PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
830 AM EST THU JAN 21 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.

STRONG EL NINO CONDITIONS CURRENTLY EXIST IN THE TROPICAL PACIFIC. THIS WARM 
EVENT IS EXPECTED TO PERSIST (THOUGH GRADUALLY WEAKEN) INTO AT LEAST EARLY 
BOREAL SPRING 2010, AND IS ANTICIPATED TO HAVE A SIGNIFICANT IMPACT ON THE US 
SURFACE TEMPERATURE AND PRECIPITATION FORECASTS INTO THE APR-MAY-JUN (AMJ) 2010 
SEASON. THE IMPACT OF EL NINO ON THE CLIMATE OVER NORTH AMERICA IS USUALLY 
GREATEST DURING THE LATE WINTER SEASON. MANY PREDICTION TOOLS INDICATE THAT THE 
EL NINO IS CURRENTLY NEAR ITS MAXIMUM STRENGTH AND WILL DIMINISH SLIGHTLY IN 
THE NEXT FEW MONTHS. THOUGH SOME MODELS PREDICT THAT THIS WARM EPISODE MAY 
EXTEND INTO SUMMER, IMPACTS ON THE US TEMPERATURE AND PRECIPITATION FOR LATE 
SPRING AND BEYOND, HOWEVER, ARE EXPECTED TO BE NEGLIGIBLE. 

THE TEMPERATURE OUTLOOK FOR FMA 2010 INDICATES AN ENHANCED LIKELIHOOD OF ABOVE 
NORMAL TEMPERATURES FROM MUCH OF THE WESTERN HALF OF THE CONUS ACROSS THE 
NORTHERN ROCKIES, AND CONTINUING EASTWARD ALONG THE CANADIAN BORDER TO THE 
UPPER GREAT LAKES REGION. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED OVER MOST 
OF MAINLAND ALASKA. BELOW NORMAL TEMPERATURES ARE FAVORED FROM CENTRAL NEW 
MEXICO EASTWARD ACROSS TEXAS AND THE GULF AND SOUTHERN ATLANTIC COAST STATES. 
IN LOCATIONS WHERE THE LIKELIHOOD OF ABOVE OR BELOW NORMAL SEASONAL TEMPERATURE 
IS SIMILAR TO THE CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES OF BELOW, NEAR, 
AND ABOVE NORMAL TEMPERATURES ARE INDICATED.

THE CHANCES OF BELOW MEDIAN PRECIPITATION DURING FMA 2010 ARE HIGHER THAN USUAL 
IN PARTS OF THE PACIFIC NORTHWEST, THE OHIO VALLEY, AND THE LOWER GREAT LAKES. 
THE CHANCES FOR ABOVE MEDIAN PRECIPITATION AMOUNTS ARE SIGNIFICANTLY ELEVATED 
ALONG THE SOUTHERN CONUS FROM CALIFORNIA TO THE SOUTHEAST, INCLUDING A 
NORTHWARD EXTENSION THROUGH THE CENTRAL HIGH PLAINS. IN LOCATIONS WHERE THE 
LIKELIHOOD OF ABOVE OR BELOW MEDIAN SEASONAL 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

WEEKLY SEA SURFACE TEMPERATURE (SST) ANOMALIES REMAIN SIGNIFICANTLY ABOVE 
AVERAGE NEAR THE EQUATOR THROUGHOUT THE CENTRAL AND EASTERN PACIFIC OCEAN.  
EQUATORIAL SST ANOMALIES AVERAGED OVER THE LAST 30 DAYS NOW EXCEED +2.0 DEGREES 
C ACROSS MUCH OF THE REGION BETWEEN 175 W AND 95 W, AND ARE MORE THAN +1.0 
DEGREES C ABOVE AVERAGE FROM 170 E TO ABOUT 90 W.  THE SST ANOMALIES IN THE 
NINO 3.4 REGION HAVE BEEN SLOWLY INCREASING IN RECENT WEEKS AND CURRENTLY 
AVERAGE +1.8 DEGREES C ABOVE NORMAL. THE SUBSURFACE HEAT CONTENT IS GENERALLY 
ABOVE AVERAGE IN THE UPPER 200 METERS OF THE TROPICAL PACIFIC OCEAN. THE 
POSITIVE SUBSURFACE OCEAN TEMPERATURE ANOMALIES EXTEND EASTWARD FROM 160 E TO 
NEAR THE COAST OF ECUADOR. AN AREA OF +6.0 DEGREES C ANOMALIES AT 50 METER 
DEPTH CAN BE FOUND NEAR THE SOUTH AMERICAN COAST. EQUATORIAL OUTGOING LONGWAVE 
RADIATION (OLR) ANOMALIES REFLECT EL NINO CONDITIONS, WITH SUPPRESSED 
CONVECTION (FOR THE MOST PART) OVER INDONESIA AND ENHANCED CONVECTION NEAR THE 
DATE LINE. HISTORICALLY, POSITIVE TEMPERATURE ANOMALIES IN THE UPPER PACIFIC 
OCEAN PRECEDE FURTHER DEVELOPMENT OF EL NINO EVENTS. THUS TROPICAL PACIFIC SSTS 
ARE LIKELY TO REMAIN CONSISTENT WITH MODERATE-TO-STRONG EL NINO CONDITIONS 
DURING THE NEXT FEW MONTHS.

