h.  The height of the base of each layer, h_sh_sh_s, shall be coded in hundreds of feet above the surface using three digits in accordance with Figure 15-6, Increments of Reportable Values of Sky Cover Height.

Figure 15-6. Increments of Reportable Values of Sky Cover Height

i.  Observers shall identify cumulonimbus or towering cumulus by appending cumulonimbus (CB) or towering cumulus (TCU), respectively, to the layer report. When the TCU or CB is appended to the layer report, accompanied by the remark, "TCU NW" or "CB NW MOV E", it is implied that the TCU or CB is associated with that layer and is within 10 SM. When the TCU or CB is outside of 10 SM, a DSNT remark is appropriate, for example, "TCU DSNT NW". (In this case, TCU or CB would not be appended to the layer in the body of the METAR.)

a.  The temperature shall be separated from the dew point following it by a solidus (/).

b.  The temperature and dew point shall be coded as two digits rounded to the nearest whole degree Celsius (see paragraph 3-9). Sub-zero temperatures and dew points shall be prefixed with an M. For example, a temperature of 4^oC with a dew point of -2^oC is coded as "04/M02". A temperature of -0.5^oC shall be coded as "M00".

c.  If the temperature is not available, the entire temperature/dew point group shall not be coded. If the dew point is not available, the temperature shall be coded followed by a solidus (/) and no entry made for dew point. For example, a temperature of 1.5^oC and a missing dew point would be reported as "02/".

The altimeter group always starts with an A (the international indicator for altimeter in inches of mercury). The altimeter shall be coded 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 coded.

Remarks shall be included in all METAR and SPECI, if appropriate. Remarks shall be separated from the altimeter group by a space and the contraction RMK. If there are no remarks, the contraction RMK shall not be entered.

a.  Remarks Categories. METAR/SPECI remarks fall into 2 major categories: Automated, Manual and Plain Language Remarks, and Additive and Maintenance Data.

b.  General Procedures for Remarks. Remarks shall be made in accordance with the following:

(1)  Use of Contractions and Abbreviations. Where plain language is called for, authorized contractions, abbreviations, and symbols should be used to conserve time and space. However, in no case should an essential remark, of which the observer is aware, 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 FAA Order 7340.1, Contractions.

(2)  Time Entries in Remarks. Time entries shall be made in minutes past the hour if the time reported occurs during the same hour the observation is taken. Hours and minutes shall be used if the hour is different, or this order prescribes the use of the hour and minutes.

(3)  Location Entries. With the exception of lightning and thunderstorms detected by an automated weather observing system, the location of phenomena within 5 statute miles of the point of observation shall be reported as occurring at the station. Phenomena between 5 and 10 statute miles shall be reported as vicinity (VC), followed by direction from the station, if known. Phenomena beyond 10 statute miles of the point of observation shall be reported as distant (DSNT) followed by the direction from the station. In the case of a tornado, the exact location should be included if possible. See paragraph 15-21, Funnel Cloud.

(4)  Movement Entries. Movement of clouds or weather, if known, shall be coded with respect to the direction toward which the phenomenon is moving.

(5)  Direction. Directions shall use the eight points of the compass coded in a clockwise order beginning with north.

(6)  Order of Entry. Insofar as possible, remarks shall be entered in the order in which they are presented in the following paragraphs.

These remarks generally elaborate on parameters reported in the body of the report. Automated and manual remarks may be generated either by an automated or manual station. Plain language remarks can only be added by an observer.

Volcanic eruptions shall be reported, whenever observed. Pre-eruption volcanic activity shall not be reported. Pre-eruption refers to unusual and/or increasing volcanic activity which could precede a volcanic eruption. The remark shall be plain language and contain the following, if known:

a.  Name of volcano.

b.  Latitude/longitude or the direction and the approximate distance from the station.

c.  Date/time (UTC) of the eruption.

d.  Size description, approximate height, and direction of movement of the ash cloud.

e.  Any other pertinent data about the eruption.

For example, a remark on a volcanic eruption would look like the following:

MT AUGUSTINE VOLCANO 70 MILES SW ERUPTED 231505 LARGE ASH CLOUD EXTENDING TO APRX 30000 FEET MOVING NE

At manual stations, tornadoes, funnel clouds, or waterspouts shall be coded in the above format, where TORNADO, FUNNEL CLOUD, or WATERSPOUT identifies the specific tornadic activity. B/E denotes the beginning and/or ending time, (hh)mm is the time of occurrence (only the minutes are required if the hour can be inferred from the report time). LOC/DIR is the location and/or direction of the phenomenon from the station, and MOV is the movement, if known. Tornadic activity shall be coded as the first remark after the "RMK" entry, unless a volcanic remark is required. For example, "TORNADO B13 6 NE" would indicate that a tornado, which began at 13 minutes past the hour, was 6 statute miles northeast of the station. At augmented ASOS sites, +FC is coded for tornadoes and waterspouts. In remarks, TORNADO, along with beginning or end time, would indicate either a tornado, funnel cloud, or waterspout began or ended.

AO1 or AO2 shall be coded in all METAR/SPECI from automated stations. Automated stations without a precipitation discriminator shall be identified as AO1; automated stations with a precipitation discriminator shall be identified as AO2.

At designated stations, the peak wind shall be coded in the above format in the next METAR where PK WND is the remark identifier, ddd is the direction of the peak wind, ff(f) is the peak wind speed since the last METAR, and (hh)mm is the time of occurrence (only the minutes are required if the hour can be inferred from the report time). There shall be one space between the two elements of the remark identifier and the wind direction/speed group; a solidus (/) (without spaces) shall separate the wind direction/
speed group and the time. For example, a peak wind of 45 knots from 280 degrees that occurred at 15 minutes past the hour would be coded "PK WND 28045/15".

At designated stations, a wind shift shall be coded in the above format, where WSHFT is the remark identifier and (hh)mm is the time the wind shift began (only the minutes are required if the hour can be inferred 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. There shall be a space between the remark identifier and the time, and if applicable, between the time and the frontal passage contraction. For example, a remark reporting a wind shift accompanied by a frontal passage that began at 30 minutes after the hour would be coded as "WSHFT 30 FROPA".

Tower visibility or surface visibility shall be coded in the above formats, where vvvvv is the observed tower/surface visibility value. A space shall be coded between each of the remark elements. For example, "TWR VIS 1 1/2" would indicate the visibility from the control tower was 1 1/2 SM.

Variable prevailing visibility shall be coded in the above format where VIS is the remark identifier, and v_nv_nv_nv_nv_n is the lowest visibility evaluated. V denotes variability between the two values, and v_xv_xv_xv_xv_x is the highest visibility evaluated. There shall be a space following the remark identifier; no spaces between the letter V and the lowest/highest values. For example, a visibility that was varying between 1/2 and 2 statute miles would be coded "VIS 1/2V2".

The sector visibility shall be coded in the above format when either the prevailing or sector visibility is less than 3 miles or is considered operationally significant, and sector visibility differs from the prevailing visibility by one or more reportable values. In the format of the remark, VIS is the remark identifier, [DIR] defines the sector to 8 points of the compass, and vvvvv is the sector visibility in statute miles, using the appropriate set of values in Figure 15-3, Reportable Visibility Values. For example, "VIS NE 2 1/2" would indicate that the visibility in the northeastern octant was 2 1/2 miles.

At designated automated stations, the visibility at a second location shall be coded in the above format, where VIS is the remark identifier, vvvvv is the measured visibility value, and [LOC] is the specific location of the visibility sensor(s) at the station. This remark shall only be generated when the condition is lower than that contained in the body of the report. For example, if the visibility measured by a second sensor located at runway 11 is 2 1/2 statute miles, the remark would be "VIS 2 1/2 RWY11".

a.  Manual Location. When lightning is observed at a manual location, the frequency, and location shall be reported. Type of lightning shall be reported, if known. The remark shall be coded in the above format. The contractions for the type of lightning shall be based on Figure 15-7, Type and Frequency of Lightning. The location and direction shall be coded in accordance with paragraph 15-18b(3). For example,

"CONS LTGIC OHD", "FRQ LTGCG VC", or "OCNL LTG DSNT W".

b.  When lightning is detected by an automated weather observing system with ALDARS:

(1)  Within 5 nautical miles of the Airport Reference Point (ARP), it will be reported as "TS" in the body of the report with no remark;

(2)  Between 5 and 10 miles of the ARP, it will be reported as "VCTS" in the body of the report with no remark;

(3)  Beyond 10 but less than 30 nautical miles of the ARP, it will be reported in remarks as "DSNT" followed by the direction from the ARP, e.g., "LTG DSNT W".

