Control; Federal Aviation Administration Order (FAAO) JO 7110.65AA, Air Traffic Control; Army Training Circular 3-04.81, Air Traffic Control Facility Operations, Training, Maintenance, and Standardization), require task certified ATC personnel to take tower visibility observations when the prevailing visibility at the point of observation or at the tower level, is less than 4 SM (6000 m). Control tower personnel task certified to take visibility observations also notify the weather technician when the observed tower prevailing visibility decreases to less than 4 SM (6000 m) or increases to or exceeds 4 SM (6000 m). 4.10.2. Weather personnel: 4.10.2.1. Evaluate prevailing visibility as soon as practicable upon receipt of tower visibility report that differs from the latest reported surface visibility. 4.10.2.2. Use tower visibility values as a guide in determining the surface visibility when portions of the horizon are obstructed by buildings, aircraft, etc. Note: The presence of a surface-based obscuration, uniformly distributed to heights above the level of the tower, is sufficient reason to consider the prevailing visibility the same as at the control tower level. 4.10.2.3. Include a tower visibility remark in the next METAR or SPECI when either the surface prevailing visibility or the control tower visibility is less than 4 SM (6000 m) and the control tower visibility differs from the surface prevailing visibility by a reportable value. 4.11. Observing Aids for Visibility. Visibility reference tools that are photographs should be high quality color photos taken on a predominantly cloud and obscuration free day. It is also recommended observing locations develop map-type visibility charts to augment the photographic visibility markers. 4.11.1. Objects in the visibility reference tool must be clearly identified with distance and direction from the observation point as well as whether the markers are day or nighttime aids (See Figure 4.1). (T-2). It is highly recommended that the visibility reference tool be in hard- copy format. AFMAN15-111 12 MARCH 2019 23 4.11.2. WFs/Dets should make use of existing detailed installation maps to determine marker distances while creating/updating visibility reference tools. Additional tools that may be available are military grid reference system maps, map display software/websites, laser range finder equipment, global positioning system, etc. If needed, WFs/Dets can submit a work order to survey the markers through the local Civil Engineering or Army equivalent agency. 4.11.3. The most suitable daytime markers are prominent dark or nearly dark colored objects (e.g., buildings, chimneys, wash-racks, hills, etc.) observed against a light-colored background; preferably the horizon sky. When using an object located in front of a terrestrial background, use caution when the object is located closer to the point of observation than it is to the terrestrial background. 4.11.4. The most suitable nighttime visibility markers are unfocused lights of moderate intensity. Runway course lights as well as TV/radio/water tower obstruction lights make good markers. Note: Do not use focused lights such as airway beacons due to their intensity. Figure 4.1. Example Visibility Checkpoint Photograph. 4.11.5. Control Tower Visibility Aids. AFMAN 13-204v3, requires control towers to maintain a visibility checkpoint chart or list of visibility markers posted in the tower. Upon request, WFs/Dets will provide whatever assistance is necessary to help prepare a chart or markers of suitable objects for determining tower visibility. (T-3) 4.12. Aircraft Mishap. Upon notification of an aircraft mishap, WFs/Dets will: 4.12.1. Immediately encode and disseminate a full element SPECI in accordance with Attachment 2. (T-1). Note: A SPECI is not required for an in-flight emergency (IFE); however, this should alert weather personnel to be prepared to take a SPECI if the IFE becomes a mishap. 4.12.2. Follow locally developed guidance and procedures in DAFMAN 15-129, Air and Space Weather Operations, to collect and save data related to the mishap. (T-1) 24 AFMAN15-111 12 MARCH 2019 4.13. Inactive/Parallel Runway Equipment. 4.13.1. Supplemental Data. ATC may occasionally authorize an aircraft to land using an inactive runway. If weather sensors are installed on the inactive runway, the ATC agency may initiate a request for observation data to control aircraft using that runway. This is a temporary measure and the current observation is not affected since the active runway is not changed (i.e. supplemental data is included in the remarks section of the observation and does not replace the active/primary sensor data). Use of data from inactive runway sensors must be based on the following factors: 4.13.1.1. Supplemental RVR data for an inactive runway can be reported in the remarks section of an observation using the same basic code form as that specified for the active runway. Example: R03R/1600FT 4.13.1.2. Supplemental wind data for an inactive/parallel runway can be reported in the remarks section of an observation when there is at least a 6 knot (kt) difference in speed (sustained or gusts) between the active wind sensor and the inactive sensor(s). Example: WND RWY 32R 300/10G15KT 4.13.1.3. Cloud heights generally do not differ from one end of a runway to the other. However, FBWOS discontinuity sensors report cloud ceiling heights as a remark in the observation. Variations in the sky condition relative to the runways, such as reported in local PIREPs, can be taken into consideration in the evaluation of sky cover as reported in the official observation. WFs/Dets may report significant or unusual variations in the sky condition in the remarks section of the observation. Example: CLD LYR AT 400FT ON APCH RWY 23 RPRTD BY PIREPS 4.13.1.4. Supplemental temperature data for an inactive/parallel runway can be reported in the remarks section of an observation (see Table A3.1, number 25) when the difference is at least one reportable value between the active and inactive sensor. Example: TEMPERATURE 23C RWY11. 4.13.2. When the accuracy or validity of data from the active weather sensor is questionable, WFs/Dets may utilize inactive/parallel runway equipment as their back-up method to obtain objective elements. However, wind data will be reported as “estimated” if obtained as back-up from an inactive sensor. Exception: WFs/Dets will not use inactive/parallel runway equipment to back-up a faulty RVR reading; encode RVRNO as part of the official observation (may still encode a supplemental RVR reading). (T-1). AFMAN15-111 12 MARCH 2019 25 Chapter 5 OBSERVATION AUGMENTATION 5.1. General. This chapter describes the requirements and procedures to augment surface weather observations produced by an FBWOS. Augmentation is the process of having position- qualified weather personnel edit or add additional data to an observation generated by an FBWOS. The two augmentation processes of supplement and back-up are covered separately in the following sections. 