679 FXUS05 KWBC 161231 PMD90D PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830 AM EDT THU MAR 16 2017 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE APRIL-MAY-JUNE (AMJ) 2017 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE U.S. FOR THE CONTIGUOUS U.S., ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE MOST LIKELY FOR AN AREA STRETCHING EASTWARD FROM THE SOUTHWEST TO MUCH OF THE CENTRAL AND EASTERN U.S. WITH THE GREATEST ODDS INDICATED FOR THE SOUTH-CENTRAL PLAINS AND EASTERN U.S. ABOVE-NORMAL TEMPERATURES ARE ALSO FAVORED FOR MUCH OF ALASKA. THE AMJ 2017 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FOR AREAS OF THE NORTHERN ROCKIES, NORTHERN PLAINS AND WESTERN AREAS OF THE GULF COAST. IN ALASKA, BELOW-MEDIAN SEASONAL PRECIPITATION AMOUNTS ARE FAVORED FOR WESTERN ALASKA. EQUAL CHANCES (EC) ARE FORECAST OVER AREAS WHERE ODDS OF ABOVE-, BELOW-, OR NEAR-NORMAL SEASONAL MEAN TEMPERATURES AND 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 OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC AS A WHOLE INDICATE THAT ENSO-NEUTRAL CONDITIONS ARE NOW IN PLACE. A RESIDUAL, GENERALLY SMALL, AREA OF BELOW NORMAL SEA SURFACE TEMPERATURES (SSTS) PERSISTS IN PROXIMITY TO THE DATE LINE, BUT IN MOST AREAS ALONG THE EQUATOR, OCEAN SURFACE TEMPERATURES ARE NOW ABOVE AVERAGE, ESPECIALLY FOR THE EASTERN AREAS OF THE BASIN WHERE THE LATEST WEEKLY VALUE OF THE NINO1+2 INDEX WAS +2.1 DEGREES C. AT DEPTH, THE UPPER-OCEAN (TOP 300 METERS) HEAT CONTENT ANOMALY SUMMED ACROSS THE BASIN FROM THE DATE LINE TO 100W BECAME POSITIVE DURING JANUARY AND CONTINUED TO INCREASE DURING FEBRUARY INTO EARLY MARCH. IT NOW REFLECTS A VALUE OF +0.4 DEGREES C INDICATING CONSIDERABLE AREAS OF ABOVE-AVERAGE OCEAN TEMPERATURES BELOW THE SURFACE. IN THE ATMOSPHERE OVER THE PAST MONTH, EASTERLY WIND ANOMALIES CONTINUED TO BE OBSERVED OVER THE WESTERN TROPICAL PACIFIC. OVER THE SAME PERIOD, ANOMALOUS TROPICAL CONVECTION INDICATED CONTINUED SUPPRESSED CONVECTION IN THE CENTRAL PACIFIC BUT CONTINUING ENHANCED CONVECTION IN THE FAR WESTERN PACIFIC PRIMARILY NORTH OF THE EQUATOR. THE REMAINING DIPOLE IN ANOMALOUS CONVECTION INDICATES SOME SIGNATURES OF THE PAST WEAK LA NINA EVENT HAVE BEEN SLOW TO FADE. PROGNOSTIC DISCUSSION OF SST FORECASTS THE CPC SST CONSOLIDATION FORECAST, WHICH INCLUDES THREE STATISTICAL FORECASTS ALONG WITH THE CFS, PREDICTS ENSO-NEUTRAL CONDITIONS WILL PERSIST FROM NOW UNTIL THE UPCOMING WINTER SEASON. THERE IS A CONSIDERABLE DIFFERENCE, HOWEVER, BETWEEN THE CFS AND THE STATISTICAL GUIDANCE AS THE CFS FAVORS AN INCREASE IN SST QUITE EARLY IN THE OUTLOOK PERIOD ENTERING EL NINO CONDITIONS DURING THE AMJ 2017 SEASON WHILE THE AFOREMENTIONED STATISTICAL TOOLS FAVOR ENSO-NEUTRAL CONDITIONS. THIS SEPARATION BETWEEN THE STATISTICAL AND DYNAMICAL MODELS IS ALSO DEPICTED BY THE LATEST IRI NINO3.4 SST FORECAST PLUME. MOREOVER, FORECASTS FROM THE DYNAMICAL SUITE OF MODELS FROM THE NMME ALSO INDICATES A MORE ROBUST AND EARLIER INCREASE IN NINO3.4 SST DURING THE SPRING AND SUMMER MONTHS. THE LATEST OFFICIAL ENSO OUTLOOK FROM CPC/IRI FAVORS ENSO-NEUTRAL CONDITIONS TO CONTINUE THROUGH AT LEAST THE NORTHERN HEMISPHERE SPRING WITH INCREASING ODDS FOR THE DEVELOPMENT OF EL NINO CONDITIONS AS AUTUMN APPROACHES WITH PROBABILITIES FOR EL NINO REACHING NEAR 50% BY JAS 2017 AND APPROXIMATELY REMAINING AT THESE ODDS THROUGH OND 2017. AT THE CURRENT TIME, THE PROSPECTS FOR A ENSO COLD EVENT ARE SMALL (UNDER 10%) FOR MUCH OF THE OUTLOOK PERIOD. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE PRIMARY TOOLS USED FOR THIS SET OF OUTLOOKS INCLUDED BOTH STATISTICAL AND DYNAMICAL MODEL FORECAST INFORMATION AND WHERE APPROPRIATE LONG TERM TRENDS. THE DYNAMICAL MODEL GUIDANCE FROM CFS, NMME AND IMME (AND THEIR PARTICIPANT INDIVIDUAL MODELS) WERE IMPORTANT CONTRIBUTORS TO THE OUTLOOKS THROUGH ASO 2017. ANTECEDENT SOIL MOISTURE AND SNOWPACK ANOMALIES IN CERTAIN REGIONS WERE ALSO INCLUDED IN THE OUTLOOKS WHERE APPROPRIATE, PRIMARILY AT EARLY LEADS. THE FAVORED ENSO-NEUTRAL CONDITIONS EARLY IN THE OUTLOOK PERIOD UNDERPINNED THE SET OF OUTLOOKS, ALTHOUGH THE LOW THREAT OF LA NINA CONDITIONS THROUGHOUT MUCH OF THE OUTLOOK PERIOD AS WELL AS INCREASING CHANCES (ALBEIT WITH HIGH UNCERTAINTY) FOR EL NINO WAS CONSIDERED IN MAKING SMALL CHANGES IN SOME OF THE OUTLOOKS AT MIDDLE AND LATER LEADS. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2017 TO AMJ 2018 TEMPERATURE THE LATEST AMJ 2017 TEMPERATURE OUTLOOK INDICATES GENERALLY MINOR CHANGES FROM THE PREVIOUS OUTLOOK. AS SHOWN, ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE FORECAST DOMAIN. FOR THE CONTIGUOUS U.S., THERE IS AN ENHANCED LIKELIHOOD OF ABOVE-NORMAL SEASONAL MEAN TEMPERATURES FOR A REGION STRETCHING FROM THE SOUTHWEST, EASTWARD TO INCLUDE MUCH OF THE CENTRAL AND EASTERN U.S. THE GREATEST ODDS (EXCEEDING 50% PROBABILITY) ARE LOCATED ACROSS THE SOUTH-CENTRAL PLAINS AND EASTERN CONUS. SHORT TERM CLIMATE PREDICTION MODELS (CFS, ECMWF, NMME SUITE AND IMME SUITE) OVERWHELMINGLY SUPPORTED THE CONTINUATION OF THIS SOLUTION INTO AND THROUGH THE SPRING WITH THE CALIBRATED PROBABILISTIC GUIDANCE FROM THE NMME INDICATING 50% OR GREATER ODDS FOR RELATIVE WARMTH IN THE AREAS HIGHLIGHTED WITH THE LARGEST OUTLOOK PROBABILITIES. NEGATIVE SOIL MOISTURE DEPARTURES IN SOME AREAS OF THIS DESIGNATED REGION ALSO CONTRIBUTED TO THE FAVORED ANOMALOUS WARMTH. SOME STATISTICAL FORECAST TOOLS AND LONG TERM TRENDS FURTHER SUPPORTED THE OUTLOOK. POSITIVE SOIL MOISTURE DEPARTURES AND ELEVATED SNOWPACK IN SOME AREAS ACROSS THE NORTHERN TIER OF THE U.S. FROM THE NORTHERN HIGH PLAINS WESTWARD TO INCLUDE MUCH OF THE WEST, ALONG WITH WEAK SHORT TERM CLIMATE PREDICTION