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METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR)

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METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR) U.S. DEPARTMENT OF TRANSPORTATION N JO 7900.11 NOTICE FEDERAL AVIATION ADMINISTRATION Effective Date: Air Traffic Organization Policy September 1, 2018 Cancellation Date: September 1, 2019 SUBJ: METAR/SPECI Reporting Changes for Snow Pellets (GS) and Hail (GR) 1. Purpose of this Notice. This Notice coincides with a revision to the Federal Meteorological Handbook (FMH-1) that was effective on November 30, 2017. The Office of the Federal Coordinator for Meteorological Services and Supporting Research (OFCM) approved the changes to the reporting requirements of small hail and snow pellets in weather observations (METAR/SPECI) to assist commercial operators in deicing operations. 2. Audience. This order applies to all FAA and FAA-contract weather observers, Limited Aviation Weather Reporting Stations (LAWRS) personnel, and Non-Federal Observation (NF- OBS) Program personnel. 3. Where can I Find This Notice? This order is available on the FAA Web site at http://faa.gov/air_traffic/publications and http://employees.faa.gov/tools_resources/orders_notices/. 4. Cancellation. This notice will be cancelled with the publication of the next available change to FAA Order 7900.5D. 5. Procedures/Responsibilities/Action. This Notice amends the following paragraphs and tables in FAA Order 7900.5. Table 3-2: Remarks Section of Observation Remarks Section of Observation Element Paragraph Brief Description METAR SPECI Volcanic eruptions must be reported whenever first noted. Pre-eruption activity must not be reported. (Use Volcanic Eruptions 14.20 X X PIREPs to report pre-eruption activity.) Encode volcanic eruptions as described in Chapter 14. Distribution: Electronic 1 Initiated By: AJT-2 09/01/2018 N JO 7900.11 Remarks Section of Observation Element Paragraph Brief Description METAR SPECI Whenever tornadoes, funnel clouds, or waterspouts begin, are in progress, end, or disappear from sight, the event should be described directly after the "RMK" element. This remark must Tornadic Activity give, insofar as known, the (Manual and phenomena, time, location and Augmented Auto) 14.21 direction from the station, and direction X X (Tornadic of movement. The time the tornadic activity_B/E(hh)mm activity began must be reported and LOC/DIR_(MOV)) prefixed with a "B," the time the tornadic activity ended or disappeared from sight must be reported and prefixed with an "E," for example, TORNADO B13 DSNT NE. This remark identifies the type of automated station. It must be included in all reports from automated stations. AO1 identifies an automated station Type of Automated 14.22 without a precipitation discriminator; X X Station (AO1, AO2) AO2 identifies an automated station with a precipitation discriminator. The absence of the remark indicates a manual station. When the peak wind exceeds 25 knots, the remark must be included in the next METAR report. ddd is the direction of the peak wind, ff(f) is the Peak Wind (PK WND peak wind speed since the last dddff(f)/(hh)mm) 14.23 X METAR report, and (hh)mm is the time (NA LAWRS of occurrence (with only the minutes reported if the hour can be inferred from the report time), for example, PK WND 28045/15. At stations with automated systems with SPECI capability and manual stations, when a wind shift occurs, WSHFT followed by a space and the time the wind shift began must be reported (with only the minutes Wind Shift 14.24 reported if the hour can be inferred X X (WSHFT_(hh)mm) from the report time). The contraction FROPA may be entered following the time if it is reasonably certain that the wind shift was the result of frontal passage, for example, WSHFT 30 FROPA. If tower visibility or surface visibility is Tower or Surface carried in the remarks, use the Visibility (TWR VIS) 14.25 A/B/C A/B/C appropriate set of values and precede (SFC VIS) the visibility with the appropriate 2 09/01/2018 N JO 7900.11 Remarks Section of Observation Element Paragraph Brief Description METAR SPECI identifier, TWR VIS or SFC VIS, for example, TWR VIS 1. Whenever the prevailing visibility is less than 3 statute miles and is variable, this remark must be entered Variable Prevailing 14.26 where min is the lowest visibility X X Visibility (VIS minVmax) evaluated and max is the highest visibility evaluated, for example, VIS 1/2V2. Sector visibility must be reported when it differs from the prevailing visibility by one or more reportable values and either the prevailing or sector visibility Sector Visibility is less than 3 miles or considered to be 14.27 X X (VIS_dd_vv) operationally significant. In the remark, dd defines the sector to 8 points of the compass and vv is the sector visibility in SM, for example, VIS N 2. When an automated station uses meteorological discontinuity