PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EDT THU AUG 17 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 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 MOST OF THE EQUATORIAL PACIFIC CURRENTLY RANGE FROM SLIGHTLY WARMER THAN NORMAL TO NEAR NORMAL... INDICATING PRIMARILY ENSO NEUTRAL CONDITIONS. MOST PREDICTION TOOLS INDICATE THAT SST ANOMALIES WILL BE NEAR OR SOMEWHAT ABOVE +0.5 DEG CENTIGRADE IN THE ENSO-SENSITIVE REGIONS OF THE PACIFIC ... SUGGESTING THAT NEUTRAL OR WEAK WARM EVENT CONDITIONS COULD HAVE SOME IMPACT ON UNITED STATES CLIMATE IN THIS SERIES OF OUTLOOKS. UNTIL WE GET A MORE DEFINITIVE IDEA OF THE LIKELIHOOD AND INTENSITY OF A WARM EVENT IN THE NEXT FEW MONTHS... WE HAVE ELECTED TO CLOSELY FOLLOW THE CONSOLIDATION FORECAST WHICH CALLS FOR DRIER THAN MEDIAN PRECIPITATION OVER THE SOUTHEAST STATES DURING THE CORE OF THE UPCOMING COLD SEASON ...NAMELY NDJ 2006 - DJF 2006 - AND JFM 2007. HISTORICAL COMPOSITES OF WEAK WARM EPISODE CONDITIONS ALSO TEND TO FAVOR BELOW MEDIAN AMOUNTS OF PRECIPITATION ACROSS THE SOUTHEAST FOR THE THREE SEASONS JUST MENTIONED. ONGOING ASSESSMENTS OF THE GLOBAL CLIMATE SYSTEM MAY REQUIRE US TO MAKE SIGNIFICANT CHANGES TO THE UPCOMING WINTER TEMPERATURE AND PRECIPITATION FORECASTS AS THE STATE AND MAGNITUDE OF ENSO BECOMES MORE CLEAR. THE TEMPERATURE OUTLOOK FOR SEP-OCT-NOV (SON) 2006 CALLS FOR WARMER THAN NORMAL CONDITIONS OVER MOST OF THE U.S. WEST OF THE MISSISSIPPI RIVER. ABOVE NORMAL TEMPERATURES ARE ALSO EXPECTED ACROSS THE GREAT LAKES - NEW ENGLAND AND THE FLORIDA PENINSULA AS WELL AS THE EASTERN HALF OF ALASKAS SOUTHERN COASTLINE. ELSEWHERE THERE ARE EQUAL CHANCES OF WARMER-THAN... COOLER-THAN... OR NEAR- NORMAL TEMPERATURES DURING SON. THE PRECIPITATION OUTLOOK FOR SEP-OCT-NOV (SON) 2006 CALLS FOR BELOW MEDIAN PRECIPITATION IN MUCH OF THE MIDWEST... AND THE PACIFIC NORTHWEST. THE FIRST IS DUE MAINLY TO TRENDS... WHILE THE LATTER IS INDICATED BY A NUMBER OF TOOLS. THE CHANCES FOR ABOVE MEDIAN PRECIPITATION ARE ENHANCED OVER FLORIDA DUE TO LONG TERM TRENDS AND THE EXPECTATION OF AN ACTIVE ATLANTIC HURRICANE SEASON. HOWEVER ... IT SHOULD BE EMPHASIZED THAT THIS PRECIPITATION OUTLOOK SHOULD NOT BE USED TO INFER CHANGES IN HURRICANE STRIKE PROBABILITIES. ABOVE MEDIAN PRECIPITATION IS ALSO PREDICTED OVER MUCH OF THE NORTHERN GREAT PLAINS WHICH IS HEAVILY FAVORED BY THE CONSOLIDATION TOOL. 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 SSTS ALONG THE EQUATOR IN THE PACIFIC ARE MOSTLY NEAR OR SLIGHTLY ABOVE +0.5 DEG C OF NORMAL. THE SSTS IN THE NINO 3.4 REGION... A CRITICAL INDICATOR FOR THE ENSO STATE... CURRENTLY AVERAGE ABOUT 0.4 DEG C ABOVE NORMAL. THE LOW LEVEL EASTERLY WINDS (AT 850 MB) IN THE TROPICAL PACIFIC AVERAGED SOMEWHAT WEAKER THAN NORMAL DURING THE MONTH OF JULY...WHILE THE SOI INDEX WAS NEGATIVE FOR THE THIRD CONSECUTIVE MONTH. THESE INDICATORS SUGGEST THAT ENSO IS STILL IN A NEUTRAL PHASE BUT APPEARS TO BE SLOWLY TRENDING TOWARD A WEAK WARM EVENT. THE UPPER OCEAN HEAT CONTENT IN THE EQUATORIAL PACIFIC HAS INCREASED MARKEDLY IN THE LAST FIVE MONTHS ... AND IS NOW NOTICEABLY ABOVE THE LONG TERM AVERAGE. MADDEN-JULIAN OSCILLATION (MJO) ACTIVITY CONTINUES TO BE WEAK OVER THE TROPICAL PACIFIC. PROGNOSTIC DISCUSSION OF SST FORECASTS A CONSOLIDATION OF NCEP SST MODELS PREDICTS THAT NINO 3.4 SSTS WILL MOST LIKELY PEAK NEAR OR SLIGHTLY ABOVE +0.5 DEG C. THERE IS MODERATE SPREAD AMONG MODEL SOLUTIONS FOR THE NEXT FEW MONTHS... INDICATING SOME UNCERTAINTY IN THE FORECAST. MODEL SPREAD DOES INCREASE SUBSTANTIALLY DURING THE SPRING AND SUMMER OF 2007. MODELS SUGGEST THAT THE CHANCES THAT THE NINO 3.4 SSTS WILL EXCEED THE 0.5 DEGREE C THRESHOLD FOR MINIMAL EL NINO RELATED IMPACTS PEAK AROUND 47 PERCENT IN OND 2006 ... DIMINISHING TO AROUND 40 PERCENT IN BOREAL WINTER (DJF 2006/7)...AND DROPPING OFF RAPIDLY THEREAFTER. THE PREDICTED CHANCES FOR LA NINA CONDITIONS ARE NEGLIGIBLE. THE ENSO PHASE IS EXPECTED TO RANGE FROM NEUTRAL TO WEAK WARM CONDITIONS WHICH WILL LIKELY PREVAIL THROUGHOUT THIS UPCOMING COLD SEASON. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE OUTLOOK FOR SON 2006 THROUGH SON 2007 IS BASED ON THE CFS... THE MULTI-MODEL ENSEMBLE FROM IRI... AND THE CDC-CCA RENDERING OF THE MOST LIKELY CONSENSUS FORECAST OF SEVERAL DYNAMICAL MODEL FORECASTS... AS WELL AS CCA... ECCA... SMLR... AND OCN. FORECASTS PRIMARILY REFLECT THE CONSOLIDATED TEMPERATURE AND PRECIPITATION PRODUCTS (A SKILL-WEIGHTED OBJECTIVE BLEND OF CFS... CCA... SMLR... AND OCN)...WITH CONSIDERATION OF A POTENTIAL COLD SEASON WEAK EL NINO. THE OUTLOOKS FOR MAM 2007 THROUGH SON 2007 ARE BASED LARGELY ON A CONSOLIDATION OF CCA... SMLR... AND OCN (CFS IS NOT AVAILABLE AFTER LEAD 6). A STATISTICAL FORECAST TOOL BASED ON ANTECEDENT SOIL MOISTURE CONDITIONS (CAS) HAD MODEST INFLUENCE ON THE LEAD 1 OUTLOOK FOR SON 2006. PROGNOSTIC DISCUSSION OF OUTLOOKS - SON 2006 TO SON 2007 TEMPERATURE: TEMPERATURE PROBABILITIES FOR SON 2006 ARE SIMILAR TO THOSE ISSUED LAST MONTH WITH SLIGHTLY EXPANDED COVERAGE OF ABOVE NORMAL MEAN TEMPERATURES ACROSS THE NORTHWEST U.S....AND THE INTRODUCTION OF WARMER THAN NORMAL TEMPERATURES FOR THE PANHANDLE OF ALASKA. MOST OF THE TOOLS SUPPORT THESE AREAS OF RELATIVE WARMTH. THE AREAS WITH ELEVATED PROBABILITIES FOR WARMTH (40% OR GREATER) INCLUDE NEW ENGLAND - THE CENTRAL GREAT PLAINS - SOUTH FLORIDA - AND THE DESERT SOUTHWEST. THE OUTLOOKS FOR OND 2006 THROUGH FMA 2007 ARE BASED MAINLY ON THE CONSOLIDATION TOOL WHICH GENERALLY FAVORS WARMTH... THOUGH TEMPERED SLIGHTLY BY THE POSSIBILITY OF WEAK WARM EPISODE CONDITIONS THIS WINTER. OUTLOOKS FOR MAM 2007 AND BEYOND ARE BASED PRIMARILY ON THE CONSOLIDATION TOOL (THE CFS COMPONENT DROPS OUT AFTER LEAD 6) WHICH IS ALMOST ENTIRELY A REFLECTION OF TEMPERATURE TRENDS. PRECIPITATION: BELOW MEDIAN PRECIPITATION IS INDICATED ACROSS MUCH OF THE MIDWEST FOR SON 2006 DUE TO RECENT TRENDS. ABOVE MEDIAN PRECIPITATION FOR FLORIDA FOR LEAD 1 IS FROM LONG TERM TRENDS AND AN ANTICIPATED ACTIVE ATLANTIC HURRICANE SEASON. FOR THE UPCOMING BOREAL WINTER THE MAIN CHALLENGE WILL BE ASSESSING THE LIKELIHOOD AND STRENGTH OF A WARM EVENT AND ITS POTENTIAL IMPACTS ON (PRIMARILY) THE LOWER 48 STATES. DURING WINTER (DJF 2006/7)... THERE IS FAIRLY GOOD AGREEMENT AMONG THE TOOLS FAVORING AN AREA OF ABOVE MEDIAN PRECIPITATION CENTERED OVER THE SOUTHERN PLAINS AND RELATIVE DRYNESS ACROSS BOTH THE NORTHWESTERN AND SOUTHEASTERN U.S.. THE REMAINING OUTLOOKS HAVE BEEN MODIFIED ONLY SLIGHTLY FROM THOSE ISSUED FOR CORRESPONDING SEASONS LAST MONTH. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: ANTHONY ARTUSA 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 SEP 21 2006. 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE $$