PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300PM EDT THURSDAY MAR 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. EL NINO CONDITIONS CONTINUE ACROSS THE TROPICAL PACIFIC. THE MOST RECENT MONTHLY SEA SURFACE TEMPERATURE DEPARTURES FROM NORMAL RANGE FROM +1.0 TO +2.0 C ABOVE NORMAL ACROSS MANY AREAS IN THE EQUATORIAL CENTRAL AND EASTERN PACIFIC. ATMOSPHERIC CONDITIONS ARE ALSO CONSISTENT WITH AN ESTABLISHED EL NINO EVENT. THE AMJ 2010 TEMPERATURE OUTLOOK INDICATES THAT ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN U.S. AND ALASKA WITH ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES FOR PORTIONS OF THE NORTHERN AND SOUTHERN GREAT PLAINS AND GULF COAST. THE CHANCES OF ABOVE MEDIAN SEASONAL TOTAL PRECIPITATION DURING AMJ 2010 ARE GREATER THAN CLIMATOLOGY FOR PARTS OF THE SOUTHEAST U.S., EAST-CENTRAL ROCKIES AND WEST-CENTRAL GREAT PLAINS. IN LOCATIONS WHERE THE LIKELIHOOD SEASONAL MEAN TEMPERATURE AND SEASONAL TOTAL PRECIPITATION IS SIMILAR TO THE CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES 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 SEA SURFACE TEMPERATURE (SST) ANOMALIES REMAIN ABOVE-NORMAL ACROSS MANY AREAS OF THE EQUATORIAL PACIFIC OCEAN. ALTHOUGH POSITIVE SST DEPARTURES HAVE DECREASED SOME IN RECENT WEEKS, A LARGE AREA OF +1.0 - +2.0 DEGREE C ANOMALIES REMAIN FROM 170 E TO 120 W AND IN AREAS NEAR THE CENTRAL AND SOUTH AMERICA COASTS. THERE IS ALSO A SMALLER AREA OF SST DEPARTURES OVER +2.0 C NEAR THE DATE LINE. AT DEPTH, POSITIVE OCEAN TEMPERATURE ANOMALIES WELL OVER +1.0 C ARE ALSO EVIDENT IN MANY AREAS FROM 170 E TO 110 W TO A DEPTH OF 100 M. THE GREATEST SUB-SURFACE ANOMALIES APPROACH VALUES CLOSE TO +6.0 C IN PROXIMITY TO THE LATEST DOWNWELLING OCEANIC KELVIN WAVE. BELOW NORMAL TEMPERATURE DEPARTURES ARE CONFINED TO THE WESTERN PACIFIC FROM 130 E TO 170 W AT A DEPTH OF GREATER THAN 50 M. ATMOSPHERIC CONDITIONS ARE ALSO CONSISTENT WITH EL NINO. ENHANCED CONVECTION IS OBSERVED ACROSS MUCH OF THE EQUATORIAL CENTRAL PACIFIC OCEAN WITH SUPPRESSED CONVECTION ANCHORED OVER THE MARITIME CONTINENT AND FAR WESTERN PACIFIC. IN RECENT WEEKS, ENHANCED CONVECTION HAS ALSO INCREASED ACROSS MANY AREAS IN THE EASTERN PACIFIC CLOSER TO CENTRAL AND SOUTH AMERICA. LOW-LEVEL WESTERLY WIND ANOMALIES ARE OBSERVED OVER PORTIONS OF THE WEST-CENTRAL AND EASTERN PACIFIC DURING THE LAST 30 DAYS, WHILE UPPER-LEVEL EASTERLY WIND ANOMALIES ARE EVIDENT ACROSS THE EAST-CENTRAL PACIIFC. PROGNOSTIC DISCUSSION OF SST FORECASTS BIAS-CORRECTED FORECASTS FROM THE NCEP CLIMATE FORECAST SYSTEM (CFS) DYNAMICAL COUPLED OCEAN-ATMOSPHERE MODEL INDICATE THAT EL NINO WILL CONTINUE INTO THE AMJ 2010 SEASON AS SHOWN BY THE SEASONAL MEAN NINO 3.4 INDEX. THEREAFTER THE CFS FORECASTS THE SEASONAL MEAN NINO 3.4 INDEX TO FALL BELOW +0.5 C DURING MJJ 2010. THE CPC SST CONSOLIDATION FORECAST (AN OBJECTIVE, SKILL WEIGHTED COMBINATION OF THE CFS AND THREE STATISTICAL SST FORECASTS) INDICATES A SEASONAL MEAN NINO 3.4 SST ANOMALY FORECAST OF +0.6 C IN AMJ 2010 DECREASING TO NEAR +0.4 BY MJJ 2010. SUBSEQUENT VALUES GENERALLY RANGE BETWEEN +0.3 TO +0.4 C FROM JJA 2010 TO DJF 2011. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS THE CPC CONSOLIDATION (A SKILL-WEIGHTED AND CALIBRATED-PROBABILITY FORECAST DERIVED FROM THE CFS, SMLR, OCN, ECCA AND CCA FORECAST TOOLS) WAS THE PRIMARY TOOL USED FOR THE MAJORITY OF THE SEASONAL TEMPERATURE AND PRECIPITATION OUTLOOKS AND ACTED AS A BACKGROUND FIRST GUESS FORECAST. ALTHOUGH THERE IS AN EXPECTATION OF A WEAKENING EL NINO, EL NINO COMPOSITES WERE UTILIZED DURING THE AMJ 2010 AND MJJ 2010 SEASONS AS THERE IS OFTEN A LAG IN ATMOSPHERIC CONDITIONS DURING CHANGES IN THE OCEAN. DURING THE FIRST TWO LEADS (AMJ 2010 AND MJJ 2010), CURRENT SNOW DEPTH, SOIL MOISTURE AND SST CONDITIONS WERE USED IN SOME AREAS TO MODIFY THE FORECAST. ALSO, THE CFS TEMPERATURE AND PRECIPITATION FORECASTS WERE USED IN SOME AREAS UP TO AND INCLUDING ASO 2010. THE TEMPERATURE AND PRECIPITATION OUTLOOKS FROM ASO 2010 THROUGH AMJ 2011 ARE BASED ON THE CPC CONSOLIDATION FORECAST. PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2010 TO AMJ 2011 TEMPERATURE THE TEMPERATURE OUTLOOKS FOR AMJ AND MJJ 2010 INDICATE THAT THE CHANCES OF BELOW NORMAL TEMPERATURES ARE ELEVATED OVER THEIR CLIMATOLOGICAL PROBABILITY FOR PARTS OF THE NORTHERN AND SOUTHERN GREAT PLAINS AND THE GULF COAST. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE WESTERN THIRD OF THE CONUS AND ALASKA. ANOMALOUS SNOW DEPTHS IN THE NORTHERN PLAINS AND THE SUBSEQUENT EXPECTED ABOVE NORMAL SOIL MOISTURE, EL NINO COMPOSITES AND DECADAL TEMPERATURE TRENDS CONTRIBUTE TO THE FORECAST OF ENHANCED CHANCES FOR BELOW NORMAL TEMPERATURES FOR THE NORTHERN PLAINS. FOR THE SOUTHERN PLAINS, A COMBINATION OF DYNAMICAL MODEL FORECASTS, ABOVE NORMAL SOIL MOISTURE AND TO A LESSER DEGREE EL NINO COMPOSITES SUPPORT ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES. BELOW NORMAL TEMPERATURES ARE FAVORED ALONG THE GULF COAST DURING AMJ 2010 DUE TO SUBSTANTIALLY BELOW-NORMAL CURRENTLY OBSERVED SSTS AND INDICATORS FROM SOME DYNAMICAL MODEL FORECASTS. FOR THE WESTERN CONUS, ABOVE-NORMAL TEMPERATURES ARE FAVORED WITH THE HIGHEST PROBABILITY ACROSS THE PACIFIC NORTHWEST DURING AMJ 2010 WHERE BELOW-NORMAL SNOWPACK, DYNAMICAL MODEL FORECASTS, LONG-TERM TRENDS AND EL NINO COMPOSITES ALL SUPPORT WARMER THAN AVERAGE CONDITIONS. ALTHOUGH INDICATORS FROM SEVERAL OF THE STATISTICAL FORECAST TOOLS SHOW A STRONG SIGNAL FOR ABNORMAL WARMTH ACROSS THE SOUTHWEST U.S., THE FORECAST PROBABILITIES ARE TEMPERED SOMEWHAT BASED ON ANOMALOUSLY HIGH SNOWPACK IN SOME AREAS AND SOME DYNAMICAL MODEL FORECASTS. BELOW-NORMAL SSTS OFF THE SOUTHERN CALIFORNIA AND SOUTHWEST ALASKA