PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 
830AM EST THURSDAY JAN 17 2013 
 
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 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 
(CFSV2). 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 OUR 
FORECAST TOOLS. 
 
ATMOSPHERIC AND OCEANIC OBSERVATIONS FROM DECEMBER AND EARLY JANUARY CONTINUE 
TO INDICATE ENSO NEUTRAL CONDITIONS. MODEL PREDICTION OF SEA SURFACE 
TEMPERATURES (SSTS) IN THE EQUATORIAL EAST-CENTRAL PACIFIC OCEAN CURRENTLY 
SUGGEST THAT THE SSTS WILL BE CLOSE TO LONG TERM AVERAGES FOR THE NEXT FEW 
MONTHS, FAVORING A CONTINUATION OF ENSO NEUTRAL CONDITIONS THROUGH THE SPRING 
OF 2013. THERE IS CURRENTLY NO CLEAR CONSENSUS FOR THE ENSO STATE BEYOND LATE 
SPRING. 
 
THE SEASONAL TEMPERATURE OUTLOOK FOR FMA 2013 INDICATES ENHANCED CHANCES FOR 
ABOVE NORMAL TEMPERATURES OVER THE NORTHEASTERN-, SOUTH-CENTRAL AND 
SOUTHWESTERN STATES. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE 
PACIFIC NORTHWEST AND NORTHERN GREAT PLAINS, AS WELL AS FOR SOUTHERN ALASKA 
INCLUDING THE PANHANDLE. 
 
THE FMA 2013 PRECIPITATION OUTLOOK FAVORS ABOVE-MEDIAN PRECIPITATION FROM NORTH 
DAKOTA EASTWARD AND SOUTHEASTWARD ACROSS THE UPPER MISSISSIPPI VALLEY AND UPPER 
GREAT LAKES REGION TO ILLINOIS, INDIANA, AND NORTHWESTERN OHIO, AND FOR MUCH OF 
THE ALASKA PANHANDLE. THE ODDS OF BELOW MEDIAN PRECIPITATION AMOUNTS ARE 
ELEVATED FOR THE SOUTHWESTERN QUARTER OF THE CONUS, AND CONTINUING EASTWARD 
ACROSS THE GULF COAST STATES. 
 
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 
 
EQUATORIAL SSTS ARE SLIGHTLY ABOVE AVERAGE IN THE WESTERN PACIFIC, CLOSE TO 
LONG TERM AVERAGES THROUGHOUT THE CENTRAL PACIFIC, AND SLIGHTLY BELOW AVERAGE 
IN THE EASTERN EQUATORIAL PACIFIC OCEAN. MOST OF THE ANOMALIES ARE WITHIN ONE 
CENTIGRADE DEGREE OF NORMAL. SST ANOMALIES IN THE NEAR-EQUATORIAL EAST-CENTRAL 
PACIFIC (NINO 3.4 REGION) HAVE SWITCHED SIGN SINCE MID-NOVEMBER 2012, WITH THE 
CURRENT WEEKLY NINO 3.4 INDEX NEAR -0.6 C. ANOMALIES IN HEAT CONTENT IN THE 
UPPER LEVELS OF THE EQUATORIAL PACIFIC OCEAN HAVE ALSO TRENDED DOWNWARD DURING 
THE MONTH OF DECEMBER. AT THE START OF DECEMBER, HEAT CONTENT ANOMALIES WERE 
NEAR ZERO. CURRENTLY THEY ARE ABOUT -0.35 C BELOW AVERAGE. UPPER- AND 
LOWER-LEVEL WINDS AVERAGED CLOSE TO NORMAL DURING DECEMBER. TROPICAL CONVECTION 
WAS ENHANCED OVER THE FAR WESTERN PACIFIC OCEAN AND INDONESIA REGION, AND 
SUPPRESSED OVER THE CENTRAL EQUATORIAL PACIFIC NEAR THE DATE LINE, AND HAS BEEN 
INFLUENCED BY THE RECENT MJO ACTIVITY. 
 
