PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY JUN 20 2013 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). 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. RECENT ATMOSPHERIC AND OCEANIC OBSERVATIONS CONTINUE TO REFLECT ENSO NEUTRAL CONDITIONS AND THE OFFICIAL ENSO OUTLOOK IS FOR A CONTINUATION OF ENSO NEUTRAL THROUGH AT LEAST THE NORTHERN HEMISPHERE SUMMER 2013. THERE IS HIGH UNCERTAINTY FOR THE STATE OF ENSO FROM LATE 2013 ONWARDS. THE JAS 2013 TEMPERATURE OUTLOOK INDICATES ELEVATED ODDS FOR ABOVE-NORMAL TEMPERATURES ACROSS MOST OF THE WESTERN CONTINENTAL U.S. STRETCHING EASTWARD ALONG THE SOUTHERN TIER TO INCLUDE PARTS OF THE WESTERN GULF COAST AND SOUTH FLORIDA. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR THE NORTH SLOPE OF ALASKA AND PORTIONS OF THE NORTHEAST. CONFIDENCE IN THE FORECAST IS HIGHEST FOR PORTIONS OF THE CENTRAL ROCKIES AND SOUTHWEST. FOR PRECIPITATION, ENHANCED ODDS OF BELOW MEDIAN PRECIPITATION ARE DEPICTED IN THE JAS OUTLOOK FOR THE PACIFIC NORTHWEST AND AREAS PRIMARILY IN WEST TEXAS. ABOVE MEDIAN PRECIPITATION AMOUNTS ARE FAVORED FOR PORTIONS OF THE TENNESSEE VALLEY AND SOUTHEAST. IN AREAS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL ACCUMULATED PRECIPITATION AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS SHOWN. 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 SST ANOMALIES REMAINED CLOSE TO ZERO FOR MUCH OF THE WESTERN AND CENTRAL PACIFIC INTO EARLY JUNE, ALTHOUGH NEGATIVE ANOMALIES INCREASED IN MAGNITUDE FOR AREAS EAST OF 120W TO THE SOUTH AMERICA COAST WITH VALUES RANGING FROM -0.5 TO -2.0 DEGREES C. IN THE MOST RECENT WEEK, HOWEVER, THE NEGATIVE ANOMALIES HAVE BECOME LESS IN MAGNITUDE. AT DEPTH, POSITIVE EQUATORIAL OCEAN TEMPERATURES ARE EVIDENT FROM 100-250 METERS FOR MUCH OF THE REGION FROM 130E TO NEAR THE DATE LINE WITH ADDITIONAL AREAS OF POSITIVE TEMPERATURE ANOMALIES FROM 50-200 METERS FOR PARTS OF THE CENTRAL PACIFIC. EQUATORIAL WINDS REMAINED NEAR AVERAGE, EXCEPT FOR WEAK LOW-LEVEL EASTERLY ANOMALIES IN THE WESTERN PACIFIC AND WEAK UPPER-LEVEL WESTERLY ANOMALIES IN THE WESTERN AND CENTRAL PACIFIC. TROPICAL CONVECTION REMAINED ENHANCED OVER AREAS IN PROXIMITY TO INDONESIA AND SUPPRESSED OVER THE CENTRAL PACIFIC. COLLECTIVELY, THE OCEANIC AND ATMOSPHERIC CONDITIONS REFLECT ENSO NEUTRAL. PROGNOSTIC DISCUSSION OF SST FORECASTS ENSO NEUTRAL CONDITIONS ARE EXPECTED TO CONTINUE THROUGH AT LEAST THE NORTHERN HEMISPHERE SUMMER 2013. THE CPC CONSOLIDATION NINO3.4 SST FORECAST PREDICTS ANOMALIES RANGING FROM 0.0 TO -0.5 DEGREES C THROUGH THE REMAINDER OF 2013 AND THE FIRST HALF OF 2014. A TENDENCY FOR BELOW NORMAL NINO3.4 SST FORECAST FROM THE CA, MARKOV AND CCA MODELS IS OFFSET BY A POSITIVE ANOMALY FORECAST GREATER THAN +0.5 DEGREES C FROM THE CFS. IN FACT, MOST DYNAMICAL MODELS INCLUDED IN THE IRI PLUME, NMME AND IMME FORECAST POSITIVE ANOMALIES