Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) Example:
/RM DISCHARGE 120 Remarks, discharge, 12,000 feet MSL
3.2.1.12.6 Clouds Remarks are used when clouds can be seen but were not encountered and reported in the sky condition group (/SK)
Examples:
/RM CB E MOV N Remarks, cumulonimbus east moving north /RM OVC BLO Remarks, overcast below
3.2.1.12.7 Plain Language If specific phraseology is not adequate, plain language is used to describe the phenomena or local geographic locations. Remarks that do not fit in other groups like DURC (during climb), DURD (during descent), RCA (reach cruising altitude), TOP, TOC (top of climb), or CONTRAILS are included.
Examples:
/RM BUMPY VERY ROUGH RIDE /RM CONTRAILS /UA/OV BIS270030/TM 1445/FL060/TP CVLT/TB LGT /RM DONNER SUMMIT PASS
3.2.1.12.8 Volcanic Eruptions Volcanic ash alone is an Urgent PIREP. A report of volcanic activity includes as much information as possible including the name of the mountain, ash cloud and movement, height of the top and bottom of the ash, etc., is included. If the report is received from a source other than a pilot, Aircraft UNKN, Flight Level UNKN, and /RM UNOFFICIAL is entered.
Example:
/UUA/OV ANC240075/TM 2110/FL370/TP DC10/WX VA/RM VOLCANIC ERUPTION 2008Z MT AUGUSTINE ASH 40S MOV SSE
Urgent Pilot Weather Report, 240 degrees at 75 nautical miles from Anchorage International Airport, Alaska, 2110 UTC, flight level 310, a DC10 reported volcanic ash, remarks, volcanic eruption occurred at 2008 UTC Mount Augustine, ash 40 nautical miles south moving southsoutheast.
3.2.1.12.9 SKYSPOTTER The SKYSPOTTER program is a result of a recommendation from the Safer Skies FAA/INDUSTRY Joint Safety Analysis and Implementation Teams. The term SKYSPOTTER indicates a pilot has received specialized training in observing and reporting in-flight weather phenomenon, pilot weather reports, or PIREPs.
When a PIREP is received from a pilot identifying themselves as a SKYSPOTTER aircraft, the additional comment “/AWC” is added at the end of the remarks section of the PIREP.
Example:
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-42
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
PIREP TEXT/RM REMARKS/AWC
3.2.2 PIREP Examples
UUA /OV ORD/TM 1235/FLUNKN/TP B727/TB MOD/RM LLWS +/- 20KT BLW 003 DURD RWY27L
Urgent Pilot Weather Report, over Chicago O’Hare Airport, Illinois, 1235 UTC, flight level unknown, from a Boeing 727, moderate turbulence, remarks, Low Level Wind Shear, airspeed fluctuations of plus or minus 20 knots below 300 feet AGL during descent, runway 27 left.
UUA /OV BAM260045/TM 2225/FL180/TP BE20/TB SEV/RM BROKE ALL THE
BOTTLES IN THE BAR
Urgent Pilot Weather Report, 260 degrees at 45 nautical miles from Hazen VOR, Nevada, 2225 UTC, 18,000 feet MSL, Beech Super King Air 200, severe turbulence, remarks, broke all the bottles in the bar.
UA /OV KMRB-KPIT/TM 1600/FL100/TP BE55/SK BKN024-TOP032/BKN-OVC043- TOPUNKN /TA M12/IC LGT-MOD RIME 055-080
Pilot Weather Report, Martinsburg, West Virginia to Pittsburgh International Airport, Pennsylvania, 1600 UTC, 10,000 feet MSL, Beechcraft Baron, base of a broken layer 2,400 feet MSL, top 3,200 feet MSL, base of a broken to overcast layer 4,300 feet MSL, top unknown, temperature minus 12, light to moderate rime ice between 5,500 to 8,000 feet MSL.
UA /OV IRW090064/TM 1522/FL080/TP C172/SK SCT090-TOPUNKN/WX FV05SM HZ/TA M04/WV 24040KT/TB LGT/RM IN CLR
Pilot Weather Report, 90 degrees and 64 nautical miles from Will Rogers VORTAC, Oklahoma City, Oklahoma, 1522 UTC, 8,000 feet MSL, Cessna 172, base of a scattered layer 9,000 feet MSL, top unknown, flight visibility 5 statute miles, haze, temperature minus 4, wind 240 degrees at 40 knots, light turbulence, remarks, in clear.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-43
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) UA /OV KLIT-KFSM/TM 0310/FL100/TP BE36/SK SCT070-TOP110/TA M03/WV 25015KT Pilot Weather Report, between Little Rock and Fort Smith, Arkansas, 0310 UTC at 10,000 feet MSL. Beech 36, base of a scattered layer at 7,000 feet MSL, top 11,000 feet MSL, temperature minus 3, wind 250 degrees at 15 knots.
