-------- Original Message --------
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NOUS41 KWBC 211900
PNSWSH
TECHNICAL IMPLEMENTATION NOTICE 07-61
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
300 PM EDT TUE AUG 21 2007
TO: NATIONAL WEATHER SERVICE /NWS/ OFFICES
FEDERAL AVIATION ADMINISTRATION /FAA/ CUSTOMERS
FAMILY OF SERVICES /FOS/ SUBSCRIBERS
WORLD AREA FORECAST SYSTEM /WAFS/ PARTNERS
AND OTHER USERS OF NWS AVIATION FORECASTS
FROM: KEVIN L. JOHNSTON
CHIEF...AVIATION SERVICES BRANCH
SUBJECT: CHANGES TO THE INTERNATIONAL CIVIL AVIATION
ORGANIZATION /ICAO/ SIGMETS ISSUED BY AVIATION
WEATHER CENTER ON NOV 7 2007
BEGINNING WEDNESDAY NOVEMBER 7 2007 AT 0000 COORDINATED UNIVERSAL
TIME /UTC/...INTERNATIONAL /ALSO KNOWN AS O-CONUS/ SIGMETS ISSUED
BY THE AVIATION WEATHER CENTER /AWC/ WILL CHANGE FORMAT AND
CONTENT. NONE OF THE CHANGES BELOW WILL AFFECT DOMESTIC /ALSO
KNOWN AS CONUS/ SIGMETS THAT ARE ALSO ISSUED BY THE AWC.
ALL INTERNATIONAL SIGMETS ISSUED BY THE AWC WILL HAVE THE
LATITUDE AND LONGITUDE AS A PREFIX FOR NORTH /N/...SOUTH
/S/...EAST /E/...AND WEST /W/ INSTEAD OF A SUFFIX. FOR EXAMPLE
THE FOLLOWING FORMAT WILL BE USED: N6030 W15030 - N5800 W15200 -
N5930 W15100.
TROPICAL CYCLONE SIGMETS WILL CONTAIN A 6 HOUR FORECAST POSITION
VALID AT THE END OF THE SIGMET VALIDITY TIME AND WILL NO LONGER
CONTAIN AN OUTLOOK POSITION.
VOLCANIC ASH CLOUD SIGMETS WILL CONTAIN A 6 HOUR FORECAST
POSITION AT THE END OF THE SIGMET VALIDITY TIME AND WILL NO
LONGER CONTAIN AN OUTLOOK POSITION.
THESE CHANGES ARE IN ACCORDANCE WITH ICAO INTERNATIONAL STANDARDS
AND RECOMMENDED PRACTICES...ANNEX 3 TO THE CONVENTION ON
INTERNATIONAL CIVIL AVIATION...METEOROLOGICAL SERVICE FOR
INTERNATIONAL AIR NAVIGATION...AMENDMENT 74...EFFECTIVE
NOVEMBER 7 2007.
IF YOU HAVE ANY QUESTIONS CONCERNING THESE CHANGES...CONTACT:
LARRY BURCH
DEPUTY DIRECTOR
AVIATION WEATHER CENTER
KANSAS CITY MISSOURI
PHONE: 816-584-7203
E-MAIL: LARRY.BURCH@xxxxxxxx
THIS AND OTHER NWS TECHNICAL IMPLEMENTATION NOTICES ARE
AVAILABLE ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
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