PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EDT THU OCT 19 2006 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS WHICH USUALLY INFLUENCE SEASONAL CLIMATE INCLUDE 1) EL NINO AND LA NINA - WHICH TOGETHER MAKE UP EL NINO/SOUTHERN OSCILLATION OR ENSO 2) TRENDS - APPROXIMATED BY THE DIFFERENCE BETWEEN THE MOST RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGY PERIOD (CURRENTLY 1971-2000) 3) TROPICAL 30-60-DAY OSCILLATION - WHICH MAY AFFECT CLIMATE VARIABILITY WITHIN A SEASON 4) THE NORTH ATLANTIC OSCILLATION (NAO) AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE ANOMALY PATTERN ESPECIALLY DURING THE COLD SEASONS 5) PERSISTENTLY DRY OR WET SOILS IN THE SUMMER AND SNOW AND ICE COVER ANOMALIES IN THE WINTER. 6) AN OBJECTIVE CONSOLIDATION (CALLED CON IN THE TEXT) OF THE OCN, CCA, SMLR AND CFS FORECASTS IS USED AS A FIRST-GUESS IN PREPARING THE FORECAST MAPS. SST ANOMALIES ACROSS THE EQUATORIAL PACIFIC BETWEEN 165E AND CLOSE TO THE SOUTH AMERICAN COAST WERE AT LEAST +0.5 DEG CENTIGRADE ABOVE NORMAL... INDICATING THAT WEAK ENSO CONDITIONS HAVE COMMENCED. THE MAGNITUDE OF THE ANOMALIES HAS CONTINUED TO INCREASE... AND SSTS ARE AT LEAST 1.0 DEG C ABOVE NORMAL IN MOST AREAS FROM 170E TO 85W. MOST PREDICTION TOOLS INDICATE THAT SST ANOMALIES IN THE NINO 3.4 REGION WILL REMAIN AT LEAST +0.5 DEG C ABOVE NORMAL ACROSS THE TROPICAL PACIFIC THROUGHOUT THE FALL AND WINTER... AND THE AVERAGE OF THE CURRENTLY AVAILABLE TOOLS IS APPROACHING +1.0 DEG C FOR THE PEAK INTENSITY. THIS IMPLIES THAT WARM EPISODE (ENSO) CONDITIONS COULD REACH MODERATE LEVELS AND MAY HAVE SIGNIFICANT IMPACTS ON THE UNITED STATES CLIMATE DURING THE NEXT THREE TO SIX MONTHS. COMPOSITES OF OBSERVED TEMPERATURE AND PRECIPITATION PATTERNS OVER THE U.S. DURING PAST WEAK AND MODERATE EL NINO CASES WERE STRONGLY CONSIDERED FOR THE OUTLOOKS FROM NOVEMBER - JANUARY (NDJ) THROUGH FEBRUARY - APRIL (FMA). HOWEVER... THERE IS STILL SOME UNCERTAINTY WITH THE EXPECTED INTENSITY OF THE EVENT...AND BECAUSE THERE IS CONSIDERABLE EVENT-TO-EVENT VARIABILITY AMONG OBSERVED EL NINO CASES. THE OVERALL TREND HAS BEEN FOR MORE RECENT FORECASTS TO INDICATE A SOMEWHAT STRONGER EVENT THAN PREVIOUS ONES HAD. ONGOING ASSESSMENTS OF THE GLOBAL CLIMATE SYSTEM MAY RESULT IN FURTHER CHANGES TO THE TEMPERATURE AND PRECIPITATION FORECASTS FOR THE UPCOMING WINTER SEASONS AS THE LIKELY MAGNITUDE OF THE DEVELOPING EL NINO BECOMES MORE CLEAR. THE TEMPERATURE OUTLOOK FOR NOV-DEC-JAN (NDJ) 2006-07 CALLS FOR WARMER THAN NORMAL CONDITIONS OVER MOST OF THE WESTERN AND NORTHERN PORTIONS OF THE CONUS EXCEPT FOR CALIFORNIA AND NEW ENGLAND... AS WELL AS FOR SOUTHEASTERN ALASKA. NEAR NORMAL TEMPERATURES ARE EXPECTED THROUGHT THE CENTRAL AND EASTERN GULF STATES INCLUDING FLORIDA. ELSEWHERE THERE ARE EQUAL CHANCES OF WARMER-THAN-... COOLER-THAN-... OR NEAR-NORMAL TEMPERATURES DURING OND. THE PRECIPITATION OUTLOOK FOR NOV-DEC-JAN (NDJ) 2006-7 CALLS FOR BELOW MEDIAN PRECIPITATION IN PARTS OF THE PACIFIC NORTHWEST AND MONTANA...AND OVER PARTS OF THE OHIO VALLEY AND CENTRAL MISSISSIPPI VALLEY. THE CHANCES FOR ABOVE MEDIAN PRECIPITATION ARE ENHANCED OVER THE SOUTHERN HALF OF NEW MEXICO... MOST OF TEXAS AND OKLAHOMA AND WESTERN PORTIONS OF ARKANSAS AND LOUISIANA...FLORIDA AND PORTIONS OF THE SOUTH ATLANTIC STATES. ELSEWHERE THERE ARE EQUAL CHANCES OF ABOVE-... BELOW-... OR NEAR-MEDIAN PRECIPITATION DURING NDJ. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOK NOTE: FOR GRAPHICAL DISPLAYS OF THE FORECAST TOOLS DISCUSSED BELOW SEE: HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/TOOLS/BRIEFING CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS IN MID-OCTOBER SSTS IN THE EQUATORIAL PACIFIC WERE MORE THAN +0.5 DEG C ABOVE NORMAL FROM 165E TO NEAR THE SOUTH AMERICAN COAST...WITH DEPARTURES OF MORE THAN +1.0 DEG C OBSERVED BETWEEN 170E AND 85W...AND UP TO +2.0 DEG C BETWEEN 120W AND 90W. THIS RESULTS IN VALUES ABOVE +0.5 IN ALL FOUR NINO INDEX AREAS...WITH THE LARGEST VALUES EXCEEDING +1.0 DEG C IN BOTH NINO 3 AND NINO 4. THE LOW LEVEL EASTERLY WINDS (AT 850 MB) IN THE TROPICAL PACIFIC AVERAGED WEAKER THAN NORMAL DURING SEPTEMBER AND HAVE BEEN GENERALLY WEAKER THAN NORMAL ACROSS MUCH OF THE CENTRAL AND EASTERN EQUATORIAL PACIFIC SINCE JULY. IN RECENT WEEKS SOME ACTUAL WESTERLY WINDS HAVE DEVELOPED NEAR THE EQUATOR JUST WEST OF THE DATE LINE. ALSO, THE SOI INDEX WAS NEGATIVE FOR THE FIFTH CONSECUTIVE MONTH. TOGETHER THESE INDICATORS SHOW THAT WEAK BUT INCREASINGLY STRONG EL NINO CONDITIONS HAVE DEVELOPED ACROSS THE TROPICAL PACIFIC. THE UPPER OCEAN HEAT CONTENT IN THE EQUATORIAL PACIFIC HAS INCREASED MARKEDLY SINCE FEBRUARY... AND IS NOW WELL ABOVE THE LONG TERM AVERAGE. THE HEAT CONTENT IS SIMILAR TO LEVELS SEEN DURING PREVIOUS MODERATE WARM ENSO EPISODES... WHICH ALSO INDICATES THAT THE CURRENT WEAK EPISODE WILL PROBABLY CONTINUE TO STRENGTHEN. MADDEN-JULIAN OSCILLATION (MJO)ACTIVITY OVER THE TROPICAL PACIFIC HAS RECENTLY INCREASED TO MODERATE LEVELS... WHICH MAY INCREASE THE INTRA-SEASONAL CLIMATE VARIABILITY BUT DOES NOT PROVIDE A RELIABLE STEADY FORCING FOR THE CLIMATE SYSTEM ON A SEASONAL BASIS. PROGNOSTIC DISCUSSION OF SST FORECASTS A CONSOLIDATION OF NCEP SST MODELS PREDICTS THAT NINO 3.4 SSTS WILL MOST LIKELY BE ABOVE +0.5 DEG C FOR THE NEXT SEVERAL SEASONS... DIMINISHING FROM +0.7 DEG C IN DJF TO +0.5 DEG C BY FMA. HOWEVER THERE IS A LARGE AMOUNT OF SPREAD AMONG THE FOUR MODEL SOLUTIONS FOR THE NEXT FEW MONTHS... INDICATING CONSIDERABLE UNCERTAINTY IN THIS FORECAST. THE ENSEMBLE MEAN OF THE CFS PREDICTS THE STRONGEST EPISODE... WITH SSTS IN NINO 3.4 PEAKING NEAR 1.3 DEG C ABOVE AVERAGE... WHILE THE CONSTRUCTED ANALOG WEAKENS ANOMALIES IN NINO 3.4 TO ABOUT +0.3 DEG C BY FMA. AN ENSEMBLE OF 17 DIFFERENT STATISTICAL AND DYNAMICAL MODELS SHOWS THAT SEVERAL MEMBERS PROVIDE SUPPORT FOR A MODERATE STRENGTH ENSO... BUT THE MAJORITY OF MEMBERS STILL FORECAST THAT THE CURRENT EVENT WILL REMAIN WEAK. IT IS NOTEWORTHY THAT THE MODELS INDICATING THE WEAKEST DEVELOPMENT NOW PREDICT STRONGER EVENTS THAN THEY DID LAST MONTH. BASED ON CURRENT CONDITIONS AND THE GENERAL WARMING TREND OBSERVED DURING THE PAST FEW MONTHS... THIS EPISODE IS EXPECTED TO STRENGTHEN AND MAY REACH MODERATE STRENGTH DURING THE UPCOMING COLD SEASON... WITH MAXIMUM IMPACT ON THE CLIMATE EXPECTED DURING DJF AND JFM. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE OUTLOOK FOR NDJ 2006-07 THROUGH NDJ 2007-08 IS BASED ON THE CFS...THE MULTI-MODEL ENSEMBLE FROM THE IRI... AND THE CDC-CCA RENDERING OF THE MOST LIKELY CONSENSUS FORECAST OF SEVERAL DYNAMICAL MODEL FORECASTS... AS WELL AS THE STATISTICAL TOOLS CCA... SMLR... AND OCN. THE CAS TOOL HAS MINIMUM SKILL FOR FORECASTS INITIALIZED IN THE FALL FOR THE COLDER PART OF THE YEAR AND WAS NOT GIVEN MUCH WEIGHT IN THIS SERIES OF FORECASTS. FORECASTS PRIMARILY REFLECT THE CONSOLIDATED TEMPERATURE AND PRECIPITATION PRODUCTS (A SKILL-WEIGHTED OBJECTIVE BLEND OF CFS... CCA... SMLR... AND OCN)... COMBINED WITH COMPOSITES FOR WEAK AND MODERATE STRENGTH WARM EPISODES DURING THE PERIOD NDJ 2006-07 THROUGH MAM 2007. THE OUTLOOKS FOR AMJ 2007 THROUGH NDJ 2007-08 ARE BASED LARGELY ON A CONSOLIDATION OF CCA... SMLR... AND OCN (CFS IS NOT AVAILABLE AFTER LEAD 6). NOTE: THE CFS MODEL WAS PREDICTING UNREASONABLY LARGE NEGATIVE TEMPERATURE ANOMALIES IN SOME SOME PARTS OF THE SOUTHWEST FOR FMA AND MAM AND WAS NOT WEIGHTED IN THE OBJECTIVELY DERIVED CON TOOL FOR THOSE PERIODS... ALTHOUGH IT WAS CONSIDERED SUBJECTIVELY. PROGNOSTIC DISCUSSION OF OUTLOOKS - NDJ 2006 TO NDJ 2007 TEMPERATURE: TEMPERATURE PROBABILITIES FOR NDJ 2006-07 ARE SIMILAR TO THOSE ISSUED LAST MONTH WITH INCREASED CONFIDENCE IN THE ABOVE NORMAL MEAN TEMPERATURES ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY. CONSISTENT WITH THE CONSOLIDATION. THE CONSOLIDATION ALSO FAVORS ABOVE NORMAL TEMPERATURES ACROSS THE SOUTHEAST AND IN THE INTERIOR SOUTHWEST... BUT THESE INDICATIONS WERE