-------- Original Message --------
307
NOUS41 KWBC 052036
PNSWSH
SERVICE CHANGE NOTICE 09-19
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
335 PM EST THU MAR 5 2009
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...AND NWS EMPLOYEES
FROM: KIM RUNK
CHIEF...INTEGRATED SERVICES DIVISION
CENTRAL REGION HEADQUARTERS KANSAS CITY MO
SUBJECT: EXPERIMENTAL CRITERION CHANGE FOR HAIL SIZE IN SEVERE
THUNDERSTORM WARNING DETERMINATION AT ALL CENTRAL
REGION WEATHER FORECAST OFFICES FROM THREE-QUARTER
/0.75/ INCH TO ONE /1/ INCH IN DIAMETER OR LARGER
EFFECTIVE BY OR BEFORE JULY 1 2009
IN A ROLL OUT IMPLEMENTATION FROM APRIL 1 THROUGH JULY 1 2009...
ALL CENTRAL REGION /CR/ WEATHER FORECAST OFFICES /WFOS/ WILL
BEGIN USING A NEW EXPERIMENTAL HAIL CRITERION FOR DETERMINING
WHEN TO ISSUE SEVERE THUNDERSTORM WARNINGS /SVR/. IN AN EFFORT
TO BETTER REPRESENT HAIL WHICH PRODUCES DAMAGE AND TO REDUCE
USER COMPLACENCY TO NUMEROUS SEVERE THUNDERSTORM WARNINGS FOR
THREE-QUARTER /0.75/ INCH DIAMETER HAIL...THE WFO/S IN CR
WILL USE HAIL CRITERION OF ONE /1/ INCH IN DIAMETER OR LARGER AS
OPPOSED TO THE REFERENCED /0.75/ INCH CRITERION. THERE IS NO
CHANGE IN HAIL CRITERION FOR AVIATION THUNDERSTORM WARNINGS
/I.E. CONVECTIVE SIGMETS/ OR FOR SPECIAL MARINE WARNINGS /SMW/.
THIS EFFORT IS AN EXPANSION OF A SUCCESSFUL EXPERIMENT CONDUCTED
IN THE KANSAS OVER THE LAST 4 SEVERE WEATHER SEASONS WHERE WFOS
USED THE ONE /1/ INCH CRITERION FOR SEVERE THUNDERSTORM
WARNINGS. DUE TO THE OVERWHELMING POSITIVE RESPONSE TO THIS
CHANGE...THE ENTIRE CENTRAL REGION WILL TEST THE NEW
EXPERIMENTAL HAIL CRITERION WITH THE POTENTIAL FOR FURTHER
EXPANSION ACROSS NWS IN THE FUTURE.
A PRODUCT DESCRIPTION DOCUMENT /SDD/ FOR THIS EXPERIMENT IS
AVAILABLE ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://PRODUCTS.WEATHER.GOV/
A MAP SHOWING AFFECTED OFFICES IS ONLINE AT /USE LOWERCASE/:
HTTP://WWW.WEATHER.GOV/OS/NOTIFICATION/RESOURCES/CR_WFOS.PDF
NO CHANGE WILL OCCUR WITH RESPECT TO WIND SPEED AND SEVERE
THUNDERSTORM WARNINGS. WINDS EQUAL TO OR IN EXCESS OF 50 KNOTS
/58 MPH/ WILL REMAIN THE CRITERION.
FOR THUNDERSTORMS EXPECTED TO PRODUCE 3/4 INCH TO 7/8 INCH
DIAMETER HAIL BUT REMAIN BELOW SEVERE WIND LIMITS...WFOS MAY
ISSUE A SIGNIFICANT WEATHER ADVISORY USING THE SPECIAL WEATHER
STATEMENT /SPS/ PRODUCT OR THE SHORT TERM FORECAST /NOW/
PRODUCT. WFOS WILL ALSO CONTINUE TO COLLECT AND DISTRIBUTE HAIL
REPORTS THAT ARE THREE-QUARTERS /0.75/ INCH IN DIAMETER OR
GREATER BY WAY OF THE LOCAL STORM REPORT /LSR/ IN AS NEAR REAL
TIME AS POSSIBLE.
FOR QUESTIONS ON THIS SERVICE CHANGE NOTICE PLEASE CONTACT:
KIM RUNK
NATIONAL WEATHER SERVICE
CENTRAL REGION HEADQUARTERS
7220 NW 101ST TERRACE
KANSAS CITY MO
PHONE: 816-268-3140
EMAIL: KIM.RUNK@xxxxxxxx
NATIONAL SERVICE CHANGE NOTICES ARE ONLINE AT /USE LOWERCASE/:
HTTP://WWW.WEATHER.GOV/OS/NOTIF.HTM
$$
