PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830AM EDT THURSDAY MAY 19 2011 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS THE MAIN FACTORS WHICH USUALLY INFLUENCE THE SEASONAL CLIMATE OUTLOOK INCLUDE: 1) EL NINO AND LA NINA - WHICH 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", AND ARE USED 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 (NOW 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 CURRENTLY KNOWN TO BE PREDICTABLE ONLY OVER A WEEK OR SO. 5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE VARIABILITY AFFECTING BOTH 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 UPGRADED PARALLEL VERSION OF THE CFS (CFSV2) BECAME OPERATIONAL IN MARCH 2011. IT IS ANTICIPATED THAT BOTH CFS VERSIONS WILL BE RUN IN PARALLEL UNTIL AT LEAST JUNE 2011. 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 OUR FORECAST TOOLS. LA NINA CONDITIONS FURTHER WEAKENED IN THE TROPICAL PACIFIC OCEAN. SEA SURFACE TEMPERATURES (SSTS) IN THE EQUATORIAL PACIFIC OCEAN ARE BELOW AVERAGE FROM AROUND 160E TO NEAR 150W, AND SST ANOMALIES BELOW -0.5C HAVE BEEN PUSHED AWAY FROM THE EQUATOR INTO BOTH HEMISPHERES. SUBSURFACE BELOW NORMAL TEMPERATURE HAVE STRONGLY DIMINISHED. UNCERTAINTY IN THE ENSO STATE BEYOND SPRING 2011 IS HIGH. THE EFFECT OF LA NINA, IF ANY, WILL BE INDIRECT. THE SOIL MOISTURE CONDITIONS IN PLACE OVER THE U.S. CLEARLY REFLECT THE LA NINA WINTER WE JUST HAD. THE TEMPERATURE OUTLOOK FOR JJA 2011 INDICATES PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ENHANCED FROM MINNESOTA TO THE OHIO VALLEY, WHILE PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTH AND ESPECIALLY IN THE INTERIOR SOUTHWEST. THE SEASONAL PRECIPITATION OUTLOOK FOR JJA 2011 CALLS FOR ENHANCED PROBABILITIES FOR BELOW MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST AS FAR EAST AS CENTRAL MONTANA. IN LOCATIONS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL PRECIPITATION AMOUNTS ARE SIMILAR TO THE CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) OF BELOW, NEAR, AND ABOVE AVERAGE TEMPERATURE AND PRECIPITATION ARE 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 NEGATIVE SST ANOMALIES HAVE DECREASED IN AMPLITUDE FROM THE CENTRAL PACIFIC TO THE SOUTH AMERICAN COAST DURING THE LAST 2 MONTHS AND ARE NOW SLIGHTLY ABOVE NORMAL IN THE EASTERN PACIFIC. THE SUBSURFACE OCEAN HEAT CONTENT MEASURED BY THE WATER TEMPERATURE IS BELOW NORMAL TO A DEPTH OF 50 TO 100 METERS FROM APPROXIMATELY THE DATE LINE TO 140W, BUT MUCH LESS SO THAN 1 MONTH AGO. OCEAN HEAT CONTENT IS SOMEWHAT ABOVE NORMAL FROM THE SURFACE TO A DEPTH OF ABOUT 125 METERS EAST OF ABOUT 115W. ABOVE NORMAL OCEAN HEAT CONTENT IN THE WEST PACIFIC HAS PERSISTED WITH POSITIVE TEMPERATURE ANOMALIES OCCASIONALLY RISING TOWARDS THE SURFACE EAST OF 140W. TOTAL EQUATORIAL OCEANIC HEAT CONTENT DEPARTURE FROM NORMAL BETWEEN 180 AND 100 W IS NOW POSITIVE, ON AVERAGE. AS OF MID-MAY, THE LARGE SCALE ATMOSPHERIC CIRCULATION OVER THE TROPICAL PACIFIC OCEAN IS ONLY VAGUELY CONSISTENT WITH LA NINA CONDITIONS. CONVECTION IS SLIGHTLY ENHANCED OVER PARTS OF THE MARITIME CONTINENT NEAR THE EQUATOR. LOW LEVEL EASTERLY TRADE WINDS ARE NEAR NORMAL OVER THE WESTERN AND CENTRAL PACIFIC AND AWAITING THE IMMINENT IMPACT OF AN MJO EVENT. OVERALL, THESE ATMOSPHERIC AND OCEANIC CONDITIONS ARE CONSISTENT WITH A WEAKENING OR NEARLY DISSIPATED LA NINA. IT IS NOT UNCOMMON FOR CERTAIN EFFECTS TO LAG. THIS SET OF OUTLOOKS IS THE FIRST ONE TO USE THE 1981-2010 CLIMATOLOGICAL NORMALS. DECADAL TRENDS, PREVIOUSLY ASSESSED RELATIVE TO THE 1971-2000 PERIOD, HAVE CHANGED CONSIDERABLY NOW THAT WE USE 1981-2010. PROGNOSTIC DISCUSSION OF SST FORECASTS STATISTICAL AND DYNAMICAL MODELS PREDICT NEGATIVE SST ANOMALIES IN THE EQUATORIAL PACIFIC TO DIMINISH SUCH THAT ENSO NEUTRAL CONDITIONS ARE EXPECTED BY JUNE 2011. THE CPC CONSOLIDATION OF THE CFS, CONSTRUCTED ANALOG, MARKOV MODEL AND CCA NINO 3.4 FORECASTS INDICATES AN ANOMALY CLOSE TO ZERO DURING JJA2011. THE CPC SST CONSOLIDATION FORECAST INDICATES THAT NINO 3.4 SST ANOMALIES ARE MOST LIKELY TO BE IN THE ENSO NEUTRAL RANGE (ANOMALIES OF FROM -0.5 TO +0.5 C) IN THE LATE SUMMER, FALL AND NEXT WINTER. THERE ARE A NUMBER OF MODELS BOTH AT NCEP AND ELSEWHERE PREDICTING EITHER A WEAK LA NINA, ENSO NEUTRAL OR EVEN WEAK EL NINO CONDITIONS, THEREFORE THE UNCERTAINTY IS CONSIDERABLE REGARDING THE ENSO STATE IN AUTUMN AND NEXT WINTER, EXCEPT THAT A STRONG EVENT IS NOT LIKELY. IN OUR U.S. FORECAST WE ASSUMED NEUTRAL CONDITIONS. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE OUTLOOKS FOR JJA 2011 ONWARD WERE PRIMARILY BASED ON THE SKILL-WEIGHTED CONSOLIDATION (CON) FORECASTS, AND THE CFS DYNAMICAL MODELS. THE CONSOLIDATION INCLUDES SMLR, CCA, OCN, ECCA AND CFS. THE CAS TOOL PLAYED A ROLE ONLY FOR THE FIRST LEAD. PROGNOSTIC DISCUSSION OF OUTLOOKS - JJA 2011 TO JJA 2012 TEMPERATURE FOR JJA 2011 PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ENHANCED FROM MINNESOTA TO THE OHIO VALLEY. PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE ELEVATED ACROSS THE SOUTH AND ESPECIALLY IN THE INTERIOR SOUTHWEST. THIS PATTERN PERSISTS, WITH REDUCED COVERAGE, INTO JAS AND ASO. SOIL MOISTURE CONDITIONS WOULD ENFORCE SUCH A SET-UP AND MANY TOOLS PICK UP ON THIS. THE FORECAST OF ABOVE NORMAL TEMPERATURES ACROSS THE SOUTH IS ALSO SUPPORTED BY TRENDS, EVEN IF TRENDS ARE WEAKER NOW THAT WE USE 1981-2010 NORMALS. IN THE LATER LEADS, THE LONGER-TERM TRENDS INCREASE THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES FOR EITHER THE NORTHEAST AND THE GREAT LAKES REGION OR SOME PORTIONS OF THE SOUTH AND SOUTHWEST. ABOVE NORMAL TEMPERATURES ARE ALSO SLIGHTLY FAVORED IN THE LATER LEADS FOR PARTS OF ALASKA, BUT ONLY OUT TO NDJ. ON THE WHOLE, COVERAGE IS MUCH LESS THAN BEFORE BECAUSE THE GENERAL WARMING TREND HAS, FOR THE MOMENT AT LEAST, BECOME PART OF THE NEW NORMAL. PRECIPITATION THE PRECIPITATION OUTLOOK FOR JJA AND JAS 2011 CALLS FOR ENHANCED PROBABILITIES FOR BELOW MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST AS FAR EAST AS CENTRAL MONTANA. BY USING 1981-2010 NORMALS WE HAVE LOST SOME TREND FEATURES WE WOULD INDICATE PREVIOUSLY, WHEN 1971-2000 WAS THE BASE PERIOD, SUCH AS PROBABILITIES FOR ENHANCED PRECIPITATION IN THE NORTHEAST IN JJA 2011. TRENDS INDICATE A GREATER LIKELIHOOD OF ABOVE MEDIAN PRECIPITATION IN FLORIDA, ALONG PARTS OF THE EAST COAST AND IN THE CENTRAL PLAINS DURING LATE SUMMER AND EARLY AUTUMN. MOST OF THE OUTLOOKS BEYOND SON 2011 SHOW EQUAL CHANCES (EC) BECAUSE OF A LACK OF CLIMATE SIGNALS, EXCEPT FOR ENHANCED CHANCES OF BELOW MEDIAN PRECIPITATION IN THE SOUTHEAST DUE TO LONG TERM TRENDS IN JFM AND FMA 2012. FORECASTER: HUUG VAN DEN DOOL 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 JUN 16 2011 1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 FORECAST RELEASE. $$