PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EST THU NOV 16 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 COMPRISE 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 - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS. 4) THE NORTH ATLANTIC OSCILLATION (NAO) AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE ANOMALY PATTERN ESPECIALLY DURING THE COLD SEASONS. THESE PHENOMENA ARE CURRENTLY KNOWN TO BE PREDICTABLE ONLY OVER A WEEK OR SO. 5) PERSISTENTLY DRY OR WET SOILS IN THE SUMMER AND SNOW AND ICE COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM. 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. THIS TECHNIQUE MAKES OPTIMUM USE OF THE KNOWN SKILL OF OUR FORECAST TOOLS. THE DEPARTURE OF TROPICAL PACIFIC SEA SURFACE TEMPERATURES (SST) FROM THEIR LONG-TERM SEASONAL AVERAGE (ANOMALIES) BETWEEN 165E AND 145W AND BETWEEN 130W AND CLOSE TO THE SOUTH AMERICAN COAST AVERAGED AT LEAST +1.0 DEG C FROM MID-OCTOBER THROUGH MID-NOVEMBER. SST ANOMALIES GREATER THAN 2 DEG C ARE FOUND IN SOME REGIONS BETWEEN 160W AND 175E. THESE SST ANOMALIES ARE CONSISTENT WITH EL NINO CONDITIONS. THE REGION BETWEEN 145W AND 130W IS GRADUALLY FILLING IN WITH NEAR +1 DEG C SST ANOMALIES. THE STRENGTH OF THIS EL NINO EVENT MUST STILL BE REGARDED AS BEING ON THE BORDER BETWEEN WEAK AND MODERATE - SINCE THE COUPLING OF THE UNUSUALLY WARM SSTS NEAR THE DATE LINE WITH THE ATMOSPHERE IN THE TROPICAL PACIFIC HAS NOT YET BECOME FULLY ESTABLISHED. THIS COUPLING IS EXPECTED TO OCCUR DURING THE NEXT MONTH OR SO. THE AVERAGE OF SSTS IN THE NINO 3.4 REGION - A BOX BOUNDED BY 120W AND 170W AND BY 5N AND 5S - IS HIGHLY RELEVANT TO THE STATUS OF EL NINO AND LA NINA. 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 WINTER AND SPRING. THE MAXIMUM NINO 3.4 SST ANOMALY OF THE CURRENTLY AVAILABLE TOOLS HAS A WIDE RANGE FROM 0.9 TO 1.4 DEG C FOR THE PEAK INTENSITY. THIS IMPLIES THAT WARM EPISODE CONDITIONS ARE LIKELY TO REACH MODERATE LEVELS AND 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-TO-MODERATE EL NINO CASES WERE STRONGLY CONSIDERED FOR THE OUTLOOKS FROM DECEMBER-JANUARY-FEBRUARY (DJF) THROUGH MARCH-APRIL-MAY (MAM). THERE IS STILL SOME UNCERTAINTY IN THE EXPECTED INTENSITY OF THE EVENT AND ITS IMPACTS DUE TO EVENT-TO-EVENT VARIABILITY AMONG THE RELATIVELY SMALL NUMBER OF OBSERVED MODERATE EL NINO CASES. MORE RECENT FORECAST TOOLS INDICATE LITTLE CHANGE IN INTENSITY FROM PREVIOUS ONES. ONGOING ASSESSMENTS OF THE GLOBAL CLIMATE SYSTEM MAY RESULT IN FURTHER CHANGES TO THE TEMPERATURE AND PRECIPITATION FORECASTS FOR THE UPCOMING WINTER AS THE LIKELY MAGNITUDE OF THE DEVELOPING EL NINO BECOMES CLEAR. THE TEMPERATURE OUTLOOK FOR DEC-JAN-FEB (DJF) 2006-07 CALLS FOR WARMER THAN NORMAL CONDITIONS OVER MOST OF ALASKA AND THE CENTRAL AND NORTHERN PORTIONS OF THE CONTINENTAL US. NEAR NORMAL TEMPERATURES ARE EXPECTED FOR THE CENTRAL AND EASTERN GULF STATES INCLUDING FLORIDA AND ALSO THROUGH THE SOUTH ATLANTIC COAST. ELSEWHERE THERE ARE EQUAL CHANCES OF WARMER-THAN- ... COOLER-THAN- ... OR NEAR-NORMAL TEMPERATURES DURING DJF - INCLUDING MUCH OF THE SOUTHWEST AND THE GREAT BASIN AND FAR WESTERN