UA /OV KAEG/TM 1845/FL UNKN/TP UNKN /RM TIJERAS PASS CLSD DUE TO FG AND LOW CLDS UNA VFR RTN KAEG.
Pilot Weather Report, over Double Eagle II Airport, Albuquerque, New Mexico, 1845 UTC, remarks, Tijeras Pass closed due to fog and low clouds, unable to fly VFR, returned to Double Eagle II Airport.
UA /OV ENA14520/TM 2200/FL310/TP B737/TB MOD CAT 350-390.
Pilot Weather Report, 145 degrees at 20 nautical miles from Kenai, Alaska, at 2200 UTC, at flight level 310, Boeing 737, moderate clear air turbulence between 35,000 and 39,000 feet MSL.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-44
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
3.3 Radar Weather Report (SD/ROB) A Radar Weather Report (SD/ROB) contains information about precipitation observed by weather radar. This is a textual product derived from the WSR-88D NEXRAD radar without human intervention. The resolution of this textual product is very coarse, up to 80 minutes old, and should only be used if no other radar information is available.
Figure 3-11. Radar Weather Report (SD/ROB) Coding Format
3.3.1 Format Reports are transmitted hourly from WSR-88D Weather Radar sites (see figure 3-12). The SD/ROB format is presented in Figure 3-8.
3.3.1.1 Location Identifier The location identifier is reported as the three-letter International Air Transport Association (IATA) code.
Example:
TLX Oklahoma City Twin Lakes, Oklahoma
3.3.1.2 Time The time of the observation is reported in four-digits Universal Time Coordinated (UTC).
Example:
1935 1935 UTC
3.3.1.3 Configuration Three types of configurations can be reported: CELL, LN (line), and AREA. Multiple configurations can be reported within one Weather Radar Report.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-45
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) A CELL is a single, isolated convective echo.
A LN (line) is a convective echo that meets the following criteria:
• Contains heavy or greater intensity precipitation
• Is at least 30 miles long
• Length is at least four times greater than width
• Contains at least 25 percent coverage
An AREA is a group of echoes of similar type, not classified as a line.
Figure 3-9 illustrates the three configurations that can be reported in a Weather Radar Report.
Figure 3-12. Radar Weather Report (SD/ROB) Configurations
3.3.1.4 Coverage Coverage of precipitation is coded in single digits representing tenths of coverage.
For echo configurations containing multiple precipitation types, coverage is coded for each type.
Total coverage is obtained by adding the individual values.
Examples:
2TRW+4R 2/10 coverage TRW+, 4/10 coverage R, 6/10 total coverage 3R6S- 3/10 coverage R, 6/10 coverage S-, 9/10 total coverage
3.3.1.5 Precipitation Type Precipitation type is determined by computer model.
Reportable types are:
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-46
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
• Rain (R )
• Rain shower (RW )
• Snow (S)
• Snow shower (SW )
• Thunderstorm ( T)
Multiple precipitation types can be reported within a configuration.
3.3.1.6 Precipitation Intensity Four precipitation intensities can be reported as shown in table 3-11.
Table 3-11. SD/ROB Reportable Intensities Symbol Intensity dBZ
- Light 0-29 (no entry) Moderate 30-40 + Heavy 41-45 ++ Heavy 46-49 X Extreme 50-56 XX Extreme 57 or more
Examples:
7R- 7/10 coverage of light rain 3R-6S 3/10 coverage light rain, 6/10 coverage moderate snow, 9/10 total coverage 2TRWX4R- 2/10 coverage thunderstorms, extreme rain showers , 4/10 coverage light rain, 6/10 total coverage
3.3.1.7 Location An area is coded with two end points and a width that defines a rectangle. Each end point is defined by an azimuth and range (AZRAN).
A line is also coded with two end points and a width that defines a rectangle. Each end point is defined by an AZRAN.
A cell is coded as a single point with a diameter (D). This point is defined by an AZRAN.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-47
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 3-13. SD/ROB AREA, Line (LN), and CELL Location Examples The “+” denotes the radar location.
3.3.1.8 Maximum Top Maximum top (MT or MTS) denotes the altitude and location of the top of the highest precipitation echo.
All radar heights are estimates and assume standard atmosphere conditions and, thus, standard radar wave propagation. MT denotes radar data alone was used to determine the maximum top. MTS denotes both satellite and radar data were used to estimate the maximum top.
The maximum top is coded as a three-digit number in hundreds of feet MSL. Location is coded as an azimuth and range (AZRAN) relative to the radar site. If echo tops are uniform in altitude, the letter “U” precedes the altitude with no AZRAN provided.
