PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY OCT 15 2015 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS STRONG EL NINO CONDITIONS REMAIN IN PLACE ACROSS THE EQUATORIAL PACIFIC OCEAN AS REPRESENTED BY BOTH OCEAN AND ATMOSPHERIC DATA. THE ONGOING EL NINO EVENT IS EXPECTED TO PEAK IN STRENGTH IN LATE AUTUMN OR EARLY WINTER WITH SEASONAL AVERAGE SEA SURFACE TEMPERATURE (SST) ANOMALIES IN THE NINO 3.4 REGION NEAR OR EXCEEDING +2.0 DEGREES CELSIUS, DIMINISHING IN MAGNITUDE THROUGH THE LATE WINTER AND SPRING. THE NOVEMBER-DECEMBER-JANUARY (NDJ) 2015 TEMPERATURE OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR THE FAR WEST, ACROSS THE NORTHERN CONTIGUOUS U.S. TO THE NORTHEAST, AND SOUTHWARD TO THE MID-ATLANTIC. WITHIN THE CONTIGUOUS U.S., THE CHANCES OF ABOVE-NORMAL TEMPERATURES ARE GREATEST ALONG THE PACIFIC COAST AND ALONG THE NORTHERN TIER FROM THE PACIFIC NORTHWEST TO THE GREAT LAKES WITH PROBABILITIES EXCEEDING 50 PERCENT. BELOW-NORMAL TEMPERATURES ARE FAVORED FROM NEW MEXICO TO LOUISIANA WHILE ABOVE-NORMAL TEMPERATURES ARE ALSO MOST LIKELY FOR ALASKA. THE NDJ 2015 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION AMOUNTS FOR CENTRAL AND SOUTHERN CALIFORNIA, THE SOUTHWEST, PARTS OF THE CENTRAL AND SOUTHERN PLAINS, THE LOWER MISSISSIPPI VALLEY, THE SOUTHEAST NORTHWARD TO THE MID-ATLANTIC. ABOVE-MEDIAN PRECIPITATION AMOUNTS ARE ALSO MOST LIKELY FOR THE SOUTHERN AND NORTHERN COASTS OF ALASKA. BELOW-MEDIAN PRECIPITATION AMOUNTS ARE MOST LIKELY FOR PARTS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES AND GREAT LAKES. 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 EQUATORIAL PACIFIC SST ANOMALIES EXCEED +2.0 DEGREES C FROM ABOUT 170 W LONGITUDE TO NEAR THE SOUTH AMERICAN COAST. SUBSURFACE OCEAN TEMPERATURES FROM NEAR THE DATE LINE EASTWARD TO THE SOUTH AMERICAN COAST ARE AT LEAST 2.0 DEGREES C ABOVE AVERAGE TO DEPTHS OF ABOUT 100 TO 150 METERS, EXCEEDING 6.0 DEGREES C ABOVE AVERAGE IN SOME LOCATIONS. THIS SUBSURFACE VOLUME OF ANOMALOUSLY WARM WATER PROVIDES A RESERVOIR OF HEAT TO HELP SUSTAIN CURRENT POSITIVE SEA SURFACE TEMPERATURES. WEST OF THE DATE LINE, NEAR-EQUATORIAL PACIFIC, SUBSURFACE OCEAN TEMPERATURES ARE BELOW AVERAGE. THE STRONG EL NINO EVENT IS ALSO WELL REPRESENTED BY THE LATEST ATMOSPHERIC CONDITIONS ACROSS THE TROPICAL PACIFIC. NEGATIVE OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES INDICATING ENHANCED CONVECTION EXTEND FROM THE DATE LINE ACROSS THE EASTERN TROPICAL PACIFIC TOWARDS CENTRAL AMERICA. POSITIVE OLR ANOMALIES INDICATING SUPPRESSED CONVECTION WERE OBSERVED OVER INDONESIA. LOW-LEVEL (850-HPA) WESTERLY WIND ANOMALIES WERE OBSERVED FROM THE WESTERN TO THE EAST-CENTRAL TROPICAL PACIFIC WHILE UPPER-LEVEL (200-HPA) EASTERLY WIND ANOMALIES ARE PRESENT OVER THE CENTRAL EQUATORIAL PACIFIC WITH WELL DEFINED ANTI-CYCLONIC CIRCULATIONS BOTH NORTH AND SOUTH OF THE EQUATOR IN THE CENTRAL PACIFIC. 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 WHICH IS CONSIDERED IN THE OUTLOOK. PROGNOSTIC DISCUSSION OF SST FORECASTS NEARLY ALL MODELS (BOTH STATISTICAL AND DYNAMICAL) USED FOR THE CURRENT OUTLOOK PREDICT NINO3.4 SST ANOMALY VALUES OF AT LEAST +1.5 DEGREES C THROUGH THE WINTER MONTHS AND INTO SPRING 2016. THE CPC SST CONSOLIDATION FORECASTS A MAXIMUM IN NINO 3.4 SST ANOMALIES OF ABOUT +2.5 DEGREES C DURING NDJ 2015-16 WITH A GRADUAL DECREASE THEREAFTER FALLING BELOW +1.5 DEGREES C IN FMA 2016 AND ENTERING ENSO NEUTRAL TERRITORY DURING THE SUMMER 2016 (THROUGH JAS 2016). THE NMME ENSEMBLE MEAN NINO3.4 FORECAST PEAKS AT NEAR +2.5 DEGREES C IN THE NOVEMBER-DECEMBER TIME PERIOD AND DECREASES TO NEAR +0.5 DEGREES C BY MAY 2016. THE CPC/IRI CONSENSUS FORECAST INDICATES APPROXIMATELY A 95 PERCENT CHANCE FOR EL NINO TO CONTINUE THROUGH BOREAL WINTER WITH PEAK 3-MONTH MEAN SST DEPARTURES IN THE NINO3.4 REGION NEAR OR EXCEEDING +2.0 DEGREES C. AT EXTENDED LEADS, THE CPC SST CONSOLIDATION FORECASTS NINO3.4 SST ANOMALIES TO BECOME LESS THAN -0.5 DEGREES C IN ASO 2016 AND APPROACH -1.2 DEGREES C BY NDJ 2016-2017. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE SEASONAL OUTLOOKS FROM NDJ 2015 THROUGH MAM 2016 RELY PRIMARILY ON THE TYPICAL CIRCULATION RESPONSE TO EL NINO CONDITIONS AND THE ASSOCIATED TEMPERATURE AND PRECIPITATION IMPACTS AS DETERMINED BY REGRESSION-BASED STATISTICAL MODELS AS WELL AS EL NINO COMPOSITES. THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), WHICH INCLUDE THE NCEP CLIMATE FORECAST SYSTEM (CFS), PLAYED A LARGE ROLE AS WELL. OUTLOOKS FOR MJJ 2016 THROUGH ASO 2016 RELY PRIMARILY ON THE CPC CONSOLIDATION FORECAST THAT COMBINES THE SMLR, CCA AND OCN STATISTICAL MODELS WITH THE CFS DYNAMICAL MODEL IN SEASONS FOR WHICH IT IS AVAILABLE. THE EXPECTATION IS FOR ENSO NEUTRAL CONDITIONS DURING THIS PERIOD. BASED ON THE BEHAVIOR OF SST ANOMALIES AFTER SEVERAL PAST STRONG EL NINO EVENTS AND THE CPC CONSOLIDATION NINO3.4 SST FORECAST, POTENTIAL LA NINA CONDITIONS WERE CONSIDERED BEGINNING IN SON 2016 THROUGH NDJ 2016-2017. PROGNOSTIC