SECTIONS OF ALASKA. THE OUTLOOK FOR HAWAII CALLS FOR BELOW-NORMAL AVERAGE TEMPERATURE FROM DJF TO FMA. THE PRECIPITATION OUTLOOK FOR DEC-JAN-FEB (DJF) 2006-7 CALLS FOR BELOW MEDIAN PRECIPITATION IN PARTS OF THE PACIFIC NORTHWEST - MONTANA AND WYOMING...AND OVER PARTS OF THE OHIO VALLEY - AND TENNESSEE - THE CENTRAL MISSISSIPPI VALLEY AND SOUTHERN SECTIONS OF THE GREAT LAKES. THE CHANCES FOR ABOVE MEDIAN PRECIPITATION ARE ENHANCED OVER THE SOUTHWEST... MOST OF TEXAS AND SOUTHERN OKLAHOMA - THE GULF COAST - FLORIDA - GEORGIA AND THE CAROLINAS. ELSEWHERE THERE ARE EQUAL CHANCES OF ABOVE-... BELOW-... OR NEAR-MEDIAN PRECIPITATION DURING DJF. THE OUTLOOK FOR HAWAII CALLS FOR BELOW-MEDIAN RAINFALL FROM DJF TO MAM. 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-NOVEMBER 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 GREATER THAN 1.5 DEG C BETWEEN 160W AND 170E. AVERAGE SST ANOMALY VALUES ARE EQUAL TO OR GREATER THAN +1.0 IN ALL FOUR NINO INDEX AREAS. THE LOW LEVEL EASTERLY WINDS (AT 850 MB) IN THE TROPICAL PACIFIC AVERAGED WEAKER THAN NORMAL DURING MID-OCTOBER TO MID-NOVEMBER AND HAVE BEEN GENERALLY WEAKER THAN NORMAL ACROSS MUCH OF THE CENTRAL AND EASTERN EQUATORIAL PACIFIC SINCE JULY. ALSO, THE SOI INDEX WAS NEGATIVE FOR THE SIXTH CONSECUTIVE MONTH. THESE INDICATORS ARE CONSISTENT WITH WEAK-TO-MODERATE EL NINO CONDITIONS. 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 - WHICH IS SIMILAR TO LEVELS SEEN DURING PREVIOUS MODERATE WARM ENSO EPISODES - HAS BEEN MAINTAINED BY MADDEN-JULIAN OSCILLATION (MJO)ACTIVITY. THE MJO IS RESPONSIBLE FOR PERIODICALLY WEAKENING THE LOW-LEVEL EASTERLIES IN THE WESTERN TROPICAL PACIFIC. THESE EVENTS GIVE RISE TO OCEANIC KELVIN WAVES - WHICH ARE RELATED TO THE DEVELOPMENT OF ANOMALOUSLY WARM SUBSURFACE WATER WHICH PROPAGATES SLOWLY EASTWARD. CURRENTLY - A REGION OF UNUSUALLY WARM WATER IS OBSERVED BETWEEN 160E AND 150W AND BETWEEN THE SURFACE AND ABOUT 250 METERS DEPTH. THIS RESERVOIR OF WARM WATER - ALONG WITH THE COUPLING OF CONVECTION TO THE ANOMALOUSLY WARM SST IN NINO 3.4 EXPECTED TO OCCUR SOON - ENSURES THAT THE EL NINO EVENT WILL CONTINUE AT LEAST THROUGH THE WINTER. PROGNOSTIC DISCUSSION OF SST FORECASTS A VARIETY OF SST FORECASTS PREDICT NINO 3.4 SST ANOMALIES FROM 0.9 DEG C TO 1.5 DEG C. THE NCEP CONSOLIDATED FORECAST IS FOR ANOMALIES IN THE 0.5-0.7 DEG C RANGE - WHICH HAS ALREADY BEEN EXCEEDED - INDICATING THAT THAT FORECAST IS LIKELY TOO CONSERVATIVE. THEREFORE 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 THROUGH FMA. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE OUTLOOK FOR DJF 2006-07 THROUGH MAM 2007 IS BASED ON TEMPERATURE AND PRECIPITATION COMPOSITES FROM WEAK AND MODERATE EL NINO YEARS. THESE EVENTS NUMBER ONLY ABOUT 4 OR 5 PER EVENT TYPE, SO THE SAMPLING ERROR IS LIKELY TO BE QUITE LARGE. OTHER TOOLS USED INCLUDE THE CFS...THE MULTI-MODEL ENSEMBLE FROM THE IRI... 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. A SKILL-WEIGHTED OBJECTIVE BLEND OF CFS... CCA... SMLR... AND OCN IS USED AS THE STARTING POINT FOR THE FORECASTS... COMBINED WITH COMPOSITES FOR WEAK AND MODERATE STRENGTH WARM EPISODES DURING THE PERIOD DJF 2006-07 THROUGH MAM 2007. THE OUTLOOKS FOR AMJ 2007 THROUGH DJF 2007-08 ARE BASED LARGELY ON A CONSOLIDATION OF CFS... CCA... SMLR... AND OCN (CFS IS NOT AVAILABLE AFTER LEAD 6). PROGNOSTIC DISCUSSION OF OUTLOOKS - DJF 2006 TO DJF 2007 TEMPERATURE: TEMPERATURE PROBABILITIES FOR DJF AND JFM 2006-07 CALL FOR ABOVE NORMAL SEASONAL AVERAGE TEMPERATURE FOR SECTIONS OF THE NORTHWEST - THE CENTRAL AND NORTHERN GREAT PLAINS - THE GREAT LAKES AND NORTHERN OHIO VALLEY - PENNSYLVANIA - NEW YORK AND NEW ENGLAND. WEAK INDICATIONS FOR ABOVE NORMAL TEMPERATURE IN THE SOUTHEASTERN AND SOUTHERN U.S. IN THE CONSOLIDATION WERE DISREGARDED OR REDUCED DUE TO THE ANTICIPATED COOLING EFFECTS OF ENHANCED RAINFALL DURING EL NINO IN THOSE REGIONS. NEAR NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHEAST DURING DJF THROUGH FMA... AND ALSO OVER PARTS OF TEXAS DURING JFM AND FMA. BECAUSE COOLER TEMPERATURES ARE MORE LIKELY IN EARLY SPRING - THE CENTER OF HIGHEST PROBABILITY FOR ABOVE NORMAL WEAKENS AND SHIFTS EASTWARD - FROM THE DAKOTAS IN DJF - TO MICHIGAN IN JFM AND FMA. EC IS PREDICTED OVER THE SOUTHWEST AND GREAT BASIN FOR DJF THROUGH FMA DUE TO POTENTIAL EFFECTS FROM ENSO AND A WEAK SIGNAL FOR WARMTH FROM CON. BY FMA - REGIONS WHERE ABOVE NORMAL TEMPERATURES ARE EXPECTED DWINDLE TO THE GREAT LAKES... THE NORTHWEST AND INTERMOUNTAIN WEST ... AND OVER ALASKA. THE OUTLOOK FOR MAM FEATURES A REGION OF ABOVE IN MUCH OF THE WEST - IN NORTHERN ALASKA - AND OVER THE LOWER MISSISSIPPI VALLEY. OUTLOOKS FOR AMJ 2007 AND BEYOND ARE BASED PRIMARILY ON THE CONSOLIDATION TOOL WHICH IS DOMINATED BY THE TREND. THE CFS MODEL - WHICH IS AVAILABLE THROUGH MJJ - PREDICTS COLD TEMPERATURE ANOMALIES IN THE SOUTHWEST THROUGH MJJ - BUT THE CONSOLIDATION - WHICH ACCOUNTS FOR THE RELATIVE SKILL OF THE TOOLS IT COMBINES - DOWNPLAYS THAT MODEL IN FAVOR OF THE STATISTICAL TOOLS - WHICH ARE MUCH WARMER IN THE SOUTHWEST. THE OUTLOOK FOR HAWAII CALLS FOR BELOW-NORMAL AVERAGE TEMPERATURE FROM DJF TO FMA. PRECIPITATION: THE PRECIPITATION OUTLOOKS FOR DJF-MAM 2006-07 CALL FOR GREATER THAN AVERAGE ODDS OF ABOVE-MEDIAN PRECIPITATION FOR CENTRAL AND SOUTHERN CALIFORNIA - SECTIONS OF THE SOUTHWEST - TEXAS - OKLAHOMA - KANSAS - LOUISIANA - FAR SOUTHERN SECTIONS OF MISSISSIPPI AND ALABAMA - FLORIDA - MUCH OF GEORGIA AND THE CAROLINAS. BELOW-MEDIAN PRECIPITATION IS LIKELY DURING DJF-FMA FOR THE MIDDLE MISSISSIPPI VALLEY - THE OHIO VALLEY THE SOUTHERN GREAT LAKES AND IDAHO AND SECTIONS OF ADJACENT STATES. EC IS PREDICTED IN OTHER AREAS, INCLUDING ALASKA. THE FORECAST FOR MAM IS SIMILAR - EXCEPT THAT EC IS PREDICTED IN THE NORTHWESTERN US. THE ENSO COMPOSITE SIGNAL IS CONSIDERED IN THIS FORECAST TO BE NEGLIGIBLE BY AMJ AND MJJ. FROM MJJ-DJF 2007-08 THE FORECAST IS BASED ENTIRELY ON WEAK SIGNALS AS CONSOLIDATED IN THE CON FORECAST TOOL. THOSE FORECASTS ARE LITTLE-CHANGED FROM LAST MONTH. THE OUTLOOK FOR HAWAII CALLS FOR BELOW-MEDIAN RAINFALL FROM DJF TO MAM. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: E. OLENIC 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 DEC 21 2006. 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE $$