[nws-changes] 20070821: ICAO sigmets-: ADMIN NOTICE NOUS41 KWBC]

[Linda Miller]

-------- Original Message --------

644 
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 at NOAA.GOV

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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