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NOUS41 KWBC 161810
PNSWSH
SERVICE CHANGE NOTICE 25-71
NATIONAL WEATHER SERVICE HEADQUARTERS, SILVER SPRING, MD
210 PM EDT TUE SEP 16 2025
TO: SUBSCRIBERS:
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
-NOAAPORT
OTHER NWS PARTNERS, USERS, AND EMPLOYEES
FROM: KEVIN STONE, ACTING CHIEF
AVIATION AND SPACE WEATHER SERVICES BRANCH
SUBJECT: VOLCANO OBSERVATORY NOTIFICATION FOR AVIATION (VONA) TO
BE TRANSMITTED VIA THE AERONAUTICAL FIXED SYSTEM (AFS) BEGINNING
IN NOVEMBER 2025.
THE VONA IS A NOTIFICATION PRODUCT USED BY STATE VOLCANO
OBSERVATORIES (SVOS) GLOBALLY TO INFORM THE AVIATION COMMUNITY
(E.G., METEOROLOGISTS, AIR TRAFFIC MANAGERS, PILOTS, AND
DISPATCHERS) OF VOLCANIC ACTIVITY THAT COULD POSE A HAZARD TO
AVIATION. THE CONTENT AND FORMAT OF THE VONA HAVE BEEN DEFINED
BY THE INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO) AND WILL
BECOME A RECOMMENDED PRACTICE FOR SVOS TO DISSEMINATE BEGINNING
BY NOVEMBER 28, 2025. WITHIN THE UNITED STATES, THE U.S.
GEOLOGICAL SURVEY (USGS) HAS BEEN DESIGNATED AS THE SVO TO ISSUE
VONAS.
IN THE INTEREST OF EFFICIENCY AND ECONOMY IN U.S. GOVERNMENT
OPERATIONS, THE NWS WILL SUPPORT THE USGS BY DISSEMINATING THE
VONA VIA EXISTING NWS INFRASTRUCTURE, PROVIDING A CONDUIT VIA
THE AFS, I.E., AERONAUTICAL MESSAGE HANDLING SYSTEM (AMHS) TO
MEET THE ICAO REQUIREMENT.
BELOW IS AN EXAMPLE OF THE ICAO FORMATTED VONA.
VONA
DTG: 20231003/1412Z
VOLCANO: SHISHALDIN 311360
PSN: N05445 W16358
AREA: ALEUTIANS
SOURCE ELEV: 9373FT AMSL
NOTICE NR: 2023/125
CURRENT COLOUR CODE: RED
PREVIOUS COLOUR CODE: ORANGE
SVO: ALASKA VOLCANO OBSERVATORY
ACT STS: ERUPTION OCCURRED
DUR: ONGOING CONS
VA CLD HGT: 40000FT AMSL
HGT SOURCE: SATELLITE
MOV: S
CTC: ALASKA VOLCANO OBSERVATORY DUTY SCIENTIST, TEL +1-907-786-
7497
RMK: SIG VA EM OBS IN SATELLITE AT 20231003/1350Z. VA EM EXP TO
BE CONS FOR SEVERAL HR.
NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE
SIGNIFICANTLY OR IF THE COLOUR CODE CHANGES
USERS WILL NEED TO ADD THE NEW WMO IDS BELOW TO RECEIVE THE VONA
VIA AFS.
ALASKAN TAC VONAS:
WMAK01 PAVO WMAK02 PAVO WMAK03 PAVO
WMAK04 PAVO WMAK05 PAVO WMAK06 PAVO
IWXXM VONAS:
LMAK01 PAVO LMAK02 PAVO LMAK03 PAVO
LMAK04 PAVO LMAK05 PAVO LMAK06 PAVO
COMMONWEALTH OF THE NORTHERN MARIANA ISLANDS (CNMI) TAC VONAS:
WMMY01 PAVO WMMY02 PAVO WMMY03 PAVO
IWXXM VONAS:
LMMY01 PAVO LMMY02 PAVO LMMY03 PAVO
AMERICAN SAMOA TAC VONAS:
WMPS01 PHVO WMPS02 PHVO
IWXXM VONAS:
LMPS01 PHVO LMPS02 PHVO
HAWAIIAN TAC VONAS:
WMPA01 PHVO WMPA02 PHVO WMPA03 PHVO
IWXXM VONAS:
LMPA01 PHVO LMPA02 PHVO LMPA03 PHVO
CALIFORNIA TAC VONAS:
WMUS01 KVOL WMUS02 KVOL WMUS03 KVOL
IWXXM VONAS:
LMUS01 KVOL LMUS02 KVOL LMUS03 KVOL
CASCADES/YELLOWSTONE TAC VONAS:
WMUS01 KVWA WMUS02 KVWA WMUS03 KVWA
WMUS04 KVWA WMUS05 KVWA WMUS06 KVWA
IWXXM VONAS:
LMUS01 KVWA LMUS02 KVWA LMUS03 KVWA
LMUS04 KVWA LMUS05 KVWA LMUS06 KVWA
FURTHER INFORMATION ON THE VONA AND THE USGS CAN BE FOUND AT:
HTTPS://WWW.USGS.GOV/PROGRAMS/VHP/VOLCANO-NOTIFICATIONS-DELIVER-
SITUATIONAL-INFORMATION
IF YOU HAVE COMMENTS OR QUESTIONS, PLEASE CONTACT:
MICHAEL L. GRAF
METEOROLOGIST/INTERNATIONAL LIAISON
NWS HEADQUARTERS
SILVER SPRING, MD
304-268-0691
MICHAEL.GRAF@NOAA.GOV
NATIONAL SERVICE CHANGE NOTICES ARE ONLINE AT:
HTTPS://WWW.WEATHER.GOV/NOTIFICATION
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