PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY APR 17 2014 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS THAT 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 FORECAST TOOLS. CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS ARE ENSO-NEUTRAL BUT THE LATEST ENSO OUTLOOK FAVORS WARM-ENSO CONDITIONS, ALSO CALLED EL NINO, TO DEVELOP IN EITHER LATE SPRING OR SUMMER 2014 WITH PROBABILITIES OF AN EL NINO IN PLACE IN EARLY FALL ASSESSED AT 60%. A LA NINA IN 2014 CAN BE VIRTUALLY RULED OUT. THE TEMPERATURE OUTLOOK FOR MAY-JUNE-JULY (MJJ) 2014 INDICATES ELEVATED ODDS OF ABOVE NORMAL TEMPERATURES FOR ALASKA AND A REGION FROM THE PACIFIC NORTHWEST TO CALIFORNIA AND NEVADA, EASTWARD ALONG THE SOUTHERN TIER OF THE CONTINENTAL U.S. AND ALSO ALONG THE EAST COAST TO INCLUDE MUCH OF NEW ENGLAND. THERE ARE ELEVATED CHANCES OF BELOW NORMAL TEMPERATURES MAINLY IN MONTANA AND NORTH DAKOTA. THE MJJ 2014 PRECIPITATION OUTLOOK CALLS FOR ENHANCED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION FOR SOUTHEAST ALASKA ALONG THE WEST COAST TO NORTHERN CALIFORNIA. ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION ARE INDICATED FOR THE FOUR CORNERS REGION OF NEW MEXICO, COLORADO, UTAH AND ARIZONA. 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 OVER THE LAST FEW MONTHS, CONSIDERABLE CHANGES HAVE OCCURRED ACROSS THE EQUATORIAL PACIFIC OCEAN, BOTH IN THE ATMOSPHERE AND IN THE OCEAN THAT HAVE INCREASED PROBABILITIES FOR THE DEVELOPMENT OF EL NINO LATER IN 2014. THERE HAS BEEN TWO STRONG WESTERLY WIND BURSTS OVER THE WESTERN PACIFIC, ONE OCCURRING DURING LATE JANUARY AND ANOTHER SPANNING LATE FEBRUARY AND EARLY MARCH. A THIRD ONE MAY BE DEVELOPING RIGHT NOW. THE FIRST WESTERLY WIND EVENT INITIATED A STRONG OCEANIC DOWN-WELLING KELVIN WAVE WHICH TRAVERSED MUCH OF THE PACIFIC OCEAN AND MIGHT IMPACT SEA SURFACE TEMPERATURE IN THE EAST PACIFIC SOON. THE SUB-SURFACE HEAT CONTENT HAS INCREASED DRAMATICALLY IN THE LAST MONTH. AT DEPTH, POSITIVE OCEAN TEMPERATURES ARE EVIDENT FROM 180W TO 90W AT DEPTHS RANGING FROM LESS THAN 50 M TO 200 M. THE GREATEST POSITIVE ANOMALIES REACH +6.0 DEGREES C. ANOMALOUS EQUATORIAL CONVECTION HAS ALSO CHANGED MARKEDLY IN RECENT MONTHS. THE SUPPRESSED CONVECTION THAT HAD BEEN SURPRISINGLY DOMINANT NEAR THE DATE LINE DURING LATE 2013 AND EARLY 2014 HAS DISAPPEARED ENTIRELY AND HAS NOW SEEN TRANSIENTS OF STRONGER THAN NORMAL CONVECTION. PROGNOSTIC DISCUSSION OF SST FORECASTS IN THE PAST MONTH THERE HAS BEEN A FURTHER INCREASE IN CHANCES FOR EL NINO LATER THIS YEAR. THE CPC SST CONSOLIDATION FORECAST NOW HAS THE SST ANOMALY FOR NINO3.4 GROWING ABOVE POSITIVE 0.5C IN JJA 2014. THE LATEST CFS NINO3.4 FORECAST INDICATES ITS ENSEMBLE MEAN CROSSING ABOVE +0.5 DEGREES C IN MJJ 2014 AND INCREASING TO MORE THAN +1.5 DEGREES C BY OND 2014. ENSEMBLE MEAN FORECASTS FROM THE IMME AND NMME INDICATE CROSSING THE 0.5 AND 1.5 THRESHOLDS IN JUNE AND OCTOBER RESPECTIVELY. AN EL NINO WATCH WAS ISSUED EARLIER IN MARCH INDICATING THAT CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT OF EL NINO SOMETIME IN THE NEXT SIX MONTHS. ACCORDING TO THE IRI/CPC CONSENSUS THE GREATEST ODDS FOR EL NINO DEVELOPMENT GENERALLY BEGIN FROM JJA 2014 ONWARDS, WITH PROBABILITIES FOR EL NINO SLIGHTLY OVER 50% AND 65% IN SUMMER AND FALL OF 2014 RESPECTIVELY. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE TEMPERATURE AND PRECIPITATION OUTLOOKS WERE MADE CONSIDERING ENSO CONDITIONS TO BE A MINOR FACTOR IN EARLY SUMMER. THEREAFTER, INCREASING CHANCES FOR EL NINO AND ASSOCIATED POTENTIAL IMPACTS WERE INCORPORATED AT LONGER LEADS ESPECIALLY FOR THE CORE WINTER 2014/15 SEASONS. GUIDANCE FROM THE CFS AS WELL AS THE NMME AND IMME AND THEIR ASSOCIATED COMPONENTS CONTRIBUTED TO THE OUTLOOKS FROM MJJ THROUGH SON 2014. IN PARTICULAR AT THE EARLY LEADS MJJ, JJA AND ASO THE NMME PROBABILITY EXPRESSION WAS USED HEAVILY. THE CON TOOL WAS THE PRIMARY DRIVER FOR THE OUTLOOKS FROM SON 2014 ONWARDS, WITH ENSO COMPOSITES AT LEAST EQUALLY CONSIDERED IMPORTANT FROM NDJ THROUGH FMA. PROGNOSTIC DISCUSSION OF OUTLOOKS - MJJ 2014 TO MJJ 2015 TEMPERATURE THE MJJ 2014 TEMPERATURE OUTLOOK INDICATES ELEVATED PROBABILITIES OF ABOVE- NORMAL SEASONAL MEAN TEMPERATURES FOR ALL OF ALASKA, WESTERN AREAS OF THE PACIFIC NORTHWEST, CALIFORNIA AND NEVADA AND EASTWARD ALONG THE SOUTHERN TIER OF THE CONUS AND ALSO ALONG THE EAST COAST TO INCLUDE MUCH OF NEW ENGLAND. THE PROBABILITIES OF BELOW-NORMAL TEMPERATURES ARE ELEVATED FOR MOST OF MONTANA AND NORTH DAKOTA. STATISTICAL TOOLS, DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME, OCN AND THE CON ALL POINTED TO ABOVE-NORMAL TEMPERATURES FOR MANY AREAS IN THE HIGHLIGHTED REGION. IN ADDITION, DRY SOIL MOISTURE CONSIDERATIONS PLAYED A ROLE AS WELL, ESPECIALLY FOR CALIFORNIA AND PARTS OF THE SOUTHWEST. OUTLOOKS FROM JJA THROUGH SON 2014 WERE LARGELY UNCHANGED FROM THE PREVIOUS OUTLOOK AND INDICATE ELEVATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR THE WESTERN AND SOUTHERN CONUS, ALONG THE EASTERN SEABOARD AND FOR ALASKA, SUPPORTED BY THE CON AND DYNAMICAL MODEL GUIDANCE. INCREASING CHANCES FOR EL NINO HAVE RESULTED IN SOME ADJUSTMENTS ESPECIALLY AT LONGER LEADS, PRIMARILY BASED ON EL NINO COMPOSITES DURING WINTER SEASONS DJF, JFM AND FMA. ABOVE-NORMAL TEMPERATURES FAVORED DURING THE LATE AUTUMN AND WINTER SEASONS WERE FURTHER REDUCED OR REMOVED ACROSS THE SOUTH AND REPLACED WITH EQUAL CHANCES, AS EL NINO TYPICALLY FAVORS BELOW-NORMAL TEMPERATURES IN THESE AREAS. WE INTRODUCED MODEST