DISCUSSION OF OUTLOOKS - NDJ 2015 TO NDJ 2016 TEMPERATURE THE TEMPERATURE OUTLOOKS FROM NDJ 2015-16 THROUGH MAM 2016 WERE ONLY SLIGHTLY CHANGED FROM THE PREVIOUS SET OF OUTLOOKS RELEASED IN MID-SEPTEMBER. FOR NDJ 2015-16, THERE ARE ENHANCED ODDS FOR ABOVE NORMAL TEMPERATURES FOR ALASKA, THE FAR WEST AND ALONG THE NORTHERN TIER OF THE CONUS. THE GREATEST PROBABILITIES ARE FOR THE ALASKA PANHANDLE AND IN THE CONTIGUOUS U.S. ALONG THE WEST COAST AND NORTHERN TIER OF THE CONUS FROM THE PACIFIC NORTHWEST TO THE GREAT LAKES. BELOW NORMAL TEMPERATURES ARE FAVORED FOR A REGION THAT INCLUDES PARTS OF THE SOUTHWEST AND SOUTHERN PLAINS. THROUGH THE WINTER AND INTO SPRING 2016, ABOVE NORMAL TEMPERATURES REMAIN FAVORED FOR MUCH OF THE NORTHERN HALF OF THE CONUS WHILE THE COVERAGE FOR ELEVATED ODDS OF BELOW NORMAL TEMPERATURES EXPANDS EASTWARD TO INCLUDE THE SOUTHEAST. FORECAST COVERAGE MAXIMIZES IN JFM AND FMA 2016 WHEN EL NINO IMPACTS TYPICALLY ARE THE GREATEST. THE FORECAST EVOLUTION IS BASED ON TOOLS ASSOCIATED WITH THE EL NINO TELECONNECTION, DYNAMICAL MODEL GUIDANCE AND ABOVE NORMAL PACIFIC OCEAN SSTS, FOR AREAS ALONG THE WEST COAST. CONSIDERATIONS OF A STRONG EL NINO EVENT RESULT IN A SLIGHT SHIFT SOUTHWARD OF FAVORED ABOVE NORMAL TEMPERATURES FOR SOME AREAS OF THE OHIO VALLEY AND MID-ATLANTIC AND A REDUCTION IN COVERAGE AND PROBABILITIES FOR BELOW NORMAL TEMPERATURES IN PARTS OF THE SOUTHEAST IN DJF 2015-16 AND JFM AND FMA 2016. THE GREATEST CHALLENGE OF THE FORECAST IS THE EXTENT OF COLD AIR INTRUSIONS INTO THE MID-ATLANTIC AND SOUTHEAST A MIDST A STRONG EL NINO. FORECAST TOOLS DIVERGE IN THESE AREAS DURING THE WINTER MONTHS. THE CFS INDICATES EL NINO IS BY FAR THE DOMINANT PLAYER WITH A WARM FORECAST ACROSS THE MAJORITY OF THE CONUS. ON THE OTHER HAND, SOME STATISTICAL FORECAST TOOLS SUCH AS THE CA, CCA AND SMLR HINT AT A COLDER FORECAST FOR THE SOUTHEAST WHERE PREDICTORS ARE TAPPING INTO CONTINUED WARM NORTH PACIFIC SSTS. STRONG EL NINO CONDITIONS, AND THE ASSOCIATED CIRCULATION, HOWEVER, COULD VERY WELL MODIFY THIS STRUCTURE. THE FORECAST IS A BALANCE BETWEEN ALL OF THESE FACTORS. A TRANSITION TO ENSO NEUTRAL CONDITIONS IS FAVORED DURING LATE SPRING AND SUMMER 2016 SO THE DRIVER OF THE OUTLOOK FROM MJJ THROUGH ASO 2016 IS THE CPC CONSOLIDATION FORECAST AND FAVORS ENHANCED ODDS OF ABOVE NORMAL TEMPERATURES FOR THE WESTERN CONUS AND PARTS OF ALASKA, THE SOUTHERN CONUS AND NORTHEAST AT VARIOUS TIMES DURING THIS PERIOD. A COMBINATION OF THE CPC CONSOLIDATION FORECAST