PROGNOSTIC DISCUSSION OF SST FORECASTS

THE CURRENT MEAN PDF CORRECTED ENSEMBLE CFS FORECAST INDICATES SST ANOMALIES IN 
THE NINO 3.4 REGION ARE PRESENTLY AT A MAXIMUM JUST UNDER +2.0 DEGREES CELSIUS. 
THE PDF CORRECTED CFS ANTICIPATES A SLOW DECLINE IN SST ANOMALIES THROUGH THE 
FIRST HALF OF 2010, WITH ANOMALY VALUES REMAINING ABOVE +0.5 DEGREES C THROUGH 
JJA.  THE CPC STATISTICAL MODELS PREDICT SOMEWHAT LOWER SST ANOMALIES, WITH FMA 
DEPARTURES FORECAST TO BE ABOUT +1.1 DEGREES C ACCORDING TO THE MARKOV MODEL 
AND NEAR +0.5 DEGREES C FOR THE CANONICAL CORRELATION ANALYSIS (CCA) AND 
CONSTRUCTED ANALOG (CA) MODELS.  THE CPC CONSOLIDATION (CON) OF THESE FOUR NINO 
3.4 SST ANOMALY FORECASTS IS ABOUT +0.8 DEGREES C FOR FMA AND SHOWS A GRADUAL 
DECREASE IN SST ANOMALIES FROM CURRENT LEVELS TO AROUND +0.5 DEGREES C BY THE 
AMJ SEASON. AFTER THAT, THE CONSOLIDATION'S PREDICTED NINO 3.4 SST ANOMALIES 
DECLINE VERY SLOWLY TO +0.3 DEGREES C BY LATE SUMMER.   

PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS

THE CFS AND CON FORECASTS GENERALLY AGREE WITH HISTORICAL EL NINO COMPOSITES 
AND ARE THE PRIMARY TOOLS USED FOR THE TEMPERATURE AND PRECIPITATION OUTLOOKS 
FOR FMA, MAM, AND TO SOME DEGREE, AMJ 2010. OTHER TOOLS, SUCH AS THE IRI AND 
ECPC, ARE IN FAIRLY GOOD AGREEMENT WITH THE CFS, CON, AND ENSO COMPOSITES, AND 
HAVE ALSO BEEN USED FOR THE EARLY LEADS. THE TEMPERATURE AND PRECIPITATION 
OUTLOOKS FOR MJJ 2010 AND BEYOND ARE BASED MOSTLY ON THE CONSOLIDATION 
FORECAST, A SKILL-WEIGHTED AND CALIBRATED PROBABILISTIC FORECAST DERIVED FROM 
THE CFS, SMLR, OCN, AND CCA FORECAST TOOLS.

PROGNOSTIC DISCUSSION OF OUTLOOKS - FMA 2010 TO FMA 2011

TEMPERATURE:

