Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
• Remarks concerning the continuance of the phenomenon during the six (6) hours following the AIRMET ending time.
• CONUS and Hawaii AIRMETS: A separate AIRMET outlook is included in the AIRMET bulletin when conditions meeting AIRMET criteria are expected to occur during the 6- hour period after the valid time of the AIRMET bulletin.
• Alaska AIRMETs: Outlook information is included in the appropriate Area Forecast zone when conditions are expected to occur during the 6-hour period after the valid time of the AIRMET bulletin.
LINE 1 - BOSS WA 211945 2 AIRMET SIERRA UPDT 3 FOR IFR AND MIN OBSCN VALID UNTIL 220200 ЗА AIRMET IFR..ME NH VT MA CT RI NY NJ AND CSTL WTRS 4A- FROM CAR TO YSJ TO 150E ACK TO EWR TO YOW TO CAR 5A OCNL CIG BLW 010/VIS BLW 3SM PCPN/BR. CONDS CONT BYD 02Z THRU 08Z.
ЗВ AIRMET MIN OBSCN..ME NH VT MA NY PA 4B FROM CAR TO MLT TO CON TO SLT TO SYR TO CAR 5B MINS OCNLY OBSCD BY CLDS/PCPN/BR. CONDS CONT BYD 02Z THRU 08Z.
Figure 6-11. AIRMET Bulletin Decoding Example Section 6: Products for Aviation Hazards Page 6-25
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) Table 6-6. Decoding an AIRMET Bulletin Line Content Description 1 BOS AIRMET area identifier S AIRMET series WA Product type 211945 Issuance UTC date/time 2 AIRMET Product type SIERRA AIRMET series UPDT 3 Update number FOR IFR AND MTN OBSCN Product description VALID UNTIL 220200 Ending UTC date/time 3A AIRMET IFR..ME NH VT MA CT RI NY NJ
AND CSTL WTRS Product type/series… Phenomenon location (states) 3B AIRMET MTN OBSCN..ME NH VT MA NY PA 4A FROM CAR TO YSJ TO 150E ACK TO EWR
TO YOW TO CAR Phenomenon location (VOR locations) 4B FROM CAR TO MLT TO CON TO SLT TO
SYR TO CAR 5A CIG BLW 010/VIS BLW 3SM PCPN/BR.
CONDS CONT BYD 02Z THRU 08Z.
Phenomenon description 5B MTNS OBSCD BY CLDS/PCPN/BR.
CONDS CONT BYD 02Z THRU 08Z.
The AIRMET bulletin in Figure 6-11 is decoded as follows:
(Line 1) AIRMET SIERRA issued for the Boston area at 1945Z on the 21st day of the month.
“SIERRA” contains information on Instrument Flight Rules (IFR) and/or mountain obscurations.
(Line 2) This is the third updated issuance of this Boston AIRMET series as indicated by “SIERRA UPDT 3” and is valid until 0200Z on the 22nd.
(Line 3A) The affected states within the BOS area are: Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New York, New Jersey, and coastal waters.
(Line 3B) The affected states within the BOS area are: Maine, New Hampshire, Vermont, Massachusetts, New York, and Pennsylvania.
(Line 4A) Within an area bounded by: Caribou, ME; to Saint Johns, New Brunswick; to 150 nautical miles east of Nantucket, MA; to Newark, NJ; to Ottawa, Ontario; to Caribou, ME
(Line 4B) Within an area bounded by: Caribou, ME to Millinocket, ME to Concord, NH to Slate Run, PA to Syracuse, NY to Caribou, ME
(Line 5A) Ceiling below 1,000 feet/visibility below 3 statute miles, precipitation/mist. Conditions continuing beyond 0200Z through 0800Z.
(Line 5B) Mountains Obscured by clouds, precipitation and mist. Conditions continuing beyond 0200Z through 0800Z.
Section 6: Products for Aviation Hazards Page 6-26
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
AIRMET Updates and Amendments If an AIRMET is amended, AMD is added after the date/time group on the FAA product line. The update number will be incremented, UPDT is added to end of the line containing the list of affected states (CONUS only). The issuance time of the AIRMET bulletin is updated to reflect the time of the amendment. The ending valid time remains unchanged.