At designated automated stations and manual stations, the beginning and ending of precipitation shall be coded in the above format, where w'w' is the type of precipitation, B denotes the beginning, and E denotes the ending, and (hh)mm is the time of occurrence (only the minutes are required if the hour can be inferred from the report time). There shall be no spaces between the elements. Report beginning/ending times of precipitation in a SPECI if that precipitation caused the SPECI. Intensity qualifiers shall not be coded. For example, if rain began at 0005, ended at 0030, and snow began at 0020, and ended at 0055, the remarks would be coded "RAB05E30SNB20E55". If the precipitation were showery, the remark would be coded "SHRAB05E30SHSNB20E55".

At designated automated stations and manual stations, the beginning and ending of thunderstorm(s) shall be coded in the above format, where TS indicates thunderstorm, B denotes the beginning, and E denotes the ending. (hh)mm is the time of occurrence (only the minutes are required if the hour can be inferred from the report time). There shall be no spaces between the elements. For example, if a thunderstorm began at 0159 and ended at 0230, the remark would be coded "TSB0159E30". These coded remarks are required in the SPECI and in the next METAR after the event.

At designated stations, thunderstorms shall be coded in the above format, where TS identifies the thunderstorm activity, LOC is the location of the thunderstorm(s) from the station, and MOV_DIR is the movement with direction, if known. For example, "TS SE MOV NE" would indicate a thunderstorm southeast of the station moving northeast. Thunderstorms beyond 10 SM shall be coded as distant, for example, "TS DSNT NW". Any other thunderstorm location or movement remarks the observer judges appropriate shall be added manually.

At designated manual stations, the hailstone size shall be coded in the above format where GR is the remark identifier and [size] is the diameter of the largest hailstone, coded in 1/4 inch increments. When the largest hailstone observed is 1/4 inch or more in diameter, it shall be coded with the contraction GR. For example, "GR 1 3/4" would indicate that the largest hailstones were 1 3/4 inches in diameter. If GS is coded in the body of the report, no size remark is required.

At augmented automated stations and at manual stations, virga shall be coded in the indicated format, when precipitation is observed to be falling from clouds but is not reaching the ground because of evaporation. The direction, DIR, of the phenomenon from the station is optional, e.g., "VIRGA" or "VIRGA SW".

At designated manual stations, the variable ceiling height shall be coded in the above format, where CIG is the remark identifier, h_nh_nh_n is the lowest ceiling height evaluated. V denotes variability between two values, and h_xh_xh_x is the highest ceiling height evaluated. There shall be one space following the remark identifier, and no spaces between the letter V and the lowest/
highest values. For example, "CIG 005V010" would indicate a ceiling that was varying between 500 and 1,000 feet.

Obscurations shall be coded in the indicated format, where w'w' is the present weather causing the obscuration at the surface or aloft, and N_sN_sN_s is the applicable sky cover amount of the obscuration aloft (FEW, SCT, BKN, OVC) or at the surface (FEW, SCT, BKN), and h_sh_sh_s is the applicable height. Surface-based obscurations shall have a height of "000". The type of present weather shall be prefixed (separated by a space) to the sky cover layer that represents the obscuration. For example, "FG SCT000" indicates that fog is hiding 3 to 4 eighths of the sky. A broken layer at 2,000 feet composed of smoke would be coded "FU BKN020".

The variable sky condition remark shall be coded in the above format, where N_sN_sN_s(h_sh_sh_s) and N_sN_sN_s identify the two operationally significant sky conditions and V denotes the variability between the two ranges. For example, "SCT V BKN" would identify a scattered layer that is variably broken. If there are several layers with the same sky condition amount in the report, the layer height shall be coded with the variable layer. For example, a cloud layer at 1,400 feet that is varying between broken and overcast would be coded "BKN014 V OVC".