MODEL SIGNALS IN THESE AREAS RESULTED IN A DESIGNATION OF EQUAL CHANCES (EC) OR A REDUCTION IN PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FROM THE PREVIOUS OUTLOOK IN THESE REGIONS. MANY OF THE REMAINING TEMPERATURE OUTLOOK MAPS SAW LITTLE CHANGE FROM THE PREVIOUS SET OF OUTLOOKS AS STATISTICAL AND DYNAMICAL FORECAST TOOL INDICATORS DID NOT VARY STRONGLY. SOME EXCEPTIONS INCLUDE THE FOLLOWING. SLIGHTLY LOWER PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE NOW INDICATED FOR AREAS OF THE WEST DURING MJJ 2017 DUE TO PREVIOUSLY MENTIONED INITIAL LAND SURFACE CONDITIONS. WARMER GUIDANCE SUPPORTED AN INCREASE IN PROBABILITIES FOR ABOVE NORMAL TEMPERATURES FOR THE EASTERN U.S. DURING JJA, JAS AND ASO 2017. LOW PROBABILITIES FOR LA NINA CONDITIONS AND CONSEQUENTLY ELEVATED ODDS FOR EL NINO CONDITIONS POTENTIALLY ENTERING THE AUTUMN FAVORED A SLIGHT INCREASE IN PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ALONG THE NORTHERN TIER IN THE CENTRAL AND EASTERN CONUS FOR SON, OND 2017 AND NDJ 2017-2018. FOR ALASKA, HIGH PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR THE NORTH SLOPE DUE TO RECENT TRENDS IN SEA ICE COVERAGE AND TIMING DURING SON AND OND 2017. PRECIPITATION FOR PRECIPITATION, THE AMJ 2017 OUTLOOK FAVORS ABOVE-MEDIAN PRECIPITATION FOR A REGION ACROSS THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS AS WELL AS ALONG THE WESTERN GULF COAST. BELOW-MEDIAN PRECIPITATION IS MOST LIKELY FOR AREAS OF WESTERN ALASKA INCLUDING THE ALEUTIANS. THE OUTLOOK IS PRIMARILY BASED ON AVAILABLE DYNAMICAL MODEL GUIDANCE AND LONG TERM TRENDS IN LOCATIONS WHERE THEY ARE DEEMED SOMEWHAT RELIABLE (I.E., NORTHERN ROCKIES, NORTHERN PLAINS). HIGHLIGHTED AREAS FOR THE MJJ THROUGH ASO 2017 SEASONS ARE IN AREAS WHERE THERE WAS CONSISTENT, ALBEIT OFTEN WEAK, SIGNATURES INDICATED BY CALIBRATED PROBABILISTIC GUIDANCE FROM THE NMME SUITE OF MODELS. THIS INCLUDES A CONTINUATION OF ELEVATED ODDS FOR ABOVE-MEDIAN PRECIPITATION FOR AREAS IN THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS. BY ASO 2017, CONSIDERATIONS AS NOTED ABOVE REGARDING INCREASING ODDS FOR EL NINO ALLOW A SLIGHT SOUTHWARD SHIFT OF THIS REGION. BELOW-MEDIAN PRECIPITATION CONTINUES FOR PARTS OF WESTERN ALASKA IN MJJ 2017 AND IS INTRODUCED IN MJJ AND JJA 2017 NEAR THE OHIO VALLEY. THERE IS A SLIGHT TILT IN THE ODDS FOR ABOVE MEDIAN PRECIPITATION FOR PORTIONS OF EASTERN MAINLAND ALASKA FROM MJJ TO JAS 2017. FOR LATER LEADS, THE LOW PROBABILITIES FOR LA NINA AT THE CURRENT TIME AND CONSEQUENTLY ELEVATED ODDS FOR POTENTIAL EL NINO CONDITIONS RESULTED IN REMOVAL OF SOME DRY SIGNALS IN PREVIOUS OUTLOOKS ACROSS THE SOUTHERN TIER OF THE U.S., IN PARTICULAR THE SOUTHEAST CONUS BEGINNING IN NDJ 2017-2018. 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 APR 20 2017 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$