5.1.1. Weather personnel must have a view of the airfield complex and maintain situational awareness of the current conditions as well as the FBWOS-sensed data and observations. (T-1). 5.1.2. When augmenting, weather personnel will: 5.1.2.1. Configure their ADS to disseminate in the augmented or manual mode. Selecting either of these dissemination modes removes the “AUTO” report modifier from the observation. When augmentation is no longer required, weather personnel must reconfigure their ADS to disseminate in the automated mode. (T-1). 5.1.2.2. Use manual observing methods to determine and report the elements of an observation. The description of these methods can be found in each subsequent chapter covering the elements of an observation. (T-1). 5.1.2.3. Documenting Augmented Observations. Use ADS (JET) Form 3813, electronic or paper AF Form 3803, or the approved electronic workbook version (Excel(R)) of AF Form 3803 (available at https://climate.af.mil/ingest). (T-1). 5.2. Supplementing FBWOSs. Supplementing is the process of manually adding observed weather conditions beyond the capabilities of the FBWOS to detect and/or report to an observation. Weather personnel will supplement observations during controlled airfield hours and check the weather at intervals not to exceed 20 minutes whenever mandatory supplemental criteria in Table 5.1 are observed or forecast to occur within 1 hour. (T-1) Note: This does not relieve weather personnel of their Severe Weather Action Plan (SWAP) responsibilities to respond to severe weather events during uncontrolled airfield hours in accordance with DAFMAN 15-129. Weather personnel will continue to have a SWAP in place to respond to severe weather threats. (T-1) 26 AFMAN15-111 12 MARCH 2019 Table 5.1. Mandatory Supplementation Conditions. Tornado (+FC) (Notes 1 & 2) Waterspout (+FC) (Notes 1 & 2) Funnel Cloud (FC) (Notes 1 & 2) Freezing Precipitation (FZDZ/FZRA) Ice Pellets (PL) Hail (GR) Sandstorm (SS)/Dust Storm (DS) (Note 3) Volcanic Ash (VA) Tower Visibility remark (Note 4) Notes: 1. The immediate reporting of tornadic activity takes precedence over all other phenomena. 2. Be prepared to supplement whenever a tornado watch is valid or warning has been issued; regardless of airfield clousure status. 3. Based on local weather warning criteria; if no warning criteria exists, this is not required. 4. Only required during controlled airfield hours. 5.2.1. When supplementing observations, weather personnel will ensure that all applicable element entries are made in the body of the observation along with accompanying remarks. (T-1). See Attachment 3 for the full list of required elements and remarks. 5.2.2. Supplementing Sandstorms/Dust Storms. Sandstorms/Dust Storms will be reported whenever a local warning for the conditions is required. (T-1). 5.3. Back-up. Back-up is the process of manually editing/adding data or dissemination capability when the primary method is not operational, unavailable or suspected to be providing erroneous data (e.g. sensor/comm. failure, dew point higher than temperature). 5.3.1. Back-up is required during controlled airfield hours and may be required during uncontrolled airfield hours when elements triggering weather warnings are erroneously reported and/or when required for supplementation criteria above; otherwise, there is no requirement to back-up the system/sensor outside controlled airfield hours. 5.3.2. Weather personnel will not replace the entire automated observation with a manual observation when backing-up malfunctioning sensors, but will follow guidance in Attachment 2 and Attachment 3 and report the individual required elements. (T-2). 5.3.3. Unrepresentative values from any equipment, regardless of the method used, will not be included in the observation and will be considered missing if they cannot be determined through other methods. (T-1). 5.4. Back-up Equipment. Use an available Air Force-certified system to back-up the primary certified observing systems (e.g., AN/FMQ-19 discontinuity sensors, AN/TMQ-53) or approved manual methods. Manual observing equipment will be operated and maintained according to this manual and the applicable T.O. or user manual. (T-1). AFMAN15-111 12 MARCH 2019 27 5.4.1. Units may use the AN/TMQ-53 as a primary or back-up without estimating values with the exception of winds, if all the following conditions are met: 5.4.1.1. The equipment is in good working condition (e.g., operating properly) and properly maintained IAW the T.O. and established maintenance schedules. 5.4.1.2. The equipment is set up and operated IAW the T.O. and is sited IAW FCM-S4- 1994, Federal Standard for Siting Meteorological Sensors at Airports, Chapters 3 and 4. Note: The AN/TMQ-53 has known sensor height exposure limitations. 5.4.1.3. The values are representative and consistent with the values from surrounding observing sites (if available). 5.4.2. For short-term sensor outages (less than 72-hrs) weather operators may use values obtained from other pieces of equipment (e.g., Laser Range Finders, tactical barometers, hand- held wind readers, or other tactical meteorological equipment). 5.4.3. Weather personnel will make every attempt to promptly log out any malfunctioning equipment unless flight safety warrants otherwise. (T-2). Exception: Do not log out the FBWOS as the result of a system restart. Refer to AFI 21-103, Equipment Inventory, Status and Utilization Reporting, for additional information. 5.5. False Freezing Precipitation Reports. Deficiency reports for false readings exist on the AN/FMQ-19 and AN/FMQ-22 freezing precipitation sensors. Until these deficiencies are corrected, in order to mitigate the risk of false freezing precipitation reports during airfield closure hours, weather personnel will evaluate the risk of freezing precipitation occurring when the temperature is, or is forecast to be between 00 and 03 degrees Celsius. (T-1). 5.5.1. DELETED. 5.5.2. If freezing precipitation is expected, no additional action is needed regarding the equipment; continue normal operations. 5.5.3. If the risk of freezing precipitation is determined to be low, the local weather personnel will coordinate with sensor maintenance personnel to manually disable the freezing precipitation sensor. (T-2). If the sensor cannot be disabled, weather leadership will ensure personnel are physically present at an airfield weather services location to back-up the system’s freezing precipitation sensor in order to prevent false freezing precipitation reports from being disseminated, even outside controlled airfield hours. (T-2). Exception: If the sensor cannot be disabled and is at a remote site without an airfield weather services element, back-up is not required. 5.5.4. Log out the freezing precipitation sensor during any period where the system is triggering false reports so the duration of each event can be tracked. 36 AFMAN15-111 12 MARCH 2019 Chapter 7 WIND 7.1. Introduction. This chapter describes the observing and reporting standards for wind data. Wind is measured in terms of velocity, a vector that includes direction and speed. To the maximum extent possible, wind is measured in an unobstructed area to minimize inconsistencies caused by local obstructions that may result in an unrepresentative report of the general wind patterns. 7.2. Wind Group (dddff(f)Gfmfm(fm)KT_dndndnVdxdxdx). 7.2.1. Direction. The true direction (ddd) the wind is blowing from is encoded in tens of degrees using three figures. Directions less than 100 degrees are preceded with a "0." For example, a wind direction of 90 is encoded "090." 7.2.2. Speed. The wind speed, ff(f), is entered as a two- or three-digit group immediately following the wind direction. The speed is encoded in whole knots using the tens and units digits. The hundreds digit is only used when the wind speed exceeds 100 knots and is never reported as a leading zero. Speeds of less than 10 knots are encoded using a leading zero in the tens position. The group always ends with KT to indicate the wind speeds are reported in knots. For example, a wind speed of 8 knots is encoded 08KT. A wind speed of 112 knots is encoded 112KT. 7.2.3. Gust. Wind gusts are encoded in the format, Gfmfm(fm). The wind gust is encoded in two or three digits immediately following the wind speed. The wind gust is encoded in whole knots using the units and tens digits and, if required, the hundreds digit. For example, a wind from due west at 20 knots with gusts to 35 knots is encoded 27020G35KT. 7.2.4. Variable Wind Direction (speeds 6 knots or less). Variable wind direction with wind speed 6 knots or less may be encoded as VRB in place of the ddd. For example, if the wind is variable at three knots, it could be encoded VRB03KT. 7.2.5. Variable Wind Direction (speeds greater than 6 knots). Wind direction varying 60 degrees or more with wind speed greater than 6 knots is encoded in the format, dndndnVdxdxdx. The variable wind direction group immediately follows the wind group. The directional variability is encoded in a clockwise direction. For example, if the wind is variable from 180 to 240 at 10 knots, is encoded 21010KT 180V240. 7.2.6. Calm Wind. Calm wind is encoded as 00000KT. 7.3. Wind Algorithms. The wind algorithm uses 5-second average wind directions and speeds to compute and report the 2-minute average in the observation. The 5-second speed is also used as the instantaneous wind to determine gusts, squalls and peak wind data. The 2-minute direction is used to determine wind shifts and the range of variability. 7.4. Standards and Reporting. FBWOS sensors determine the wind direction, speed, gusts, wind shifts and peak wind at all automated observing locations. See Table 7.1 for a quick reference of wind element reporting characteristics. AFMAN15-111 12 MARCH 2019 37 7.4.1. Wind direction is determined by averaging the direction the wind is coming from with regards to true north, over a 2-minute period. Wind direction is reported using a 3-digit compass heading rounded to the nearest 10 degrees, or when meeting criteria below, may be reported as variable (VRB). Note: At OCONUS locations where the host nation is responsible for the airfield observation, winds may be reported using a different standard (i.e. 10-minute average instead of 2-minute). 7.4.2. Wind Speed is determined by averaging the speed over a 2-minute period and is reported in whole knots. 7.4.3. Wind gusts are determined by evaluating the most recent 10-minutes of wind speed data for rapid fluctuation in speed with a variation of 10 knots or more between peaks and lulls. The speed of a gust shall be the maximum instantaneous wind speed. 7.4.4. Peak Wind Speed is the highest instantaneous wind speed measured within the aerodrome during the specified reporting period. The hourly peak wind data is only reported in the remarks of a METAR when the speed is greater than 25 knots; see Attachment 3 for remark format. The daily peak wind data is reported in the summary of the day regardless of speed. For incomplete wind records, data may still be used if it is determined by the weather technician that the peak wind speed occurred outside the period of missing data; otherwise, treat the element as missing. 7.4.5. Wind Shifts are a change in direction by at least 45 degrees that occurs in less than 15 minutes and has sustained winds of at least 10kts throughout the shift. See Attachment 3 for remark format. Table 7.1. Wind Observing Standards. 38 AFMAN15-111 12 MARCH 2019 7.5. Manual Observing Methods. 7.5.1. Predominant wind direction, speed, gusts, and shifts are determined by the primary active wind sensor; peak wind data is determined by all available runway sensors. Data obtained from alternate equipment may be used as a guide for determining winds when the primary sensor is considered unrepresentative or inoperative. Note: Winds will be reported as estimated when obtained from any source other than the properly sited wind sensor for the active runway (T-2). See Attachment 3 for remark format. 7.5.2. To determine wind direction manually using a compass (or digital measuring device), face into the wind in an unobstructed area and take a 2-minute average reading of the wind direction; convert this magnetic direction to true direction where applicable. While determining the predominant direction, take note of the limits of variability for reporting when applicable. Note: Do not use the movement of clouds, regardless of how low they are, in determining the surface wind direction. 7.5.3. To determine wind speed manually, using an approved anemometer face into the wind in an unobstructed area with the device held at eye-level and take a 2-minute average reading of the wind speed. Use the same method over a 10-minute period to determine gusts when applicable. If an instrument is not available, use the Beaufort scale (Table 7.2) to determine the wind speed. Table 7.2. Beaufort Scale of Winds. Wind Equivalent -- Beaufort Scale Beaufort # MPH KTS Terminology Description 0 5,000 but ≤10,000 To nearest 500 > 10,000 To nearest 1,000 Table 11.2. Priority for Reporting Layers. Priority Layer Description 1 Lowest few layer 2 Lowest broken layer 3 Overcast layer 4 Lowest scattered layer 5 Second lowest scattered layer 6 Second lowest broken layer 7 Highest broken layer 8 Highest scattered layer 11.2.3. Vertical visibility is encoded in the format, VVhshshs, where VV identifies an indefinite ceiling and hshshs is the vertical visibility into the indefinite ceiling in hundreds of feet. There is no space between the group identifier and the vertical visibility. 11.2.4. Clear skies are encoded in the format, CLR or SKC, where CLR is the abbreviation used by all FBWOS locations and SKC is used by manual stations to indicate no clouds are present. 58 AFMAN15-111 12 MARCH 2019 11.2.5. Each layer is separated from other layers by a space. The sky cover for each layer reported is encoded by using the appropriate reportable contraction. The report of clear skies (CLR or SKC) is reported by itself. The abbreviations FEW, SCT, BKN and OVC will be followed, without a space, by the height of the cloud layer. (T-0). 11.2.6. A partial obscuration will be encoded with the reportable layer construction corresponding to the amount of the sky that is obscured followed by the layer height. A surface- based obscuration will have a layer height of 000. A remark will also be appended for any surface-based obscurations. For example: fog obscuring 2/8ths of the sky would be encoded in the body of the report as FEW000 and clarified in the remarks as FG FEW000. (T-0). 11.3. Sky Condition Algorithms. An FBWOS derives sky condition by detecting the frequency and height of clouds that move over the sensor over a continuously averaged period of 30 minutes. The data collected from the sensor is processed into coverage amount, height and variability of clouds. 11.3.1. FBWOS sensors are capable of reproducing a sky condition report comparative to that of a human weather technician but may perform poorly in situations where clouds develop in the vertical but have little horizontal movement (i.e. convective clouds either remain directly over sensor and are over-reported or do not pass over the sensor and are under-reported). When equipped with multiple ceilometers, the data from the discontinuity sensors are examined and compared with the primary sensor to determine the requirement to report non-uniform ceiling conditions IAW Attachment 3. 11.3.2. FBWOSs report sky condition from 100ft up to a maximum of 25,000ft. Note: Some systems may report heights exceeding 25,000ft. 11.4. Standards and Reporting. Sky condition is an evaluation of all obscurations/clouds making up layers at different heights and is reported in oktas (eighths) using a code form with appended height above the surface. Sky condition is reported in all METAR and SPECI observations. 11.4.1. Clouds and/or obscuring phenomena (not necessarily all of the same type) with bases at approximately the same level constitute a layer. They may be either continuous or composed of detached elements. A trace aloft is evaluated as 1/8th; however, a surface-based obscuring phenomenon is only classified as a layer when it covers at least 1/8th of the sky. All layers are treated as opaque. 11.4.2. Heights of layers are reported using a three-digit value representing hundreds of feet above the surface and are rounded to a reportable increment. Layer heights up to 5,000ft are reported to the nearest 100 feet, layer heights between 5,000ft and 10,000ft are reported to the nearest 500ft and layers above 10,000ft are reported to the nearest 1,000ft. When a value falls halfway between two reportable increments, the lower value is reported. 11.4.3. Sky cover is determined using the summation principle. This principle states that the sky cover at any level is equal to the sky cover in all lower levels up to and including the layer in question. In other words, no layer can be classified as less than the layers below it and no total sky cover can be greater than 8/8ths. See Figure 11.1 for an example of the summation principle. AFMAN15-111 12 MARCH 2019 59 11.4.4. Sky cover code forms reflect the degree of sky coverage based on a summation of the amount of clouds/obscuring phenomena at and below layer being evaluated. The approved code forms are listed below (with encoded form in parenthesis): 11.4.4.1. Sky Clear (SKC or CLR) - The absence of any clouds/obscuring phenomena; 0/8ths coverage. Note: Sometimes encoded as NCD or NSC by automated stations and organizations outside of AF weather to indicate No (Significant) Clouds Detected below 12,000ft (or 25,000ft with the 25K algorithm); CLR, NCD and NSC do not necessarily indicate clear skies. 11.4.4.2. Few (FEW) - A trace through 2/8ths coverage. 11.4.4.3. Scattered (SCT) - 3/8ths through 4/8ths coverage. 11.4.4.4. Broken (BKN) - 5/8ths through less than 8/8ths. Note: The lowest BKN or greater layer represents the ceiling. 11.4.4.5. Overcast (OVC) - The sky is completely covered by clouds/obscuring phenomena; 8/8ths coverage. Note: All layers are treated as opaque (i.e. an overcast layer of thin cirrus can be seen through however the sky is still overcast). 11.4.4.6. Vertical Visibility (VV) - The sky is completely covered by a surface-based phenomena (e.g. snow, fog); 8/8ths coverage. The terms totally obscured and indefinite ceiling may also be used in relation to this sky condition. Note: Vertical Visibility constitutes a ceiling. 11.4.5. For aviation purposes, the reported ceiling is defined as the lowest height at which the summation of layers equals broken or greater coverage (> 5/8ths) or the maximum height that can be observed into a vertical visibly obscuration. 11.4.6. A variable ceiling represents a situation in which the height of the ceiling rapidly increases and decreases by specified amounts during the period of observation and the ceiling is below 3,000ft. See Table 11.3 for additional reporting criteria. Table 11.3. Criteria for Variable Ceiling. Ceiling (feet) Variation Amount (feet) < 1,000  200 > 1,000 and  2,000  400 > 2,000 and < 3,000  500 11.4.7. A variable sky condition represents a situation in which a layer varies rapidly in coverage amount by at least one reportable value during the period of the observation and the layer is below 3,000ft. 11.4.8. Sky cover and ceiling heights from PIREPS should be used to maintain situational awareness and to compare against the determined or sensor derived sky condition. Convert cloud bases reported in PIREPs from mean sea level (MSL) to above ground level (AGL) before comparing to the local data. Reevaluate sky cover and ceiling heights when PIREPS indicate an operationally significant difference from the current observation. 60 AFMAN15-111 12 MARCH 2019 11.5. Manual Observing Methods. The legacy Qualification Training Package Observing – Trainer’s Guide, found on the AFWKC and the WMO-No. 407 International Cloud Atlas, Volume II both contain references and photographs for identifying the various cloud forms and can be used as a resource when determining significant cloud types and amounts. Sky condition will be evaluated in all METAR and SPECI observations. (T-1). 11.5.1. All layers visible from the point of observation are considered in sky cover reports. A maximum of six layers may be reported. When more than six layers are present, use Table 11.2 to determine reporting priority. 11.5.2. When observed, significant cloud types will be reported in the observation using the following guidance. (T-1). 11.5.2.1. When observed and within 10nm, cloud layers with cumulonimbus (CB) or towering cumulus (TCU) are identified by appending the contractions CB and/or TCU to the layer height and are further described in column 13 remarks. Note: Only one contraction is appended to each layer in the body of the observation; CB has priority if both are observed at the same layer height. 11.5.2.2. When observed and beyond 10nm, CB and TCU are not appended to the cloud layer report. In this case, only a column 13 remark is used (e.g., CB 14NW-20NNE MOV SE AND TCU DSNT S). 11.5.2.3. All other significant cloud features are reported in column 13 as remarks following guidance in Attachment 3. 11.5.3. To determine total layer coverage and total sky cover, from a location that affords the maximum view of the celestial dome, mentally divide the sky into halves, quarters and/or eighths and estimate the layer coverage amount starting with the lowest layer. Using the summation principle, add each successive layer amount in eighths estimated. See Figure 11.1 for sky cover example. 11.5.3.1. When evaluating interconnected layers formed by the horizontal extension of cumulus, a layer will only be treated as separate if the base appears horizontal and at a different height than the parent cloud. Otherwise, the entire cloud is regarded as a single layer and is annotated with the height of the base of the parent cloud (i.e. a well-developed anvil from a CB may be treated as its own separate layer). 11.5.3.2. Determine total layer and sky cover amount based on what is actually seen, to include the bases and sides of clouds or obscuring phenomenon. Do not reduce coverage estimation to compensate for the packing effect that is commonly seen with cumuliform clouds. The packing effect is observed as an increased sky coverage amount due to the viewing angle of the sides of clouds when looking to the horizon. See Figure 11.2 for an example of the packing effect. AFMAN15-111 12 MARCH 2019 61 Figure 11.1. Sky Cover Evaluation Example. Figure 11.2. Illustration of the Packing Effect. 62 AFMAN15-111 12 MARCH 2019 11.5.4. The primary method for determining layer height is using the equipment derived height from an installed ceilometer. When determining layer height, treat layers as uniform; the height overhead is the same as the height of the entire layer. In the absence of the primary ceilometer or when it is determined to be malfunctioning, determine the layer height for each observed element using one of the following methods. Note: Determining layer height based on the speed of movement of individual cloud elements is not a reliable method. 11.5.4.1. Deployable meteorological equipment such as an AN/TMQ-53 ceilometer. 11.5.4.2. A handheld ceilometer. When used, this device must be held as perpendicular to the ground as possible and used only to measure cloud bases directly overhead. If held at an angle, it erroneously displays heights as too great. 11.5.4.3. PIREPs from aircraft in the local area. 11.5.4.4. Known heights of unobscured portions of natural landmarks or objects. 11.5.4.5. Observation of a weather balloon; dew point depression from upper air profiles. 11.5.4.6. Convective Cloud Height Table. Use Table 11.4 to estimate the height of cumulus clouds formed in the vicinity of the observing location. Note: This method is most accurate in determining cloud bases below 5,000ft. This method cannot be used to determine heights of non-cumuliform clouds or for locations in mountainous/hilly terrain. Table 11.4. Convective Cloud Height Estimates. CONVECTIVE CLOUD-BASE HEIGHT TABLE Surface Dewpoint Estimated Cloud Surface Dewpoint Estimated Cloud Depression (°C) Base Height (ft) Depression (°C) Base Height (ft) 0.5 200 10.5 4,200 1.0 400 11.0 4,400 1.5 600 11.5 4,600 2.0 800 12.0 4,800 2.5 1,000 12.5 5,000 3.0 1,200 13.0 5,200 3.5 1,400 13.5 5,400 4.0 1,600 14.0 5,600 4.5 1,800 14.5 5,800 5.0 2,000 15.0 6,000 5.5 2,200 15.5 6,200 6.0 2,400 16.0 6,400 6.5 2,600 16.5 6,600 7.0 2,800 17.0 6,800 7.5 3,000 17.5 7,000 8.0 3,200 18.0 7,200 8.5 3,400 18.5 7,400 9.0 3,600 19.0 7,600 9.5 3,800 19.5 7,800 10.0 4,000 20.0 8,000 64 AFMAN15-111 12 MARCH 2019 Chapter 13 PRESSURE 13.1. Introduction. This chapter describes the observing and reporting standards for pressure measurements. All pressure values are initially derived from the atmospheric pressure as measured by a barometer and may be reported in either inches of mercury (iHg) or hectopascals (hPa). 13.2. Altimeter (APHPHPHPH). The altimeter group always starts with an A (the international indicator for altimeter in inches of mercury). The altimeter is encoded as a four-digit group immediately following the A using the tens, units, tenths, and hundredths of inches of mercury. The decimal point is not encoded. 13.3. Pressure Measurement Algorithms. The FBWOS sensors measure the barometric pressure and then based on that value, compute the pressure parameters (e.g., station pressure, altimeter setting, and sea-level pressure). Computations are made each minute. In addition to the pressure parameters, the FBWOS also generates pressure change and pressure tendency remarks for possible inclusion in the observations. FBWOS pressure sensors are capable of measuring pressure from 17.5 to 32.5 iHg (600 to 1,100 hPa). 13.4. Standards and Reporting. At a minimum, all observations will include an altimeter setting (ALSTG) in the body of the observation; additional pressure computations are recorded and reported in accordance with this manual and local directives. (T-1). All pressure values will be rounded down to the nearest reportable value. (T-1). In the United States and at US military organizations overseas, pressure data is expressed as iHg for station pressure and ALSTGs and as hPa for sea-level pressure (SLP); however, MAJCOMs may direct the use of hPa for reporting purposes. Note: The common international unit of measure is hPa for all pressure data. 13.4.1. All pressure-related values are considered estimated any time the readings are suspect in the opinion of weather personnel or when pressure is obtained through any method other than the primary sensor. Exception: The AN/TMQ-53 may be used as a back-up without estimating pressure values if it has been set-up and properly maintained IAW FCMS4-1994 and the T.O., and the values are representative and consistent with other reports in the area. 13.4.2. The primary measurements of atmospheric pressure used in observations are the station pressure and the altimeter setting. 13.4.2.1. Station pressure is defined as the atmospheric pressure computed for the level of the station elevation. This initial pressure calculation is used to derive all other pressure reports. Station pressure is not disseminated but is recorded at 3-hourly intervals on the observation form. Note: Station pressure may be referred to by the acronym “QFE” by the international community. 13.4.2.2. The altimeter setting is a computed pressure value that an aircraft altimeter scale is set to so it indicates the altitude above MSL of an aircraft on the ground at the location for which the value was determined. Note: The letter “A” is used to identify an ALSTG in observations at CONUS locations and OCONUS US military locations. The letter “Q” is used by the international community; additionally, an ALSTG may be referred to by the acronym “QNH.” AFMAN15-111 12 MARCH 2019 65 13.4.3. Additional derived pressure-related reports are added to observations when occurring and/or at regular intervals in accordance with this manual, higher headquarters guidance, and local procedures. These reports include but are not limited the following: 13.4.3.1. Sea-level Pressure (SLP) is a report of the theoretical reduction of station pressure to sea level. Where the earth’s surface is above sea level, it is assumed the atmosphere extends to sea level below the observing location and the properties of the hypothetical atmosphere are related to conditions observed at the unit. Note: SLP may be referred to by the acronym “QFF” by the international community. 13.4.3.2. Pressure tendency is a coded report (5-group) included on the 3-hourly observations that indicates the characteristic and amount of pressure change during the 3- hour period preceding the observation. 13.4.3.3. Pressure falling rapidly (PRESFR) and pressure rising rapidly (PRESRR) are remarks used to indicate a rapid fluctuation in pressure has occurred. These remarks are reported in column 13 whenever the station pressure changes at a rate of at least 0.06 iHg per hour (0.01 iHg per 10 minutes) with a change of at least 0.02 iHg having occurred at the time of observation. 13.4.3.4. Pressure Altitude (PA) is an altitude in the standard atmosphere at which a given pressure is observed. It is the indicated altitude above or below the 29.92 iHg constant- pressure surface. Note: PA may be referred to by the acronym “QNE” by the international community. 13.4.3.5. Density Altitude (DA) is the PA corrected for virtual temperature deviations from the standard atmosphere. 13.4.3.6. Field Elevation (Ha) is the officially designated elevation of an airfield/site above mean sea level. It is the elevation of the highest point on any of the runways of the airfield/site. 13.4.3.7. Station Elevation (Hp) is the officially designated height above sea level to which station pressure pertains; generally, the same as field elevation. Table 13.1. Units of Measure and Resolution of Pressure Parameters. Parameter Unit of Measure Resolution Station Pressure Inches of Mercury 0.005 iHg Altimeter Setting Inches of Mercury 0.01 iHg Sea Level Pressure Hectopascals 0.1 hPa Pressure Altitude Feet 10 ft Density Altitude Feet 10 ft 13.5. Manual Observing Methods. All organizations with a permanent weather observing mission in direct support of flying operations will have a primary pressure measurement instrument and will designate a back-up pressure measuring instrument. (T-1). The primary method to obtain pressure measurements are by directly reading the sensor output from an FBWOS or its associated software (i.e. JET). 66 AFMAN15-111 12 MARCH 2019 13.5.1. Pressure Measurement Instrumentation. Obtain pressure data using an instrument from the following priority list. When using back-up equipment, follow the procedures in the applicable T.O. or user’s manual and treat all values as estimated (see paragraph 13.4.1 for exception). 13.5.1.1. AN/FMQ-19, Automatic Meteorological Station (AMS). 13.5.1.2. AN/FMQ-22/23 AMS. 13.5.1.3. Automated Surface Observing System (ASOS). 13.5.1.4. AN/TMQ-53, Tactical Meteorological Observing System. 13.5.1.5. Altimeter Setting Indicator (ASI). 13.5.1.6. Aircraft altimeter. 13.5.1.7. Other MAJCOM-approved device. 13.5.2. Station Pressure. Determine the station pressure by taking a direct reading, and if necessary, applying the posted pressure correction obtained during a scheduled barometer comparison. 13.5.3. Altimeter Setting. Read directly from the pressure measuring device. 13.5.3.1. If a direct readout of the primary method is unavailable, ASLTG is computed using the current station pressure value and the locally designated method (e.g. online forecaster tools found on AFW-WEBS and OWS websites, pressure reduction calculator, ALSTG quick reference chart). 13.5.3.2. If required for international aviation purposes, use Table 13.2 to convert values from iHg to hPa. AFMAN15-111 12 MARCH 2019 67 Table 13.2. ALSTG - iHg to hPa. IHg 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 0.09 Hectopascals 28.0 948 948 948 949 949 949 950 950 950 951 28.1 951 951 952 952 952 953 953 953 954 954 28.2 955 955 955 956 956 956 957 957 957 958 28.3 958 958 959 959 959 960 960 960 961 961 28.4 961 962 962 962 963 963 963 964 964 964 28.5 965 965 965 966 966 966 967 967 967 968 28.6 968 968 969 969 969 970 970 970 971 971 28.7 971 972 972 972 973 973 973 974 974 974 28.8 975 975 976 976 976 977 977 977 978 978 28.9 978 979 979 979 980 980 980 981 981 981 29.0 982 982 982 983 983 983 984 984 984 985 29.1 985 985 986 986 986 987 987 987 988 988 29.2 988 989 989 989 990 990 990 991 991 991 29.3 992 992 992 993 993 993 994 994 994 995 29.4 995 995 996 996 997 997 997 998 998 998 29.5 999 999 999 1000 1000 1000 1001 1001 1001 1002 29.6 1002 1002 1003 1003 1003 1004 1004 1004 1005 1005 29.7 1005 1006 1006 1006 1007 1007 1007 1008 1008 1008 29.8 1009 1009 1009 1010 1010 1010 1011 1011 1011 1012 29.9 1012 1012 1013 1013 1013 1014 1014 1014 1015 1015 30.0 1015 1016 1016 1016 1017 1017 1018 1018 1018 1019 30.1 1019 1019 1020 1020 1020 1021 1021 1021 1022 1022 30.2 1022 1023 1023 1023 1024 1024 1024 1025 1025 1025 30.3 1026 1026 1026 1027 1027 1027 1028 1028 1028 1029 30.4 1029 1029 1030 1030 1030 1031 1031 1031 1032 1032 30.5 1032 1033 1033 1033 1034 1034 1034 1035 1035 1035 30.6 1036 1036 1036 1037 1037 1037 1038 1038 1038 1039 30.7 1039 1040 1040 1040 1041 1041 1041 1042 1042 1042 30.8 1043 1043 1043 1044 1044 1044 1045 1045 1045 1046 30.9 1046 1046 1047 1047 1047 1048 1048 1048 1049 1049 NOTE: The hPa values in this table are truncated to their reportable value (i.e. rounded down to the nearest whole hPa) 13.5.4. Sea-Level Pressure. Determine the SLP by taking a direct reading from the FBWOS. If a direct readout of the primary method is unavailable, SLP is computed using the current station pressure and the locally designated method (e.g. online forecaster tools found on AFW- WEBS and OWS websites, pressure reduction calculator, or SLP quick reference chart). Note: In addition to when using back-up equipment, SLP is also considered estimated when the 12- hour mean temperature is estimated. 13.5.5. Pressure Tendency. Determine the pressure tendency by taking a direct reading from the FBWOS during the 3-hourly observations. 68 AFMAN15-111 12 MARCH 2019 13.5.5.1. If a direct readout of the pressure tendency is unavailable, compute the tendency using the following procedures: 13.5.5.1.1. Determine the pressure tendency from the 3-hour trend of the ALSTGs. Using the code figures in Table 13.3, choose the figure which best describes the character of the change from the trend. 13.5.5.1.2. Determine the difference (without regard to positive or negative) in station pressure from the 3-hour period to the nearest 0.005-inch by subtracting the current station pressure from the station pressure from 3 hours ago. Use Table 13.4 to select the code figure that corresponds to the net change. Note: Limited-duty units can access the FBWOS software to obtain past pressure information when if available. 13.5.5.2. Consider the 3-hour pressure tendency group (5appp) as indeterminable when any portion of the group is impossible to determine. Annotate the reason for not reporting the group in column 90 (e.g. sensor outage). Table 13.3. Pressure Tendency Character. General Description Pressure Characterization Code Figure Increasing, then decreasing 0 Increasing, then steady, or increasing then increasing 1 Atmospheric pressure more slowly now higher than 3 hours Increasing steadily or unsteadily 2 ago Decreasing or steady, then increasing; or increasing 3 then increasing more rapidly Increasing, then decreasing 0 Atmospheric pressure Steady 4 now same as 3 hours ago Decreasing, then increasing 5 Decreasing, then increasing 5 Decreasing, then steady; or decreasing then 6 Atmospheric pressure decreasing more slowly now lower than 3 hours Decreasing steadily or unsteadily 7 ago Steady or increasing, then decreasing; or decreasing 8 then decreasing more rapidly AFMAN15-111 12 MARCH 2019 69 Table 13.4. Amount of Pressure Change in Last 3 Hours. Code figure, Difference in Pressure (iHg and hPa) Code Inches hPa Code Inches hPa Code Inches hPa Code Inches hPa Figure of Hg Figur of Hg Figure of Hg Figure of Hg e 000.000 0.0 051.150 5.1 102.300 10.2 152.450 15.2 002.005 0.2 052.155 5.2 103.305 10.3 154.455 15.4 003.010 0.3 054.160 5.4 105.310 10.5 156.460 15.6 005.015 0.5 056.165 5.6 107.315 10.7 157.465 15.7 007.020 0.7 058.170 5.8 108.320 10.8 159.470 15.9 008.025 0.8 059.175 5.9 110.325 11.0 161.475 16.1 010.030 1.0 061.180 6.1 112.330 11.2 163.480 16.3 012.035 1.2 063.185 6.3 113.335 11.3 164.485 16.4 014.040 1.4 064.190 6.4 115.340 11.5 166.490 16.6 015.045 1.5 066.195 6.5 117.345 11.7 168.495 16.8 017.050 1.7 068.200 6.8 119.350 11.9 169.500 16.9 019.055 1.9 069.205 6.9 120.355 12.0 171.505 17.1 020.060 2.0 071.210 7.1 122.360 12.2 173.510 17.3 022.065 2.2 073.215 7.3 124.365 12.4 174.515 17.4 024.070 2.4 075.220 7.5 125.370 12.5 176.520 17.6 025.075 2.5 076.225 7.6 127.375 12.7 178.525 17.8 027.080 2.7 078.230 7.8 129.380 12.9 179.530 17.9 029.085 2.9 080.235 8.0 130.385 13.0 181.535 18.1 030.090 3.0 081.240 8.1 132.390 13.2 183.540 18.3 032.095 3.2 083.245 8.3 134.395 13.4 185.545 18.5 034.100 3.4 085.250 8.5 135.400 13.5 186.550 18.6 036.105 3.6 086.255 8.6 137.405 13.7 188.555 18.8 037.110 3.7 088.260 8.8 139.410 13.9 190.560 19.0 039.115 3.9 090.265 9.0 141.415 14.1 191.565 19.1 041.120 4.1 091.270 9.1 142.420 14.2 193.570 19.3 042.125 4.2 093.275 9.3 144.425 14.4 195.575 19.5 044.130 4.4 095.280 9.5 146.430 14.6 196.580 19.6 046.135 4.6 097.285 9.7 147.435 14.7 198.585 19.8 047.140 4.7 098.290 9.8 149.440 14.9 200.590 20.0 049.145 4.9 100.295 10.0 151.445 15.1 201.595 20.1 203.600 20.3 NOTE: Code figures in this table are based on the conversion from inches of mercury to hectopascals since station pressure is taken in inches of mercury. However, other code figures not listed (e.g., 016 for 1.6 hPa) are also used at locations where station pressure is determined in hectopascals. 70 AFMAN15-111 12 MARCH 2019 13.5.6. Pressure Altitude (PA) and Density Altitude (DA). PA and DA are automatically computed by FBWOSs, displayed on the ADS (e.g., JET) and TMQ-53 sensor displays, and disseminated locally to ATC agencies. If a direct readout of the primary method is unavailable, PA and DA can also be computed using the OWS or AFW-WEBS Forecaster Tools.. 13.5.6.1. FBWOS and JET software compute DA using different formulas; the formula used by JET takes into account water vapor and the FBWOS does not. AF weather organizations should provide their supported units with DA values obtained directly from the ADS and TMQ-53 sensor displays when available. (T-3). 13.5.6.2. When the primary pressure sensor is inoperative, notify ATC agencies that the reported PA and DA values are estimated. 13.5.7. Rapid Pressure Changes. The FBWOS/JET automatically enter this remark if the condition is detected. If unavailable, manually determine whether the pressure change at the time of an observation and report the condition in the remarks of the observation using the format in Attachment 3. 13.6. Comparison and Calibration Procedures. Each unit with an AN/TMQ-53, a hand-held barometer, and/or equivalent will establish a barometer comparison/calibration program. (T-3). Note: Comparisons should be delayed during periods of high wind speeds (25 knots or higher, sustained or gusting), rapid temperature changes or steep horizontal and/or vertical temperature gradients (i.e. frontal system in area or frontal passage). 13.6.1. Record and document barometer comparisons on a locally developed worksheet/spreadsheet, or MAJCOM or higher headquarters approved form/worksheet/spreadsheet. Retain the last two barometer comparisons on file and dispose of all others. 13.6.2. Deployable barometers (e.g., AN/TMQ-53, handheld barometer). 13.6.2.1. At a minimum, compare barometers against a standard barometer annually, before deployment, when first deployed, if relocated during a deployment, and as soon as practical after redeployment. 13.6.2.2. Determine a mean correction by making at least four comparisons, not less than 15 minutes apart, against the standard barometer. 13.6.2.2.1. For handheld barometers, the standard barometer is the local observing system (i.e., AN/FMQ-19, AN/FMQ-23, or AN/TMQ-53). 13.6.2.2.2. For the AN/TMQ-53, the standard barometer can be either the local observing system or, when available, a maintenance standard barometer (used by airfield systems/depot maintenance personnel). 