At designated stations, the significant cloud types remark shall be coded in all reports as described below. (Cumulonimbus of any kind and towering cumulus are also identified in the body of the report in the sky condition group.)

a.  Cumulonimbus or Cumulonimbus Mammatus (CB or CBMAM_LOC_ (MOV_DIR). Cumulonimbus or cumulonimbus mammatus, as appropriate, (for which no thunderstorm is being reported) shall be coded in the above format, where CB or CBMAM is the cloud type, LOC is the direction from the station, and MOV_DIR is the movement with direction (if known). The cloud type, location, movement and direction entries shall be separated from each other with a space. For example, "CB W MOV E" would indicate that a CB up to 10 statute miles west of the point of observation, was moving toward the east. If the cloud was more than 10 statute miles away, the remark would be "CB DSNT W".

b.  Towering Cumulus (TCU_[DIR]). Towering cumulus clouds shall be coded in the format, TCU_[DIR], where TCU is the cloud type and DIR is the direction from the point of observation. The cloud type and direction entries shall be separated by a space. For example, "TCU W" would indicate towering cumulus clouds up to 10 statute miles west of the point of observation.

c.  Altocumulus Castellanus (ACC_[DIR]). Altocumulus Castellanus shall be coded in the format, ACC_[DIR], where ACC is the cloud type and DIR is the direction from the point of observation. The cloud type and direction entries shall be separated by a space. For example, "ACC NW" would indicate altocumulus castellanus up to 10 statute miles northwest of the point of observation.

d.  Standing Lenticular or Rotor Clouds (CLD_[DIR]). Stratocumulus standing lenticular (SCSL), altocumulus standing lenticular (ACSL), or cirrocumulus standing lenticular (CCSL), or rotor clouds shall be coded in the format, CLD_[DIR], where CLD is the cloud type and DIR is the direction from the point of observation. The cloud type and direction entries shall be separated by a space. For example, altocumulus standing lenticular clouds observed southwest through west of the point of observation would be coded "ACSL SW-W"; an apparent rotor cloud northeast of the point of observation would be coded "APRNT ROTOR CLD NE"; and cirrocumulus standing lenticular clouds south of the point of observation would be coded "CCSL S".

At designated automated stations, the ceiling height at a second location shall be coded in the above format, where CIG is the remark identifier, hhh is the measured height of the ceiling, and [LOC] is the specific location of the ceilometer(s) at the station. This remark shall only be generated when the ceiling is lower than that contained in the body of the report. For example, if the ceiling measured by a second sensor located at runway 11 is broken at 200 feet, the remark would be "CIG 002 RWY11".

At designated automated stations and manual stations, when the pressure is rising or falling rapidly at the time of the observation, the remark PRESRR or PRESFR shall be included in the report.

At automated stations and designated manual stations, sea-level pressure shall be reported in the above format. The remark begins with SLP and is coded using the tens, units, and tenths of the sea-level pressure in hectopascals. For example, a sea-level pressure of 998.2 hectopascals would be coded as "SLP982". For a METAR, if sea-level pressure is not available at stations where it would normally be reported, it is coded as "SLPNO".

If a report is taken to document weather conditions when notified of an aircraft mishap, the remark ACFT_MSHP shall be included in the report, but not transmitted. The act of non-transmission shall be indicated by enclosing the remark in parentheses in the record, i.e., "(ACFT MSHP)".

At staffed stations where SPECI's are not taken, the remark NOSPECI shall be coded to indicate that no changes in weather conditions will be reported until the next METAR.

At designated manual stations, the snow increasing rapidly remark shall be coded, in the next METAR, whenever the snow depth increases by 0.5 inch (1 inch to the nearest whole inch) or more in the past hour, and the reportable value (in whole inches) of the total depth of snow on the ground increases by one inch or more. The remark shall be coded in the above format, where SNINCR is the remark indicator, "inches-hour" is the depth increase in the past hour, and "inches on ground" is the total depth of snow on the ground at the time of the report. The depth increase in the past hour and the total depth on the ground are separated from each other by a solidus (/). For example, a report of "SNINCR 2/10" indicates a snow depth increase of 2 inches in the last hour with a total depth on the ground of 10 inches.