AND THE POTENTIAL FOR THE DEVELOPMENT OF LA NINA CONDITIONS ARE THE DRIVER FOR THE OUTLOOKS FROM SON 2015 THROUGH NDJ 2015-16. PROBABILITIES INDICATED ON THE FORECAST MAPS ARE ONLY SLIGHTLY TILTED BASED ON LA NINA ACROSS SOME AREAS OF THE INTERIOR AND SOUTHERN CONUS AT THE CURRENT TIME GIVEN THE FORECAST LEAD. A VERY HIGH PROBABILITY OF ABOVE-NORMAL TEMPERATURES IS INDICATED FOR THE NORTH SLOPE OF ALASKA DURING THE OND SEASON DUE TO ANOMALOUSLY OPEN SEA ICE DURING THAT TIME OF YEAR. PRECIPITATION THE NDJ 2015-16 PRECIPITATION OUTLOOK FAVORS ABOVE-MEDIAN PRECIPITATION FROM PARTS OF CALIFORNIA ACROSS THE SOUTHERN TIER OF THE CONUS AND UP THE EASTERN SEABOARD TO THE MID-ATLANTIC. BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR PARTS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES AND HIGH PLAINS, AND GREAT LAKES. BOTH THE NORTH AND SOUTH COASTS OF ALASKA ARE FAVORED TO SEE ABOVE-MEDIAN PRECIPITATION OVER THE SEASON. ENHANCED CHANCES OF ABOVE-MEDIAN PRECIPITATION FOR THE NORTHERN COAST OF ALASKA ARE RELATED TO THE ANOMALOUSLY OPEN SEA ICE CONDITIONS. AS WE PROGRESS THROUGH THE WINTER AND INTO THE SPRING OF 2016, THE ABOVE HIGHLIGHTED PATTERNS ARE ADJUSTED SO THAT BOTH COVERAGE AND PROBABILITIES ARE MAXIMIZED IN JFM 2016. PROBABILITIES PEAK AT GREATER THAN 70% FOR FLORIDA AND GREATER THAN 60% FOR SOUTHERN CALIFORNIA AND ARIZONA. FOR BELOW MEDIAN PRECIPITATION, ODDS INCREASE TO GREATER THAN 50% DURING THIS SEASON IN TWO AREAS, THE NORTHERN ROCKIES AND GREAT LAKES. THE EL NINO TELECONNECTION BASED ON COMPOSITES AND OTHER ASSOCIATED FORECAST TOOLS ALONG WITH THE NMME AND ITS COMPONENTS ARE THE PRIMARY DRIVER OF THE OUTLOOK THROUGH MAM 2016. CONSISTENT WITH A SOUTHWARD AND EASTWARD SHIFTED STORM TRACK DURING EL NINO AND NMME DYNAMICAL MODEL GUIDANCE, BELOW MEDIAN PRECIPITATION IS HIGHLIGHTED FOR CENTRAL MAINLAND ALASKA FROM DJF 2015-16 THROUGH MAM 2016. DECADAL TRENDS AS DEPICTED IN SOME OF THE STATISTICAL FORECAST TOOLS IS THE DRIVER FOR THE SMALL HIGHLIGHTED AREAS FROM MJJ THROUGH JAS 2016. AT THE EXTENDED LEADS, THE POTENTIAL FOR LA NINA CONDITIONS ARE THE PRIMARY BASIS FOR THE VERY SLIGHT TILT IN THE ODDS FOR BELOW MEDIAN PRECIPITATION FOR SOME AREAS ALONG THE SOUTHERN TIER OF THE CONUS AND LATER THE SOUTH COAST OF ALASKA AND FOR ABOVE MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST FROM SON 2016 THROUGH NDJ 2016-17. 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 NOV 19 2015 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$