PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 830 AM EST THU FEB 18 2010 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 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). 9) AN OBJECTIVE CONSOLIDATION (ABBREVIATED CON IN THE TEXT) 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. AN EL NINO EVENT CONTINUES IN THE TROPICAL PACIFIC WITH MONTHLY SEA SURFACE TEMPERATURES IN THE EQUATORIAL PACIFIC AVERAGING FROM 1 TO 2 DEGREES C ABOVE NORMAL. EL NINO CONDITIONS ARE EXPECTED TO PERSIST INTO THE BOREAL SPRING, IMPACTING US SURFACE TEMPERATURE AND PRECIPITATION OUTLOOKS FOR MAM AND AMJ 2010. THE TEMPERATURE OUTLOOK FOR MAM 2010 INDICATES ABOVE NORMAL TEMPERATURES ARE MORE LIKELY THAN NEAR OR BELOW NORMAL TEMPERATURES FOR MUCH OF THE NORTHWEST, AND WESTERN GREAT LAKES REGION. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED OVER MOST OF ALASKA, EXCEPT FOR THE WESTERN ALEUTIANS AND THE SOUTHERN ALASKAN PANHANDLE. BELOW NORMAL TEMPERATURES ARE MORE LIKELY FROM EASTERN NEW MEXICO AND THE SOUTHERN PLAINS THROUGH THE GULF COAST AND SOUTHERN ATLANTIC COAST STATES. IN LOCATIONS WHERE THE LIKELIHOOD OF ABOVE OR BELOW NORMAL SEASONAL MEAN TEMPERATURE IS SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES OF BELOW, NEAR, AND ABOVE NORMAL TEMPERATURES ARE INDICATED. THE CHANCES OF BELOW MEDIAN PRECIPITATION DURING MAM 2010 ARE GREATER THAN CLIMATOLOGY IN NORTHWESTERN OREGON AND WESTERN WASHINGTON AS WELL AS THE NORTHERN GREAT LAKES REGION INTO NORTHERN NEW YORK STATE. THE CHANCES FOR ABOVE MEDIAN PRECIPITATION AMOUNTS ARE ELEVATED FOR THE SOUTHWEST FROM SOUTHERN CALIFORNIA INTO TEXAS, EXTENDING NORTHWARD INTO THE CENTRAL HIGH PLAINS. IN LOCATIONS WHERE THE LIKELIHOOD OF ABOVE OR BELOW MEDIAN SEASONAL ACCUMULATED PRECIPITATION IS SIMILAR TO THE CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES OF BELOW, NEAR, AND ABOVE MEDIAN 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 SEA SURFACE TEMPERATURE (SST) ANOMALIES REMAIN SIGNIFICANTLY ABOVE THEIR CLIMATOLOGICAL MEAN VALUES NEAR THE EQUATOR THROUGHOUT THE CENTRAL AND EASTERN PACIFIC. MEAN EQUATORIAL SST ANOMALIES FOR THE LAST 30 DAY PERIOD EXCEED +1.0 C FROM 175 E TO 105 W, AND ARE MORE THAN +2.0 C FROM 170 W TO 150 W. SST ANOMALIES FOR THE NINO 3.4 REGION HAVE BEEN DECREASING IN RECENT WEEKS WITH THE CURRENT MEAN APPROXIMATELY +1.2 C. WHILE THE NDJ SEASONAL MEAN NINO 3.4 INDEX WAS +1.8 DEGREES C INDICATING A STRONG EL NINO EVENT, MOST DYNAMICAL AND STATISTICAL SST FORECASTS INDICATE THAT THE SEASONAL SST ANOMALY WILL DECREASE OVER THE NEXT SEVERAL SEASONS, THOUGH THE SPREAD BETWEEN ENSO FORECASTS BECOMES VERY LARGE FOLLOWING MJJ 2010. LOW-LEVEL WESTERLY WIND ANOMALIES WERE OBSERVED OVER THE WEST-CENTRAL PACIFIC DURING THE LAST 30 DAYS, WHILE UPPER-LEVEL ANTICYCLONES CAN BE SEEN TO THE NORTH AND SOUTH OF THE EQUATOR. EQUATORIAL OUTGOING LONGWAVE RADIATION ANOMALIES REFLECT EL NINO CONDITIONS, INDICATING ENHANCED CONVECTION NEAR THE DATE LINE AND SUPPRESSED CONVECTION OVER THE MARITIME CONTINENT. POSITIVE TEMPERATURE ANOMALIES AT UPPER LEVELS OF THE EQUATORIAL PACIFIC OCEAN ARE AN INDICATION OF PERSISTENCE OF EL NINO CONDITIONS. THE SUBSURFACE HEAT CONTENT IN THE EQUATORIAL PACIFIC HAS BEEN PERSISTENTLY ABOVE NORMAL WITH CURRENT ANOMALIES GREATER THAN +1.0 C TO A DEPTH OF AT LEAST 150 M FROM 170 E TO 100 W. THEREFORE EL NINO CONDITIONS ARE LIKELY TO PERSIST THROUGH THE NEXT THREE-MONTH SEASON OR LONGER. PROGNOSTIC DISCUSSION OF SST FORECASTS BIAS-CORRECTED FORECASTS FROM THE NCEP CLIMATE FORECAST SYSTEM (CFS) DYNAMICAL COUPLED OCEAN-ATMOSPHERE MODEL INDICATE THAT THE SEASONAL MEAN NINO 3.4 INDEX WILL DECLINE TO A MODERATE EL NINO EVENT (ANOMALY BETWEEN +1.0 AND +1.5 C) BY FMA 2010, AND WILL BECOME A WEAK EL NINO (ANOMALY BELOW +1.0 C) BY AMJ 2010. CPC STATISTICAL SST FORECASTS FROM CANONICAL CORRELATION ANALYSIS, CONSTRUCTED ANALOG AND MARKOV MODELS PREDICT A LOWER BUT STILL POSITIVE SST ANOMALY, WITH MAM FORECAST TO BE BELOW +1.0 C ACCORDING TO ALL THREE CPC STATISTICAL MODELS. THE CPC SST CONSOLIDATION OF THESE FOUR NINO 3.4 SST ANOMALY FORECASTS HAS A MEAN VALUE OF ABOUT +0.7 DEGREES C FOR MAM 2010 BUT REMAINS ABOVE +0.5 C THROUGH JJA. FROM THE CPC SST CONSOLIDATION, A NINO 3.4 INDEX BETWEEN ZERO AND +1.0 APPEARS MOST LIKELY BY THE JJA 2010 SEASON. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE CPC CONSOLIDATION WAS THE PRIMARY TOOL USED FOR THE SEASONAL TEMPERATURE AND PRECIPITATION OUTLOOKS. THOUGH THE PREDICTED STRENGTH AND IMPACTS FROM EL NINO CONDITIONS DECREASE AFTER THE MAM SEASON, THERE IS A SIGNIFICANT PROBABILITY OF SOME IMPACTS OF AN EL NINO INTO MJJ. THE CFS MAINTAINS STRONG EL NINO CONDITIONS INTO MJJ. THE CFS TEMPERATURE AND PRECIPITATION FORECAST COMBINED WITH EL NINO COMPOSITES WERE USED TO MODIFY THE CONSOLIDATION FOR THE FIRST 3 LEADS FROM MAM TO MJJ. THE TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JJA 2010 THROUGH MAM 2011 ARE BASED ON THE CPC CONSOLIDATION FORECAST, A SKILL-WEIGHTED AND CALIBRATED-PROBABILITY FORECAST DERIVED FROM THE CFS, SMLR, OCN, ECCA AND CCA FORECAST TOOLS. PROGNOSTIC DISCUSSION OF OUTLOOKS - MAM 2010 TO MAM 2011 TEMPERATURE: THE TEMPERATURE OUTLOOK FOR MAM 2010 INDICATES THAT THE CHANCES OF BELOW NORMAL TEMPERATURES ARE ELEVATED OVER THEIR CLIMATOLOGICAL PROBABILITY FOR MUCH OF THE SOUTHEAST, WHILE ABOVE NORMAL TEMPERATURES ARE FAVORED FOR THE NORTHWEST AND WESTERN GREAT LAKES REGIONS, CONSISTENT WITH EL NINO COMPOSITES AND THE CFS ENSEMBLE PROBABILITY TEMPERATURE FORECAST. THE INCREASED LIKELIHOOD OF BELOW NORMAL TEMPERATURES IN PARTS OF THE SOUTHWEST THAT IS INDICATED BY THE CFS FORECAST AND EL NINO COMPOSITES IS DIMINISHED BY THE STRONG POSITIVE TREND IN THIS REGION FOLLOWING THE CONSOLIDATION. ANOMALOUS SNOW DEPTHS IN THE NORTHERN PLAINS AND THE SUBSEQUENT ABOVE NORMAL SOIL MOISTURE CONTRIBUTE TO THE FORECAST FOR THE FIRST THREE LEADS. THE FORECAST OF ENHANCED CHANCES FOR BELOW NORMAL TEMPERATURES IN AMJ AND MJJ FOR THE NORTHERN PLAINS IS ALSO CONSISTENT WITH ENSO COMPOSITES AND DECADAL