PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830 AM EDT THU OCT 20 2016 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS ALTHOUGH THE CURRENT OCEANIC AND ATMOSPHERIC STATE REFLECT ENSO-NEUTRAL CONDITIONS, OBSERVATIONS IN BOTH THE ATMOSPHERE AND OCEAN HAVE TRENDED TOWARD THOSE CONSISTENT WITH LA NINA IN RECENT WEEKS. A LA NINA WATCH HAS BEEN REISSUED, AND THE LATEST CPC/IRI CONSENSUS ENSO FORECAST INDICATES PROBABILITIES FOR LA NINA NEAR 70% DURING AUTUMN 2016, CONTINUING INTO THE WINTER OF 2016-2017, ALBEIT AT A LOWER PROBABILITY AT THE CURRENT TIME. LA NINA REMAINS A CONSIDERATION IN THE OUTLOOKS THROUGH THE WINTER. THE NDJ 2016-2017 TEMPERATURE OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR MOST OF THE CONTIGUOUS U.S. AND ALASKA, WITH THE EXCEPTIONS BEING AREAS OF EAST-CENTRAL ALASKA AND A REGION ALONG THE NORTHERN TIER OF THE U.S. THAT STRETCHES FROM PARTS OF THE PACIFIC NORTHWEST EASTWARD THROUGH THE GREAT LAKES. THE EXCEPTIONS ARE WHERE THERE IS MORE UNCERTAINTY IN THE OUTLOOK RELATIVE TO THE REST OF THE FORECAST DOMAIN. THE GREATEST LIKELIHOOD FOR ABOVE-NORMAL TEMPERATURES IS FOR AREAS OF THE U.S. SOUTHWEST WHERE LA NINA CONSIDERATIONS, SHORT-TERM CLIMATE MODEL OUTPUT AND HISTORICAL TRENDS FAVOR HIGHER PROBABILITIES. THE NDJ 2016-2017 PRECIPITATION OUTLOOK INDICATES INCREASED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES, NORTHERN GREAT PLAINS, AND GREAT LAKES AS WELL AS AREAS IN WESTERN AND NORTHERN ALASKA. BELOW-MEDIAN PRECIPITATION IS FAVORED FOR MUCH OF THE SOUTHERN TIER OF THE CONTIGUOUS U.S. WITH THE GREATEST PROBABILITIES ALIGNED FROM EASTERN TEXAS TO THE FLORIDA PANHANDLE. THE OUTLOOK IS BASED ON A NUMBER OF FACTORS INCLUDING LA NINA CONSIDERATIONS AND SHORT TERM CLIMATE MODEL OUTPUT. 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 IN THE TROPICAL PACIFIC, BOTH OCEANIC AND ATMOSPHERIC OBSERVATIONAL INDICATORS (ON AVERAGE) HAVE TRENDED TOWARD VALUES AND PATTERNS THAT ARE CONSISTENT WITH LA NINA CONDITIONS OVER THE PAST FEW WEEKS. SEA SURFACE TEMPERATURES (SSTS) ALONG THE EQUATOR IN THE PACIFIC BASIN REMAIN BELOW AVERAGE FROM 170W TO 100W, WHILE SSTS ARE ABOVE AVERAGE ACROSS THE FAR WESTERN PACIFIC AND IN A HORSESHOE PATTERN NORTH AND SOUTH OF THE AREA OF COOLER THAN NORMAL SSTS ALONG THE EQUATOR. IN THE NINO3.4 REGION, THE MOST RECENT WEEKLY ANOMALY VALUE IS -0.6 DEGREES C WHILE THE MOST RECENT THREE-MONTH AVERAGE NINO3.4 SST ANOMALY IS -0.5 DEGREES C FOR THE JAS SEASON. A RESERVOIR OF ANOMALOUSLY COOL SUBSURFACE WATERS CONTINUES AT DEPTH AND EXTENDS TO MORE THAN 150 METERS BELOW THE SURFACE, WITH THE LARGEST NEGATIVE ANOMALIES OF 2-4 DEGREES C BELOW AVERAGE FROM 50-150 METERS BETWEEN 140W-170W. ENHANCED CONVECTION HAS BECOME MORE ORGANIZED ACROSS THE MARITIME CONTINENT, THE FAR WESTERN PACIFIC AND NORTHERN AUSTRALIA IN RECENT WEEKS WHILE SUPPRESSED CONVECTION ACROSS THE CENTRAL PACIFIC HAS CONTINUED. THIS DIPOLE PATTERN IN ANOMALOUS CONVECTION HAS BECOME MORE ROBUST OVER THE LAST FEW WEEKS. MOREOVER, TRADE WINDS OVER THE PACIFIC BASIN HAVE INCREASED WITH EASTERLY ANOMALIES NOW MORE PREVALENT IN THIS AREA IN ADDITION TO PERSISTENT WESTERLY