PROGNOSTIC DISCUSSION OF SST FORECASTS 
 
ENSO-NEUTRAL CONDITIONS ARE FORECAST TO CONTINUE WELL INTO BOREAL SPRING 2013. 
THE CFSV2 NINO 3.4 SST ANOMALY FORECAST IS ONCE AGAIN ON THE COOL END OF 
AVAILABLE DYNAMICAL AND STATISTICAL PREDICTIONS, WITH AN ENSEMBLE MEAN NEAR 
-0.25 DEGREES C FOR FMA AND MAM 2013. MOST OF THE SUITE OF DYNAMICAL AND 
STATISTICAL MODELS PREDICT NINO 3.4 SSTS BETWEEN -0.25 C AND +0.50 C FOR THE 
NEXT SEVERAL SEASONS (THROUGH MJJ). A STATISTICAL CONSOLIDATION OF TOOLS RUN AT 
NCEP INDICATES SLIGHTLY NEGATIVE NINO 3.4 SST ANOMALIES THROUGH SPRING, WHILE 
THE NMME ENSEMBLE MEAN STARTS WITH SLIGHTLY NEGATIVE SST ANOMALIES AND ENDS 
WITH SLIGHTLY POSITIVE SST ANOMALIES BY THE END OF SPRING. THERE IS A LARGE 
AMOUNT OF SPREAD AMONG THE VARIOUS MODELS BEYOND MJJ 2013. THUS THE SST 
FORECASTS SUPPORT ENSO NEUTRAL CONDITIONS WELL INTO THE UPCOMING SPRING, 
FOLLOWED BY UNCERTAIN CONDITIONS IN THE ENSO STATE BEYOND THAT TIME. 
 
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS 
 
FORECASTS WERE MADE WITH THE EXPECTATION OF ENSO NEUTRAL CONDITIONS WELL INTO 
BOREAL SPRING. THE FORECASTS WERE MAINLY BASED ON DYNAMICAL MODEL OUTPUT FROM 
THE CFSV2, NMME AND IMME FROM FMA THROUGH MJJ 2013, WITH SOME INPUT FROM 
STATISTICAL FORECAST TOOLS, LONG-TERM TRENDS AND THE CON WHERE DEEMED HELPFUL. 
LONGER LEAD OUTLOOKS WERE BASED ON THE CON FROM JJA 2013 ONWARDS, WHICH 
PRIMARILY REFLECTS TRENDS. ENSO-NEUTRAL COMPOSITES DURING NEGATIVE PDO PERIODS 
WERE ALSO CONSIDERED. 
 
PROGNOSTIC DISCUSSION OF OUTLOOKS - FMA 2013 TO FMA 2014 
 
TEMPERATURE 
 
THE TEMPERATURE OUTLOOK FOR FMA 2013 INDICATES ENHANCED ODDS FOR ABOVE NORMAL 
TEMPERATURES FOR NORTHEASTERN-, SOUTH-CENTRAL AND SOUTHWESTERN PORTIONS OF THE 
CONUS. BELOW NORMAL TEMPERATURES ARE FAVORED FROM MUCH OF THE PACIFIC NORTHWEST 
ACROSS THE FAR NORTHERN ROCKIES AND ACROSS THE NORTHERN GREAT PLAINS, AND FOR 
THE SOUTHERN HALF OF ALASKA INCLUDING THE ALASKAN PANHANDLE. THIS FORECAST WAS 
PRIMARILY BASED ON DYNAMICAL MODEL PREDICTIONS FROM THE CFSV2, THE NMME AND THE 
IMME, AND TO SOME EXTENT THE CON TOOL. THE CFSV2 AND NMME SOLUTIONS INDICATE 
CONSIDERABLE UNCERTAINTY IN THE FMA TEMPERATURE OUTLOOK FOR A LARGE PORTION OF 
THE EASTERN CONUS. THIS MAY BE DUE, IN PART, TO ENHANCED CHANCES OF HIGH 
LATITUDE BLOCKING AND A NEGATIVE AO/NAO DURING MUCH OF FEBRUARY, THE FIRST 
MONTH IN THE THREE MONTH SEASON. IN CONTRAST, THE IMME AND THE CON PREDICT 
ENHANCED ODDS OF ABOVE NORMAL TEMPERATURES ACROSS THE EASTERN CONUS, WHICH IS 
CONSIDERED TO BE TOO RISKY GIVEN THE RECENT SUDDEN STRATOSPHERIC WARMING AND 
HISTORICAL TENDENCY FOR HIGH-LATITUDE BLOCKING TO OFTEN FOLLOW IN THE WEEKS 
AHEAD. THE AREAS HIGHLIGHTED FAVORING BELOW NORMAL TEMPERATURES ACROSS THE 
NORTH-CENTRAL AND NORTHWESTERN CONUS AND SOUTHERN ALASKA ARE CONSISTENT WITH 
NEGATIVE PDO PHASE COMPOSITES. THIS LENDS SOME ADDITIONAL CONFIDENCE BEYOND 
WHAT WOULD ORDINARILY BE EXPECTED OF A SEASONAL FORECAST DURING ENSO-NEUTRAL 
CONDITIONS. 
 
