Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 6: Products for Aviation Hazards Page 6-58 Prediction (NCEP) Central Operations (NCO). The Anchorage VAAC is managed by the AAWU. The areas of responsibility for each VAAC are:
Washington VAAC
o FIRs in CONUS and adjacent coastal waters (Figures 6-1 and 6-18) o The Oakland Oceanic FIR over the Pacific Ocean (Figures 6-3 and 6-18) o The New York FIR over the western Atlantic Ocean (Figures 6-2 and 6-18) o FIRs over and adjacent to the Caribbean, and Central and South America north of 10 degrees south latitude (Figure 6-2 and 6-18)
Anchorage VAAC o The Anchorage FIR (Figures 6-3 and 6-18).
o Russian FIRs north of 60 degrees north latitude and east of 150 degrees east longitude (Figure 6-18).
6.6.2 Volcanic Ash Advisory Statement (VAAS) A Volcanic Ash Advisory Statement (VAAS) provides information on hazards to aircraft flight operations caused by a volcanic eruption.
6.6.2.1 Issuance Volcanic Ash Advisory Centers (VAACs) are responsible for providing ash movement and dispersion guidance to Meteorological Watch Offices (MWOs) and neighboring VAACs. There are nine VAACs worldwide, two of which are located in the US (Figure 6-18). Each VAAC issues Volcanic Ash Advisory Statements and provide guidance to Meteorological Watch Offices (MWOs) for SIGMETs involving volcanic ash.
A VAAS may be issued within 6 hours of an eruption and every 6 hours thereafter. However, it can be issued more frequently if new information about the eruption is received.
6.6.2.2 Format A VAAS summarizes the known information about an eruption. It may include the location of the volcano, height of the volcano summit, height of the ash plume, a latitude/longitude box of the ash dispersion cloud, and a forecast of ash dispersion. The height of the ash cloud is estimated by meteorologists analyzing satellite imagery and satellite cloud drift winds combined with any pilot reports, volcano observatory reports, and upper-air wind reports.
6.6.2.3 VAAS Issued by the Washington VAAC Example
VOLCANIC ASH ADVISORY ISSUED: 2003JUL10/1300Z VAAC: WASHINGTON
VOLCANO: ANATAHAN 0804-20 LOCATION: N1621E14540 AREA: MARIANA ISLANDS
SUMMIT ELEVATION: 2585 FT (788 M)
ADVISORY NUMBER: 2003/251
INFORMATION SOURCE: GOES 9 IMAGERY. GFS MODEL WINDS FORECAST
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 6: Products for Aviation Hazards Page 6-59 ERUPTION DETAILS: ASH AND GAS EMISSIONS SINCE MAY 10.
OBS ASH DATE/TIME: 09/1202Z.
OBS ASH CLOUD: ASH NOT IDENTIFIABLE FROM SATELLITE DATA.
WINDS SFC/FL080 MOVING SW 10-15 KNOTS.
FCST ASH CLOUD +6H: SEE SIGMETS.
REMARKS: THE ASH PLUME OBSERVED IN VISIBLE IMAGERY IS TOO THIN AND DIFFUSE TO BE SEEN IN INFRARED AND MULTISPECTRAL IMAGAERY. ANY ASH UP TO FL080 SHOULD MOVE TOWARDS THE SW AT 10-15 KNOTS.
NEXT ADVISORY: WILL BE ISSUED BY 2003JUL10/1900Z.
6.6.3 Volcanic Ash Advisory (VAA) The Volcanic Ash Advisory (VAA) is advisory information on volcanic ash cloud issued in abbreviated plain language, using approved ICAO abbreviations and numerical values of self explanatory nature.
6.6.3.1 VAA Issuance Volcanic Ash Advisory Centers (VAACs) are responsible for providing ash movement and dispersion guidance to Meteorological Watch Offices (MWOs) and neighboring VAACs. There are nine VAACs worldwide, two of which are located in the US (Figure 6-18). Each VAAC issues Volcanic Ash Advisory Statements and provide guidance to Meteorological Watch Offices (MWOs) for SIGMETs involving volcanic ash.
VAAs are issued as necessary, but at least every six hours until such time as the volcanic ash cloud is no longer identifiable from satellite data, no further reports of volcanic ash are received from the area, and no further eruptions of the volcano are reported.
6.6.3.2 VAA Format The VAA format conforms to the “Template for advisory message for volcanic ash” included in ICAO Annex 3.
6.6.3.3 Volcanic Ash Advisory (VAA) Example
FVAK21 PAWU 190615
VOLCANIC ASH ADVISORY ISSUED: 20030419/0615Z VAAC: ANCHORAGE VOLCANO: CHIKURACHKI, 900-36 LOCATION: N5019 E15527 AREA: KAMCHATKA NORTHERN KURIL ISLANDS SUMMIT ELEVATION: 7674 FT (2339 M) ADVISORY NUMBER: 2003-02 INFORMATION SOURCE: SATELLITE AVIATION COLOR CODE: NOT GIVEN ERUPTION DETAILS: NEW ERUPTION OCCURRED APPROX 190500 UTC.
HEIGHT IS ESTIMATED AT FL300. ESTIMATE IS BASED
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 6: Products for Aviation Hazards Page 6-60 ON OBSERVEDAND MODEL WINDS. MOVEMENT APPEARS TO BE E AT 75 KTS.
OBS ASH DATA/TIME: 19/0500Z OBS ASH CLOUD: VA EXTENDS FM NEAR VOLCANO EWD TO N50 E160.
FCST ASH CLOUD +6HR: 30NM EITHER SIDE OF LN FM NIPPI N49 E159 - N50 E175.
FCST ASH CLOUD +12HR: 30NM EITHER SIDE OF LN FM N50 E168 - N50 E180.
FCST ASH CLOUD +18HR: 30NM EITHER SIDE OF LN FM N51 E175 - N50 E185.
NEXT ADVISORY: 20030419/1500Z REMARKS: UPDATES AS SOON AS INFO BECOMES AVAILABLE.
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-1 7 FORECAST TEXT PRODUCTS
7.1 Area Forecasts (FA) An Area Forecast (FA) is a forecast in an abbreviated plain language of specified weather phenomena covering a flight information region or other area designated by the meteorological authority. The Area Forecast in conjunction with the AIRMETs and SIGMETs are used to determine forecast enroute weather and to interpolate conditions at airports which do not have a Terminal Aerodrome Forecast (TAF).
Note…Hazardous weather (e.g., IFR, icing, turbulence, etc.) meeting AIRMET or SIGMET criteria are not forecast in the CONUS or Hawaii FAs. Valid AIRMETs and SIGMETs must be used in conjunction with the FA to determine hazardous weather information for the flight.
All Area Forecasts are available on the Aviation Weather Center (AWC) web site at:
http://aviationweather.gov/products/fa/.
Alaska Area Forecasts can also be found on the Alaska Aviation Weather Unit (AAWU) web site at: http://aawu.arh.noaa.gov/areaforecasts.php
7.1.1 Area Forecast Issuance Area forecasts are issued by the following offices for the following areas:
The Aviation Weather Center (AWC)
o Conterminous U.S (CONUS) - Six (6) FAs covering separate geographical areas of the CONUS, excluding the Gulf of Mexico coastal waters west of 85W (Figure 7-1).
o Gulf of Mexico: The northern Gulf of Mexico, including the Houston Oceanic FIR, the Gulf of Mexico portion of the Miami Oceanic FIR, and the coastal waters west of 85W longitude (Figure 7-1 and 7-2).
o Caribbean Sea: Portions of the Gulf of Mexico (south of the Houston Oceanic FIR to approximately 22N latitude), the Caribbean Sea and adjacent portions of the North Atlantic (Figure 7-3).
The Alaskan Aviation Weather Unit (AAWU)
o Alaska: Seven (7) FAs covering separate geographical areas of Alaska and the adjacent coastal waters, including the Pribilof Islands and Southeast Bering Sea (Figure 7-5).
WFO Honolulu, Hawaii
o Hawaii: The main Hawaiian Islands and adjacent coastal waters extending out 40 nautical miles from the coastlines (Figure 7-4).
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 SFO San Francisco
CHI BOS Salt Lake City NSLC Chicago Boston
•DFW MIA® Dallas/Fort Worth Miami GULF of Mexico Figure 7-1. AWC Area Forecast Regions- Contiguous U.S.
Coastal Waters FAGX20 Gulf of Mexico Houston Miami Oceanic FIR Oceanic FIR Figure 7-2. AWC Area Forecast Region and WMO Header - Gulf of Mexico AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-2
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-3
Figure 7-3. AWC Area Forecast Region and WMO Header - Caribbean
Figure 7-4. WFO Honolulu Area Forecast Region and WMO header - Hawaii
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-4
Figure 7-5. AAWU Flight Advisory and Area Forecast Zones - Alaska
Table 7-1. AAWU Area Forecast Zones – Alaska 1 Arctic Coast Coastal 14 Southern Southeast Alaska 2 North Slopes of the Brooks Range 15 Coastal Southeast Alaska 3 Upper Yukon Valley 16 Eastern Gulf Coast 4 Koyukuk and Upper Kobuk Valley 17 Copper River Basin 5 Northern Seward Peninsula-Lower Kobuk Valley 18 Cook Inlet-Susitna Valley 6 Southern Seward Peninsula-Eastern Norton Sound 19 Central Gulf Coast 7 Tanana Valley 20 Kodiak Island 8 Lower Yukon Valley 21 Alaska Peninsula-Port Heiden to Unimak Pass 9 Kuskowim Valley 22 Unimak Pass to Adak 10 Yukon-Kuskowim Delta 23 St. Lawrence Island-Bering Sea Coast 11 Bristol Bay 24 Adak to Attu 12 Lynn Canal and Glacier Bay 25 Pribilof Islands and Southeast Bering Sea 13 Central Southeast Alaska
7.1.2 Area Forecast Standardization All Area Forecasts follow these standards:
All heights or altitudes are referenced to above mean sea level (AMSL), unless otherwise noted (i.e., prefaced by AGL or CIG), and annotated using the height in hundreds of feet, consisting of three digits (e.g., 040). For heights at or above 18,000
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-5 feet, the level is preceded by FL to represent flight levels (e.g., FL180). Tops are always referenced to AMSL.
References to latitude and longitude are in whole degrees and minutes following the model: Nnn[nn] or Snn[nn], Wnnn[nn] or Ennn[nn] with a space between latitude and longitude and a hyphen between successive points. Example: N3106 W07118 – N3011 W7209
Messages are prepared in abbreviated plain language using contractions from the Federal Aviation Administration (FAA) Order 7340.1Z for domestic products and International Civil Aviation Organization (ICAO) document 8400for international products issued for Oceanic FIRs. A limited number of non-abbreviated words, geographical names and numerical values of a self-explanatory nature may also be used.
Weather and obstructions to visibility are described using the weather abbreviations for surface weather observations (METAR/SPECI). See the Federal Meteorological Handbook (FMH) No. 1 – Surface Observations or Section 3.1 of this document.
Heights are identified as follows:
o For heights below 3,000 feet, increments are in 100’s of feet o For heights from 3,000 to 5,000 feet, increments are in 500’s of feet o For heights greater than 5,000 feet, increments are in 1,000’s of feet.
7.1.3 Area Forecast Issuance Schedule Area forecasts are scheduled products issued at the following times.
Table 7-2. Area Forecast (FA) Issuance Schedule Boston and Miami (UTC) Chicago and Fort Worth (UTC) San Francisco and Salt Lake City (UTC) Gulf of Mexico (UTC) Caribbean (UTC) Hawaii (UTC) Alaska (UTC) 1st Issuance 0845 DT 0945 ST 0945 DT 1045 ST 1045 DT 1145 ST 0130 0330 0340 0145 DT 0245 ST 2nd Issuance 1745 DT 1845 ST 1845 DT 1945 ST 1945 DT 2045 ST 1030 0930 0940 0745 DT 0845 ST 3rd Issuance 0045 DT 0145 ST 0145 DT 0245 ST 0245 DT 0345 ST 1830 1530 1540 0145 DT 1445 ST 4th Issuance N/A N/A N/A N/A 2130 2140 1945 DT 2045 ST Note: DT - Daylight Time, ST - Standard Time
7.1.4 Area Forecast Amendments Area Forecasts are under continuous review and amended at the discretion of the forecaster.
“AMD” is included after the date/time group on the FAA product line. The date/time group on the WMO and FAA lines is updated to indicate the time of the correction. The ending valid time remains unchanged.
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-6
7.1.5 Area Forecast Corrections Area Forecasts containing errors are corrected. “COR” is included after the date/time group on the FAA product line. The date/time group on the WMO and FAA lines is updated to indicate the time of the correction. The ending valid time remains unchanged.
7.1.6 Area Forecast Format – Conterminous U.S. (CONUS) Area forecasts issued for the conterminous U.S. (CONUS) cover the airspace between the surface and 45,000 feet AMSL and include the following elements.
Synopsis: brief discussion of the synoptic weather affecting the FA area during the 18- hour valid period.
Clouds and Weather: description of the clouds and weather for the first 12-hour period for each state or group of states including the following elements.
o Cloud amount (SCT, BKN or OVC) for clouds with bases higher than or equal to 1,000 feet AGL and below FL180 o Cloud bases and tops (AMSL) associated with the above bullet o Precipitation o Visibilities between 3 and 6 statute miles (SM) and obstruction(s) to visibility o Sustained surface winds 20 knots or greater
12 to 18-hour categorical outlook: IFR, marginal VFR (MVFR), or VFR, including expected precipitation and/or obstruction(s) to visibility
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-7
Figure 7-6. Area Forecast – CONUS Communication and Product Header Example
Table 7-3. Decoding a CONUS Area Forecast Communication and Product Header Line Content Description 1 DFW Area Forecast region identifier C Indicates VFR clouds and weather forecast FA Product type 120945 Issuance and beginning of valid date/time (UTC) 2 SYNOPSIS AND VFR CLDS/WX Statement of weather information contained in this forecast message 3 SYNOPSIS VALID UNTIL 130400 Synopsis valid date and time 4 CLDS/WX VALID UNTIL 122200…OTLK VALID 122200-130400 The clouds and weather section valid time. The valid date and time of the outlook.
5 OK TX AR TN MS AL AND CSTL WTRS Description of the area for which the FA is valid.
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-8
Figure 7-7. Area Forecast - Clouds and Weather Element Example
The “Clouds and Weather” element above is decoded as follows:
South central and southeast Texas:
Scattered to broken bases at 1,000 feet above ground level (AGL). Tops at 3,000 feet above mean sea level (MSL). Visibility 3 to 5 statute miles in mist. Between 1400 and 1600 UTC…clouds bases becoming scattered at 3,000 feet AGL. 1900 UTC…scattered bases at 5,000 feet AGL. 12 to 18 hour categorical outlook…VFR.
Oklahoma:
Panhandle and northwest…scattered bases at 3,000 feet AGL, scattered to broken bases at 10,000 feet AGL. Tops at flight level 20,000 feet MSL. 1500 UTC…scattered bases at 4,000 feet AGL, scattered bases at 10,000 feet AGL. After 2000 UTC…scattered thunderstorms with rain showers developing..a few possible severe. Cumulonimbus tops to flight level 45,000 feet MSL. Outlook…VFR.
Remainder of the state…Ceilings broken at 2,000 feet AGL. Tops at 5,000 feet MSL.
Visibilities 3 to 5 statute miles in mist. 1400 UTC…scattered to broken bases at 4,000 feet AGL.
Tops at 10,000 feet MSL. 1800 UTC…ceilings broken 6,000 feet AGL. Tops to flight level 18,000 feet MSL. 2200 UTC…scattered thunderstorm with rain showers developing…a few possibly severe. Cumulonimbus tops above flight level 45,000 feet MSL. 12-18 hour categorical outlook…VFR.
7.1.6.1 Area Forecast – Conterminous U.S. (CONUS) Examples
7.1.6.1.1 Area Forecast – BOS Example
FAUS41 KKCI 150845 (ICAO product header) FA1W (NWS AWIPS Communication header) BOSC FA 150845 (Area forecast region, product type, issuance date/time)
SYNOPSIS AND VFR CLDS/WX SYNOPSIS VALID UNTIL 160300
Aviation Weather Services, Advisory Circular 00-45F, Revision 1 AC 00-45F (July 2008) Section 7: Forecast Text Products Page 7-9 CLDS/WX VALID UNTIL 152100...OTLK VALID 152100-160300
ME NH VT MA RI CT NY LO NJ PA OH LE WV MD DC DE VA AND CSTL WTRS
SEE AIRMET SIERRA FOR IFR CONDS AND MTN OBSCN.
TS IMPLY SEV OR GTR TURB SEV ICE LLWS AND IFR CONDS.
NON MSL HGTS DENOTED BY AGL OR CIG.
SYNOPSIS...CDFNT EXTDD FROM CSTL SXNS OF ME SWWD THRU LOW OVR WRN MA...THEN CONTD SWWD ACRS SERN PA AND NERN WV INTO A LOW OVR SWRN KY. FNT WILL SAG SLOLY SWD DURG PD. BY 03Z...CDFNT WILL EXTD FROM
SRN NEW ENG CSTL WTRS ACRS THE DELMARVA PENINSULA AND ALG THE NC/TN BDR INTO A LOW PRES SYS OVR NWRN AL.
.
ME NH VT CIG BKN-OVC020 LYR FL240. OCNL -RA BR. BECMG 1518 OCNL -SN BR OVR NRN PTNS AREA. OTLK...MVFR CIG.
.
MA RI CT SCT050 BKN080-100 LYR FL240. OCNL VIS 3SM BR. BECMG 1215 WRN MA/CT ISOL -TSRA CB TOP FL310. BECMG 1518 CIG OVC 010-020. OCNL -RA BR.
OTLK...MVFR CIG RA BR.
.
NY LO SERN NY...SCT050 BKN080-100 LYR FL240. OCNL VIS 3SM BR. BECMG 0912 WDLY SCT -TSRA CB TOPS FL310. BECMG 1518 CIG OVC 010-020. OCNL -RA BR.
OTLK...MVFR CIGS RA BR.
NRN AND WRN NY/LO...SCT-BKN015-025 BKN-OVC030-050 LYR FL240. OCNL -RA BR. BECMG 1215 OCNL -SN BR. BECMG 1821 SCT 030-050 BKN100 TOP 150.
OTLK...VFR.
.
PA NJ NRN AND WRN PA...CIG OVC010-020 LYR FL240. OCNL –RA BR. BECMG 1821 BKN-SCT015-025 OVC-BKN050 TOP 150. OTLK...MVFR CIG BR.
SERN PA/NJ...BKN050 BKN-OVC080-100 LYR FL240. WDLY SCT –TSRA CB TOP FL330. BECMG 1518 CIG OVC010-020. OCNL –RA BR. OTLK...MVFR CIG RA BR.
.
OH LE CIG OVC020 LYR FL240. OCNL -RA BR. BECMG 1518 NRN OH/LE PTNS...OCNL -RASN BR. BECMG 1821 CIGS BKN-SCT015-025 OVC-BKN050 TOP 150.
OTLK...MVFR CIG BR.
.
WV SCT-BKN060 BKN-OVC100-120 LYR FL240. OCNL VIS 3SM BR. BECMG 1518 WDLY SCT -SHRA/ISOL –TSRA CB TOPS FL330. BECMG 1821 CIG OVC010-020. OCNL - RA BR. OTLK...MVFR CIG RA BR.
.
VA MD DC DE SCT-BKN060 BKN-OVC100-120 LYR FL240. OCNL VIS 3SM BR. BECMG 1518 WDLY SCT -SHRA/ISOL –TSRA CB TOP FL330. BECMG 1821 CIG OVC010-020. OCNL -RA BR. OTLK...MVFR CIG RA BR.
.