-------- Original Message --------
579
NOUS41 KWBC 021207
PNSWSH
SERVICE CHANGE NOTICE 08-35
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
808 AM EDT FRI MAY 2 2008
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...AND NWS EMPLOYEES
FROM: THOMAS GRAZIANO
CHIEF...HYDROLOGIC SERVICES BRANCH
SUBJECT: COMBINED SEVERE THUNDERSTORM AND FLASH FLOOD
WARNINGS TO BE ISSUED IN THE WESTERN UNITED
STATES EFFECTIVE JULY 1 2008
EFFECTIVE TUESDAY JULY 1 2008 AT 1200 COORDINATED UNIVERSAL TIME
/UTC/ NWS WEATHER FORECAST OFFICES /WFO/ IN THE WEST WILL ISSUE
COMBINED SEVERE THUNDERSTORM AND FLASH FLOOD WARNINGS WHEN
CONDITIONS MEETING CRITERIA FOR BOTH TYPES OF WARNINGS RESULT
FROM THE SAME THUNDERSTORM. ALL NWS WEATHER FORECAST OFFICES IN
WASHINGTON...OREGON...IDAHO...MONTANA...CALIFORNIA...NEVADA...
UTAH AND ARIZONA MAY ISSUE THE COMBINED WARNING. HOWEVER...
ISSUANCE OF THE COMBINED WARNING IS EXPECTED TO BE A VERY RARE
OCCURRENCE OUTSIDE OF THE SOUTHWESTERN STATES CALIFORNIA...
NEVADA...UTAH AND ARIZONA/ DURING THE SOUTHWEST MONSOON SEASON.
THE COMBINED WARNINGS AND FOLLOW-UP STATEMENTS WILL BE ISSUED
USING THE FLASH FLOOD WARNING /FFW/ AND FLASH FLOOD STATEMENT
/FFS/ AWIPS IDENTIFIERS.
THE COMBINED PRODUCT WILL BE IMPLEMENTED AS A MEANS OF PROVIDING
WARNINGS FOR THUNDERSTORMS WITH BOTH FLASH FLOODING AND SEVERE
CHARACTERISTICS /LARGE HAIL AND/OR DAMAGING WINDS/. PREVIOUS
TESTS OF COMBINED WARNINGS WERE SUCCESSFUL WITH IMPLEMENTATION
PENDING OPERATIONAL USE OF VALID TIME EVENT CODE /VTEC/ IN FLASH
FLOOD PRODUCTS. NOW THAT VTEC IS PROVIDED IN FLASH FLOOD
PRODUCTS...COMBINED WARNINGS ARE POSSIBLE AND PREFERRED BY LOCAL
DISSEMINATION PARTNERS WHERE THESE TYPES OF STORMS OCCUR.
PRODUCT EXAMPLES ARE AVAILABLE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.WEATHER.GOV/OS/WATER/HYDRO/COMBINED_EXAMPLES.TXT
TRADITIONAL FLASH FLOOD WARNINGS WILL CONTAIN A SINGLE PRIMARY
VTEC LINE...WHILE COMBINED WARNINGS WILL CONTAIN TWO PRIMARY VTEC
LINES...ONE FOR THE FLASH FLOOD WARNING AND ONE FOR THE SEVERE
THUNDERSTORM WARNING. NO SEPARATE SEVERE THUNDERSTORM WARNING
TEXT PRODUCT /SVR/ WILL BE ISSUED IN THESE CASES. FURTHER
DETAILS ON THE USE OF VTEC CODE CAN BE FOUND AT THE FOLLOWING WEB
SITE /USE LOWER CASE/:
HTTP://WWW.NWS.NOAA.GOV/OM/VTEC/
PARTNERS AND USERS WHO ALREADY RECEIVE NWS FLASH FLOOD WARNINGS
DO NOT HAVE TO MAKE ANY CHANGES TO RECEIVE THE COMBINED WARNINGS.
IF YOU HAVE QUESTIONS REGARDING THESE PRODUCTS...PLEASE CONTACT:
CRAIG SCHMIDT
CHIEF METEOROLOGICAL SERVICES DIVISION
NATIONAL WEATHER SERVICE
WESTERN REGION HEADQUARTERS
125 SOUTH STATE STREET ROOM 1311
SALT LAKE CITY UT 84138
PHONE: 801-524-4000 X266
E-MAIL: CRAIG.SCHMIDT@xxxxxxxx
NWS SERVICE CHANGE NOTICES ARE ONLINE AT /USE LOWER CASE/:
HTTP://WWW.NWS.NOAA.GOV/OM/NOTIF.HTM
$$