COASTS RESULT IN A FORECAST FOR EQUAL CHANCES FOR ABOVE-, BELOW-, OR NEAR-NORMAL TEMPERATURES IN THESE AREAS. NO SUBSTANTIAL CLIMATE SIGNALS ARE PRESENT FROM THE FORECAST TOOLS ACROSS THE REMAINDER OF THE U.S. SO CLIMATOLOGICAL PROBABILITIES FOR THE THREE CATEGORIES ARE INDICATED. THE LATER LEADS FROM JJA 2010 TO AMJ 2011 ARE LARGELY BASED ON THE CON WITH MOST OF THE PREDICTABILITY OF SEASONAL MEAN TEMPERATURES ARISING FROM RECENT TRENDS. FOR THE JJA 2010 TO ASO 2010 SEASONS, ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE WESTERN CONUS, PARTS OF ALASKA AND THE SOUTHEAST U.S.. ELEVATED CHANCES FOR BELOW-NORMAL TEMPERATURES ARE INDICATED DURING JJA 2010 ACROSS PARTS OF THE UPPER-MISSISSIPPI VALLEY MAINLY AS A RESULT OF DYNAMICAL MODEL FORECASTS. INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE EXPECTED PRIMARILY ACROSS THE SOUTHWEST U.S. AND PARTS OF THE GREAT LAKES AND NORTHEAST DURING SON 2010 THROUGH NDJ 2010. THEREAFTER THROUGH AMJ 2011, INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED ACROSS THE SOUTHWEST U.S. AND PARTS OF ALASKA, WITH ELEVATED CHANCES OF BELOW-NORMAL TEMPERATURES FOR PARTS OF THE WEST COAST DURING SON 2010 AND NORTHERN PLAINS IN AMJ 2011. PRECIPITATION THE PRECIPITATION OUTLOOK FOR AMJ 2010 INDICATES INCREASED CHANCES FOR ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE WEST-CENTRAL PLAINS, EAST-CENTRAL ROCKIES AND SOUTHEAST U.S.. EL NINO COMPOSITES ARE THE PRIMARY DRIVERS FOR THE HIGHLIGHTED AREA ACROSS THE SOUTHEAST U.S., WHILE THE CFS AND CON FORECAST TOOLS SUPPORT ENHANCED CHANCES FOR WETTER-THAN-NORMAL CONDITIONS FOR THE WESTERN AREA. NO SUBSTANTIAL CLIMATE SIGNALS ARE PRESENT FROM THE FORECAST TOOLS ACROSS THE REMAINDER OF THE U.S. SO CLIMATOLOGICAL PROBABILITIES FOR ABOVE-, NEAR- AND BELOW-MEDIAN PRECIPITATION ARE INDICATED. FOR MJJ 2010, EL NINO COMPOSITES, SOIL MOISTURE CONSIDERATIONS AND DYNAMICAL MODEL FORECASTS SUPPORT ENHANCED CHANCES FOR ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE CENTRAL AND SOUTHERN PLAINS AND SOUTHEAST U.S. FROM JJA 2010 THROUGH AMJ 2011, THE CON WAS THE PRIMARY BASIS FOR THE FORECASTS WITH THE STRONGEST INFLUENCE FROM LONG-TERM TRENDS AND STATISTICAL FORECAST TOOLS. SOME NOTABLE HIGHLIGHTED AREAS INCLUDE ENHANCED CHANCES FOR BELOW-MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST AND ABOVE-MEDIAN PRECIPITATION FOR PARTS OF THE CENTRAL AND NORTHERN PLAINS FROM JJA 2010 THROUGH ASO 2010. DECADAL PRECIPITATION TRENDS INDICATE AN INCREASED LIKELIHOOD OF BELOW MEDIAN PRECIPITATION FOR THE SOUTHEAST FROM DJF 2011 TO MAM 2011, AND FOR THE SOUTH COAST OF ALASKA FROM FMA 2011 TO AMJ 2011. NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES). FORECASTER: JON GOTTSCHALCK 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 15 2010 1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 FORECAST RELEASE. 17888