PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830 AM EDT THU MAR 17 2016 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS WHILE EL NINO CONDITIONS PEAKED IN LATE 2015, A STRONG EL NINO IS CURRENTLY PRESENT, AS EVIDENT IN BOTH SEA SURFACE TEMPERATURE AND ATMOSPHERIC CONDITIONS ACROSS THE EQUATORIAL PACIFIC OCEAN. A TRANSITION TO ENSO-NEUTRAL IS EXPECTED DURING THE LATE SPRING OR EARLY SUMMER 2016. THE LIKELIHOOD OF LA NINA DEVELOPING BY NEXT WINTER IS SUBSTANTIAL, AND ESSENTIALLY UNCHANGED FROM LAST MONTH'S ASSESSMENT. THE CHANCES OF DEVELOPING LA NINA CONDITIONS EXCEED 50 PERCENT FROM AUTUMN OF 2016 ONWARD, WITH POTENTIAL IMPACTS TO THE SEASONAL CLIMATE OF NORTH AMERICA. THE APRIL-MAY-JUNE (AMJ) 2016 TEMPERATURE OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE CONTINENTAL U.S., HAWAII, AND ALL OF ALASKA. ABOVE-NORMAL TEMPERATURE ARE LIKELY FOR MOST OF THE WEST, FROM THE CENTRAL AND NORTHERN ROCKY MOUNTAINS ACROSS THE NORTHERN GREAT PLAINS INTO THE GREAT LAKES REGION, AS WELL AS MOST OF THE REGION TO THE EAST OF THE MISSISSIPPI RIVER VALLEY. THE CHANCES OF ABOVE-NORMAL TEMPERATURES ARE HIGHEST FOR THE PACIFIC NORTHWEST, THE NORTHEAST, AND THE MID-ATLANTIC COAST, EXCEEDING 50 PERCENT IN THESE REGIONS. BELOW-NORMAL TEMPERATURES ARE MORE LIKELY FOR A SMALL AREA OF CENTRAL TEXAS. THE AMJ 2016 PRECIPITATION OUTLOOK INDICATES A SLIGHT INCREASE IN CHANCES OF ABOVE-MEDIAN PRECIPITATION ACROSS MUCH OF THE SOUTHERN CONTINENTAL U.S. AND SOME INCREASE IN CHANCES OF BELOW-MEDIAN PRECIPITATION FOR PARTS OF THE NORTHWEST AND THE WESTERN GREAT LAKES STATES. ABOVE-MEDIAN PRECIPITATION IS MOST LIKELY FROM CENTRAL AND NORTHERN CALIFORNIA ACROSS THE GREAT BASIN AND THE CENTRAL AND SOUTHERN ROCKIES INTO PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS STATES, AS WELL AS FOR THE GULF COAST AND SOUTHERN ATLANTIC COAST STATES. THE CHANCES OF ABOVE-MEDIAN PRECIPITATION ARE ONLY SLIGHTLY FAVORED OVER MOST OF THIS AREA, WITH GREATER PROBABILITIES IN PARTS OF THE SOUTHWEST AND COASTAL AREAS OF THE SOUTHEAST INCLUDING FLORIDA. ABOVE-MEDIAN PRECIPITATION IS ALSO FORECAST TO BE MOST LIKELY FOR MUCH OF ALASKA. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY FOR HAWAII. EQUAL CHANCES (EC) ARE FORECAST IN AREAS WHERE THE LIKELIHOOD OF SEASONAL MEAN TEMPERATURES OR SEASONAL ACCUMULATED PRECIPITATION AMOUNTS ARE EXPECTED TO BE SIMILAR TO CLIMATOLOGICAL PROBABILITIES. 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 SST REMAINS ANOMALOUSLY ABOVE CLIMATOLOGICAL MEANS. THE NINO 3.4 REGION, THREE-MONTH MEAN, SST ANOMALY PEAKED AT 2.3 DEGREES C, COMPARABLE TO THE 1997-98 EL NINO EVENT, BEFORE DECREASING SLIGHTLY TO 2.2 DEGREES C IN THE MOST RECENT THREE-MONTH AVERAGE ANOMALY. SUBSURFACE OCEAN TEMPERATURES FROM THE INTERNATIONAL DATE LINE TO ABOUT 90W LONGITUDE NEAR THE SOUTH AMERICAN COAST ARE AT LEAST 2.0 DEGREES C ABOVE AVERAGE TO A DEPTH OF ABOUT 50 METERS. NEGATIVE ANOMALIES AT DEPTH EXCEEDING -2.0 DEGREES C FROM 50 TO 200 METERS HAVE PROGRESSIVELY PUSHED EASTWARD TO NEAR 140W IN THE LAST TWO MONTHS. THIS EMERGENCE OF NEGATIVE HEAT ANOMALIES AT DEPTH IS AN INDICATOR OF THE POSSIBILITY OF TRANSITION TO LA NINA CONDITIONS DURING 2016. STRONGLY ENHANCED CONVECTION OCCURRED OVER THE CENTRAL EQUATORIAL PACIFIC DURING FEBRUARY AND EARLY MARCH, STRETCHING FROM NEAR 160E TO 140W. LOW-LEVEL WESTERLY WIND ANOMALIES WERE OBSERVED OVER THE CENTRAL EQUATORIAL PACIFIC IN LATE FEBRUARY AND EARLY MARCH, BUT HAVE RECENTLY WEAKENED. THE MADDEN-JULIAN OSCILLATION (MJO) PLAYED A LARGE ROLE IN TROPICAL ATMOSPHERIC VARIABILITY DURING THIS EL NINO EVENT, THROUGH EARLY MARCH, AND CURRENT SUBSEASONAL FORECASTS INDICATE SOME CONTINUED MJO ACTIVITY. SEE THE MONTHLY FORECAST DISCUSSION FOR FURTHER INFORMATION. THE EXTRA-TROPICAL PACIFIC OCEAN REMAINS CONSISTENT WITH THE POSITIVE PHASE OF THE PACIFIC DECADAL OSCILLATION WITH ABOVE AVERAGE SSTS SOUTH OF ALASKA AND ALONG THE WEST COAST. STRONG POSITIVE SST ANOMALIES IN THE ATLANTIC NEAR THE EAST COAST HAVE PERSISTED FOR SEVERAL MONTHS AND POSSIBLY INFLUENCE THE CLIMATE AS WELL. PROGNOSTIC DISCUSSION OF SST FORECASTS WITH THIS EL NINO EVENT WEAKENING IN TERMS OF SST ANOMALIES, THE IMPORTANT QUESTIONS FOR THE SEASONAL FORECAST ARE HOW QUICKLY THE EVENT AND RELATED IMPACTS DISSIPATE AND WHAT IS THE LIKELIHOOD OF A TRANSITION TO A LA NINA EVENT, WHICH FREQUENTLY FOLLOWS EL NINO EVENTS. THE CPC SST CONSOLIDATION CONTINUES TO FORECAST A RETURN TO NEUTRAL CONDITIONS BY MJJ AND MORE THAN 80% CHANCE OF LA NINA BY NEXT WINTER. THERE IS A LARGE SPREAD AMONG THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) MEMBERS IN TERMS OF THE TRAJECTORY OF TROPICAL SST ANOMALIES AND EXPECTED CONDITIONS BY WINTER OF 2016-17. THE CFS AND NCAR MODELS MAINTAIN ANOMALOUSLY WARM SSTS MUCH LONGER THAN OTHER MODELS, WHILE OTHER NMME CONSTITUENT MODELS PREDICT NEGATIVE SST ANOMALIES BY THE END OF SUMMER. IT IS OF NOTE THAT THE CFS AND NCAR MODELS USE A SIMILAR SET OF INITIAL CLIMATE CONDITIONS. THE CPC/IRI CONSENSUS FORECAST INDICATES THAT THE TRANSITION TO ENSO NEUTRAL IS MOST LIKELY BY EARLY SUMMER, AND THE PROBABILITY OF LA NINA DEVELOPING FIRST EXCEEDS 50% IN SON. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS WHILE EL NINO IS WEAKENING, THE SEASONAL OUTLOOK FOR AMJ 2016 IS STILL LARGELY INFLUENCED BY EL NINO. THE CURRENT EL NINO CONDITIONS ARE STRONG AND LIKELY WILL BE AT LEAST MODERATE AS APRIL BEGINS. SST ANOMALIES IN THE NINO 3.4 REGION ARE FORECAST TO REMAIN ABOVE +0.5 C FOR THE AMJ AVERAGE. DYNAMICAL MODELS OF THE NMME CONSISTENTLY PREDICT RELATIVELY GREATER HEIGHTS ACROSS CANADA AND LOWER HEIGHTS ACROSS THE SOUTHERN U.S. IN THEIR AMJ FORECASTS, CONSISTENT WITH AN EL NINO. HIGHER PROBABILITIES FOR ABOVE-NORMAL, ACROSS THE NORTHERN TIER, ARE IN PART DUE TO EL NINO. SSTS IN THE NORTH PACIFIC ARE EXPECTED TO ALSO INFLUENCE THE CIRCULATION PATTERN IN AMJ AND MJJ, THROUGH RIDGING OVER WESTERN NORTH AMERICA IN NMME FORECASTS. THE NMME, THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), AND THE INDIVIDUAL MODEL ENSEMBLE OF THE NCEP CLIMATE FORECAST SYSTEM (CFS) CONTRIBUTE TO THE SEASONAL OUTLOOKS THROUGH SUMMER 2016. OUTLOOKS FROM SON 2016 THROUGH AMJ 2017 RELY PRIMARILY ON CPC STATISTICAL MODELS, INCLUDING REGRESSIONS TO THE NINO 3.4 SST ANOMALY FOR THE IMPACT OF A LIKELY TRANSITION TO A LA NINA EVENT. WITH THE PREDICTION OF ENSO NEUTRAL CONDITIONS BY SUMMER 2016, ENSO REGRESSIONS WERE NOT CONSIDERED DURING THE WARM SEASONS OF 2016. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2016 TO AMJ 2017 TEMPERATURE THE AMJ TEMPERATURE OUTLOOK IS SIMILAR TO THE OUTLOOK FROM A MONTH AGO, WITH SOME INCREASE IN PROBABILITIES, CONSISTENT WITH SHORTER LEAD TIMES AND DYNAMICAL MODEL FORECASTS. ALL TEMPERATURE TOOLS PREDICT INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS THE NORTHERN HALF OF THE CONTINENTAL U.S. THROUGH THE EARLY SPRING, CONSISTENT WITH AN EL NINO. EQUAL CHANCES OF BELOW-NORMAL AND ABOVE-NORMAL, OR INCREASED CHANCES OF BELOW-NORMAL ARE INDICATED IN PARTS OF THE SOUTH-CENTRAL CONTIGUOUS U.S. INCREASED CHANCES OF ABOVE-NORMAL TEMPERATURES CONTINUE ACROSS MUCH OF THE CONTIGUOUS U.S. AND ALASKA THROUGH THE SUMMER INTO AUTUMN, AS INDICATED BY MODEL FORECASTS, INFLUENCED BY THE COMBINED SIGNALS OF GLOBAL SEA SURFACE TEMPERATURE ANOMALIES AND A WARMING CLIMATE ON DECADAL TIMESCALES. INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES FORECAST ACROSS PARTS OF THE SOUTHERN CONTIGUOUS U.S. AND A SLIGHT INCREASE IN THE PROBABILITY FOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTHERN U.S. FROM NDJ 2016 THROUGH AMJ 2017 ARE BASED LARGELY ON THE IMPACTS OF LIKELY LA NINA CONDITIONS. AN INCREASED PROBABILITY OF ABOVE-NORMAL TEMPERATURES FOR THE NORTH SLOPE OF ALASKA DURING THE AUTUMN IS DUE TO THE LIKELIHOOD OF ANOMALOUSLY OPEN SEA ICE AND THE FEEDBACK BETWEEN SEA ICE COVERAGE AND CHANGES IN THE CLIMATE STATE. PRECIPITATION THE AMJ AND MJJ 2016 PRECIPITATION OUTLOOKS FOLLOW A PATTERN THAT IS ON AVERAGE ASSOCIATED WITH EL NINO. ENHANCED CHANCES FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST FOR AMJ AND MJJ 2016 FROM NORTHERN AND CENTRAL CALIFORNIA, ACROSS THE CENTRAL ROCKIES AND SOUTHWEST, INTO THE CENTRAL AND SOUTHERN GREAT PLAINS, AND FOR AMJ INTO THE GULF AND SOUTHERN ATLANTIC COASTS. EQUAL CHANCES IS INDICATED FOR SOUTHERN CALIFORNIA AND SOUTH-WESTERN ARIZONA, WHERE CLIMATOLOGICAL PRECIPITATION IS VERY LOW DURING THIS SEASON. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY THROUGH MJJ FOR NORTHERN REGIONS OF THE PACIFIC NORTHWEST AND THE WESTERN GREAT LAKES. A SLIGHTLY INCREASED CHANCE OF ABOVE-MEDIAN PRECIPITATION IS FORECAST FOR WESTERN AND NORTHERN ALASKA INTO SUMMER BY DYNAMICAL MODELS, RESULTING FROM ANOMALOUSLY OPEN SEA ICE AND WARM OPEN OCEAN TEMPERATURES. DURING AUTUMN OF 2016 AND WINTER OF 2016-17, THE INCREASING LIKELIHOOD OF DEVELOPING LA NINA CONDITIONS IS THE PRIMARY FACTOR FOR INCREASED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. AND THE SOUTHERN COAST OF ALASKA, AND INCREASED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST AND OHIO VALLEY AND CENTRAL GREAT LAKES. 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 21 2016 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$