PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY MAR 20 2014 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS THAT USUALLY INFLUENCE THE SEASONAL CLIMATE OUTLOOK INCLUDE: 1) EL NINO AND LA NINA - WHICH TOGETHER COMPRISE EL NINO/SOUTHERN OSCILLATION OR ENSO. IMPACTS OF THESE EVENTS ARE SUMMARIZED BY SEPARATING 3-MONTH OBSERVATIONS FROM 3 OR MORE DECADES INTO EL NINO, NEUTRAL, AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN COMPUTING ANOMALIES. THESE ARE CALLED "ENSO COMPOSITES", WHICH ARE USED AT TIMES TO SUBJECTIVELY MODIFY THE FORECAST. 2) TRENDS - APPROXIMATED BY THE OCN TOOL AS THE DIFFERENCE BETWEEN THE MOST RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGY PERIOD (CURRENTLY 1981-2010). 3) THE TROPICAL 30-60 DAY OSCILLATION - SOMETIMES CALLED MADDEN JULIAN OSCILLATION (MJO) - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS. 4) THE NORTH ATLANTIC OSCILLATION (NAO) AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE ANOMALY PATTERN ESPECIALLY DURING THE COLD SEASONS. THESE PHENOMENA ARE CONSIDERED LESS PREDICTABLE ON A SEASONAL TIMESCALE THAN ENSO. 5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE VARIABILITY AFFECTING THE TROPICS AND THE NORTH PACIFIC AND NORTH AMERICAN REGIONS, BUT WHICH VARIES ON A MUCH LONGER TIME-SCALE THAN ENSO. 6) PERSISTENTLY DRY OR WET SOILS IN THE SPRING AND SUMMER AND SNOW AND ICE COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM. 7) STATISTICAL FORECAST TOOLS - CANONICAL CORRELATION ANALYSIS (CCA), SCREENING MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOGUE (CA) AND ENSEMBLE CCA (ECCA). 8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM (CFS). AN EXPERIMENTAL MODEL FORECAST SYSTEM, THE NATIONAL MULTI-MODEL ENSEMBLE, COMPRISED OF SEVERAL MODELS AND DESIGNATED NMME, MAY ALSO BE USED EXPERIMENTALLY AND SUBJECTIVELY UNTIL IT IS INCLUDED INTO THE CONSOLIDATION. AN INTERNATIONAL MODEL ENSEMBLE DESIGNATED IMME IS ALSO AVAILABLE. 9) CONSOLIDATION (CON) - AN OBJECTIVE, SKILL-WEIGHTED COMBINATION OF THE OCN, CCA, SMLR, ECCA, AND CFS FORECASTS IS USED AS A FIRST GUESS IN PREPARING THE FORECAST MAPS. THIS TECHNIQUE MAKES OPTIMUM USE OF THE KNOWN SKILL OF FORECAST TOOLS. CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS REMAIN ENSO-NEUTRAL AND THE LATEST ENSO OUTLOOK FAVORS ENSO-NEUTRAL CONDITIONS TO CONTINUE THROUGH THE NORTHERN HEMISPHERE SPRING OF 2014. HOWEVER, AN EL NINO WATCH HAS BEEN ISSUED WHICH INDICATES CONDITIONS ARE FAVORABLE FOR EL NINO DEVELOPMENT WITHIN THE NEXT SIX MONTHS. THE TEMPERATURE OUTLOOK FOR APRIL-MAY-JUNE (AMJ) 2014 INDICATES ELEVATED ODDS OF ABOVE NORMAL TEMPERATURES FOR ALASKA AND A REGION FROM THE WESTERN PACIFIC NORTHWEST TO CALIFORNIA AND NEVADA, EASTWARD ALONG THE SOUTHERN TIER OF THE CONTINENTAL U.S. THERE ARE ELEVATED CHANCES OF BELOW NORMAL TEMPERATURES FROM MONTANA TO THE GREAT LAKES. THE AMJ 2014 PRECIPITATION OUTLOOK CALLS FOR ENHANCED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION FOR SOUTHEAST ALASKA AND ALONG THE ENTIRE WEST COAST, WITH THE HIGHEST PROBABILITIES FOR AREAS OF NORTHERN CALIFORNIA AND THE ALASKA PANHANDLE. IN AREAS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL ACCUMULATED PRECIPITATION AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS SHOWN. 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 OVER THE LAST SEVERAL WEEKS, CONSIDERABLE CHANGES HAVE OCCURRED ACROSS THE EQUATORIAL PACIFIC OCEAN, BOTH IN THE ATMOSPHERE AND IN THE OCEAN THAT HAVE INCREASED PROBABILITIES FOR THE DEVELOPMENT OF EL NINO LATER IN 2014. SEA SURFACE TEMPERATURES (SSTS) ACROSS THE EQUATORIAL WESTERN PACIFIC HAVE INCREASED AND ANOMALIES ARE NOW POSITIVE FROM NEAR NEW GUINEA TO JUST EAST OF THE DATE LINE AND RANGE FROM +0.5 TO +1.0 DEGREES C, WITH SOME AREAS NEAR THE DATE LINE GREATER THAN +1.0 DEGREES C. MOREOVER, THERE HAS BEEN TWO STRONG WESTERLY WIND BURSTS OVER THE WESTERN PACIFIC, ONE OCCURRING DURING LATE JANUARY AND ANOTHER SPANNING LATE FEBRUARY AND EARLY MARCH. THE FIRST WESTERLY WIND EVENT INITIATED A STRONG OCEANIC DOWNWELLING KELVIN WAVE WHICH IS IN THE PROCESS OF TRAVERSING THE PACIFIC OCEAN AT THE CURRENT TIME. AT DEPTH, POSITIVE OCEAN TEMPERATURES ARE EVIDENT FOR THE MAJORITY OF THE PACIFIC BASIN FROM 150E TO NEAR 110W AT DEPTHS RANGING FROM 75 M TO 200 M. THE GREATEST POSITIVE ANOMALIES REACH +6.0 DEGREES C NEAR 160W AT A DEPTH OF 150 M. ANOMALOUS EQUATORIAL CONVECTION HAS CONTINUED TO SLOWLY EVOLVE EASTWARD WITH TIME OVER THE INDO-PACIFIC WARM POOL REGION SINCE LATE 2013. ENHANCED CONVECTION DURING THE LAST MONTH HAS BEEN CENTERED OVER THE WESTERN PACIFIC WITH SUPPRESSED CONVECTION THAT HAD BEEN DOMINANT NEAR THE DATE LINE DURING LATE 2013 HAVING SHIFTED SLIGHTLY EAST AND WEAKENING CONSIDERABLY. PROGNOSTIC DISCUSSION OF SST FORECASTS IN THE PAST MONTH THERE HAS BEEN A NOTICEABLE INCREASE IN CHANCES FOR EL NINO LATER THIS YEAR IN THE CONTEXT OF MODEL FORECASTS AS WELL. THE CPC SST CONSOLIDATION FORECAST NOW HAS THE SST ANOMALY FOR NINO3.4 BECOMING POSITIVE IN AMJ 2014 PRIMARILY DUE TO CFS AND CCA FORECASTS. IN FACT, THE CCA IS THE MOST AGGRESSIVE FOR EL NINO OF THE STATISTICAL SST FORECASTS WITH ITS ANOMALY FORECAST GREATER THAN +0.5 C FROM JJA 2014 THROUGH DJF 2014-15. THIS IS AN INTERESTING AND NOTABLE DIFFERENCE AS COMPARED TO LAST SPRING AND SUMMER WHEN THE STATISTICAL SST FORECASTS GENERALLY DIFFERED FROM DYNAMICAL MODELS, WHICH MORE STRONGLY FAVORED EL NINO DEVELOPMENT LAST AUTUMN. THE LATEST CFS NINO3.4 FORECAST INDICATES NEARLY ALL MEMBERS NOW INDICATE POSITIVE ANOMALIES THROUGHOUT THE PERIOD WITH THE ENSEMBLE MEAN CROSSING ABOVE +0.5 DEGREES C NEAR AMJ 2014 AND INCREASING TO +1.0 DEGREES C BY OND 2014. ENSEMBLE MEAN FORECASTS FROM THE IMME AND NMME INDICATE CROSSING THIS THRESHOLD IN JUNE AND JULY RESPECTIVELY. AN EL NINO WATCH WAS ISSUED EARLIER IN MARCH INDICATING THAT CONDITIONS ARE FAVORABLE FOR THE DEVELOPMENT OF EL NINO SOMETIME IN THE NEXT SIX MONTHS. THE GREATEST ODDS FOR EL NINO DEVELOPMENT GENERALLY BEGIN FROM JAS 2014 ONWARDS, WITH PROBABILITIES FOR ENSO NEUTRAL CONDITIONS DURING THIS PERIOD SLIGHTLY OVER 40%. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE TEMPERATURE AND PRECIPITATION OUTLOOKS WERE MADE CONSIDERING ENSO NEUTRAL CONDITIONS TO BE MOST LIKELY THROUGH SPRING INTO EARLY SUMMER. THEREAFTER, INCREASING CHANCES FOR EL NINO AND ASSOCIATED POTENTIAL IMPACTS WERE INCORPORATED AT LONGER LEADS BEGINNING IN JAS 2014 THROUGH THE JFM 2015 SEASON, BUT THE CHANGES, AT THIS TIME, ARE MINOR. AT EARLY LEADS, ESPECIALLY AMJ 2014, CONSIDERATIONS OF ANTECEDENT SOIL MOISTURE, SNOW COVER, ANOMALOUSLY DEEP FROZEN SOIL AND GREAT LAKES ICE COVERAGE CONTRIBUTED TO THE OUTLOOK. GUIDANCE FROM THE CFS AS WELL AS THE NMME AND IMME AND THEIR ASSOCIATED COMPONENTS CONTRIBUTED TO THE OUTLOOKS FROM AMJ THROUGH ASO 2014. THE CON TOOL WAS THE PRIMARY DRIVER FOR THE OUTLOOKS FROM SON 2014 ONWARDS, ALTHOUGH INCREASING CHANCES FOR EL NINO MODIFIED LAST MONTHS SET OF OUTLOOKS WHERE APPROPRIATE. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2014 TO AMJ 2015 TEMPERATURE THE AMJ 2014 TEMPERATURE OUTLOOK INDICATES ELEVATED PROBABILITIES OF ABOVE- NORMAL SEASONAL MEAN TEMPERATURES FOR ALL OF ALASKA, WESTERN AREAS OF THE PACIFIC NORTHWEST, CALIFORNIA AND NEVADA AND EASTWARD ALONG THE SOUTHERN TIER OF THE CONUS. THE PROBABILITIES OF BELOW-NORMAL TEMPERATURES ARE ELEVATED FOR AREAS STRETCHING FROM CENTRAL MONTANA ACROSS THE NORTHERN PLAINS TO THE GREAT LAKES. STATISTICAL TOOLS, DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME, OCN AND THE CON ALL POINTED TO ABOVE-NORMAL TEMPERATURES FOR MANY AREAS IN THE HIGHLIGHTED REGION. IN ADDITION, DRY SOIL MOISTURE CONSIDERATIONS PLAYED A ROLE AS WELL, ESPECIALLY FOR CALIFORNIA AND PARTS OF THE SOUTHWEST. STATISTICAL FORECAST TOOLS KEYING ON ANOMALOUSLY WARM NORTH PACIFIC SSTS AND WET SOIL MOISTURE CONDITIONS ACROSS THE NORTHERN ROCKIES FAVORED BELOW-NORMAL TEMPERATURES FOR PARTS OF THE NORTHERN ROCKIES AND NORTHERN PLAINS AND THIS IS INDICATED BY THE CON TOOL. FURTHER EAST, SOME DYNAMICAL MODELS FAVOR CONTINUED TROUGHING ACROSS EASTERN NORTH AMERICA ESPECIALLY IN APRIL AND THIS ALONG WITH POTENTIAL IMPACTS FROM ANOMALOUSLY HIGH GREAT LAKES ICE COVER FAVOR EXTENSION OF THIS FORECAST AREA TO INCLUDE THE GREAT LAKES AREA. ANOMALOUSLY DEEP FROZEN SOIL IN MANY AREAS OF THE MIDWEST ALSO SUPPORT THIS FORECAST. OUTLOOKS FROM MJJ THROUGH JAS 2014 WERE LARGELY UNCHANGED FROM THE PREVIOUS OUTLOOK AND INDICATE ELEVATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR THE WESTERN AND SOUTHERN CONUS, ALONG THE EASTERN SEABOARD AND FOR ALASKA, SUPPORTED BY THE CON AND DYNAMICAL MODEL GUIDANCE. INCREASING CHANCES FOR EL NINO AS SUMMER APPROACHES 2014 HAVE RESULTED IN SOME ADJUSTMENTS AT LONGER LEADS, PRIMARILY BASED ON EL NINO COMPOSITES