PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830AM EDT THURSDAY MAR 17 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 (CURRENTLY 1971-2000). 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) IS EXPECTED TO BECOME OPERATIONAL BY LATE 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 CONTINUE IN THE TROPICAL PACIFIC OCEAN. SEA SURFACE TEMPERATURES (SSTS) IN THE EQUATORIAL PACIFIC OCEAN ARE BELOW AVERAGE FROM AROUND 160E TO NEAR 110W, WITH SSTS BETWEEN 1 AND 1.5 DEGREES C BELOW NORMAL IN SOME AREAS. ANOMALOUSLY COOL SSTS IMPACT THE LARGE SCALE ATMOSPHERIC CIRCULATION THROUGHOUT THE TROPICAL PACIFIC REGION, INFLUENCING THE MEAN ATMOSPHERIC CIRCULATION PATTERNS OVER NORTH AMERICA. FORECASTS FROM MOST SST PREDICTION MODELS INDICATE LA NINA CONDITIONS TO DIMINISH THROUGH THE SPRING, SUCH THAT ENSO NEUTRAL CONDITIONS ARE EXPECTED BY JUNE 2011. UNCERTAINTY IN THE ENSO STATE IS HIGH GOING INTO SUMMER AND NEXT YEAR. THE TEMPERATURE OUTLOOK FOR AMJ 2011 REFLECTS LA NINA CONDITIONS. BELOW NORMAL TEMPERATURES ARE MOST LIKELY IN WASHINGTON STATE AND WESTERN OREGON AND FROM THE NORTHERN ROCKIES NEAR THE CANADIAN BORDER ACROSS THE NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY. ABOVE NORMAL TEMPERATURES ARE MOST LIKELY FROM THE INTERIOR SOUTHWEST THROUGH THE SOUTHERN PLAINS TO THE GULF COAST AND SOUTH ATLANTIC STATES. THE SEASONAL PRECIPITATION OUTLOOK FOR AMJ 2011 IS ALSO A REFLECTION OF CURRENT LA NINA CONDITIONS. BELOW MEDIAN PRECIPITATION IS MOST LIKELY FOR MUCH OF THE SOUTHWEST, EASTWARD THROUGH SOUTHERN TEXAS AND ALONG THE GULF COAST TO SOUTHERN FLORIDA. ABOVE MEDIAN PRECIPITATION IS MOST LIKELY IN PARTS OF THE NORTHERN PLAINS. 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 WHILE A LARGE AREA OF THE TROPICAL SSTS REMAIN BELOW NORMAL, NEGATIVE SST ANOMALIES HAVE DECREASED IN AMPLITUDE FROM THE CENTRAL PACIFIC TO THE SOUTH AMERICAN COAST DURING THE LAST MONTH AND ARE NOW SLIGHTLY ABOVE NORMAL IN THE FAR 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 170E TO 120W. OCEAN HEAT CONTENT IS BELOW NORMAL TO A GREATER DEPTH IN THE FAR EASTERN PACIFIC, WITH A SHALLOW LAYER OF ABOVE NORMAL TEMPERATURES NEAR THE SURFACE. ABOVE NORMAL OCEAN HEAT CONTENT IN THE WEST PACIFIC HAS CONTINUED TO EXPAND EASTWARD WITH POSITIVE TEMPERATURE ANOMALIES RISING TOWARDS THE SURFACE EAST OF 140W. TOTAL EQUATORIAL OCEANIC HEAT CONTENT BETWEEN 180 AND 100 W IS NOW SLIGHTLY POSITIVE, AFTER EXTENSIVE NEGATIVE ANOMALIES OBSERVED AT THE END OF 2010 BEGAN TO WEAKEN IN JANUARY 2011. THE LARGE SCALE ATMOSPHERIC CIRCULATION OVER THE TROPICAL PACIFIC OCEAN IS CONSISTENT WITH LA NINA CONDITIONS AS OF MID-MARCH. CONVECTION IS SLIGHTLY ENHANCED OVER PARTS OF THE MARITIME CONTINENT NEAR THE EQUATOR. GREATER ENHANCED CONVECTION IS OBSERVED BOTH TO THE NORTH OF THE EQUATOR, AND TO THE SOUTH OVER AUSTRALIA AND THE EASTERN INDIAN OCEAN, WHILE CONVECTION IS SUPPRESSED OVER THE WESTERN AND CENTRAL EQUATORIAL PACIFIC OCEAN, EAST OF ABOUT 140E. LOW LEVEL EASTERLY TRADE WINDS ARE ENHANCED OVER THE WESTERN AND CENTRAL PACIFIC. WESTERLY WIND ANOMALIES AT UPPER LEVELS ARE ENHANCED OVER THE CENTRAL AND EAST-CENTRAL PACIFIC WITH ANOMALOUS OFF-EQUATORIAL CYCLONIC CIRCULATIONS IN THE SUBTROPICS OF BOTH HEMISPHERES. OVERALL, THESE ATMOSPHERIC AND OCEANIC CONDITIONS ARE CONSISTENT WITH A MODERATE LA NINA. PROGNOSTIC DISCUSSION OF SST FORECASTS STATISTICAL AND DYNAMICAL MODELS PREDICT NEGATIVE SST ANOMALIES IN THE EQUATORIAL PACIFIC TO DIMINISH DURING THE SPRING OF 2011 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 COOLER THAN -0.5 C ONLY THROUGH MAM2011, AND THE LIKELY POSSIBILITY OF A TRANSITION FROM LA NINA TO ENSO NEUTRAL CONDITIONS BEFORE THE SUMMER. THE CPC SST CONSOLIDATION FORECAST INDICATES THAT NINO 3.4 SST ANOMALIES ARE MOST LIKELY TO BE IN THE ENSO NEUTRAL RANGE FROM -0.5 TO +0.5 C IN THE SUMMER. THERE IS A FAIRLY EQUAL DISTRIBUTION OF MODEL FORECASTS PREDICTING LA NINA, ENSO NEUTRAL OR EL NINO CONDITIONS AFTER THAT TIME, AND UNCERTAINTY IS HIGH REGARDING THE ENSO STATE IN AUTUMN AND NEXT WINTER. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE CFS, CCA AND SMLR TEMPERATURE AND PRECIPITATION FORECASTS FOR AMJ 2010 ARE CONSISTENT WITH LA NINA COMPOSITES. THE OUTLOOKS FOR AMJ 2011 WERE PRIMARILY BASED ON LA NINA COMPOSITES, THE SKILL-WEIGHTED CONSOLIDATION (CON) FORECASTS, AND THE CFS DYNAMICAL MODEL. WITH AN INCREASED LIKELIHOOD OF ENSO NEUTRAL CONDITIONS BY JUNE, LA NINA IMPACTS ARE NOT EXPECTED TO CONTINUE SIGNIFICANTLY INTO THE FOLLOWING SEASONS. THE MJJ AND JJA TEMPERATURE OUTLOOKS REFLECT SOME LINGERING LA NINA IMPACTS PRIMARILY RESULTING FROM SOIL MOISTURE ANOMALIES. THIS PRIMARILY INCREASES THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES IN THE SOUTHERN U.S. WHERE SOIL MOISTURE IS BELOW NORMAL, AND BELOW NORMAL TEMPERATURES IN THE CENTRAL MISSISSIPPI AND OHIO VALLEYS, WHERE SOIL MOISTURE IS ABOVE NORMAL. THE OUTLOOKS FOR MJJ 2011 AND THEREAFTER ARE BASED ON THE CONSOLIDATION WHICH IS PRIMARILY INFLUENCED AT THOSE LEADS BY TEMPERATURE AND PRECIPITATION TRENDS RELATED TO DECADAL VARIABILITY AND CHANGES IN THE LONG TERM CLIMATE STATE. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2011 TO AMJ 2012 TEMPERATURE THE 3-MONTH TEMPERATURE OUTLOOK FOR AMJ 2010 PRIMARILY REFLECTS EXPECTED LA NINA IMPACTS, DECREASING OVER THE SEASON, AND THE CPC CONSOLIDATION FORECAST. PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ENHANCED FROM THE PACIFIC NORTHWEST EASTWARD ACROSS THE NORTHERN ROCKIES TO THE WESTERN GREAT LAKES REGION. THE OCN PREDICTS A STRONG TREND FOR ABOVE NORMAL TEMPERATURES IN NORTHERN ALASKA, AND INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ACROSS THE INTERIOR SOUTHWEST. FOR MJJ 2011, THERE IS AN ELEVATED CHANCE OF BELOW NORMAL TEMPERATURES IN THE NORTHERN PLAINS, WHICH REFLECTS RECENT LONG-TERM VARIABILITY AND INITIALLY VERY WET SOIL IN THIS REGION. APART FROM THIS, OUTLOOKS FOR MJJ 2011 THROUGH MAM 2012 PRIMARILY REFLECT DECADAL OR LONGER VARIABILITY IN THE LONG TERM CLIMATE STATE. AT EARLY LEADS, AN INCREASED CHANCE OF ABOVE NORMAL TEMPERATURES IS INDICATED FOR MUCH OF THE WEST. IN THE LATER LEADS, THE LONGER-TERM TRENDS INCREASE THE LIKELIHOOD OF ABOVE NORMAL TEMPERATURES FOR THE NORTHEAST AND THE GREAT LAKES REGION. ABOVE NORMAL TEMPERATURES ARE ALSO SLIGHTLY FAVORED IN THE LATER LEADS FOR ALASKA, WHERE WARMING TRENDS HAVE BEEN RELIABLE INDICATORS OF SEASONAL MEAN TEMPERATURES. PRECIPITATION THE PRECIPITATION OUTLOOK FOR AMJ 2011 SHOWS THE EXPECTED IMPACT OF CIRCULATION ANOMALIES ASSOCIATED WITH LA NINA. THE CHANCES OF BELOW MEDIAN PRECIPITATION ARE INCREASED ACROSS MUCH OF THE SOUTHERN U.S. AND IN PARTICULAR, THE SOUTHWEST. IN SPITE OF THE FORECASTED WEAKENING OF LA NINA IN THE SPRING, SOIL MOISTURE ANOMALIES IN REGIONS WITH A WINTER PRECIPITATION DEFICIT MAY DECREASE LOCAL MOISTURE SOURCES THROUGH EVAPORATION AND INCREASE THE CHANCES FOR THE CONTINUATION OF BELOW MEDIAN PRECIPITATION INTO SPRING. DECADAL TRENDS LEAD TO ENHANCED CHANCES OF BELOW MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST AND OF ABOVE MEDIAN PRECIPITATION IN NEW ENGLAND THROUGH SUMMER INTO EARLY AUTUMN. TRENDS ALSO INDICATE A GREATER LIKELIHOOD OF ABOVE MEDIAN PRECIPITATION IN SOUTHERN FLORIDA AND 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. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: DAN COLLINS 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 21 2011 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE. $$