RANGING FROM 0.0 TO +0.5 DEGREES C DURING THE LATE SUMMER AND AUTUMN 2013. THE LARGE RANGE OF NINO3.4 SST FORECASTS BETWEEN STATISTICAL AND DYNAMICAL MODELS RESULT IN A HIGHLY UNCERTAIN ENSO OUTLOOK DURING THE SECOND HALF OF 2013. TAKEN AS A WHOLE, THE SST FORECASTS FAVOR A CONTINUATION OF ENSO NEUTRAL AND CONSIDERING NONE OF THE TOOLS PREDICT PARTICULARLY STRONG ANOMALIES FOR THIS COMING WINTER, ENSO NEUTRAL CONDITIONS ARE SLIGHTLY FAVORED FOR THE COLD SEASON 2013-2014 AT THIS TIME. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE TEMPERATURE AND PRECIPITATION OUTLOOKS WERE MADE CONSIDERING ENSO NEUTRAL CONDITIONS TO BE MOST LIKELY THROUGH EARLY 2014. THE FORECASTS FROM JAS THROUGH NDJ 2013-14 WERE BASED ON A COMBINATION OF BOTH TRADITIONAL STATISTICAL TOOLS AND DYNAMICAL MODEL GUIDANCE FROM THE CFS ALONE, THE NMME AND THE IMME. INITIAL SOIL MOISTURE CONDITIONS PLAYED A ROLE IN THE OUTLOOKS DURING JAS AND ASO 2013. THE CON AND OCN WERE GIVEN INCREASING WEIGHT IN THE FORECASTS STARTING IN SON 2013 AND THESE WERE THE PRIMARY DRIVERS FOR THE OUTLOOKS FROM NDJ 2013-2014 ONWARDS. PROGNOSTIC DISCUSSION OF OUTLOOKS - JAS 2013 TO JAS 2014 TEMPERATURE THE TEMPERATURE OUTLOOKS FOR JAS AND ASO 2013 ARE SIMILAR AND INDICATE ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES FOR MOST OF THE WESTERN CONUS, THE SOUTHERN GREAT PLAINS, THE WESTERN GULF COAST, PARTS OF THE NORTHEAST AND THE NORTH SLOPE OF ALASKA. DURING JAS 2013, ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED FOR SOUTHERN FLORIDA. THE HIGHEST PROBABILITIES IN BOTH SEASONS ARE LOCATED ACROSS THE CENTRAL ROCKIES, GREAT BASIN AND SOUTHWEST. THESE FORECASTS ARE BASED ON LOW INITIAL SOIL MOISTURE CONDITIONS, LONG TERM TRENDS AND DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME. AN IMPORTANT CHANGE FOR THE JAS AND ASO 2013 OUTLOOKS FROM PREVIOUS FORECASTS, IS THE REMOVAL OF ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES FOR AREAS STRETCHING FROM THE NORTHERN PLAINS ACROSS THE MIDWEST TO THE SOUTHEAST. ANOMALOUSLY WET INITIAL SOIL MOISTURE CONDITIONS, MORE RECENT FORECASTS FROM THE NMME AND IMME OF MEAN NEAR TO WEAKLY BELOW AVERAGE TEMPERATURES AND THE POTENTIAL FOR ABOVE-MEDIAN PRECIPITATION IN SOME AREAS SUPPORT THE CHANGE. THE NORTH SLOPE OF ALASKA IS MORE LIKELY TO EXPERIENCE ABOVE NORMAL TEMPERATURES FOR JAS THROUGH OND 2013 AS INDICATED BY THE DECADAL TEMPERATURE TRENDS, IN PART DUE TO REDUCED ARCTIC OCEAN SEA ICE COVER IN THIS REGION DURING RECENT YEARS FOR THE SPRING THROUGH AUTUMN SEASONS. GIVEN THE HIGH UNCERTAINTY OF THE ENSO PHASE AS WE MOVE THROUGH THE AUTUMN 2013 INTO THE COLD SEASON OF 2013-14, THE TEMPERATURE OUTLOOKS FROM SON 2013 ONWARDS ARE PRIMARILY DRIVEN BY THE CON AND OCN TOOLS AND TO A LESSER EXTENT BY NMME AND IMME GUIDANCE PRIOR TO AND INCLUDING NDJ 2013-14. ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE FORECAST FOR THE GREAT PLAINS AND GREAT LAKES DURING SON AND OND 2013 AND THEN MOST OF THE CONUS IN NDJ 2013-14. ABOVE NORMAL TEMPERATURES ARE FAVORED TO CONTINUE FOR PARTS OF THE SOUTH-CENTRAL U.S AND NORTHEAST THROUGH FMA 2014. AN ADDITION TO THE FMA AND MAM 2014 TEMPERATURE OUTLOOKS IS THE INTRODUCTION OF AN AREA OF ENHANCED ODDS FOR BELOW NORMAL TEMPERATURES FOR PARTS OF THE PACIFIC NORTHWEST SUPPORTED BY THE CON AND OCN AND IS CONSISTENT WITH THE CURRENT LONG TERM NEGATIVE PHASE OF THE PDO. ENHANCED CHANCES FOR ABOVE NORMAL TEMPERATURES FOR THE NORTH SLOPE OF ALASKA ARE ONCE AGAIN EVIDENT FROM FMA 2014 ONWARDS. IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF BELOW, NEAR AND ABOVE NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED. PRECIPITATION THE JAS AND ASO 2013 PRECIPITATION OUTLOOK HIGHLIGHTS AN ENHANCED LIKELIHOOD OF ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHEAST U.S. AND BELOW MEDIAN PRECIPITATION FOR AREAS IN THE PACIFIC NORTHWEST AND NORTHERN ROCKIES AS WELL AS PORTIONS OF THE SOUTHERN HIGH PLAINS. THESE AREAS ARE PRIMARILY BASED ON THE CON AND DYNAMICAL MODEL GUIDANCE FROM THE NMME AND IMME. CONSIDERATION FOR THE POTENTIAL OF AN ABOVE-AVERAGE ATLANTIC HURRICANE SEASON, AS MAINLY RELATED BY LONG TERM TRENDS, ALSO CONTRIBUTED TO THE TILT IN THE ODDS FOR ABOVE-MEDIAN PRECIPITATION FOR SOME PARTS OF THE SOUTHEAST CONUS. THE REGION IN THE PACIFIC NORTHWEST IS DUE MAINLY TO DECADAL TRENDS TOWARD BELOW MEDIAN PRECIPITATION, WITH SOME SUPPORT FROM THE CFS AND NMME DYNAMICAL MODEL GUIDANCE. THERE WAS GOOD CONSENSUS FROM THE CFS, NMME AND IMME MODEL GUIDANCE FAVORING ABOVE-MEDIAN PRECIPITATION ACROSS THE TENNESSEE VALLEY AND SOUTHEAST. FORECAST TOOLS THIS MONTH SHOW STRONGER SIGNALS FOR MONSOON PRECIPITATION THAN IN PREVIOUS MONTHS WITH THE FOCUS FOR PRECIPITATION PRIMARILY OVER WESTERN AREAS OF THE MONSOON REGION. THIS IS ESPECIALLY TRUE EARLY IN THE JAS 2013 PERIOD. ALTHOUGH THERE ARE INCREASING CHANCES FOR ABOVE-MEDIAN PRECIPITATION ACROSS WESTERN AREAS OF THE MONSOON REGION, UNCERTAINTY REMAINS HIGH FOR THE MONSOON SEASON AS A WHOLE, AS DYNAMICAL MODELS HAVE LOW SKILL IN PREDICTING SEASONAL MONSOON PRECIPITATION, SO EQUAL CHANCES IS DESIGNATED FOR MOST OF THE MONSOON REGION. ALONG THESE LINES, FAVORED BELOW-MEDIAN PRECIPITATION HAS BEEN SHIFTED EASTWARD TO ONLY INCLUDE FAR EASTERN NEW MEXICO, WESTERN TEXAS AND SMALL PARTS OF NEARBY STATES, WHERE THERE REMAINS SOME SUPPORT FROM FORECAST TOOLS, INCLUDING VERY LOW INITIAL SOIL MOISTURE VALUES. DECADAL TRENDS FOR BELOW MEDIAN PRECIPITATION ALSO EMERGE IN THE SOUTHEAST FOR NDJ 2013 THROUGH JFM 2014. IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF BELOW, NEAR AND ABOVE MEDIAN SEASONAL TOTAL PRECIPITATION AMOUNTS ARE INDICATED. 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 JUL 18 2013 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$