PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EST THURSDAY NOV 15 2012 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS WHICH USUALLY INFLUENCE THE SEASONAL CLIMATE OUTLOOK INCLUDE: 1) EL NINO AND LA NINA - WHICH TOGETHER COMPRISE EL NINO/SOUTHERN OSCILLATION OR ENSO. IMPACTS OF THESE EVENTS ARE SUMMARIZED BY SEPARATING 3-MONTH OBSERVATIONS FROM 3 OR MORE DECADES INTO EL NINO, NEUTRAL, AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN COMPUTING ANOMALIES. THESE ARE CALLED "ENSO COMPOSITES", WHICH ARE USED AT TIMES TO SUBJECTIVELY MODIFY THE FORECAST. 2) TRENDS - APPROXIMATED BY THE OCN TOOL AS 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 1981-2010). 3) THE TROPICAL 30-60 DAY OSCILLATION - SOMETIMES CALLED MADDEN JULIAN OSCILLATION (MJO) - 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 CONSIDERED LESS PREDICTABLE ON A SEASONAL TIMESCALE THAN ENSO. 5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE VARIABILITY AFFECTING THE TROPICS AND THE NORTH PACIFIC AND NORTH AMERICAN REGIONS, BUT WHICH VARIES ON A MUCH LONGER TIME-SCALE THAN ENSO. 6) PERSISTENTLY DRY OR WET SOILS IN THE SPRING AND 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. 7) STATISTICAL FORECAST TOOLS - CANONICAL CORRELATION ANALYSIS (CCA), SCREENING MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOGUE (CA) AND ENSEMBLE CCA (ECCA). 8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS). THE UPGRADED PARALLEL VERSION OF THE CFS (CFSV2) BECAME OPERATIONAL IN LATE MARCH OF 2011. BOTH VERSIONS OF CFS ARE CURRENTLY RUN IN PARALLEL. AN EXPERIMENTAL MODEL FORECAST SYSTEM, THE NATIONAL MULTI-MODEL ENSEMBLE, COMPRISED OF SEVERAL MODELS AND DESIGNATED NMME, MAY ALSO BE USED EXPERIMENTALLY AND SUBJECTIVELY UNTIL IT IS INCLUDED INTO THE CONSOLIDATION. AN INTERNATIONAL MODEL ENSEMBLE DESIGNATED IMME IS ALSO AVAILABLE. 9) CONSOLIDATION (CON) - AN OBJECTIVE, SKILL WEIGHTED COMBINATION OF THE OCN, CCA, SMLR, ECCA, 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. ENSO NEUTRAL CONDITIONS ARE FAVORED THROUGH THE WINTER 2012-13 AND THE LATEST OBSERVATIONS AND MODEL PREDICTIONS EMPHASIZE A HIGH DEGREE OF UNCERTAINTY IN SOME AREAS OF THE UNITED STATES FOR THE UPCOMING WINTER AND SUBSEQUENT SEASONS. THE DJF 2012-13 TEMPERATURE OUTLOOK INDICATES ENHANCED CHANCES FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE WESTERN CONTINENTAL U.S. STRETCHING ACROSS THE SOUTH CENTRAL GREAT PLAINS TO THE WESTERN GULF COAST. BELOW NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE NORTHERN GREAT PLAINS AND WESTERN GREAT LAKES AND THE FLORIDA PENINSULA. FOR ALASKA, THERE ARE ELEVATED ODDS FOR ABOVE-NORMAL TEMPERATURES ALONG THE NORTH SLOPE AND BELOW NORMAL TEMPERATURES FOR THE SOUTHEAST AND ALASKA PANHANDLE. THE DJF 2012-13 PRECIPITATION OUTLOOK FAVORS ABOVE-AVERAGE PRECIPITATION FOR AN AREA IN THE TENNESSEE VALLEY AND BELOW-AVERAGE PRECIPITATION FOR PARTS OF CALIFORNIA, NEVADA, SOUTHEAST ALASKA AND THE ALASKA PANHANDLE. IN LOCATIONS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL PRECIPITATION AMOUNTS ARE SIMILAR TO THE CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) OF BELOW, NEAR, AND ABOVE-AVERAGE TEMPERATURE AND PRECIPITATION ARE INDICATED. BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS 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 EQUATORIAL PACIFIC SSTS ALONG THE EQUATOR REMAIN NEAR TO ABOVE-AVERAGE (UP TO +1.5 DEGREES C) WEST OF ABOUT 120W AND THESE HAVE INCREASED DURING THE MONTH OF OCTOBER. NEAR AVERAGE SSTS ARE CURRENTLY EVIDENT ACROSS THE EAST PACIFIC EASTWARD OF THIS LONGITUDE. THE UPPER OCEAN HEAT CONTENT REMAINS ABOVE-AVERAGE ACROSS MUCH OF THE CENTRAL AND EASTERN PACIFIC AT A DEPTH GENERALLY RANGING FROM 50 - 150 M EAST OF THE DATE LINE. WHILE THE SUBSURFACE AND SURFACE PACIFIC OCEAN HAS RECENTLY WARMED, THE TROPICAL ATMOSPHERE REMAINED LARGELY CONSISTENT WITH ENSO-NEUTRAL. UPPER- AND LOWER-LEVEL WINDS WERE NEAR AVERAGE, AND THE STRENGTH OF ANOMALOUS CONVECTION DECREASED OVER THE PAST MONTH. OCEAN SURFACE TEMPERATURES ARE ALSO BELOW AVERAGE IN PARTS OF THE NORTH PACIFIC OCEAN, GULF OF ALASKA AND OFF THE SOUTHEAST U.S. COAST. PROGNOSTIC DISCUSSION OF SST FORECASTS ENSO-NEUTRAL CONDITIONS ARE FORECAST THROUGH THE NORTHERN HEMISPHERE WINTER 2012-13. THE CPC SST CONSOLIDATION FORECAST FOR THE NINO3.4 REGION AND ALL OF ITS MODEL COMPONENTS FORECAST ENSO NEUTRAL THROUGH NORTHERN HEMISPHERE SUMMER 2013. THE CFSV2 HAS THE LOWEST FORECAST SSTS DURING THE WINTER MONTHS AND HAS VALUES SLIGHTLY BELOW ZERO UNTIL LATER SPRING. MOREOVER, ENSEMBLE MEANS OF FORECASTS FROM BOTH THE NMME AND IMME FOR THE NINO3.4 REGION FORECAST ENSO-NEUTRAL INTO AT LEAST THE SUMMER 2013 PERIOD, ALTHOUGH SOME MEMBERS OF THE MODELS USED IN EACH OF THESE SYSTEMS DO FORECAST ANOMALIES ABOVE 0.5 DEGREES C DURING THIS PERIOD. THE IRI NINO3.4 FORECAST PLUME ALSO TELLS A SIMILAR STORY WITH A MAJORITY OF MODELS INDICATING ENSO NEUTRAL INTO SUMMER 2013. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS FORECASTS WERE MADE WITH THE EXPECTATION OF ENSO NEUTRAL CONDITIONS DURING THE WINTER AND SPRING MONTHS GIVEN THE LATEST OBSERVATIONS AND SST FORECASTS CITED EARLIER. THE FORECASTS WERE BASED ON DYNAMICAL MODEL OUTPUT FROM THE CFSV2, NMME AND IMME AS WELL AS INPUT FROM SOME STATISTICAL FORECAST TOOLS, LONG-TERM TRENDS AND THE CON WHERE DEEMED HELPFUL. LONGER LEAD OUTLOOKS WERE BASED ON THE CON FROM MJJ 2013 ONWARDS. ENSO-NEUTRAL COMPOSITES DURING NEGATIVE PDO PERIODS WERE CONSIDERED. AS ALWAYS, A SIGNIFICANT WILDCARD IN THE UPCOMING WINTER OUTLOOK IS THE UNCERTAINTY ASSOCIATED WITH THE PHASE OF THE ARCTIC OSCILLATION (AO) WHICH THE MAJORITY OF THE CURRENT LITERATURE INDICATES LOSES PREDICTABILITY QUITE RAPIDLY BEYOND A FEW WEEKS. PROGNOSTIC DISCUSSION OF OUTLOOKS - DJF 2012 TO DJF 2013 TEMPERATURE THE DJF 2012-13 TEMPERATURE OUTLOOK INDICATES ENHANCED ODDS FOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE WESTERN CONTINENTAL U.S. STRETCHING ACROSS THE SOUTH CENTRAL PLAINS TO THE WESTERN GULF COAST AND WAS PRIMARILY BASED ON REASONABLE AGREEMENT AMONGST DYNAMICAL MODEL OUTPUT FROM THE CFSV2, THE NMME AND THE IMME. BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE FLORIDA PENINSULA CONSISTENT WITH THE PREVIOUS OUTLOOK AND IS SUPPORTED BY LONG-TERM TRENDS, NEARBY CURRENT BELOW-NORMAL SSTS AND SOME DYNAMICAL MODEL OUTPUT. THE ENHANCED LIKELIHOOD FOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTHERN PLAINS AND WESTERN GREAT LAKES IS PRIMARILY BASED ON CONSISTENT SIGNATURES IN CLIMATE MODEL OUTPUT FROM THE CFSV2, NMME AND IMME FORECASTS. FOR ALASKA, THERE ARE ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES ALONG THE NORTH SLOPE CONSISTENT WITH RECENT POSITIVE TRENDS IN THIS AREA AND FURTHER SUPPORTED BY LONG-RUNNING AND CONSISTENT FORECASTS FROM DYNAMICAL MODELS OVER THE LAST FEW MONTHS. ENHANCED ODDS FOR BELOW NORMAL