13.6.2.3. Apply the mean correction (or adjust the software to reflect the correction) to a fifth pressure reading. If the corrected reading differs from the standard barometer by more than 0.01iHg (0.34hPa), re-accomplish the steps above. If the corrected reading exceeds 0.03iHg (1.01hPa), discontinue use and replace the device (for the AN/TMQ-53, turn in to depot maintenance). AFMAN15-111 12 MARCH 2019 71 13.6.2.4. At locations that do not have a standard barometer, and while deployed, compare each barometer against any available calibrated pressure instrument (e.g., aircraft altimeter) following the same procedures above. MARK D. KELLY, Lt Gen, USAF Deputy Chief of Staff, Operations 72 AFMAN15-111 12 MARCH 2019 Attachment 1 GLOSSARY OF REFERENCES AND SUPPORTING INFORMATION References AFPD 15-1, Weather Operations, 14 November 2019 AFI 11-201, Flight Information Publication, 30 November 2018 DELETED AFI 11-202, Volume 3, General Flight Rules, 10 August 2016 DELETED AFI 13-204, Volume 3, Airfield Operations Procedures and Programs, 1 September 2010 DELETED AFI 15-127, Weather Training, 27 January 2021 DELETED AFI 15-128, Weather Force Structure, 21 June 2019 DAFI 21-103, Equipment Inventory, Status and Utilization Reporting, 1 November 2022 DELETED AFI 33-360, Publications and Forms Management, 1 December 2015 DAFMAN 15-129, Air and Space Weather Operations, 07 September 2023 DELETED AFMAN 33-363, Management of Records, 1 March 2008 AFMAN 13-204, Volume 3, Air Traffic Control, 22 July 2020 DAFMAN 90-161, Publishing Processes and Procedures, 18 October 2023 AR 95-1, Flight Regulations, 22 March 2018 AR 95-2, Airspace, Airfields/Heliports, Flight Activities, Air Traffic Control, and Navigational Aids, 31 March 2016 FAAO JO 6560.20C, Siting Criteria for Automated Weather Observing Systems, 6 September, 2017 FAAO JO 7340.2M, Contractions, 2 February 2023 FAAO JO 7350.9EE, Location Identifiers, 15 June 2023 FAAO JO 7110.65AA, Air Traffic Control, 20 April 2023 Federal Meteorological Handbook No. 1 (FCM-H1), Surface Weather Observations and Reports, July 2019 DELETED FCM-S4-1994, Federal Standard for Siting Meteorological Sensors at Airports, August 1994 FCM-S4-2019, Federal Standard for Siting Meteorological Sensors at Airports, July 2019 TC 3-04.15, Air Traffic Control Facility Operations, Training, Maintenance, and Standardization, 8 October 2019 TC 3-04.81, Air Traffic Control Facility Operations, Training, Maintenance, and Standardization, 29 October 2010 Qualification Training Package Observing, Trainer’s Guide, 15 February 2010 AFMAN15-111 12 MARCH 2019 73 UFC 3-260-01, Airfield and Heliport Planning and Design, 04 February 2019 WMO-No. 306, Manual on Codes, Vol I, International Codes, 2019 Edition WMO-No. 306, Manual on Codes, Vol II, Regional Codes and National Coding Practices, 2011 Edition WMO-No. 407, International Cloud Atlas, Volume II, 1987 Prescribed Forms AF Form 3803, Surface Weather Observations (METAR/SPECI JET Form 3818, Surface Weather Observations (METAR/SPECI) Adopted Forms DAF Form 679, Department of the Air Force Publication Compliance Item Waiver Request/Approval AFTO Form 747, Cyberspace Infrastructure System Acceptance DAF Form 847, Recommendation for Change of Publication AF Form 3622, Air Traffic Control/Weather Certification and Rating Record AF Form 4058, Airfield Operations Policy Waiver Abbreviations and Acronyms Minus “-“—Light intensity no symbol—Moderate intensity Plus “+”—Heavy intensity Forward slash “/”—Indicates visual range data follows; separator between temperature and dew point data ACC—Altocumulus Castellanus ACFT MSHP—Aircraft Mishap ACSL—Altocumulus Standing Lenticular Cloud ADS—Automated Dissemination System AFMAN—Air Force Manual AFW-WEBS—Air Force Weather Web Services ALSTG—Altimeter Setting AO1—ASOS/AWOS stations without a precipitation discriminator AO2—Remark included in METAR/SPECI observations from FBWOS WFs/Dets without augmentation (or ASOS/AWOS stations with a precipitation discriminator) AO2A—Remark included in METAR/SPECI observations from FBWOS WFs/Dets with manual augmentation 74 AFMAN15-111 12 MARCH 2019 AOL—Alternate Operating Location APRNT—Apparent APRX—Approximately ASOS—Automated Surface Observing System ATC—Air Traffic Control AURBO—Aurora AUTO—Automated Report B—Began BC—Patches BKN—Broken BL—Blowing BR—Mist C—Center (With Reference To Runway Designation) CB—Cumulonimbus Cloud CBMAM—Cumulonimbus Mammatus Cloud CCSL—Cirrocumulus Standing Lenticular Cloud CHI—Cloud-Height Indicator CHINO—Cloud-height-indicator, Sky Condition At Secondary Location Not Available CIG—Ceiling CLR—Clear CONTRAILS—Condensation Trails CONUS—Continental United States COR—Correction to A Previously Disseminated Report DAF—Department of the Air Force DAFMAN—Department of the Air Force Manual DoD—Department Of Defense DR—Low Drifting DS—Dust storm DSNT—Distant DU—Widespread Dust DZ—Drizzle E—East, Ended AFMAN15-111 12 MARCH 2019 75 ESTMD—Estimated FAA—Federal Aviation Administration FAAO—Federal Aviation Administration Order FBWOS—Fixed Base Weather Observing System FC—Funnel Cloud FEW—Few Clouds FG—Fog FIBI—Filed But Impracticable To Transmit FIRST—First Observation After A Break In Coverage At An Augmented Observing FLIP—Flight Information Publication FROPA—Frontal Passage FT—Feet FU—Smoke FZ—Freezing FZRANO—Freezing Rain Information Not Available G—Gust GR—Hail (any size) GS—Snow Pellets hPa—Hectopascals (millibars) HZ—Haze IAW—In Accordance With IC—Ice Crystals ICAO—International Civil Aviation Organization IFR—Instrument Flight Rules ILS—Instrument Landing System JET—Joint Environmental Toolkit KT—Knots L—Left (With Reference To Runway Designation) LAST—Last Observation Before A Break In Coverage At An Augmented Observing LOC—Location LST—Local Standard Time LTG—Lightning 76 AFMAN15-111 12 MARCH 2019 LWR—Lower M—Minus, Less Than MAJCOM—Major Air Force Command METAR—Aviation Routine Weather Report MI—Shallow MMLS—Mobile Microwave Landing System MOV—Move, Moving, Moved MT—Mountains N—North N/A—Not Applicable NE—Northeast NW—Northwest OCONUS—Outside Continental United States OFCM—Office of the Federal Coordinator for Meteorology OHD—Overhead OVC—Overcast OWS—Operational Weather Squadron P—Greater Than (used with RVR) PAR—Precision Approach Radar PCPN—Precipitation PK WND—Peak Wind PL—Ice Pellets PNO—Precipitation Amount Not Available PO—Dust/Sand Whirls (Dust Devils) PR—Partial PRESFR—Pressure Falling Rapidly PRESRR—Pressure Rising Rapidly PWINO—Precipitation Identifier Sensor Not Available PY—Spray R—Right (With Reference To Runway Designation) RA—Rain RMK—Remark AFMAN15-111 12 MARCH 2019 77 RVR—Runway Visual Range RVRNO—Runway Visual Range Information Not Available RWY—Runway S—South SA—Sand SCSL—Stratocumulus Standing Lenticular Cloud SCT—Scattered SE—Southeast SFC—Surface SG—Snow Grains SH—Shower(s) SLP—Sea Level Pressure SLPNO—Sea Level Pressure Not Available SM—Statute Miles SN—Snow SNINCR—Snow Increasing Rapidly SPECI—Aviation S