SEASONAL FORECASTS FROM THE NMME, IMME, CFSV2 (AND TO A LESSER EXTENT THE CON) 
INDICATE ENHANCED CHANCES FOR ABOVE NORMAL TEMPERATURES THROUGHOUT MOST OF THE 
SOUTHERN AND EASTERN CONUS DURING MAM 2013, WITH PREDICTED AREAS OF BELOW 
NORMAL TEMPERATURES GRADUALLY RECEDING AND AREAS OF ABOVE NORMAL TEMPERATURES 
GRADUALLY EXPANDING IN COVERAGE BY MJJ. WITH THE START OF THE GROWING SEASON IN 
MARCH AND APRIL, SOIL MOISTURE CONSIDERATIONS BECOME INCREASINGLY IMPORTANT. 
SOIL MOISTURE IS CURRENTLY VERY LOW ACROSS THE SOUTHERN PLAINS, AND WITH 
ELEVATED CHANCES OF BELOW MEDIAN PRECIPITATION AMOUNTS PREDICTED FOR THE 
REMAINDER OF WINTER, IT APPEARS THAT DRY SOIL MOISTURE CONDITIONS WILL PERSIST 
INTO THE SPRING. PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE MAXIMIZED OVER 
THIS REGION DURING MAM AND ESPECIALLY AMJ, BASED ON SOIL MOISTURE EXPECTATIONS. 
FOR JJA AND BEYOND, FORECASTS ARE LARGELY SIMILAR TO THOSE ISSUED LAST MONTH, 
AND ARE PREDOMINATELY DETERMINED BY LONG-TERM TRENDS. 
 
IN AREAS WITHOUT STRONG OR RELIABLE CLIMATE SIGNALS, EQUAL CHANCES FOR 
BELOW-NORMAL, NEAR-NORMAL, OR ABOVE-NORMAL SEASONAL MEAN TEMPERATURES IS 
PREDICTED. 
 
PRECIPITATION 
 
THE PRECIPITATION OUTLOOK FOR FMA 2013 INDICATES ELEVATED CHANCES FOR BELOW 
MEDIAN PRECIPITATION AMOUNTS OVER THE SOUTHWESTERN QUARTER OF THE CONUS, 
CONTINUING EASTWARD ACROSS THE GULF COAST STATES. THERE ARE ELEVATED ODDS OF 
ABOVE MEDIAN PRECIPITATION ACROSS NORTH DAKOTA, THE UPPER MISSISSIPPI VALLEY 
AND UPPER GREAT LAKES REGION, AND EASTERN SECTIONS OF THE CORN BELT. ABOVE 
MEDIAN PRECIPITATION IS ALSO FAVORED OVER THE ALASKA PANHANDLE. THE FMA 
PRECIPITATION OUTLOOK IS PRIMARILY BASED ON THE CFSV2 MODEL, THE NMME, THE 
IMME, AND TO A LESSER EXTENT THE CON. A SIMILAR PATTERN IS FORECAST FOR MAM 
2013, BUT FOR SUBSEQUENT SEASONS THE FAVORED AREA OF ABOVE MEDIAN PRECIPITATION 
DROPS OUT, WITH EC DEEMED THE BEST BET. BY JJA, THE ONLY RELIABLE SIGNAL IS FOR 
ENHANCED ODDS OF BELOW MEDIAN PRECIPITATION ACROSS THE PACIFIC NORTHWEST, DUE 
PRIMARILY TO LONGER-TERM TRENDS. IT IS DIFFICULT TO EXTRACT USEFUL SIGNALS 
ELSEWHERE, MAINLY BECAUSE OF THE UNCERTAINTY REGARDING THE ENSO STATE AFTER THE 
SPRING SEASON. FROM SON TO DJF 2013/14, THERE ARE NO RELIABLE INDICATIONS 
FAVORING ONE TERCILE OVER ANOTHER, SO EC IS PREDICTED FOR THE ENTIRE NATION. 
BEYOND THIS, LONGER-TERM TRENDS BEGIN TO FAVOR INCREASED ODDS OF BELOW MEDIAN 
PRECIPITATION ACROSS THE SOUTHEAST. 
 
IN AREAS WITHOUT STRONG OR RELIABLE CLIMATE SIGNALS, EQUAL CHANCES FOR BELOW, 
NEAR, OR ABOVE-MEDIAN SEASONAL PRECIPITATION AMOUNTS IS PREDICTED. 
 
FORECASTER: ANTHONY ARTUSA 
 
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 FEB 21 2013 
 
 
1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 
FORECAST RELEASE. 
$$