AIRMET Corrections AIRMETs containing errors are corrected by adding COR after the date/time group on the FAA product line. The issuance time of the AIRMET bulletin is updated to reflect the time of the correction. The ending valid time remains unchanged.
AIRMET Examples
CONUS AIRMET Example
WAUS43 KKCI 091445 CHIZ WA 091445 AIRMET ZULU UPDT 4 FOR ICE AND FRZLVL VALID UNTIL 092100 AIRMET ICE...KS IA MO IL FROM 30WSW FOD TO DBQ TO 50NW DEC TO 50SW FAM TO OSW TO MKC TO 30WSW FOD MOD ICE BTN FRZLVL AND FL200. FRZLVL 060-100. CONDS ENDG BY 21Z.
.
OTLK VALID 2100-0300Z...ICE IA MO WI IL IN KY BOUNDED BY BAE-BVT-PXV-50SW FAM-50NW DEC-DBQ-BAE MOD ICE BTN FRZLVL AND FL200. FRZLVL 080-100. CONDS CONTG THRU
03Z.
.
FRZLVL...RANGING FROM SFC-120 ACRS AREA MULT FRZLVL 015-085 BOUNDED BY 40W INL-YQT-SSM-70NNE ASP-YVV-DXO-40NE FWA-40SSE BJI-40W INL SFC ALG 50NNW ISN-70W FAR-GFK-40NE ODI-40SW DXO 040 ALG ISN-70S BIS-30W ABR-30E ABR-60S FAR-30SW BRD-30NE FWA 080 ALG GLD-SLN-30W BDF-50S JOT-40SE IND-30SW CVG-40SW LOZ
AIRMET (WAUS43) issued by the Meteorological Watch Office (Aviation Weather Center) in Kansas City, Missouri on the 9th day of the month at 1445 UTC. This AIRMET (WA) is the Zulu series bulletin for the Chicago Area Forecast region (CHIZ) issued on the 9th day of the month at 1445 UTC. This is the 4th update to the Zulu series bulletin for icing and freezing levels and is valid until the 9th day of the month at 2100 UTC.
Section 6: Products for Aviation Hazards Page 6-27
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) The first (and only) AIRMET noted within the bulletin is for icing affecting Kansas, Iowa, Missouri and Illinois. Within an area bounded from 30 nautical miles west-southwest of Fort Dodge, Iowa (FOD) to Dubuque, Iowa (DBQ) to 50 nautical miles northwest of Decatur, Illinois (DEC) to 50 nautical miles southwest of Farmington, Missouri (FAM) to Oswego, Kansas (OSW) to Kansas City, Missouri (MKC) to 30 nautical miles west-southwest of Fort Dodge, Iowa (FOD). Moderate icing between the freezing level and flight level 200 (approximately 20,000 feet MSL). The freezing level is between 6,000 feet MSL and 10,000 feet MSL. Conditions ending by 2100 UTC.
An outlook for icing between 2100 UTC to 0300 UTC exists over: Iowa, Missouri, Wisconsin, Illinois, Indiana and Kentucky. Within an area bounded by Milwaukee, Wisconsin (BAE) to Lafayette, Indiana (BVT) to Pocket City, Indiana (PXV) to 50 nautical miles southwest of Farmington, Missouri (FAM) to 50 nautical miles northwest of Decatur, Illinois (DEC) to Dubuque, Iowa (DBQ) to Milwaukee, Wisconsin (BAE). Moderate icing between the freezing level and flight level 200 (approximately 20,000 feet MSL). The freezing level is between 8,000 feet MSL and 10,000 feet MSL. Conditions continuing through 0300 UTC.
The freezing level ranges from the surface to 12,000 feet MSL across the Chicago Area Forecast region. Multiple freezing levels exist between 1,500 feet MSL and 8,500 feet MSL within an area bounded by 40 nautical miles west of International Falls, Minnesota (INL) to Thunder Bay, Ontario, Canada to Sault Saint Marie, Michigan (SSM) to 70 nautical miles northnortheast of Oscoda, Michigan (ASP) to Wiarton, Ontario, Canada to Detroit, Michigan (DXO) to 40 nautical miles northeast of Fort Wayne, Indiana (FWA) to 40 nautical miles south-southeast of Bemidji, Minnesota (BJI) to 40 nautical miles west of International Falls, Minnesota (INL).
