Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 6-6. Convective SIGMET Decoding Example
Table 6-2. Decoding a Convective SIGMET Line Content Description 1 MKC Issuing Office (AWC) C Region (East, Central or West) WST Product Identifier 221855 Issuance date/time (DDHHMM) 2 CONVECTIVE SIGMET Product type 20 Issuance number C Region (East, Central or West) 3 VALID UNTIL 2055Z Valid ending time (UTC) 4 ND SD States/areas affected 5 FROM 90W MOT-GFK-ABR-90W MOT Phenomenon location (high altitude VOR coordinates) 6 INTSFYG AREA SEV TS MOVG FROM 24045KT. TOPS ABV FL450. WIND GUSTS TO 60KTS RPRTD.
TORNADOES…HAIL TO 2 IN… WIND GUSTS TO 65KTS POSS ND PTN Phenomenon description, movement, cloud top, remarks
The Convective SIGMET in Figure 6-6 is decoded as the following:
(Line 1) Convective SIGMET issued for the central portion of the United States on the 22nd at 1855Z.
(Line 2) This is the 20th Convective SIGMET issued on the 22nd for the central United States as indicated by “20C.”
(Line 3) Valid until 2055Z
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-10
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) (Line 4) The affected states are North and South Dakota.
(Line 5) From 90 nautical miles west of Minot, ND; to Grand Forks, ND; to Aberdeen, SD; to 90 nautical miles west of Minot, ND.
(Line 6) An intensifying area of severe thunderstorms moving from 240 degrees at 45 knots (to the northeast). Thunderstorm tops above Flight Level 450. Wind gusts to 60 knots reported.
Tornadoes, hail to 2 inches in diameter, and wind gusts to 65 knots possible in the North Dakota portion.
6.1.4.5 Convective SIGMET Outlook Each Convective SIGMET bulletin includes a 2- to 6-hour outlook at the end of the bulletin. The content and order of each bulletin is as follows:
• Beginning and ending valid times
• Location of expected Convective SIGMET issuances delineated by high-altitude VOR coordinates for the outlook valid time.
• Discussion of forecast
6.1.4.6 Convective SIGMET Cancellations Convective SIGMETs are not cancelled but are superseded by the next Convective SIGMET in the series.
6.1.4.7 Convective SIGMET Amendments Amended Convective SIGMETs are NOT issued. Instead, a new Convective SIGMET is issued for that region.
6.1.4.8 Convective SIGMET Corrections Corrections to Convective SIGMETs are issued as necessary. The corrected Convective SIGMET is identified by a “COR” located at the end of the first line after the issuance UTC date/time.
6.1.4.9 Convective SIGMET Bulletin Examples
WSUS33 KKCI 091855 SIGW CONVECTIVE SIGMET...NONE .
OUTLOOK VALID 092055-100055 TS ARE NOT EXPD.
Convective SIGMET bulletin for the western region of the conterminous U.S.(WSUS33) issued by the Meteorological Watch Office (WMO) (Aviation Weather Center) in Kansas City, Missouri (KKCI) on the 9th day of the month at 1855 UTC. The National Weather Service AWIPS communication header for this product is SIGW.
No Convective SIGMETs are in effect.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-11
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) The outlook portion of the Convective SIGMET bulletin is valid from the 9th day of the month at 2055 UTC to the 10th day of the month at 0055 UTC. Thunderstorms are not expected.
WSUS32 KKCI 091855 SIGC MKCC WST 091855 CONVECTIVE SIGMET 21C VALID UNTIL 2055Z AR OK FROM 20S RZC-40SSW FSM DMSHG LINE TS 25 NM WIDE MOV FROM 27025KT. TOPS TO FL320.
.
OUTLOOK VALID 092055-100055 FROM 40NE BUM-60SE SGF-50WSW LIT-40W GGG-60ENE ABI-ADM-50WNW BUM-40NE BUM WST ISSUANCES EXPD. REFER TO MOST RECENT ACUS01 KWNS FROM STORM PREDICTION CENTER FOR SYNOPSIS AND METEOROLOGICAL DETAILS.
