-------- Original Message --------
968
NOUS41 KWBC 101546
PNSWSH
SERVICE CHANGE NOTICE 08-56 AMENDED
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1045 AM EST WED DEC 10 2008
TO: SUBSCRIBERS:
-FAMILY OF SERVICES
-NOAA WEATHER WIRE SERVICE
-EMERGENCY MANAGERS WEATHER INFORMATION NETWORK
OTHER NWS PARTNERS...AND NWS EMPLOYEES
FROM: AHSHA N. TRIBBLE
CHIEF...CLIMATE SERVICES DIVISION
OFFICE OF CLIMATE...WATER AND WEATHER SERVICES
SUBJECT: AMENDED: EL NINO SOUTHERN OSCILLATION /ENSO/
ALERTS...AS NEEDED...IN THE ENSO DIAGNOSTIC
DISCUSSION POSTPONED UNTIL FEBRUARY 5 2009.
REFER TO: SERVICE CHANGE NOTICE 08-56 SENT ON
SEPTEMBER 24 2008
AMENDED TO POSTPONE EFFECTIVE DATE FOR THIS CHANGE FROM
DECEMBER 11 2008 TO FEBRUARY 5 2009 FOR TECHNICAL REASONS.
STARTING ON THURSDAY FEBRUARY 5 2009...THE NWS CLIMATE
PREDICTION CENTER /CPC/ WILL INCLUDE AN ENSO ALERT FOR AN
EL NINO OR LA NINA...AS NEEDED...IN THE BEGINNING SECTION OF
THE MONTHLY ENSO DIAGNOSTIC DISCUSSION. AN ENSO ALERT WILL
BE A WATCH... ADVISORY...OR FINAL ADVISORY /I.E. END OF AN
EL NINO OR LA NINA/.
THE ENSO DIAGNOSTIC DISCUSSION HAS ALWAYS INDICATED THE
EXPECTED OCCURRENCE /OR LACK OF OCCURRENCE/ OF EL NINO OR
LA NINA FOR THE NEXT THREE MONTHS. WITH SIGNIFICANT IMPACTS
IN VARIOUS AREAS OF THE UNITED STATES OFTEN ASSOCIATED WITH
CLIMATE VARIABILITY PATTERNS RELATED TO EL NINO AND
LA NINA...CPC WILL NOW USE AN ALERT TO HIGHLIGHT WHEN
EL NINO OR LA NINA IS EXPECTED TO DEVELOP...CONTINUE OR END.
1. AN ENSO WATCH WILL BE ISSUED WHEN A TRANSITION TO EL NINO
OR LA NINA CONDITIONS IS EXPECTED IN THE NEXT 3 MONTHS.
2. AN ENSO ADVISORY WILL BE ISSUED WHEN EL NINO OR LA NINA
CONDITIONS ARE ALREADY OBSERVED AND EXPECTED TO CONTINUE.
3. AN ENSO FINAL ADVISORY WILL BE ISSUED WHEN EITHER EL NINO
OR LA NINA CONDITIONS HAVE ENDED.
CPC DEFINES EL NINO /OR LA NINA/ CONDITIONS AS EXISTING WHEN:
A ONE-MONTH POSITIVE /NEGATIVE/ SST ANOMALY IN THE NINO 3.4
REGION OF 0.5C /-0.5C/ OR GREATER /LESS/ IS OBSERVED AND IS
EXPECTED TO PERSIST FOR AT LEAST 3 CONSECUTIVE MONTHS AND
AN ATMOSPHERIC RESPONSE TYPICALLY ASSOCIATED WITH EL NINO
/LA NINA/ IS OBSERVED OVER THE EQUATORIAL PACIFIC REGION AS
PER EL NINO/LA NINA DOCUMENTATION ON THE FOLLOWING CPC WEB
PAGE: /USE LOWER CASE/
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/EN
SOCYCLE/ENSO_CYCLE.SHTML
CPC USUALLY ISSUES THE MONTHLY ENSO DIAGNOSTICS DISCUSSION
ON THE THURSDAY FROM THE 5TH TO THE 11TH...AT AROUND 9:00
A.M. EASTERN LOCAL TIME. IF NECESSARY THE ISSUANCE DATE MAY
BE CHANGED WITH ADVANCE NOTICE /E.G. DUE TO HOLIDAYS/. IT IS
ISSUED UNDER THE FOLLOWING:
WMO HEADING - FXUS24 KWNC AWIPS ID - PMDENS
ON THE INTERNET /LOWER CASE/ AT:
HTTP://WWW.CPC.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/
ENSO_ADVISORY/
THE WARNING TERM WILL NOT BE USED IN THE ENSO ALERT SYSTEM
SINCE WARNINGS ALMOST ALWAYS HAVE A NET NEGATIVE CONNOTATION
FOR IMPACTS FROM SHORT-TERM WEATHER EVENTS. SINCE ENSO
EVENTS HAVE A MORE NEUTRAL NET EFFECT THROUGH BOTH POSITIVE
AND NEGATIVE IMPACTS FROM ENSO RELATED CLIMATE VARIABILITY
PATTERNS...AN ADVISORY IS MORE APPROPRIATE FOR ENSO ALERTS.
ALL OTHER INFORMATION IN THE ENSO DIAGNOSTIC DISCUSSION WILL
CONTINUE TO BE ISSUED. CPC WILL CONTINUE TO ADDRESS CURRENT
OCEANIC AND ATMOSPHERIC CONDITIONS IN THE PACIFIC AND
RELATED CLIMATE VARIABILITY PATTERNS INCLUDING:
-ANALYSIS OF CURRENT AND RECENT PATTERNS IN SURFACE AND
SUBSURFACE WATER TEMPERATURE ANOMALIES IN THE TROPICAL
PACIFIC
-RELATED ANALYSES SUCH AS RAINFALL...OUTGOING LONG WAVE
RADIATION...ETC.
-INFLUENCING FACTORS SUCH AS MADDEN-JULIAN OSCILLATIONS
...KELVIN WAVES...ETC
-STATISTICAL AND COUPLED MODEL PREDICTIONS.
FOR ADDITIONAL INFORMATION ON ENSO ALERT POLICY AND THE ENSO
DIAGNOSTIC DISCUSSION...CONTACT
MICHAEL S. HALPERT
NWS CLIMATE PREDICTION CENTER - W/NP5
5200 AUTH RD
CAMP SPRINGS MD 20746
301-763-8000 EXT 7535
NWS NATIONAL NOTICES ARE ONLINE AT /USE LOWERCASE/
HTTP://WWW.WEATHER/GOV/OS/NOTIF.HTM
$$