Agencies may have other information significant to their operations, such as information on fog dispersal operations, runway conditions, and other information important to aircraft operations.

Additive data groups are only reported at designated stations. The maintenance data groups are only reported from automated stations.

Precipitation Additive Data. At designated stations, the amount of liquid precipitation shall be evaluated as the depth of precipitation that accumulates in an exposed vessel during the time period being evaluated. The amount of freezing or frozen precipitation shall be the water equivalent of the solid precipitation accumulated during the appropriate time period. Precipitation measurements shall be in inches, tenths of inches, or hundredths of inches depending on the precipitation being measured (see Figure 15-8, Units of Measure for Precipitation). The depth of freezing and/or frozen precipitation shall be the actual vertical depth of the precipitation accumulated on a horizontal surface during the appropriate time period. If snow falls, melts, and refreezes, the depth of ice formed shall be included in the measurement.

At designated automated stations, the hourly precipitation amount remark shall be coded in the format, Prrrr, where P is the group indicator and rrrr is the water equivalent of all precipitation that has occurred since the last METAR. The amount shall be coded in hundredths of an inch. For example, "P0009" would indicate 9/100 of an inch of precipitation fell in the past hour; "P0000" would indicate that less than 1/100 of an inch of precipitation fell in the past hour. The group shall be omitted if no precipitation occurred since the last METAR.

NWS and FAA have developed an algorithm to be applied to the ASOS freezing rain sensor that can accurately measure and report the amount of surface ice accretion at a specific point over a given time period. The ASOS freezing rain sensor, and the newly developed ice accretion algorithm will generate information that will be included in the remarks section of a METAR/ SPECI. Ice accretion remarks shall only be included in the METAR and SPECI reports when accretion is occurring, or has occurred during the reporting period. The remark will be updated each minute when encoded. This requirement is for automated encoding of these remarks, and no manual backup is required. Although the ice accretion remark was not available at the time of this writing, it is scheduled to be available following an upcoming ASOS software revision. The format for the hourly, 3-hourly, and 6-hourly reports follows.

a.  Hourly Ice Accretion Amount (I1nnn). This remark provides the ice accretion amount during the preceding hour. The accretion of ice over the past one hour time period in one-hundredths of an inch (0.01 in.) would have the format: "I1nnn"; where "I" is the icing indicator for the group, "1" is the reported time period (one hour), and "nnn" is the thickness accumulated to the nearest one-hundredth of an inch (0.01 in.), during the reported time period (one hour). This remark shall be reset immediately after the hourly METAR report is transmitted. When this remark is included in the ASOS software, it will most likely be encoded immediately following the hourly precipitation amount, and before the 3- and 6-hour precipitation amount.

b.  3-Hourly Ice Accretion Amount (I3nnn). This remark provides the ice accretion amount during the last three hours, and is included in the reports taken at the intermediate synoptic times of 0300, 0900, 1500, and 2100 UTC. The accretion of ice over the past three hour time period in one-hundredths of an inch (0.01 in.) would have the format: "I3nnn"; where "I" is the icing indicator for the group, "3" is the reported time period (three hours), and "nnn" is the thickness accumulated to the nearest one-hundredth of an inch (0.01 in.), during the reported time period (three hours). This remark shall be reset immediately after the intermediate synoptic or mandatory synoptic METAR is transmitted (0300, 0600, 0900, 1200, 1500, 1800, 2100 and 0000 UTC). When this remark is included in the ASOS software, it will most likely be encoded immediately following the hourly ice accretion amount, and before the 3- and 6-hour precipitation amount.

c.  6-Hourly Ice Accretion Amount (I6nnn). This remark provides the ice accretion amount during the last six hours, and is included in the reports taken at the synoptic times of 0600, 1200, 1800, and 0000 UTC. The accretion of ice over the past six hour time period in one-hundredths of an inch (0.01 in.) would have the format: "I6nnn"; where "I" is the icing indicator for the group, "6" is the reported time period (six hours), and "nnn" is the thickness accumulated to the nearest one-hundredth of an inch (0.01 in.), during the reported time period (six hours). This remark shall be reset immediately after the mandatory synoptic METAR is transmitted (0600, 1200, 1800, and 0000 UTC). When this remark is included in the ASOS software, it will most likely be encoded immediately following the hourly ice accretion amount, and before the 3- and 6-hour precipitation amount.