Convective SIGMET bulletin for the central region of the conterminous U.S.(WSUS32) issued by the Meteorological Watch Office (Aviation Weather Center) in Kansas City, Missouri (KCCI) on the 9th day of the month at 1855 UTC. The National Weather Service AWIPS communication header for this product is SIGC.
Convective SIGMET (WST) for the central region of the conterminous U.S. issued by the Aviation Weather Center in Kansas City, Missouri (MKCC) on the 9th day of the month at 1855 UTC. Convective SIGMET 21C is the 21st Convective SIGMET issued for the central region of the conterminous US on the 9th day of the month. Valid until 2055 UTC. States affected are Arkansas (AR) and Oklahoma (OK). Bounded within an area from 20 nautical miles south of Razorback, Arkansas (RZC), to 40 nautical miles south-southwest of Fort Smith, Arkansas (FSM). A diminishing line of thunderstorms 25 nautical miles wide moving from 270 degrees (to the east) at 25 knots. Thunderstorms tops to FL320 (approximately 32,000 ft MSL).
The outlook portion of the Convective SIGMET bulletin is valid from the 9th day of the month at 2055 UTC to the 10th day of the month at 0055 UTC. Within an area bounded from 40 nautical miles northeast of Butler, Missouri (BUM), to 60 nautical miles southeast of Springfield, MO (SGF), to 50 nautical miles west-southwest of Little Rock, Arkansas (LIT), to 40 nautical miles west of Longview, Texas (GGG), to 60 nautical miles east-northeast of Abilene, Texas (ABI), to Ardmore, Oklahoma (ADM), to 50 nautical miles west-northwest of Butler, Missouri (BUM), to 40 nautical miles northeast of (BUM). Convective SIGMET issuances are expected. Refer to the most recent Day 1 Convective Outlook (ACUS01 KWNS) from the Storm Prediction Center (SPC) for a synopsis and meteorological details.
6.1.4.9.1 Convective SIGMET Bulletin – Tropical Cyclone Example
WSUS31 KKCI 211355 SIGE MKCE WST 211355 CONVECTIVE SIGMET 1E VALID UNTIL 1555Z
NC SC FL GA AND CSTL WTRS AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-12
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) FROM 30SSE CLT-160SE ILM-140ENE OMN-60E TLH-ABY-30SSE CLT AREA SEV EMBD TS MOV FROM 21015KT. TOPS ABV FL450.
TORNADOES...WIND GUSTS TO 60KT POSS.
TS ASSOCD WITH TROPICAL STORM ALBERTO.
.
OUTLOOK VALID 211555-211955 FROM 30E RDU-180SE ECG-140SSE ILM-180E PBI-40SE PBI-40S EYW-90SW EYW-70W SRQ-50N CTY-40N MCN-30NW SPA-30E RDU REF WW 475.
WST ISSUANCES EXPD. REFER TO MOST RECENT ACUS01 KWNS FROM STORM PREDICTION CENTER FOR SYNOPSIS AND METEOROLOGICAL DETAILS. REFER TO MOST RECENT WTNT21 KNHC FROM TROPICAL PREDICTION CENTER FOR DETAILS ON TROPICAL STORM ALBERTO.
Convective SIGMET bulletin for the eastern region of the conterminous U.S.(WSUS31) issued by the Meteorological Watch Office (Aviation Weather Center) in Kansas City, Missouri (KCCI) on the 21st day of the month at 1355 UTC. The National Weather Service AWIPS communication header for this product is SIGE.
Convective SIGMET (WST) for the eastern region of the conterminous U.S. issued by the Aviation Weather Center in Kansas City, Missouri (MKCE) on the 21st day of the month at 1355 UTC. Convective SIGMET 1E is the 1st Convective SIGMET issued for the eastern region of the conterminous US on the 21st day of the month. Valid until 1555 UTC. States affected are North Carolina (NC), South Carolina (SC), Florida (FL), Georgia (GA) and adjacent coastal waters.