WIND ANOMALIES OVER THE PAST MONTH CENTERED BETWEEN 100-120 E. UPPER-LEVEL WINDS ARE ANOMALOUSLY WESTERLY OVER THE EQUATORIAL PACIFIC FROM THE DATE LINE EASTWARD. SSTS IN THE NORTH PACIFIC AND ALONG THE COAST OF ALASKA REMAIN ABOVE AVERAGE, ALTHOUGH THESE DEPARTURES FROM NORMAL IN AREAS OF THE NORTH PACIFIC HAVE DECREASED SOME OVER THE PAST MONTH. POSITIVE SST ANOMALIES PERSIST IN THE WESTERN ATLANTIC NEAR THE U.S. EAST COAST, AND THE GULF OF MEXICO. PROGNOSTIC DISCUSSION OF SST FORECASTS THE CPC SST CONSOLIDATION FORECAST, WHICH INCLUDES THREE STATISTICAL FORECASTS ALONG WITH THE CFS, PREDICTS A WEAK LA NINA FROM NDJ 2016-2017 THROUGH JFM 2017 WITH ENSO-NEUTRAL CONDITIONS FAVORED THEREAFTER. THE STATISTICAL GUIDANCE IN THIS FRAMEWORK IS SLIGHTLY WARMER THAN THE CFS. THE NORTH AMERICAN MULTI MODEL ENSEMBLE (NMME) ENSEMBLE MEAN FORECAST FOR THE NINO3.4 SST ANOMALY IS SIMILAR TO THE ABOVE WITH A FORECAST NEAR -0.5 DEGREES C THROUGH DECEMBER 2016 BEFORE TRENDING TO NEAR ZERO BY MARCH 2017. BASED ON THE LATEST OBSERVATIONAL AND MODEL FORECAST INDICATORS, THE OFFICIAL CPC/IRI ENSO OUTLOOK FAVORS LA NINA CONDITIONS THROUGH THE DJF SEASON WITH PROBABILITIES RANGING FROM NEAR 70% DURING NDJ 2016-2017 TO NEAR 55% BY DJF 2016-2017. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE SUBSEQUENT TEMPERATURE AND PRECIPITATION OUTLOOKS CONSIDERED LA NINA CORRELATIONS AND COMPOSITES, STATISTICAL TOOLS, SUCH AS REGRESSIONS BASED ON THE CPC CONSOLIDATED SST FORECAST AND THE CONSTRUCTED ANALOG BASED ON GLOBAL SST ANOMALY PATTERNS. ALSO CONSIDERED WERE THE CALIBRATED PROBABILISTIC FORECASTS FROM THE NMME, GUIDANCE FROM PARTICIPANTS MODELS OF THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME) AND THE CPC CONSOLIDATION (CPC CON) FORECAST. OTHER FACTORS INCLUDED POTENTIAL INFLUENCE FROM MORE LOCAL, COASTAL SSTS. PROGNOSTIC DISCUSSION OF OUTLOOKS - NDJ 2016 TO NDJ 2017 TEMPERATURE THE TEMPERATURE OUTLOOK FOR NDJ 2016-2017 FAVORS ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONTIGUOUS U.S. AND ALASKA, SUPPORTED BY A COMBINATION OF FACTORS. THESE FACTORS CONSIST OF LA NINA IMPACTS VIA COMPOSITES, CORRELATIONS AND REGRESSIONS ANCHORED TO THE CPC SST CONSOLIDATION FORECAST WITH TRENDS, STATISTICAL FORECAST TOOLS INCLUDING THE CA BASED ON GLOBAL SST AND THE CCA, AND DYNAMICAL MODEL GUIDANCE FROM THE NMME. PROBABILITIES ARE GREATEST ACROSS THE SOUTHWEST WHERE THE AFOREMENTIONED STATISTICAL TOOLS (INCLUDING TRENDS) AND DYNAMICAL MODEL GUIDANCE ARE IN THE BEST AGREEMENT. THERE IS INCREASED UNCERTAINTY, PREDOMINATELY DURING DECEMBER AND JANUARY FOR PARTS OF THE NORTHERN PACIFIC NORTHWEST, NORTHERN GREAT PLAINS AND GREAT LAKES REGIONS AND FORECAST TOOLS ARE MORE MIXED IN THESE AREAS SO EC IS INDICATED. FOR ALASKA, ABOVE NORMAL TEMPERATURES ARE FAVORED FOR COASTAL AREAS AND IS SUPPORTED BY ABOVE AVERAGE NEAR-COASTAL SSTS, TRENDS IN SEA ICE COVERAGE AND DYNAMICAL MODEL GUIDANCE. INTO AND THROUGH THE WINTER, BELOW NORMAL TEMPERATURES ARE INTRODUCED FIRST FOR PORTIONS OF THE NORTHERN GREAT PLAINS AND WESTERN GREAT LAKES AND LATER EXPANDED AND SHIFTED WESTWARD TO INCLUDE NORTHERN AREAS OF THE ROCKIES AND PACIFIC NORTHWEST BY FMA 2017. THE HIGHLIGHTED AREAS FOR THIS EVOLUTION ARE WHERE THE GREATEST AGREEMENT AND CONSISTENCY IN FORECAST TOOLS WAS INDICATED. CONSIDERATIONS OF LA NINA (REGRESSIONS ANCHORED TO THE CPC SST CONSOLIDATION AND TRENDS) OVER THE COURSE OF THIS PERIOD AND STATISTICAL GUIDANCE FROM THE CCA AND LATER CA WERE UTILIZED FOR THE OUTLOOK. ABOVE NORMAL TEMPERATURES REMAIN FAVORED ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. WITH THE GREATEST PROBABILITIES OVER THE SOUTHWEST. ODDS FOR ABOVE-NORMAL TEMPERATURES DECREASE ACROSS PARTS OF THE INTERIOR WEST OVER THIS PERIOD, CONSISTENT WITH DYNAMICAL MODEL GUIDANCE. THE OUTLOOKS FROM MAM 2017 AND BEYOND PRIMARILY REFLECT INPUT FROM THE CPC CON, TRENDS AND THE CA BASED ON GLOBAL SST AND SUCH FAVOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE CONUS AND ALASKA. DYNAMICAL MODEL GUIDANCE FROM THE NMME WAS CONSIDERED FOR THE MAM 2017 OUTLOOK AND TRENDS IN SEA ICE EXTENT INCREASE PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR THE NORTH SLOPE OF ALASKA DURING SON AND OND 2017. PRECIPITATION THE NDJ 2016-2017 PRECIPITATION OUTLOOK WAS PRIMARILY BASED ON CONSIDERATIONS OF LA NINA CONDITIONS (REGRESSIONS ANCHORED TO THE CPC SST CONSOLIDATION WITH TRENDS) AND RELATIVELY STRONG AND CONSISTENT SIGNALS IN CALIBRATED DYNAMICAL MODEL GUIDANCE FROM THE NMME. ABOVE MEDIAN PRECIPITATION IS FAVORED FOR NORTHWEST ALASKA AND PORTIONS OF THE PACIFIC NORTHWEST, NORTHERN ROCKIES, NORTHERN GREAT PLAINS AND GREAT LAKES. BELOW MEDIAN PRECIPITATION IS FAVORED ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. WITH THE GREATEST PROBABILITIES ALONG THE GULF COAST. IN ADDITION, BELOW-MEDIAN PRECIPITATION IS INTRODUCED DURING DJF 2016-2017 AND JFM 2017 FOR COASTAL SOUTH-CENTRAL ALASKA SUPPORTED BY LA NINA CONSIDERATIONS AND DYNAMICAL MODEL GUIDANCE. THE PRECIPITATION OUTLOOK REMAINS SIMILAR, TO THE FIRST ORDER, THROUGH FMA 2017 WITH A FAVORED ACTIVE NORTHERN STREAM AND WETTER THAN AVERAGE CONDITIONS MOST LIKELY IN THE AFOREMENTIONED AREAS. COVERAGE FOR ABOVE-MEDIAN PRECIPITATION IS SLIGHTLY INCREASED IN DJF 2016-17 AND JFM 2017 IN SOME AREAS AS ANY LA NINA INFLUENCE LIKELY MAY BE MORE PRONOUNCED IN THESE SEASONS AND SIGNALS FROM THE DYNAMICAL MODEL GUIDANCE ARE SLIGHTLY STRONGER. BELOW MEDIAN PRECIPITATION REMAINS FAVORED FOR THE SOUTHERN TIER DURING THESE SEASONS WITH THE LOWEST COVERAGE AND PROBABILITIES INDICATED IN FMA 2017. POSITIVE PRECIPITATION TRENDS CONTRIBUTE TO THE OUTLOOK ACROSS SOME AREAS OF THE NORTHERN PLAINS AND GREAT LAKES BEGINNING IN FMA 2017 AND THIS CONTINUES THROUGH MJJ 2017. A POSITIVE TREND SIGNAL IS ALSO EVIDENT AND DEPICTED ACROSS THE NORTHEAST CONUS FROM JJA 2017 THROUGH SON 2017. DRIER THAN AVERAGE CONDITIONS ARE FAVORED FOR MAM AND AMJ 2017 ACROSS THE SOUTHWEST BASED ON NEGATIVE HISTORICAL PRECIPITATION TRENDS. 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/LONG_RANGE/TOOLS.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/PRODUCTS/SOILMST_MONITORING/US/OUTLOOK/OUTLOOK.SHTM L (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 17 2016 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$