The freezing level is at the surface along a line from 50 nautical miles north-northwest of Williston, North Dakota (ISN) to 70 nautical miles west of Fargo, North Dakota (FAR) to Grand Forks, North Dakota (GFK) to 40 nautical miles northeast of Nodine, Minnesota (ODI) to 40 nautical miles southwest of Detroit, Michigan (DXO). The freezing level is at 4,000 feet MSL along a line from Williston, North Dakota (ISN) to 70 nautical miles south of Bismarck, North Dakota (BIS) to 30 nautical miles west of Aberdeen, South Dakota (ABR) to 30 nautical miles east of Aberdeen, South Dakota (ABR) to 60 nautical miles south of Fargo, North Dakota (FAR) to 30 nautical miles southwest of Brainerd, Minnesota (BRD) to 30 nautical miles northeast of Fort Wayne, Indiana. The freezing level is 8,000 feet MSL along a line from Goodland, Kansas (GLD) to Salina, Kansas (SLN) to 30 nautical miles west of Bradford, Illinois (BDF) to 50 nautical miles south of Joliet, Illinois to 40 nautical miles southeast of Indianapolis, Indiana (IND) to 30 nautical miles southwest of Covington, Kentucky (CVG) to 40 nautical miles southwest of London, Kentucky (LOZ).
Hawaii AIRMET Example
WAHW31 PHFO 090945 WA0HI HNLT WA 091000 AIRMET TANGO UPDATE 1 FOR TURB VALID UNTIL 091600 AIRMET TURB...KAUAI OAHU MOLOKAI LANAI MAUI OVR AND IMDT N THRU E OF MTS.
MOD TURB BLW 100. CONDS CONTG BYD 1600Z.
Section 6: Products for Aviation Hazards Page 6-28
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) AIRMET (WAHW31) issued by the Meteorological Watch Office (Weather Forecast Office) in Honolulu, Hawaii on the 9th day of the month at 0945 UTC. The National Weather Service AWIPS communication code for this product is WA0HI. This AIRMET (WA) is the Tango series bulletin for the Hawaii Area Forecast region (HNLT) issued on the 9th day of the month at 1000 UTC. This is the 1st update to the Tango series bulletin for turbulence and is valid until the 9th day of the month at 1600 UTC.
The first (and only) AIRMET noted within the bulletin is for turbulence affecting the islands of Kauai, Oahu, Molokai, Lanai and Maui, over and immediately north through east of the mountains. Moderate turbulence below 10,000 feet MSL. Conditions continuing beyond 1600 UTC.
Alaska AIRMET Example
WAAK47 PAWU 011740 WA7O JNUS WA 011740 AIRMET SIERRA FOR IFR AND MT OBSC VALID UNTIL 012100 .
LYNN CANAL AND GLACIER BAY JB W OF LYNN CANAL..MTS OCNL OBSC IN CLDS/PCPN.
SPRDG E. INTSF.
.
CNTRL SE AK JC PAOH−PAFE LN W..MTS OCNL OBSC IN CLDS/PCPN. SPRDG E. INTSF.
.
ERN GLF CST JE MTS OCNL OBSC IN CLDS/PCPN. IMPRG.
.
SE AK CSTL WTRS JF OCNL CIG BLW 010 VIS BLW 3SM SN BLSN. NC.
AIRMET (WAAK47) issued by the Meteorological Watch Office (Alaska Aviation Weather Unit) in Anchorage, Alaska on the 1st day of the month at 1740 UTC. The National Weather Service AWIPS communication code for this product is WA7O. This AIRMET (WA) is the Sierra series bulletin for the Juneau forecast area issued on the 1st day of the month at 1740 UTC. This is the AIRMET Sierra series for IFR and mountain obscuration valid until the 1st day of the month at 2100 UTC.