Examples:
MT 150 19/32 Maximum top 15,000 feet MSL at 19 degrees, 32 nautical miles MT 340 182/98 Maximum top 34,000 feet MSL at 182 degrees, 98 nautical miles MTS 520 5/121 Maximum top with satellite data 52,000 feet MSL at 5 degrees, 121 nautical miles
3.3.1.9 Cell Movement Cell movement is the average motion of all the cells within a configuration. It is coded in the following format: the cell movement group is indicated by the letter C followed by four digits.
The first two digits represent the direction the cell(s) is (are) moving from in tens of degrees referenced to true north. The last two digits represent the speed of the configuration in knots.
Movement of areas and lines is not coded.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-48
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Examples:
C0209 Cell movement from 20 degrees at 9 knots C2043 Cell movement from 200 degrees at 43 knots C3616 Cell movement from 360 degrees at 16 knots
3.3.1.10 Remarks Remarks contain information about the radar’s status and type of report. Currently, all weather radar reports are automated.
Table 3-12. Weather Radar Report Remarks and Meaning
REMARK MEANING PPINE Equipment normal and operating, but no echoes observed PPINA Observation not available PPIOM Radar out for maintenance AUTO Report derived from an automated weather radar
3.3.1.11 Digital Section The information contained in the digital section is used primarily to create the Radar Summary Chart. However, with the proper grid overlay chart for the corresponding radar site, the digital section code can also be used to determine precipitation location and intensity. (See Figure 3- 11 for an example of a digital code plotted from the Oklahoma City, Oklahoma, Weather Radar Report.)
Each digit represents the maximum precipitation intensity found within a grid box as determined by the weather radar. Light intensity is denoted by a 1, 2 is for moderate, 3 and 4 is for heavy, 5 and 6 is used for extreme precipitation. These digits were once commonly referred to as VIP levels because precipitation intensity, and therefore the digit, was derived using a video integrator processor (VIP). Whereas the old WSR-57 and WSR-74 weather radar video integrator processors displayed six data levels, the WSR-88D weather radar displays sixteen data levels. The data levels are still converted back to six levels for use in the Radar Weather Report. To avoid confusion, the term VIP should no longer be used to describe precipitation intensity. For example, if a grid box is coded with the number 2, it would be described as “moderate” precipitation,” not “VIP 2” or “level 2” precipitation.
A grid box is identified by two letters. The first represents the row in which the box is found and the second letter represents the column. For example MO1 identifies the box located in row M and column O as containing light precipitation. A code of MO1234 indicates precipitation in four consecutive boxes in the same row. Working from left to right: box MO = 1, box MP = 2, MQ = 3, and box MR = 4.
A Weather Radar Report contains data about precipitation echoes only. It does not contain information about important non-precipitation echoes such as clouds, fronts, dust, etc., which can be detected by weather radar under certain circumstances.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-49
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) HQ N HI HJ HM
• HP HQ HR JG IP JK JL
KG JM JN JO JP
KJ KK KL JS KN КР
LK LM I KS
MG LM UN LO LP
MI MJ MK ML ILO LR
AMILX MN MO MP NI INJ NK NL NM 1 MR †MS /Og NN I NO INP au 1 NQ INR >G PI IPJ PK /PL OL OM ON 100 /OP 0Q OR ros ан PN 4 PO PP IPQ ак PS 1 PT ам ON RI OR
RK AL RM
ISH SI SJ RP RO RS RT SM SN
ITH TI TJ TK TL TM S SP SQ SA SS ST
I TO TP Figure 3-14. SD/ROB Digital Section Information Plotted on a PPI Grid Overlay Example (See Table 3-11 for Intensity Level Codes 1 through 6.)
3.3.2 Examples GRB 1135 AREA 4TRW+ 9/101 133/76 54W MT 310 45/47 C2428 AUTO Green Bay, Wisconsin, automated Radar Weather Report at 1135 UTC. An area of echoes, 4/10 coverage, contained thunderstorms and heavy rain showers. Area is defined by points (referenced from GRB radar site) at 9 degrees, 101 nautical miles and 133 degrees, 76 nautical miles. These points, plotted on a map and connected with a straight line, define the center line of the echo pattern. The width of the area was 54 nautical miles; i.e., 27 nautical miles either side of the center line. Maximum top was 31,000 feet MSL located at 45 degrees and 47 nautical miles from Green Bay. Cell movement was from 240 degrees at 28 knots.
ICT 1935 IN 9TRWX 274/84 216/93 22W MTS 440 260/48 C2131 AUTO Wichita, Kansas, automated Radar Weather Report at 1935 UTC. A line of echoes, 9/10 coverage, contained thunderstorm with intense rain showers. The center of the line extended AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-50
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) from 274 degrees, 84 nautical miles to 216 degrees, 93 nautical miles. The line was 22 nautical miles wide.