Within an area bounded from 30 nautical miles south-southeast of Charlotte, North Carolina (CLT) to 160 nautical miles southeast of Wilmington, North Carolina (ILM) to 140 nautical miles east-northeast of Ormond Beach, Florida (OMN) to 60 nautical miles east of Tallahassee, Florida (TLH) to Albany, Georgia (ABY) to 30 nautical miles south-southeast of Charlotte, North Carolina (CLT). An area of severe embedded thunderstorms moving from 210 degrees at 15 knots. Cumulonimbus tops above flight level 450 (approximately 45,000 feet MSL) Tornadoes and surface wind gust to 60 knots are possible. The thunderstorms are associated with Tropical Storm Alberto.
The outlook portion of the Convective SIGMET bulletin is valid from the 21st day of the month at 1555 UTC to the 21st day of the month at 1955 UTC. Within an area bounded from 30 nautical miles east of Raleigh-Durham, North Carolina (RDU) to 180 nautical miles southeast of Elizabeth City, North Carolina (ECG) to 140 south-southeast of Wilmington, North Carolina (ILM) to 180 nautical miles east of (PBI) to 40 nautical miles southeast of West Palm Beach, Florida (PBI) to 40 nautical miles south of Key West, Florida (EYW) to 90 nautical miles southwest of Key West, Florida (EYW) to 70 nautical miles west of Sarasota, Florida (SRQ) to 50 nautical miles north of Cross City, Florida (CTY) to 40 nautical miles north of Macon, Georgia (MCN) to 30 nautical miles northwest of Sparta, Georgia (SPA) to 30 nautical miles east of Raleigh-Durham, North Carolina (RDU). Refer to Weather Watch Notification Message 475.
Convective SIGMET issuances are expected. Refer to the most recent Day 1 Convective Outlook (ACUS01 KWNS) from the Storm Prediction Center (SPC) for a synopsis and meteorological details. Refer to the most recent Tropical Cyclone Forecast/Advisory (WTNT21 KNHC) from the Tropical Prediction Center (TPC) for details on Tropical Storm Alberto.
6.1.5 SIGMET – Outside the Conterminous U.S. (O-CONUS)
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-13
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
6.1.5.1 SIGMET Issuance Criteria – Outside the Conterminous U.S. (O-CONUS) SIGMETs outside the Conterminous U.S. (O-CONUS SIGMETs) are issued when any of the following is occurring or expected to occur affecting an area greater than 3,000 square miles or, in the judgment of the forecaster, an area having the potential to have a significant effect on the safety of aircraft operations.
• Thunderstorm - of type below *
o Obscured (OBSC TS)
o Embedded (EMBD TS)
o Widespread (WDSPR TS)
o Squall line (SQL TS)
o Isolated severe (ISOL SEV TS)
• Severe Turbulence (SEV TURB)
• Severe Icing (SEV ICE)
o With Freezing rain (SEV ICE (FZRA)
• Widespread Duststorm (WDSPR DS)
• Widespread Sandstorm (WDSPR SS)
• Volcanic Ash (VA)
• Tropical Cyclone (TC)
NOTE: Obscured, embedded, or squall line thunderstorms do not have to reach 3,000 square miles criteria.
*Tornado (TDO), Funnel Cloud (FC), Waterspout (WTSPT), and Heavy Hail (HVY GR) may be used as a further description of the thunderstorm as necessary.
6.1.5.2 SIGMET Issuance Time and Valid Period – Outside the Conterminous U.S. (O- CONUS) A SIGMET is an unscheduled product issued any time conditions reaching SIGMET criteria are occurring or expected to occur within a 4-hour period. A SIGMET outside the conterminous U.S. (O-CONUS) can have a valid period up to, but not exceeding, four (4) hours, except for volcanic ash (VA) and tropical cyclone (TC) which can be valid up to six (6) hours. SIGMETs for continuing phenomena will be reissued at least every 4 (or 6) hours as long as SIGMET conditions continue to occur in the area for responsibility.
6.1.5.3 SIGMET Format – Outside the Conterminous U.S. (O-CONUS) O-CONUS SIGMETs contain the following information, related to the specific phenomena and in the order indicated:
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-14
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
• Phenomenon and its description (e.g., SEV TURB).
• An indication whether the information is observed, using OBS and/or FCST. The time of observation will be given in UTC.
• Location of the phenomenon referring, where possible to latitude and longitude, and flight levels (altitude) covering the affected area during the SIGMET valid time.
SIGMETs for volcanic ash cloud and tropical cyclones contain the positions of the ash cloud, tropical cyclone center and radius of convection at the start of the validity time of the SIGMET.
• Movement towards or expected movement using sixteen points of the compass, with speed in knots, or stationary, if appropriate.
• Thunderstorm maximum height as FL.
• Changes in intensity; using as appropriate, the abbreviations Intensifying (INTSF), Weakening (WKN), or No Change (NC).
• Forecast position of volcanic ash cloud or the center of the tropical cyclone at the end of the validity period of the SIGMET message.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-15
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 6-7. SIGMET Outside the Conterminous U.S. Decoding Example
Table 6-3. Decoding a SIGMET Outside of the Conterminous U.S. (O-CONUS) Line Content Description 1 WSPA07 ICAO communication header PHFO Issuance MWO 010410 Issuance UTC date/time 2 SIGPAT NWS AWIPS communication header 3 KZOA Area Control Center SIGMET Product type TANGO SIGMET series 2 Issuance number VALID 010410/010800 Valid period UTC date/time PHFO Issuance office 4 OAKLAND OCEANIC FIR Flight Information Region (FIR) FRQ TS OBS AND FCST WI 200NM N3006 W14012 - N2012 W15016 CB TOP FL400 MOV W 10KT WKN.
Phenomenon description
The SIGMET in Figure 6-7 is decoded as the following:
(Line 1) The WMO product header is WSPA07. Issued by the PHFO on the 1st day of the month at 0410 UTC.
(Line 2) The NWS AWIPS communication header is SIGPAT.
(Line 3) For the Oakland (KZOA) Area Control Center. This is the 2nd issuance of SIGMET Tango series, valid from the 1st day of the month at 0410 UTC until the 1st day of the month at 0800 UTC, issued by the Honolulu Meteorological Watch Office.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-16
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) (Line 4) Concerning the Oakland Oceanic Flight Information Region (FIR), frequent thunderstorms observed and forecast within 200 nautical miles of 30 degrees and 6 minutes north; 140 degrees and 12 minutes west; to 20 degrees and 12 minutes north, 150 degrees and 16 minutes west, cumulonimbus tops to flight level 400 moving west at 10 knots, weakening.
6.1.5.4 SIGMETs for Volcanic Ash A SIGMET for volcanic ash cloud is issued for volcanic eruptions. A volcanic eruption is any volcanic activity including the emission of volcanic ash, regardless of the eruption’s magnitude.
Initial Volcanic Ash SIGMETs may be issued based on credible pilot reports in the absence of a Volcanic Ash Advisory (VAA), but are updated once a VAA is issued. Volcanic ash SIGMETs will continue to be issued until the ash cloud is no longer occurring or expected to occur over the area of responsibility.
SIGMETs for volcanic ash cloud are valid up to six (6) hours and provide an observed or forecast location of the ash cloud at the beginning of the SIGMET. A six-hour forecast position for the ash cloud, valid at the end of the validity period of the SIGMET message, is also included. SIGMETs are reissued at least every six (6) hours while the volcanic ash cloud hazard exists or is expected to exist.
6.1.5.5 SIGMETs for Tropical Cyclone A SIGMET for a tropical cyclone may be issued for non-frontal synoptic-scale cyclones meeting the following criteria.
• Originates over tropical or sub-tropical waters with organized convection and definite cyclonic surface wind circulation.
• Wind speeds reach 35 knots independent of the wind averaging time used by the Tropical Cyclone Advisory Center (TCAC).
SIGMETs for tropical cyclones will be valid up to six (6) hours. SIGMETs for tropical cyclones will include two positions. The first position included will be the TCAC advisory position. The second position will be the forecast position valid at the end of the SIGMET period.
In addition to the two storm positions, SIGMETs will include associated convection when applicable. SIGMETs will be reissued at least every six (6) hours while the tropical cyclone wind remains or are expected to remain above 34 knots.
6.1.5.6 SIGMET Cancellation– Outside the Conterminous U.S. (O-CONUS) SIGMETs are cancelled when the phenomena is no longer occurring or expected to occur in the area of responsibility.
6.1.5.7 SIGMET Amendments– Outside the Conterminous U.S. (O-CONUS) SIGMET amendments will NOT be issued. Instead, the next SIGMET in the series is issued to accomplish the update. The valid time of the new SIGMET is reset to reflect the new 4-hour valid period (6-hour for VA and TC SIGMETs).
6.1.5.8 SIGMET Corrections– Outside the Conterminous U.S. (O-CONUS) Corrections to SIGMETs are issued as necessary. This is done by issuing a new SIGMET in the series which advances the SIGMET number and cancels the previous SIGMET.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-17
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
6.1.5.9 SIGMET Example– Outside the Conterminous U.S. (O-CONUS)
WSPA07 PHFO 010358 SIGPAT KZOA SIGMET TANGO 1 VALID 010400/010800 PHFO- OAKLAND OCEANIC FIR. EMBD TS OBS BY SATELLITE WITHIN AREA BOUNDED BY N2055 W15000 - N1950 W14945 - N1922 W15130 - N2027 W15048 – N2055 W15000. CB TO TOP FL400. MOV W 10KT. WKN.
SIGMET (SWPA07) issued by the Meteorological Watch Office (Weather Forecast Office) in Honolulu, Hawaii (PHFO) on the 1st day of the month at 0358 UTC. The National Weather Service AWIPS communication header for this product is SIGPAT. This SIGMET concerns the Oakland Oceanic FIR. This is the first (1) issuance of SIGMET series Tango valid from the 1st day of the month at 0400 UTC until the 1st day of the month at 0800 UTC. Within the WFO Honolulu portion of the Oakland Oceanic FIR, embedded thunderstorms observed by satellite within an area bounded by 20 degrees/55 minutes north, 150 degrees/00 minutes west to 19 degrees/50 minutes north, 14 degrees/45 minutes west to 19 degrees/22 minutes north, 151 degrees/30 minutes west to 20 degrees/27 minutes north, 150 degrees/48 minutes west to 20 degrees/55 minutes north, 150 degrees/00 minutes west. Cumulonimbus tops to flight level 400 (approximately 40,000 feet MSL). The thunderstorms are moving west at 10 knots and weakening.
6.1.5.9.1 SIGMET for Volcanic Ash Example
WVNT06 KKCI 082030 TJZS SIGMET FOXTROT 2 VALID 082030/090230 KKCI- SAN JUAN FIR VA FROM SOUFRIERE HILLS LOC 1642N06210W VA CLD OBS AT 2030Z SFC/060 WI N1730 W06400 - N1700 W06300 - N1650 W06300 - N1710 W06400 - N1730 W06400. MOV W 15KT. FCST 0230Z VA CLD APRX N1730 W06500 - N1700 W06300 - N1650 W06300 - N1710 W06500 - N1730 W06500.
The ICAO communication header for this product is WVNT06. It is a SIGMET issued by the Aviation Weather Center (KCCI) in Kansas City, Missouri on the 8th day of the month at 2030 UTC. This is the second (2) issuance of SIGMET series Foxtrot valid from the 8th day of the month at 2030 UTC until the 9th day of the month at 0230 UTC. Within the San Juan Oceanic FIR, volcanic ash from Soufriere Hills volcano located at 16 degrees/42 minutes north, 62 degrees/10 minutes west. Volcanic ash cloud observed at 2030 UTC from the surface to 6,000 feet MSL within an area bounded by 17 degrees/30 minutes north, 64 degrees/00 minutes west to 17 degrees/00 minutes north, 63 degrees/00 minutes west to 16 degrees/50 minutes north, 63 degrees/00 minutes west to 17 degrees/10 minutes north, 64 degrees/00 minutes west to 17 degrees/30 minutes north, 64 degrees/00 minutes west. Moving to the west at 15 knots.
Forecast at 0230 UTC, volcanic ash cloud located approximately at 17 degrees/30 minutes north, 65 degrees/00 minutes west to 17 degrees/00 minutes north, 63 degrees/00 minutes west to 16 degrees/50 minutes north, 63 degrees/00 minutes west to 17 degrees/10 minutes north, 65 degrees/00 minutes west to 17 degrees/30 minutes north, 65 degrees/00 minutes west.
6.1.5.9.2 SIGMET for Tropical Cyclone Example
WSNT03 KKCI 081451 SIGA0C AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-18
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009) KZNY SIGMET CHARLIE 11 VALID 081500/082100 KKCI- NEW YORK OCEANIC FIR TC KYLE OBS N3106 W07118 AT 1500Z CB TOP FL500 WI 120NM OF CENTER MOV WSW 5 KT NC FCST 2100Z TC CENTER N3142 W07012
The ICAO communication header for this product is WSNT03. It is a SIGMET issued by the Aviation Weather Center (KCCI) in Kansas City, Missouri on the 8th day of the month at 1451 UTC. The National Weather Service AWIPS communication header for this product is SIGPAT.
This is the eleventh (11) issuance of SIGMET series Charlie valid from the 8th day of the month at 1500 UTC until the 8th day of the month at 2100 UTC. Within the New York Oceanic FIR, Tropical Cyclone Kyle observed at 31 degrees/6 minutes north, 71 degrees/18 minutes west at 1500 UTC, cumulonimbus tops to flight level 500 (approximately 50,000 feet MSL), within 120 nautical miles of the center, moving from west-southwest at 5 knots, no change in intensity is forecast, at 2100 UTC the tropical cyclone center will be at 31 degrees/42 minutes north, 70 degrees/12 minutes west.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-19
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
6.2 Airmen’s Meteorological Information (AIRMET) An AIRMET is a concise description of the occurrence or expected occurrence of specified en route weather phenomena which may affect the safety of aircraft operations, but at intensities lower than those which require the issuance of a SIGMET. AIRMETs are intended for dissemination to all pilots in flight to enhance safety and are of particular concern to operators and pilots of aircraft sensitive to the phenomena described and to pilots without instrument ratings. AIRMETs are issued by the responsible Meteorological Watch Office (MWO) to give notice to operators and aircrews of potentially hazardous en route conditions.
• AIRMETs are available for the conterminous U.S. (CONUS) on the Aviation Digital Data Service (ADDS) web site at: http://adds.aviationweather.noaa.gov/airmets/
• AIRMETs are available for Alaska on the Alaska Aviation Weather Unit (AAWU) web site at:
http://aawu.arh.noaa.gov/
• AIRMETs are available for Hawaii on the NWS WFO Honolulu web site at:
http://www.prh.noaa.gov/hnl/pages/aviation.php
6.2.1 AIRMET Issuance AIRMETs are issued from the three Meteorological Watch Offices (MWO) located at the Aviation Weather Center (AWC), the Alaska Aviation Weather Unit (AAWU), and the Weather Forecast Office (WFO) in Honolulu. Their areas of responsibility are:
• AWC: The conterminous U.S. and adjacent coastal waters (CONUS) (Figure 6-8)
• AAWU: Alaska and adjacent coastal waters (Figure 6-9)
• WFO Honolulu: Hawaii and adjacent waters (Figure 6-10)
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-20
Aviation Weather Services, Advisory Circular 00-45F, Change 2 (March 2009)
Figure 6-8 AWC AIRMET Areas of Responsibility – Conterminous U.S.
AC 00-45F, CHG 2 Section 6: Products for Aviation Hazards Page 6-21