For the Lynn Canal and Glacier Bay forecast regions, Juneau region B...west of Lynn Canal…mountains occasionally obscured in clouds and precipitation. Conditions spreading east and intensifying during the forecast period.
Section 6: Products for Aviation Hazards Page 6-29
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) For the Central Southeast Alaska forecast region, Juneau region C…from a Hoonan, Alaska (PAOH) to Kake, Alaska (PAFE) line westward, mountains occasionally obscured in clouds and precipitation. Conditions spreading east and intensifying during the forecast period.
For the Eastern Gulf Coast forecast region, Juneau region E…Mountains occasionally obscured in clouds and precipitation. Conditions improving during the forecast period.
For the Southeast Alaska Coastal Waters, Juneau region F…Occasional ceiling below 1,000 feet AGL, visibility below 3 statute miles in snow and blowing snow. No change in conditions is expected during the forecast period.
Section 6: Products for Aviation Hazards Page 6-30
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) Graphical Airman’s Meteorological Advisory (G-AIRMET) The Graphical-AIRMET product, known as the "G-AIRMET," is a decision-making tool based on weather "snapshots" displayed at short time intervals. The G-AIRMET identifies hazardous weather in space and time more precisely than text products, enabling pilots to maintain high safety margins while flying more efficient routes.
The National Weather Service’s (NWS) goal is to maximize aviation safety and air space efficiency by providing the most accurate and timely weather information possible to enhance both pre-flight and in-flight decision making. For decades, NWS has issued text-based AIRMETs that have provided broad-scale descriptions of hazardous weather. Often referred to as a time "smear", the text-based AIRMET requires meteorologists to describe hazardous weather over large geographical areas for six-hour periods. G-AIRMET provides more precise, and informative weather hazard depictions than the text only AIRMET.
Aviation weather users have found that pictures are worth a thousand contractions. G-AIRMETs provide a better path from the aviation meteorologist to the weather user, by providing precise, interactive and easy to understand graphical displays. Meteorologists can put their energy into creating and updating G-AIRMET weather graphics, while the traditional text AIRMET is generated from G-AIRMET information.
G-AIRMETs are available for the conterminous U.S. (CONUS) and adjacent coastal waters only and can be viewed on Aviation Digital Data Service (ADDS) Web site using the G-AIRMET display tools.
G- AIRMET Issuance G-AIRMETs are issued by the Aviation Weather Center (AWC) every 6 hours and updated/amended as necessary, coincident with the text AIRMET products.
Table 6-7. G-AIRMET Issuance Schedule 1st Scheduled Issuance (UTC) 2nd Scheduled Issuance (UTC) 3rd Scheduled Issuance (UTC) 4th Scheduled Issuance (UTC) CONUS 0255 0855 1455 2055
G- AIRMET Content Graphical AIRMET Snapshots (G-AIRMET) are graphical forecasts of en-route weather hazards valid at discrete times no more than 3 hours apart for a period of up to 12 hours into the future (00, 03, 06, 09 and 12 hours). 00 hour represents the initial conditions, and the subsequent 3- hourly graphics depict the area affected by the particular hazard at that valid time. G-AIRMET snapshots may be viewed as static (single) images, combined, and looped using the tools provided on the web page.
Section 6: Products for Aviation Hazards Page 6-31
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010) G-AIRMET depicts the following en-route aviation weather hazards: Instrument flight Rule conditions (IFR)
• Areas of cloud ceilings with bases less than 1000 feet above ground level (AGL) and/or areas of surface visibilities below 3 statute miles, including the weather causing the visibility restriction. The cause of the visibility restriction includes only PCPN, FU, HZ, BR, FG, and BLSN.
Celling & Visiblity Turb High Turb Low Icing Mountain Obscuration Low Level Wind Shear Surface Winds Freezing Level Clear Slower Loop speed Faster Play 182 212 002 032 G-AIRMET VALID: 1800 UTC MON 26 APR 2010 ›CPN/BI ISSUED: 1445 UTC MON 26 APR 2010 Ceiling & Visibility IFR Turb High 1400 280 Turb LOW gồO Icing 160/120 240 -*- Obsch Mitn CL6S/BR LL Wind Shear LLWS < > Sfo Winds a - Frzg Lvl 0°: 120 Figure 6-12. G-AIRMET - Ceiling and Visibility (IFR) Snapshot Example Section 6: Products for Aviation Hazards Page 6-32
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
• Mountain Obscuration
• Areas of widespread mountain obscuration where Visual Meteorological Conditions (VMC) cannot be maintained, including the weather causing the obscuration. The weather causing the obscuration includes only CLDS, PCPN, FU, HZ, BR, and FG.
Ceiling & Visiblity Turb High Turb Low Icing Mountain Obscuration Low Level Wind Shear Surface Winds Freezing Level Clear Slower Loop speed Faster Play 82 21Z 002 03Z G-AIRMET VALID: 1800 UTC MON 26 APR 2010
PCPN/BR _ĎS/ PN/BR ISSUED: 1445 UTC MON 26 APR 2010 Ceiling & Visibility Turb High (400 280 Turb Low o Icing 1837120 —*- Obsch Mitn CLO$/BR LL Wind Shear LLWS < > Frzg Lvl 0°: 120 Figure 6-13. G-AIRMET - Mountain Obscuration Snapshot Example Section 6: Products for Aviation Hazards Page 6-33
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
• Icing
• Areas of moderate airframe icing, other than convectively induced, including the vertical extent (base and top). Altitude variations in the base of icing layers may be denoted (e.g., "080 / 060" indicates the altitude varies between 6,000 and 8,000 feet above mean seal level (AMSL)).
Ceiling & Visiblity Turb High Turb Low Icing Mountain Obscuration Low Level Wind Shear Surface Winds Freezing Level Clear Slower Loop speed Faster Play 182 21Z O0Z 03Z G-AIRMET VALID: 1800 UTC MON 26 APR 2010 1š0 060/020 100/080 080/060 1086 Ово.
ISSUED: 1445 UTC MON 26 APR 2010 Visibility Ceiling & TER Turb High 400 280 Turb LoW SEE Icing 1887920 —*— Obscn Mtn CL63/BR --- LL Wind Shear Sfc Winds → Fizg LvI [0: 120] AW Figure 6-14. G-AIRMET - Icing Snapshot Example Section 6: Products for Aviation Hazards Page 6-34
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
• Freezing Level
• Freezing level is defined as the lowest freezing level above the ground or at the SFC as appropriate. Freezing levels above the ground are delineated at 4000 feet intervals above mean sea level (AMSL). Areas with multiple freezing levels above the ground are delineated including the vertical extent (base and top).
Ceiling & Visiblity Turb High Turb Low Icing Mountain Obscuration • Low Level Wind Shear Surface Winds Freezing Level Clear Slower Loop speed Faster Play 182 212 002 032 G-AIRMET VALID: 1800 UTC MON 26 APR 2010 0*: 080 *: 040 ISSUED: 1445 UTC MON 26 APR 2010 Ceiling & Visibility TER Turb High 400 280 Turb Low SPe Icing 1887920 —*— Obsch Mtn CL6S/BR --- LL Wind Shear LLWS < → Sfc Winds → Frzg LvI [0°: 120] AW Figure 6-15. G-AIRMET - Freezing Level Snapshot Example Section 6: Products for Aviation Hazards Page 6-35
Aviation Weather Services, Advisory Circular 00-45G Change 1 (July 2010)
• Turbulence
• Areas of moderate turbulence, other than convectively induced, including the vertical extent (base and top).
Ceiling & Visiblity Turb High Turb Low Icing Mountain Obscuration Low Level wind Shear Surface Winds Freezing Level Clear Slower Loop speed Faster Play 18Z 21Z O0Z |Q3Z G-AIRMET VALID: 1800 UTC MON 26 APR 2010 410 ISSUED: 1445 UTC MON 26 AFR 2010 Ceiling & IF F 163Ÿ920 Visibility BR Turb High 400 280 Obscn [CLOS/BR) -- - Mitn LL Wind Shear [LLWS → Sto Winds → Figure 6-16. G-AIRMET - Turbulence-High Snapshot Example Section 6: Products for Aviation Hazards Page 6-36