PROBABILITIES FOR BELOW-NORMAL TEMPERATURES IN THE SOUTHEAST ONLY FOR DJF, JFM AND FMA. ALSO, DURING THE LATE AUTUMN AND WINTER SEASONS THROUGH JFM 2015, THE AREA OF ELEVATED ABOVE-NORMAL TEMPERATURES WAS EXTENDED WESTWARD TO THE NORTHERN ROCKIES. AFTER FMA THE FORECAST IS BASED ON CON, WHICH REFLECTS MAINLY LONG TERM TRENDS AT THESE LEADS. IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF BELOW, NEAR AND ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED. PRECIPITATION CLIMATE SIGNALS FOR PRECIPITATION ARE OFTEN QUITE WEAK AND WHAT SIGNALS ARE INDICATED FROM VARIOUS FORECAST TOOLS OFTEN CONFLICT, EVEN AT THE EARLIEST LEAD. BUT ON THIS OCCASION WE INTRODUCED TWO SETS OF NON-EC PROBABILITIES RELATIVE TO THE PREVIOUS RELEASE. THE FIRST IS ELEVATED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION IN THE INTERIOR SOUTHWEST FOR MJJ-JAS AS INDICATED STRONGLY BY THE NMME PROBABILITIES OF BOTH THE CURRENT AND THE PREVIOUS MONTH. THE SECOND SET, FOR NDJ TO FMA ARE BASED ON EL NINO COMPOSITES WHICH TYPICALLY SHOW WETNESS IN THE SOUTHEAST AND A DRY AREA IN THE OHIO VALLEY. PROBABILITIES ASSIGNED TO THESE ARE MODEST AT THIS TIME BECAUSE OF THE LONG LEAD AND EL NINO NEXT WINTER IS NOT CERTAIN BY ANY MEANS. THE MJJ 2014 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF BELOW-MEDIAN SEASONAL ACCUMULATED PRECIPITATION FOR THE WEST COAST FROM NORTHERN CALIFORNIA NORTHWARD TO INCLUDE THE ALASKA PANHANDLE AND PARTS OF SOUTHEAST ALASKA. ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION ARE INDICATED FOR THE FOUR CORNERS REGION OF NEW MEXICO, COLORADO, UTAH AND ARIZONA. MOST OF THE OUTLOOK IS DESIGNATED AS EQUAL CHANCES, OR CLIMATOLOGICAL PROBABILITIES OF BELOW, NEAR AND ABOVE-MEDIAN SEASONAL ACCUMULATED PRECIPITATION. THE PRIMARY DRIVER FOR THE MJJ OUTLOOK WAS DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME. SIMILAR SUPPORT AND RATIONALE IS USED FOR JJA AND JAS 2014. BEYOND JAS 2014, THE UNCERTAINTY OF PRECIPITATION GUIDANCE INCREASES AND FEW CLEAR SIGNALS ARE INDICATED UNTIL WE COME TO NDJ. FOR NDJ THROUGH FMA EL NINO CONDITIONS FAVOR ABOVE-MEDIAN PRECIPITATION ACROSS THE SOUTHEAST AND BELOW MEDIAN PRECIPITATION IN THE OHIO VALLEY. SMALL SEASON TO SEASON DIFFERENCES WERE BASED ON THE ENSO COMPOSITES. IF PROSPECTS FOR EL NINO CONTINUE TO INCREASE, ABOVE-MEDIAN PRECIPITATION MAY BEGIN TO BE NOTED WITH HIGHER PROBABILITIES AND SOMEWHAT LARGER AREAS. BEYOND FMA 2014 ALL MAPS ARE EC. IN AREAS WHERE CLIMATE SIGNALS FOR PRECIPITATION ARE WEAK OR UNRELIABLE, EQUAL CHANCES OF BELOW, NEAR AND ABOVE MEDIAN SEASONAL ACCUMULATED PRECIPITATION ARE INDICATED. FORECASTER: HUUG VAN DEN DOOL 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 MAY 15 2014 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$