DISREGARDED OR REDUCED DUE TO THE POTENTIAL COOLING EFFECTS OF ENSO IN THOSE REGIONS. DUE TO THESE POSSIBLE COOLING IMPACTS FROM ENSO COUNTERBALANCED BY RECENT WARMING TRENDS... NEAR NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHEAST DURING NDJ THROUGH FMA... AND ALSO OVER PARTS OF TEXAS DURING JFM AND FMA. THE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES WERE ALSO INCREASED ACROSS THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY DURING DJF AND JFM... CONSISTENT WITH THE CPC CONSOLIDATION. WEAK PROBABILITIES FOR ABOVE NORMAL TEMPERATURES OVER PARTS OF THE SOUTHWEST AND GREAT BASIN IN THE FORECAST SUITE ISSUED LAST MONTH WERE REPLACED BY EC DUE TO POTENTIAL EFFECTS FROM ENSO AND LACK OF ANY SIGNIFICANT SIGNAL FOR WAMRTH FROM CON. OUTLOOKS FOR AMJ 2007 AND BEYOND ARE BASED PRIMARILY ON THE CONSOLIDATION TOOL (THE CFS COMPONENT DROPS OUT AFTER LEAD 6) WHICH IS DOMINATED BY THE TREND. PRECIPITATION: THE PRECIPITATION OUTLOOK FOR NDJ 2006-07 IS BASED PRIMARILY ON THE CPC CONSOLIDATION... WITH MODIFICATIONS DUE TO INDICATIONS FROM OTHER MODELS AND COMPOSITES OF WEAK AND MODERATE PAST EL NINOS. THE MAIN CHANGE FROM THE PREVIOUS SET OF FORECASTS WAS A SLIGHT FURTHER INCREASE IN THE AREA AND CONFIDENCE OF THE FORECASTS FOR ABOVE MEDIAN PRECIPITATION OVER MUCH OF THE SOUTHWEST DUE TO THE EXPECTED DEVELOPMENT OF WEAK TO MODERATE EL NINO CONDITIONS. FORECASTS FOR NDJ 2006-07 THROUGH MAM 2007 WERE LARGELY BASED ON COMPOSITES OF WEAK AND MODERATE STRENGTH WARM EPISODES. THE REMAINING OUTLOOKS HAVE BEEN MODIFIED ONLY SLIGHTLY FROM THOSE ISSUED FOR CORRESPONDING SEASONS LAST MONTH... AND WERE BASED EXCLUSIVELY ON THE CPC CONSOLIDATION... WHICH PRIMARILY REFLECTS TRENDS. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: A J WAGNER STARTING WITH THE SEASONAL OUTLOOK RELEASED IN FEBRUARY, 2006, THE GLOSSARY OF TERMS WILL NO LONGER APPEAR WITH THIS MESSAGE. INSTEAD, TERMS THAT ARE IN THE GLOSSARY WILL BE LINKED TO THEIR DEFINITION. FOR A DESCRIPTION OF THE STANDARD FORECAST TOOLS - THEIR SKILL - AND THE FORECAST FORMAT PLEASE SEE OUR WEB PAGE AT HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/DISC.HTML (USE LOWER CASE LETTERS) INFORMATION ON THE FORMULATION AND SKILL OF THE CAS FORECASTS MAY BE FOUND AT: HTTP://WWW.CPC.NCEP.NOAA.GOV/SOILMST/FORECASTS.HTML (USE LOWERCASE LETTERS) NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR VALID PERIOD. WITHIN ANY GIVEN VALID PERIOD OBSERVATIONS AND SHORT AND MEDIUM RANGE FORECASTS SHOULD BE CONSULTED. THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT MONTH ON THU NOV 16 2006. 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE $$