PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY MAR 19 2015 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE CURRENT ATMOSPHERIC AND OCEANIC STATE IS CONSISTENT WITH POSITIVE, CENTRAL-EQUATORIAL PACIFIC SEA SURFACE TEMPERATURE (SST) ANOMALIES AND WEAKLY COUPLED, ATMOSPHERIC EL NINO CONDITIONS. THE OFFICIAL ENSO OUTLOOK STATES THAT THERE IS APPROXIMATELY A 50% CHANCE THAT EL NINO CONDITIONS WILL CONTINUE THROUGH BOREAL SUMMER 2015. IF EL NINO CONDITIONS PERSIST THROUGH BOREAL SUMMER, IT IS HISTORICALLY LIKELY THAT CONDITIONS WILL PERSIST INTO THE FOLLOWING WINTER. EL NINO IMPACTS ARE GENERALLY MOST SIGNIFICANT TO THE CLIMATE VARIABILITY OF NORTH AMERICA DURING THE COLD SEASONS. THE APRIL THROUGH JUNE (AMJ) 2015 TEMPERATURE OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR ALASKA, WEST OF THE ROCKY MOUNTAINS, AND IN NORTHERN STATES EXTENDING ACROSS THE NORTHERN PLAINS TO THE WESTERN GREAT LAKES. PROBABILITIES OF BELOW-NORMAL TEMPERATURES ARE ENHANCED FOR EASTERN ARIZONA AND WESTERN TEXAS. THE APRIL THROUGH JUNE (AMJ) 2015 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR THE INTERIOR OF ALASKA, THE U.S. SOUTHWEST, AND THE SOUTHEAST EXCLUDING THE LOWER FLORIDA PENINSULA. THE PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ARE INCREASED FOR COASTAL REGIONS OF THE PACIFIC NORTHWEST, AS WELL AS THE WESTERN GREAT LAKES REGION, INCLUDING EASTERN PARTS OF THE DAKOTAS AND NORTHERN IOWA. IN AREAS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL ACCUMULATED PRECIPITATION AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS 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 IN THE LAST MONTH SST ANOMALIES HAVE BEEN POSITIVE IN THE CENTRAL EQUATORIAL PACIFIC AND NEGATIVE IN THE EASTERN EQUATORIAL PACIFIC. THE MOST RECENT WEEKLY AVERAGE SST ANOMALY IN THE NINO 3.4 REGION WAS +0.5 C, WITH A +1.0 C ANOMALY IN THE NINO 4 REGION AND A -0.2 C ANOMALY IN THE NINO 3 REGION. FOR SEVERAL MONTHS AN AREA OF POSITIVE SST ANOMALIES HAS EXTENDED IN A HORSESHOE PATTERN FROM THE NORTH PACIFIC ALONG THE WEST COAST OF NORTH AMERICA AND SOUTHWESTWARD TO THE CENTRAL EQUATORIAL PACIFIC. THIS ANOMALOUS SST PATTERN PROJECTS ONTO THE NORTH PACIFIC MODE OF VARIABILITY AND THE SST PATTERN OF THE PACIFIC DECADAL OSCILLATION (PDO). THE LATEST MONTHLY VALUE OF THE PDO INDEX FOR FEBRUARY 2015 IS +2.30 WITH HISTORICALLY HIGH POSITIVE VALUES RECORDED FOR DECEMBER, JANUARY AND FEBRUARY, 2015. LOW-LEVEL WESTERLY WIND ANOMALIES AT 850 HPA WERE OBSERVED RECENTLY OVER THE CENTRAL, EQUATORIAL PACIFIC. IN THE PAST MONTH, CONVECTION WAS ENHANCED NEAR THE DATE LINE AS INDICATED BY NEGATIVE ANOMALIES IN THE OUTGOING LONGWAVE RADIATION (OLR). THESE ATMOSPHERIC CONDITIONS COUPLED WITH THE PERSISTENT POSITIVE SST ANOMALY OVER THE CENTRAL EQUATORIAL PACIFIC FOR THE LAST SEVERAL MONTHS HAS BEEN DETERMINED TO MEET THE CRITERIA TO BE CONSIDERED EL NINO CONDITIONS. POSITIVE SUBSURFACE TEMPERATURE ANOMALIES EXPANDED ACROSS THE CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC DURING THE LAST TWO MONTHS ASSOCIATED WITH THE DOWNWELLING PHASE OF AN EQUATORIAL KELVIN WAVE, WHILE NEGATIVE ANOMALIES ONLY REMAIN IN A SMALL REGION NEARER TO THE SURFACE IN THE EASTERN PACIFIC. ANOMALOUS HEAT CONTENT OF THE EQUATORIAL PACIFIC FROM THE SURFACE TO A DEPTH OF 300 METERS HAS NOW ATTAINED THE GREATEST POSITIVE VALUE SINCE SPRING 2014. THE CURRENT POSITIVE SUBSURFACE HEAT ANOMALY PROVIDES A SOURCE OF WARMER-THAN-AVERAGE OCEAN WATER FOR CONTINUATION OF POSITIVE SURFACE TEMPERATURE ANOMALIES FOR THE NEXT SEVERAL SEASONS. PROGNOSTIC DISCUSSION OF SST FORECASTS THE MAJORITY OF DYNAMICAL AND STATISTICAL MODELS FORECAST THE SEASONAL AVERAGE NINO 3.4 SST ANOMALY THROUGH NEXT AUTUMN TO REMAIN NEAR OR ABOVE THE +0.5 C THRESHOLD USED TO DETERMINE EL NINO EVENTS. MOST DYNAMICAL MODELS PREDICT AN INCREASE IN THE NINO 3.4 INDEX WITH TIME TO ABOVE +1.0 C, WHILE MOST STATISTICAL MODELS INDICATE A CONTINUATION OF WEAK EL NINO SST CONDITIONS BETWEEN +0.5 C AND +1.0 C OR A REDUCTION OF ANOMALIES TO BELOW +0.5 C. THE CPC NINO 3.4 INDEX CONSOLIDATION PREDICTS A GREATER THAN 50% PROBABILITY THAT SEASONAL MEAN ANOMALIES WILL REMAIN ABOVE +0.5 C INTO NEXT WINTER, WITH PROBABILITIES NEARER TO 60% IN THE SPRING. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE SEASONAL TEMPERATURE AND PRECIPITATION OUTLOOKS FOR THE THREE-MONTH APRIL, MAY AND JUNE (AMJ) SPRING SEASON THROUGH THE AUGUST, SEPTEMBER AND OCTOBER (ASO) SEASON ARE BASED PRIMARILY ON COUPLED OCEAN-ATMOSPHERE DYNAMICAL MODEL FORECASTS FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME), INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS), AND THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), WHICH COMBINES THE CFS WITH THE EUROPEAN CENTER AND METEO-FRANCE CLIMATE MODELS. OUTLOOKS AT LONGER LEAD TIMES, BEGINNING WITH THE SEPTEMBER, OCTOBER AND NOVEMBER (SON) 2015 SEASON THROUGH AMJ 2016 RELIED SOMEWHAT ON THE CPC CONSOLIDATION TEMPERATURE AND PRECIPITATION FORECASTS. CONSISTENCY OF THE OUTLOOKS WITH CORRELATIONS BETWEEN SEASONAL MEAN TEMPERATURE OR PRECIPITATION AND SEASONAL NINO 4, NINO 3.4 OR PDO INDICES WERE ALSO CONSIDERED, ESPECIALLY FOR LATE AUTUMN 2015 AND NEXT WINTER. POTENTIAL IMPACTS OF INTERANNUAL MODES OF CLIMATE VARIABILITY WERE NO LONGER USED TO ADJUST THE OUTLOOKS FOR SEASONS FOLLOWING JANUARY, FEBRUARY AND MARCH (JFM) 2015, WHICH FOLLOW THE CPC CONSOLIDATION FORECAST CLOSELY. OUTLOOKS FOLLOWING JFM 2015 DERIVE CLIMATE SIGNALS PRIMARILY FROM DECADAL CLIMATE TRENDS. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2015 TO AMJ 2016 TEMPERATURE BEGINNING WITH THE AMJ 2015 SEASONAL TEMPERATURE OUTLOOK AND CONTINUING THROUGH THE REMAINDER OF 2015, THE PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE ENHANCED OVER MUCH OF THE U.S. WEST AND ALASKA. ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES EXTEND ACROSS THE NORTHERN PLAINS INTO THE WESTERN GREAT LAKES IN SPRING 2015. BELOW-NORMAL TEMPERATURES ARE MOST LIKELY FOR PORTIONS OF EASTERN ARIZONA AND WESTERN TEXAS. THESE FORECASTS ARE SUPPORTED BY CLIMATE MODEL GUIDANCE FROM THE NMME AND IMME, AS WELL AS CONSISTENT WITH CORRELATIONS WITH EL NINO AND PDO INDICES. FROM MJJ 2015 THROUGH ASO 2015, PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE INCREASED FOR THE ENTIRE GREAT LAKES REGION INTO THE NORTHEAST, AS INDICATED BY A CONSENSUS OF NMME AND IMME GLOBAL CLIMATE MODEL FORECASTS. ABOVE-NORMAL TEMPERATURES CONTINUE TO BE MOST LIKELY IN NEW ENGLAND THROUGH NEXT SPRING 2016 AND FOR LARGER PORTIONS OF THE NORTHEAST FROM JFM 2016 ONWARD, FOLLOWING OBSERVED DECADAL TEMPERATURE TRENDS. GREATER CHANCES OF ABOVE-NORMAL TEMPERATURES EXTEND DOWN THE EASTERN SEABOARD FROM JJA THROUGH ASO 2015 AND ALONG PARTS OF THE GULF COAST FROM JAS THROUGH OND 2015, CONSISTENT WITH THE LONGER-LEAD SEASONAL FORECASTS OF DYNAMICAL MODELS. PROBABILITIES OF ABOVE-NORMAL TEMPERATURES CONTINUE TO BE ENHANCED FOR ALL OF ALASKA THROUGH OND 2015, AND FOR THE SOUTHERN COAST OF ALASKA INTO DJF 2015/2016. INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES CONTINUE FOR THE NORTH SLOPE OF ALASKA THROUGHOUT THE NEXT YEAR, DUE TO DECADAL CLIMATE TRENDS. PRECIPITATION THE AMJ 2015 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR THE SOUTHWEST AND ACROSS MOST OF THE SOUTHEAST, AS WELL AS FOR INTERIOR ALASKA, AS PREDICTED BY THE CONSENSUS OF NMME AND IMME MODEL FORECASTS AND CONSISTENT WITH REGRESSIONS TO EL NINO AND PDO INDICES. DURING THE AMJ 2015 SEASON, BELOW-MEDIAN PRECIPITATION IS MOST LIKELY FOR COASTAL REGIONS OF THE PACIFIC NORTHWEST AND FOR EASTERN PARTS OF THE NORTHERN PLAINS AND THE WESTERN PORTIONS OF THE GREAT LAKES REGION. THE OUTLOOK FOR MJJ 2015 IS VERY SIMILAR TO AMJ 2015. ENHANCED PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION CONTINUE FOR PARTS OF THE SOUTHWEST INTO JAS 2015, AND ENHANCED PROBABILITIES FOR BELOW-MEDIAN PRECIPITATION CONTINUE FOR PARTS OF THE PACIFIC NORTHWEST THROUGH ASO 2015, EXPANDING NORTHWARD INTO THE ALASKA PANHANDLE FROM MJJ THROUGH ASO 2015. THESE OUTLOOKS ARE STRONGLY SUPPORTED BY CLIMATE MODEL FORECASTS FROM THE NMME AND IMME, AS WELL AS CONSISTENT WITH POSITIVE EL NINO AND PDO INDICES. FROM SON 2015 ONWARD, ALL SEASONAL PRECIPITATION OUTLOOKS INDICATE EQUAL CHANCES (EC) OVER THE ENTIRE FORECAST DOMAIN, AS CLIMATE SIGNALS ARE WEAK OR INCONSISTENT. A DECADAL PRECIPITATION TREND INDICATING A TENDENCY FOR BELOW-MEDIAN PRECIPITATION OVER PARTS OF THE SOUTHEAST IN WINTER IS OPPOSED BY THE INCREASED LIKELIHOOD OF EL NINO IMPACTS, WHICH FAVOR ABOVE-MEDIAN PRECIPITATION AMOUNTS OVER THE SOUTHEAST IN WINTER. FORECASTER: DAN COLLINS 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 APR 16 2015 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$