TRENDS, AS IS A SMALL AREA OF ENHANCED CHANCES OF BELOW NORMAL TEMPERATURES IN THE SOUTHERN PLAINS. THE LATER LEADS FROM JJA 2010 TO MAM 2011 ARE BASED ON THE CONSOLIDATION WITH PREDICTABILITY OF SEASONAL MEAN TEMPERATURES ARISING FROM DECADAL CLIMATE VARIABILITY. A PERSISTENT AREA OF INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES IS SEEN FOR ALL LEADS IN THE SOUTHWEST, WITH THE EXCEPTION OF MAM 2010, WHERE THIS POSITIVE TREND IS COUNTERED BY THE IMPACTS OF EL NINO. INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES EXPAND INTO THE SOUTHEAST DURING THE SUMMER SEASONS BEGINNING IN JJA AND ENDING IN ASO, AND COVER PARTS OF THE NORTHEAST FROM JAS TO OND. THE INCREASED LIKELIHOOD OF ABOVE NORMAL SEASONAL MEAN TEMPERATURES BEGINS FOR PARTS OF THE NORTH CENTRAL U.S. IN AUTUMN EXPANDING SOUTHWARD THROUGH ALL OF THE CENTRAL U.S. IN WINTER, WITH THE GREATEST LIKELIHOOD REMAINING FOR THE SOUTHWEST. UNCERTAINTY IN THE POSSIBILITY OF THE EL NINO CONDITIONS REDEVELOPING NEXT AUTUMN AND WINTER RESULTS IN THE CONTINUATION OF INCREASED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES IN THE SOUTHWEST THOUGH MAM 2011. TEMPERATURE OUTLOOKS FOR ALASKA INDICATE GREATER THAN NORMAL PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR MOST OF THE STATE INTO JJA 2010, CONSISTENT WITH CFS FORECASTS WITH SUPPORT FROM THE STATISTICAL TOOLS. AFTER JAS 2010, STRONGER TREND SIGNALS INDICATED BY STATISTICAL TOOLS HAVE BEEN USED FOR THE TEMPERATURE OUTLOOK OVER ALASKA. PRECIPITATION: ENHANCED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR THE SOUTHWEST FROM SOUTHERN CALIFORNIA INTO TEXAS ARE DERIVED FROM THE CFS FORECAST AND EL NINO COMPOSITES, AS IS THE AREA OF ENHANCED CHANCES OF BELOW MEDIAN PRECIPITATION IN THE PACIFIC NORTHWEST. THE AREA OF GREATER THAN CLIMATOLOGICAL PROBABILITY OF BELOW MEDIAN PRECIPITATION IN THE NORTHERN GREAT LAKES REGION IS DERIVED FROM THE CFS PRECIPITATION FORECAST, WHILE REMAINING CONSISTENT WITH EL NINO IMPACTS. GREATER THAN NORMAL PROBABILITIES OF ABOVE MEDIAN PRECIPITATION FOR PARTS OF THE SOUTHEAST ARE INDICATED BY EL NINO COMPOSITES. INCREASED CHANCES OF ABOVE MEDIAN PRECIPITATION CONTINUE FOR FLORIDA AND PARTS OF THE SOUTHEAST IN THE NEXT TWO LEADS, AND FOR SMALL AREAS OF TEXAS, NEW MEXICO AND COLORADO INTO AMJ AND TEXAS IN MJJ, CONSISTENT WITH EL NINO COMPOSITES. FROM JJA 2010 THROUGH ASO 2010, DECADAL TRENDS IN PRECIPITATION PRODUCE INCREASED CHANCES OF BELOW MEDIAN PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST AND ABOVE MEDIAN PRECIPITATION FOR AREAS OF THE CENTRAL PLAINS. FROM JAS THROUGH SON, DECADAL TRENDS INDICATE ENHANCED CHANCES OF ABOVE MEDIAN PRECIPITATION FOR PARTS OF FLORIDA AND THE SOUTHEAST. DECADAL PRECIPITATION TRENDS INDICATE INCREASED LIKELIHOOD OF BELOW MEDIAN PRECIPITATION FOR THE SOUTHEAST FROM DJF INTO MAM 2011, AND FOR THE SOUTH COAST OF ALASKA FOR FMA AND MAM 2011. 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 THU MAR 18 2010 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE. $$