-------- Original Message --------
001
NOUS41 KWBC 061146
PNSWSH
SERVICE CHANGE NOTICE 09-36
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
746 AM EDT WED MAY 6 2009
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...AND NWS EMPLOYEES
FROM: CRAIG SCHMIDT
CHIEF...METEOROLOGICAL SERVICES DIVISION
WESTERN REGION HEADQUARTERS SALT LAKE CITY UT
SUBJECT: EXPERIMENTAL CRITERION CHANGE FOR HAIL SIZE IN SEVERE
THUNDERSTORM WARNING DETERMINATION AT ALL WESTERN
REGION WEATHER FORECAST OFFICES FROM THREE-QUARTER
/0.75/ INCH TO ONE /1/ INCH IN DIAMETER OR LARGER
EFFECTIVE JUNE 1 2009
ON JUNE 1 2009...ALL WESTERN REGION /WR/ 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 WFOS IN WR 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/.
A SERVICE CHANGE NOTICE /SCN/ ANNOUNCING THE NWS CENTRAL
REGION/S /CR/ SIMILAR EXPERIMENT IS AVAILABLE ONLINE AT /USE
LOWER CASE LETTERS/:
HTTP://WWW.WEATHER.GOV/OS/NOTIFICATION/SCN09-19HAIL_CHANGE.TXT
A PRODUCT DESCRIPTION DOCUMENT /PDD/ FOR THIS WR EXPERIMENT IS
AVAILABLE ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://PRODUCTS.WEATHER.GOV/
THIS EXPERIMENT WILL BE IMPLEMENTED FOR ALL AREAS IN EIGHT
WESTERN STATES: ARIZONA...CALIFORNIA...IDAHO...MONTANA...
NEVADA...OREGON...UTAH AND WASHINGTON.
NO CHANGE WILL OCCUR WITH RESPECT TO WIND SPEED IN SEVERE
THUNDERSTORM WARNINGS. WINDS EQUAL TO OR IN EXCESS OF 50 KNOTS
/58 MPH/ WILL REMAIN THE CRITERION.
FOR THUNDERSTORMS EXPECTED TO PRODUCE AROUND 3/4 INCH TO 7/8
INCH DIAMETER HAIL BUT REMAIN BELOW SEVERE WIND LIMITS...WR WFOS
ARE EXPECTED TO USE THE SPECIAL WEATHER STATEMENT /SPS/...
HEADLINED AS A SIGNIFICANT WEATHER ADVISORY. 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/ AS USUAL.
IF YOU HAVE QUESTIONS...PLEASE CONTACT:
CRAIG SCHMIDT
NATIONAL WEATHER SERVICE
WESTERN REGION HEADQUARTERS
125 SOUTH STATE STREET
ROOM 1311
SALT LAKE CITY UT 84138
801-524-4000
CRAIG.SCHMIDT@xxxxxxxx
NATIONAL SERVICE CHANGE NOTICES ARE ONLINE AT /USE LOWER CASE LETTERS/:
HTTP://WWW.WEATHER.GOV/OM/NOTIF.HTM
$$
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