NOUS41 KWBC 241425
PNSWSH
SERVICE CHANGE NOTICE 08-56
NATIONAL WEATHER SERVICE HEADQUARTERS WASHINGTON DC
1025 AM EDT WED SEP 24 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: NEW EL NIÑO SOUTHERN OSCILLATION /ENSO/ ALERTS
TO BE INCLUDED AS NEEDED IN THE ENSO DIAGNOSTIC
DISCUSSION: EFFECTIVE DECEMBER 11 2008.
STARTING ON THURSDAY DECEMBER 11 2008...THE NWS CLIMATE
PREDICTION CENTER /CPC/ WILL INCLUDE AN ENSO ALERT FOR AN
EL NIÑO OR LA NIÑA... AS NEEDED...IN THE FRONT SECTION OF
THE MONTHLY ENSO DIAGNOSTIC DISCUSSION. AN ENSO ALERT WILL
BE A WATCH... ADVISORY...OR FINAL ADVISORY /I.E. END OF AN
EL NIÑO OR A LA NIÑA/.
THE ENSO DIAGNOSTIC DISCUSSION HAS ALWAYS INDICATED THE
EXPECTED OCCURRENCE /OR LACK OF OCCURRENCE/ OF EL NIÑO OR
LA NIÑA FOR THE NEXT THREE MONTHS. BECAUSE EL NIÑO OR
LA NIÑA MAY AFFECT CLIMATE VARIABILITY PATTERNS THAT COULD
SIGNIFICANTLY IMPACT VARIOUS AREAS OF THE UNITED
STATES...CPC WILL NOW USE AN ALERT SYSTEM TO HIGHLIGHT WHEN
EL NIÑO OR LA NIÑA IS EXPECTED TO DEVELOP...CONTINUE OR END.
1. AN ENSO WATCH WILL BE ISSUED WHEN A TRANSITION TO EL NIÑO
OR LA NIÑA CONDITIONS IS ANTICIPATED WITHIN THE NEXT
THREE MONTHS.
2. AN ENSO ADVISORY WILL BE ISSUED WHEN EL NIÑO OR LA NIÑA
CONDITIONS ARE ALREADY OBSERVED AND EXPECTED TO CONTINUE.
3. AN ENSO FINAL ADVISORY WILL BE ISSUED WHEN EITHER EL NIÑO
OR LA NIÑA CONDITIONS HAVE ENDED.
CPC DEFINES EL NIÑO OR LA NIÑA CONDITIONS AS EXISTING WHEN:
A ONE-MONTH POSITIVE /NEGATIVE/ SEA SURFACE TEMPERATURE
ANOMALY OF 0.5C /-0.5C/ OR GREATER /LESS/ IS OBSERVED IN THE
NIÑO 3.4 REGION OF THE EQUATORIAL CENTRAL PACIFIC OCEAN /5N-
5S AND 120W-170W/ AND IS EXPECTED TO PERSIST FOR AT LEAST
THREE CONSECUTIVE MONTHS...AND
AN ATMOSPHERIC RESPONSE TYPICALLY ASSOCIATED WITH EL NIÑO
/LA NIÑA/ IS OBSERVED OVER THE EQUATORIAL PACIFIC REGION AS
PER EL NIÑO/LA NIÑA DOCUMENTATION ON THE FOLLOWING CPC WEB
PAGE: /USE LOWER CASE/
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/
ENSOCYCLE/ENSO_CYCLE.SHTML
CPC USUALLY ISSUES THE MONTHLY ENSO DIAGNOSTICS DISCUSSION
ON THE THURSDAY FROM THE 5TH AND THE 11TH OF THE MONTH...AT
AROUND 9:00 A.M. EASTERN LOCAL TIME. WITH ADVANCE NOTICE...
CPC MAY CHANGE THE ISSUANCE DATE /E.G. DUE TO HOLIDAYS/. THE
PRODUCT IS ISSUED UNDER THE FOLLOWING:
WMO HEADING - FXUS24 KWNC AWIPS ID - PMDENS
ON THE INTERNET AT /USE LOWER CASE/:
HTTP://WWW.CPC.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/
ENSO_ADVISORY/
THE TERM WARNING WILL NOT BE USED IN THE ENSO ALERT SYSTEM
BECAUSE WARNINGS ALMOST ALWAYS HAVE A NEGATIVE CONNOTATION.
BECAUSE ENSO EVENTS RESULT IN POSITIVE AND NEGATIVE IMPACTS
RELATED TO CLIMATE VARIABILITY PATTERNS...AN ADVISORY IS
MORE APPROPRIATE.
CPC WILL CONTINUE TO ISSUE ALL OTHER INFORMATION IN THE ENSO
DIAGNOSTIC DISCUSSION. CPC WILL CONTINUE TO ADDRESS CURRENT
OCEANIC AND ATMOSPHERIC CONDITIONS IN THE PACIFIC AND
RELATED CLIMATE VARIABILITY PATTERNS. THIS INCLUDES THE
FOLLOWING:
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 SERVICE CHANGE NOTICES ARE ONLINE AT:
HTTP://WWW.WEATHER.GOV/OS/NOTIF.HTM
$$
NNNN