d.  Missing Data. If the freezing rain sensor is inoperative for more than 25 percent of the reporting period, the icing remark shall be considered missing. Missing groups shall be encoded as I1///, I3///, or I6///, as appropriate. If no icing is detected, then the groups shall not be encoded. Note that an automated icing event will always report at least 0.01 in. of ice accretion.

At designated stations, the 3- and 6-hourly precipitation group shall be coded in the above format, where 6 is the group indicator and RRRR is the amount of precipitation. The amount of precipitation (water equivalent) accumulated in the past 3 hours shall be reported in the 3-hourly report and the amount accumulated in the past 6 hours shall be reported in the 6-hourly report. The amount of precipitation shall be coded in inches, using the ten, units, tenths, and hundredths digits of the amount. When an indeterminable amount of precipitation has occurred during the period, RRRR shall be coded "6////". For example, 2.17 inches of precipitation would be coded "60217". A trace shall be coded "60000".

At designated stations, the 24-hour precipitation amount shall be coded in the above format, where 7 is the group indicator and R₂₄R₂₄R₂₄R₂₄ is the 24-hour amount of precipitation included in the 1200 UTC (or other agency-designated time) report whenever more than a trace of precipitation (water equivalent) has fallen in the past 24 hours. The amount of precipitation shall be coded by using the tens, units, tenths, and hundredths of inches (water equivalent) for the 24-hour period. If more than a trace (water equivalent) has occurred and the amount cannot be determined, the group shall be coded "7////". For example, 1.25 inches of precipitation (water equivalent) in the past 24 hours shall be coded "70125".

At designated stations, the total snow depth on ground group shall be coded in the 0000 and 1200 UTC observations whenever there is more than a trace of snow on the ground. It shall be coded in the 0600 and 1800 UTC observations if there is more than a trace of snow on the ground and more than a trace of precipitation (water equivalent) has occurred within the past 6 hours. The remark shall be coded in the format 4/sss, where 4/ is the group indicator and sss is the snow depth in whole inches using three digits. For example, a snow depth of 21 inches shall be coded as "4/021".

At designated manual stations, the water equivalent of snow on ground group is reported each day in the 1800 UTC report if the average snow depth is 2 inches or more. The remark shall be coded in the format 933RRR, where 933 is the group indicator and RRR is the water equivalent of snow, i.e., snow, snow pellets, snow grains, ice pellets, ice crystals, hail, on the ground. The water equivalent shall be reported in tens, units, and tenths of inches, using three digits. Do not code the group if it consists entirely of hail. A water equivalent of snow of 3.6 inches would be coded as "933036" and a water equivalent of 12.5 would be coded as "933125".

At designated manual stations, this group shall be reported and coded in 3- and 6-hourly reports when clouds are observed. The predominant low cloud (C_L), middle cloud (C_M), and high cloud (C_H) shall be identified in accordance with the WMO International Cloud Atlas, Volumes I and II, the WMO Abridged International Cloud Atlas, or other agency observing aids for cloud identification. A "0" shall be coded for the low, middle, or high cloud type if no cloud is present at that classification. A solidus (/) shall be coded for layers above an overcast. For example, a report of "8/6//" would indicate an overcast layer of stratus clouds; a report of "8/903" would indicate cumulonimbus type low clouds, no middle clouds, and dense cirrus high clouds.

At designated manual stations, the duration of sunshine shall be coded in the 0800 UTC report. If the station is closed at 0800 UTC, the group shall be coded in the first 6-hourly METAR after the station opens. The duration of sunshine shall be coded in the format 98mmm, where 98 is the group indicator and mmm is the total minutes of sunshine. The minutes of sunshine that occurred the previous calendar day is coded by using the hundreds, tens, and units digits. For example, 96 minutes of sunshine would be coded "98096". If no sunshine occurred, the group would be coded "98000".