To display graphically, plot the center points on a map and connect the points with a straight line; then plot the width. Since the thunderstorm line was 22 nautical miles wide, it extended 11 nautical miles either side of your plotted line.
The maximum top is 44,000 feet MSL at 260 degrees, 48 nautical miles from Wichita. Cell movement was from 210 degrees at 31 knots.
GGW 1135 AREA 3S- 95/129 154/81 34W MT 100 130/49 0805 AUTO
Glasgow, Montana, automated Radar Weather Report at 1135 UTC. An area, 3/10 coverage, of light snow. The area’s centerline extended from points at 95 degrees, 129 nautical miles to 154 degrees, 81 nautical miles from Glasgow. The area was 34 nautical miles wide. The maximum top was 10,000 feet MSL, at 130 degrees, 49 nautical miles from Glasgow. Cell movement was from 80 degrees at 5 knots.
JGX 2235 AREA 2TRW++6R- 67/130 308/45 106W MT 380 66/54 C2038 AUTO
Atlanta, Georgia, automated Radar Weather Report at 2235 UTC. An area of echoes, total coverage 8/10, with 2/10 of thunderstorms with very heavy rain showers and 6/10 coverage of light rain (This suggests that the thunderstorms were embedded in an area of light rain). The area was 53 nautical miles either side of the line defined by the two points, 67 degrees, 130 nautical miles and 308 degrees, 45 nautical miles from Atlanta. Maximum top was at 38,000 feet and was located on the 66 degree radial of JGX at 54 nautical miles. Cell movement was from 200 degrees at 38 knots.
HKM 0235 CELL TRW+ 19/22 D5 MT 270 18/23 C0414 AUTO
Kohala, Hawaii, automated Radar Weather Report at 0235 UTC. A cell, containing thunderstorms with very heavy rain showers, 5 miles in diameter, was located 19 degrees, 22 nautical miles from Kohala. Maximum top was 27,000 feet located at 18 degrees, 23 nautical miles from Kohala. Movement was from 40 degrees at 14 knots.
TLX 0435 PPINE AUTO
Oklahoma City, Oklahoma, automated Radar Weather Report at 0435 UTC, detected no echoes.
AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-51
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) KIMSK
KGGW OKMVX KDI
OKIFX OKBIS KELX KABE O КИРУ KGRB O
KMAX KUDX KARY KRIW →KIE ADITY C КОСх KBB X KIŘx КСУУ кадк KOAX O
OKRCE OKILN KRLX KDAX *KUEX ILLO KFTGO OKEAX
KICK KPUX O KE SX KDDCO ÖKIT ÖKSEF *EMEX KRAI OKVTX KEYXO KNKX KIWA KF SX ' KABX KPDE OKLBB HUN KIng -OKFDR CATLE OKSRX KLZK KGWO KNOA KHIS KBMX RESP OKCA Cas -KYUX кНіх KIGX KEMY OKFWS ÖESHY КРОЕ KJAN KE OXO KÅIT KGRK O KLCH' киХО
KDEX KEWE PAPD Figure 3-15. WSR-88D Weather Radar Network Sites AC 00-45F, CHG 2 Section 3: Observed Text Products Page 3-52
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) 4 RADAR AND SATELLITE IMAGERY
4.1 Radar
4.1.1 Description Radar images are graphical displays of precipitation and non-precipitation targets detected by weather radar. WSR-88D Doppler radar displays these targets on a variety of products which can be found on the internet on the National Weather Service (NWS) Doppler Radar Images web site at: http://radar.weather.gov/ridge/
4.1.2 Modes of Operation The WSR-88D Doppler radar has two operational modes, Clear Air and Precipitation.
4.1.2.1 Clear Air Mode In Clear Air Mode, the radar is in its most sensitive operation. This mode has the slowest antenna rotation rate which permits the radar to sample the atmosphere longer. This slower sampling increases the radar's sensitivity and ability to detect smaller objects in the atmosphere.
The term "clear air" does not imply "no-precipitation" mode. Even in Clear Air Mode, the WSR- 88D can detect light, stratiform precipitation (e.g., snow) due to the increased sensitivity.
Many of the radar returns in Clear Air Mode are airborne dust and particulate matter. The WSR- 88D images are updated every 10 minutes when operating in this mode.
4.1.2.2 Precipitation Mode Precipitation targets typically provide stronger return signals to the radar than non-precipitation targets. Therefore, the WSR-88D is operated in Precipitation Mode when precipitation is present although some non-precipitation echoes can still be detected in this operating mode.
The faster rotation of the WSR-88D in Precipitation Mode allows images to update at a faster rate approximately every 4 to 6 minutes.
AC 00-45F, CHG 2 Section 4: Radar and Satellite Imagery Page 4-1