TEMPERATURES ARE ALSO INDICATED FOR PARTS OF SOUTHEAST ALASKA AND THE ALASKA PANHANDLE. AREAS HIGHLIGHTED FOR BELOW NORMAL TEMPERATURES ACROSS THE NORTH CENTRAL CONUS AND ALASKA ARE CONSISTENT WITH NEGATIVE PDO PHASE COMPOSITES. THE LACK OF A STRONG ENSO SIGNAL, ALWAYS-PRESENT UNCERTAINTY IN THE PHASE AND PERSISTENCE OF THE AO OVER THE ENTIRE WINTER SEASON, CONSIDERABLE DIFFERENCES IN DYNAMICAL CLIMATE MODEL OUTPUT MAKE EC OR EQUAL CHANCES FOR ABOVE-, NEAR- OR BELOW-NORMAL TEMPERATURES THE APPROPRIATE CHOICE FOR MUCH OF THE EASTERN U.S.. AS WE MOVE FORWARD TOWARDS SPRING 2013, ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE WEST. THIS HIGHLIGHTED AREA FIRST SPREADS EASTWARD ALONG THE SOUTHERN TIER OF THE U.S. WITH TIME AND THEN EXPANDS EASTWARD AND NORTHWARD TO INCLUDE MUCH OF THE LOWER 48 BY AMJ 2013. THIS IS PRIMARILY BASED ON NMME AND IMME MODEL OUTPUT GIVEN UNCERTAINTY WITH ENSO AS WE MOVE FORWARD INTO 2013. BELOW-NORMAL TEMPERATURES REMAIN FAVORED FOR JFM 2013 ACROSS PARTS OF THE NORTHERN PLAINS. THIS AREA IS THEN TRANSITIONED TO EC DURING FMA 2013. ELEVATED ODDS FOR BELOW NORMAL TEMPERATURES ARE INDICATED FOR A SMALL AREA OF THE PACIFIC NORTHWEST FOR MAM AND AMJ 2013 SUPPORTED BY THE CCA, LONG-TERM TRENDS AND THE CON. THE TEMPERATURE OUTLOOKS FROM MJJ 2013 ONWARDS ARE BASED ON THE CON TOOL, DOMINATED BY LONG-TERM TRENDS, GIVEN WEAK OR UNCERTAIN CLIMATE FORCING DURING THIS PERIOD. IN AREAS WITHOUT STRONG OR RELIABLE CLIMATE SIGNALS, EQUAL CHANCES FOR BELOW-NORMAL, NEAR- NORMAL, OR ABOVE-NORMAL SEASONAL MEAN TEMPERATURES IS PREDICTED. PRECIPITATION GIVEN ENSO NEUTRAL CONDITIONS AND CONSIDERABLE SPREAD AND VARIABILITY IN CLIMATE DYNAMICAL MODEL FORECASTS, ESPECIALLY THE CFSV2, ONLY A FEW NON-EC AREAS ARE HIGHLIGHTED ON THE DJF 2012-13 PRECIPITATION OUTLOOK. AREAS WHERE SOMEWHAT MORE CONSISTENT SIGNALS WERE INDICATED INCLUDE AN ENHANCED LIKELIHOOD FOR ABOVE-MEDIAN PRECIPITATION IN THE TENNESSEE VALLEY AND BELOW-MEDIAN PRECIPITATION FOR PARTS OF CALIFORNIA, NEVADA, SOUTHEAST ALASKA AND THE ALASKA PANHANDLE. THESE AREAS ARE LOCATIONS WHERE THERE WAS SOME CONSENSUS IN CFSV2, NMME AND IMME MODEL OUTPUT AND CONSISTENT WITH TYPICAL NEGATIVE PDO CIRCULATION. THE ABOVE-MEDIAN PRECIPITATION SIGNAL ACROSS THE TENNESSEE VALLEY CONTINUES THROUGH FMA 2013 IN LINE WITH NMME AND IMME FORECASTS. ENHANCED ODDS FOR BELOW-MEDIAN PRECIPITATION HIGHLIGHTED IN DJF 2012-13 EXPANDS EASTWARD ACROSS THE SOUTHWEST TO PARTS OF THE SOUTHERN PLAINS DURING THE COURSE OF SPRING 2013 AND CONTINUES FOR PARTS OF THE SOUTHWEST AND SOUTHERN PLAINS ONLY DURING AMJ AND MJJ 2013. THESE FORECASTS ARE BASED ON THE DYNAMICAL MODEL CONSIDERATIONS AND THE CON FORECAST. IN AREAS WITHOUT STRONG OR RELIABLE CLIMATE SIGNALS, EQUAL CHANCES FOR BELOW, NEAR, OR ABOVE-MEDIAN SEASONAL PRECIPITATION AMOUNTS IS PREDICTED. FORECASTER: JON GOTTSCHALCK THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, FOLLOWING THE WORLD METEROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3 COMPLETE DECADES AS THE CLIMATIC REFERENCE PERIOD. THE PROBABILITY ANOMALIES FOR TEMPERATURE AND PRECIPITATION BASED ON THESE NEW NORMALS BETTER REPRESENT SHORTER TERM CLIMATIC ANOMALIES THAN THE FORECASTS BASED ON OLDER NORMALS. FOR A DESCRIPTION OF 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 FORMATION OF 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 DEC 20 2012 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$