At designated stations, the hourly temperature and dew point group shall be coded in the above format, where T is the group indicator, s_n is the sign of the temperature, T'T'T' is the temperature, and T'_dT'_dT'_d is the dew point. The sign of the temperature and dew point shall be coded as 1 if the value is below 0^oC and 0 if the value is 0^oC or higher. The temperature and dew point shall be reported in tens, units, and tenths of degrees Celsius. There shall be no spaces between the entries. For example, a temperature of 2.6^oC and dew point of -1.5^oC would be reported in the body of the report as "03/M01" and the Ts_nT'T'T's_nT'_dT'_dT'_d group as "T00261015". If dew point is missing, report the temperature; if the temperature is missing, do not report the temperature/dew point group.

At designated stations, the 6-hourly maximum temperature group shall be coded in the above format, where 1 is the group indicator, s_n is the sign of the temperature, T_xT_xT_x is the maximum temperature in tenths of degrees Celsius using three digits. The sign of the maximum temperature shall be coded as 1 if the maximum temperature is below 0^oC and 0 if the maximum temperature is 0^oC or higher. For example, a maximum temperature of -0.1^oC would be coded "11001"; 14.2^oC would be coded "10142".

At designated stations, the 6-hourly minimum temperature group shall be coded in the above format, where 2 is the group indicator, s_n is the sign of the temperature, and T_nT_nT_n is the minimum temperature in tenths of degrees Celsius using three digits. The sign of the minimum temperature shall be coded as 1 if the minimum temperature is below 0^oC and 0 if the minimum temperature is 0^oC or higher. For example, a minimum temperature of -2.1^oC would be coded "21021"; 1.2^oC would be coded "20012".

At designated stations, the 24-hour maximum temperature and the 24-hour minimum temperature shall be coded in the above format, where 4 is the group indicator, s_n is the sign of the temperature, T_xT_xT_x is the maximum 24-hour temperature, and T_nT_nT_n is the 24-hour minimum temperature. Temperature shall be coded in tenths of degrees Celsius using three digits. The sign of the maximum or minimum temperature shall be coded as 1 if it is below 0^oC and 0 if it is 0^oC or higher. For example, a 24-hour maximum temperature of 10.0^oC and a 24-hour minimum temperature of -1.5^oC would be coded "401001015".

At designated stations, the 3-hourly pressure tendency group shall be coded in the format 5appp where 5 is the group indicator, a is the character of pressure change over the past 3 hours, and ppp is the amount of barometric change in tenths of hectopascals using the tens, units, and tenths digits (see Figure 15-9, Characteristics of Barometer Tendency). The character a shall be coded by selecting the code figure from Figure 15-9 that best described the pressure change in the past 3 hours. For example, a steady increase of 3.2 hectopascals in the past three hours would be coded "52032". The ppp shall be coded based on the absolute value of the change of either the station pressure or the altimeter setting in the past 3 hours in tenths of hectopascals and using the tens, units, and tenths digits (see Figure 15-10, 3-Hour Change in Pressure). For example, a steady increase of 3.2 hectopascals in the past 3 hours would be coded "52032".

At designated stations, sensor status indicators should be reported as indicated below:

a.  When automated stations are equipped with a precipitation identifier and that sensor is not operating, the remark PWINO shall be coded.

b.  When automated stations are equipped with a tipping bucket rain gauge and that sensor is not operating, PNO shall be coded.

c.  When automated stations are equipped with a freezing rain sensor and that sensor is not operating, the remark FZRANO shall be coded.

d.  When automated stations are equipped with a lightning detection system and that sensor is not operating, the remark TSNO shall be coded.

e.  When automated stations are equipped with a secondary visibility sensor and that sensor is not operating, the remark VISNO_LOC shall be coded.

f.  When automated stations are equipped with a secondary ceiling height indicator and that sensor is not operating, the remark CHINO_LOC shall be coded.

A maintenance indicator sign $ shall be coded when an automated weather observing system detects that maintenance is needed on the system.

15-62.   TRANSMISSION TIMES

For transmission times of observations, refer to the latest version of Order 7110.10, Flight Services, Chapter 9, FAA Weather Services.