DURING VARIOUS SEASONS. ELEVATED CHANCES FOR ABOVE-NORMAL TEMPERATURES FOR AREAS ACROSS THE SOUTHERN TIER OF THE CONUS WERE REDUCED AND THEN ELIMINATED IN THE SOUTHWEST DURING ASO AND SON RESPECTIVELY. ABOVE-NORMAL TEMPERATURES FAVORED DURING THE LATE AUTUMN AND WINTER SEASONS WERE REMOVED ACROSS THE SOUTH AND REPLACED WITH EQUAL CHANCES, AS EL NINO TYPICALLY FAVORS BELOW-NORMAL TEMPERATURES IN THESE AREAS. IF PROSPECTS FOR EL NINO CONTINUE TO INCREASE, PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS THE SOUTH MAY BE ELEVATED IN SUBSEQUENT OUTLOOKS. ALSO, DURING THE LATE AUTUMN AND WINTER SEASONS THROUGH JFM 2015, THE AREA OF ELEVATED ABOVE-NORMAL TEMPERATURES WAS EXTENDED WESTWARD TO THE NORTHERN ROCKIES. IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF BELOW, NEAR AND ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED. PRECIPITATION CLIMATE SIGNALS FOR PRECIPITATION ARE QUITE WEAK AND WHAT SIGNALS ARE INDICATED FROM VARIOUS FORECAST TOOLS OFTEN CONFLICT, EVEN AT THE EARLIEST LEAD. MOREOVER, POTENTIAL TRANSITIONING TOWARDS EL NINO FURTHER ADDS UNCERTAINTY IN THE PRECIPITATION OUTLOOKS AS WE MOVE FORWARD INTO THE SUMMER MONTHS. THE AMJ 2014 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF BELOW-MEDIAN SEASONAL ACCUMULATED PRECIPITATION FOR THE WEST COAST NORTHWARD TO INCLUDE THE ALASKA PANHANDLE AND PARTS OF SOUTHEAST ALASKA. MUCH OF THE OUTLOOK IS DESIGNATED AS EQUAL CHANCES, OR CLIMATOLOGICAL PROBABILITIES OF BELOW, NEAR AND ABOVE-MEDIAN SEASONAL ACCUMULATED PRECIPITATION. THE PRIMARY DRIVER FOR THE AMJ OUTLOOK WAS DYNAMICAL MODEL GUIDANCE FROM THE CFS, NMME AND IMME, WITH THE GREATEST PROBABILITIES ACROSS NORTHERN CALIFORNIA AND THE ALASKA PANHANDLE WHERE AGREEMENT WAS GENERALLY THE BEST. SIMILAR SUPPORT AND RATIONALE IS USED FOR MJJ 2014, BUT SOUTHERN PORTIONS OF THE HIGHLIGHTED AREA ARE REMOVED AS THESE AREAS HAVE ENTERED THEIR CLIMATOLOGICAL DRY SEASON IN EARNEST. BEYOND MJJ 2014, THE UNCERTAINTY OF PRECIPITATION GUIDANCE INCREASES AND FEW CLEAR SIGNALS ARE INDICATED, ALTHOUGH INCREASING CHANCES FOR EL NINO HAVE RESULTED IN SOME ADJUSTMENTS AT LONGER LEADS PRIMARILY BASED ON EL NINO COMPOSITES. ELEVATED CHANCES FOR BELOW-MEDIAN PRECIPITATION IS HIGHLIGHTED FOR PARTS OF THE WESTERN GULF COAST FROM JJA THROUGH ASO 2014 (ALSO SUPPORTED BY THE NMME AND IMME) AS WELL AS THE REMOVAL OF THE DRY SIGNAL ACROSS PARTS OF THE SOUTHEAST CONUS DURING NDJ, DJF AND JFM SEASONS. EL NINO CONDITIONS FAVOR ABOVE-MEDIAN PRECIPITATION DURING THESE SEASONS AND AREAS. IF PROSPECTS FOR EL NINO CONTINUE TO INCREASE, ABOVE-MEDIAN PRECIPITATION MAY BEGIN TO BE NOTED ON SUBSEQUENT OUTLOOKS. IN AREAS WHERE CLIMATE SIGNALS FOR PRECIPITATION ARE WEAK OR UNRELIABLE, EQUAL CHANCES OF BELOW, NEAR AND ABOVE MEDIAN SEASONAL ACCUMULATED PRECIPITATION ARE INDICATED. 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 APR 17 2014 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$