sensors, remarks must be added to identify site Visibility at Second specific visibilities which differ from Location (VIS vv conditions reported in the body of the 14.28 X3 X3 location) report. vv is the visibility value (NA LAWRS) measured at the secondary location. This remark must only be generated when the condition is lower than that contained in the body of the report. When lightning is manually observed, the frequency and location must be reported, along with the type of lightning, if known. For example, OCNL LTG OHD, FRQ LTGCG VC NE. When lightning is detected by an Lightning automated sensor (i.e. ALDARS) (Frequency_LTG(type) within 5NM of the ARP, it is reported 14.29 X X _ as "TS" in the body of the report with [LOC]) no remark; within 5-10NM of the ARP, it is reported as "VCTS" in the body of the report with no remark. Beyond 10NM from the ARP lightning is reported in remarks as "LTG DSNT" followed by direction from the ARP, for example, OCNL LTG DSNT NE. 3 09/01/2018 N JO 7900.11 Remarks Section of Observation Element Paragraph Brief Description METAR SPECI At stations with automated systems with SPECI capability and Manual Stations, when precipitation begins or ends, the next METAR report must include the type of phenomena, the Beginning/Ending Time beginning and/or ending time (prefixed of Precipitation with a B and/or E). If the beginning or 14.30 X X2 (WX)B(mm)E(mm) ending of the precipitation type (hail, (NA LAWRS freezing precipitation, or ice pellets) initiated the SPECI report, then that SPECI report must include the type of phenomena, the beginning and/or ending time, and should also be reported in the next METAR report. When thunderstorms begin or end, the SPECI report must include the type of Beginning/Ending Time phenomena, the beginning and/or of Thunderstorms 14.31 ending time (prefixed with a B and/or X X (TS)B(mm)E(mm) E), and should also be reported in the next METAR report, for example, TSB05E45 Thunderstorm location and movement, Thunderstorm Location 14.32 if known, must be encoded. For X X (TS_LOC_(MOV_DIR)) example, TS SE MOV NE. At augmented automated stations and at manual stations, the size of the largest hailstone is coded in 1/4 inch Hailstone Size (GR_ increments, identified with the 14.33 X X {INCHES}) contraction GR. When small hail less than 1/4 inch in size is occurring the hailstone size is reported in remarks as “GR LESS THAN 1/4”. When precipitation is observed to be falling from clouds, but is not reaching Virga the ground because of evaporation, 14.34 X X (VIRGA_{Direction}) report VIRGA; the direction from the station is optional, for example, VIRGA or VIRGA SW. Whenever the ceiling is below 3,000 feet and is variable, enter min as the Variable Ceiling Height 14.35 lowest ceiling height evaluated and X X (CIG minVmax) max as the highest ceiling height evaluated, for example, CIG 005V010. When the sky condition contains an obscuration, either at the surface or aloft (other than clouds), the type of Obscurations 14.36 phenomena in the layer, plus the sky X X (w’w’_(NsNsNs) hshshs) cover at the layer and the height must be reported in remarks, for example, FG SCT000 or FU BKN015. 4 09/01/2018 N JO 7900.11 Remarks Section of Observation Element Paragraph Brief Description METAR SPECI This remark must identify the layer that is varying and indicate the range of Variable Sky Condition variability. If there are several layers (NsNsNs(hshshs)_V_NsN 14.37 X X of the same coverage, the variable sNs) layer must be identified by including the layer height. When observed, the following clouds are reported in remarks: 1.) Cumulonimbus (CB) or Cumulonimbus Mammatus (CBMAM), distance, direction from the station, direction of movement, for example, CB W MOV E, CB DSNT W. 2.) Towering Cumulus (TCU), distance, and direction from the station, for example, TCU W. 3.) Altocumulus Castellanus (ACC), Significant Cloud Types 14.38 A A direction from station, for example, ACC NW. 4.) Standing Lenticular (stratocumulus SCSL; altocumulus ACSL, or cirrocumulus CCSL) or rotor clouds, direction from the station, for example, ACSL SW-W, APRNT ROTOR CLD NE, CCSL S. Cumulonimbus of any kind and towering cumulus are also identified in the body of the report. When an automated station uses meteorological discontinuity sensors, remarks must be added to identify site Ceiling Height at specific sky conditions which differ Second Location (CIG_ 14.39 from conditions reported in the body of X3 X3 {height}_ the report. This remark must only be {LOC}) (NA LAWRS generated when the ceiling is lower than that contained in the body of the report, for example, CIG_002_RY11. When the pressure is rising or falling Pressure Rising or rapidly at the time of the observation, Falling Rapidly 14.40 the remark Pressure Rising Rapidly X X (PRESRR) (PRESFR) (PRESRR) or Pressure Falling Rapidly (NA LAWRS) (PRESFR) must be included.
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