THE TEMPERATURE OUTLOOKS FOR FMA AND MAM 2010 INDICATE THAT THE CHANCES OF 
BELOW NORMAL TEMPERATURES ARE ELEVATED OVER THEIR CLIMATOLOGICAL LIKELIHOOD FOR 
MUCH OF THE SOUTHERN THIRD OF THE U.S. FROM THE SOUTHERN ROCKY MOUNTAINS TO THE 
EAST COAST. ABOVE NORMAL TEMPERATURES ARE FAVORED FROM MUCH OF THE WESTERN HALF 
OF THE CONUS ACROSS THE NORTHERN AND CENTRAL ROCKIES, AND CONTINUING EASTWARD 
ALONG THE CANADIAN BORDER TO THE UPPER GREAT LAKES REGION. ABOVE NORMAL 
TEMPERATURES ARE ALSO FAVORED OVER MOST OF MAINLAND ALASKA. EL NINO 
TELECONNECTIONS BECOME STRONGER IN THE LATTER PART OF WINTER, SO THE RECENT 
COLD TEMPERATURES EXPERIENCED IN THE CENTRAL PART OF THE COUNTRY DURING THE 
FIRST HALF OF JANUARY 2010 ARE EXPECTED TO HAVE LITTLE BEARING ON MEAN 
TEMPERATURES IN LATE WINTER AND EARLY SPRING. EL NINO TELECONNECTIONS WEAKEN IN 
THE SPRINGTIME, AND TOGETHER WITH AN EXPECTED WEAKENING OF EL NINO ITSELF, 
LEAVE ONLY TREND RELATED TEMPERATURE SIGNALS FOR AMJ AND BEYOND OVER MOST OF 
THE COUNTRY EXCEPT FOR PORTIONS OF THE SOUTHERN GREAT PLAINS. BELOW NORMAL 
TEMPERATURES ARE INDICATED FOR THIS LATTER REGION IN AMJ 2010, BASED ON CFS 
GUIDANCE AND LATE SEASON ENSO COMPOSITES. A RELATIVELY SMALL AREA OF BELOW 
NORMAL TEMPERATURES IS FORECAST FOR THE CORN BELT REGION DURING MJJ, SUPPORTED 
BY THE CFS AND CON.

LONG TERM TRENDS FAVOR ABOVE NORMAL TEMPERATURES OVER MUCH OF ALASKA AND THE 
WESTERN CONUS IN LATE SPRING AND SUMMER.  ABOVE NORMAL TEMPERATURES ARE ALSO 
MORE LIKELY ALONG PARTS OF THE EASTERN SEABOARD AND GULF COAST IN SUMMER.  THE 
RELIABILITY OF TREND SIGNALS DIMINISHES IN THE FALL SEASON, WITH ABOVE NORMAL 
TEMPERATURES FAVORED ONLY IN PARTS OF THE SOUTHWESTERN AND EXTREME NORTHEASTERN 
CONUS, AND NORTHERN ALASKA BY OND. TRENDS FOR ABOVE NORMAL TEMPERATURES BECOME 
STRONG ENOUGH TO RELIABLY ALTER THE ODDS FOR MUCH OF THE CENTRAL CONUS AND IN 
PARTS OF ALASKA IN THE WINTER SEASON 2010-2011.

PRECIPITATION:

THE PRECIPITATION OUTLOOKS FOR FMA AND MAM 2010 ARE BASED ON THE CFS, THE CON, 
AND ON THE EXPECTED IMPACTS OF AN EL NINO EVENT, AS DEPICTED BY EL NINO 
COMPOSITES.  THESE TOOLS INDICATE AN AREA OF ENHANCED PROBABILITY OF BELOW 
MEDIAN PRECIPITATION FOR THE PACIFIC NORTHWEST DURING FMA 2010, AND INTO MAM 
2010, AS EXPECTED IN EL NINO WINTERS. BELOW MEDIAN PRECIPITATION AMOUNTS ARE 
ALSO FAVORED FOR MUCH OF THE OHIO VALLEY AND LOWER GREAT LAKES DURING FMA 2010, 
LARGELY DUE TO EL NINO.  THE CHANCES FOR ABOVE MEDIAN PRECIPITATION ARE 
ELEVATED FOR MUCH OF THE SOUTHERN U.S., EXTENDING INTO THE CENTRAL HIGH PLAINS 
DURING FMA.  THE SIGNAL IS STRONGEST IN PARTS OF THE SOUTHWESTERN U.S., SOUTH 
TEXAS, AND FLORIDA.  THIS IS MAINLY A RESULT OF AN EXPECTED ENHANCED SOUTHERN 
JET STREAM ASSOCIATED WITH EL NINO.  THE EL NINO SIGNAL FADES IN MAM AND IS 
EXPECTED TO HAVE NEGLIGIBLE IMPACTS OVER THE US BY AMJ.  IF THIS WARM EVENT 
HOLDS ON LATER THAN EXPECTED, THE ABOVE MEDIAN PRECIPITATION MAY PERSIST NEAR 
THE SOUTHERN HIGH PLAINS INTO AMJ 2010. 

THE OUTLOOKS FOR AMJ AND BEYOND ARE BASED ON LONG TERM PRECIPITATION TRENDS, 
WHICH ARE VERY WEAK IN COMPARISON TO NORMAL YEAR-TO-YEAR VARIABILITY. MOST OF 
THE U.S. SHOWS EQUAL CHANCES OF BELOW, NEAR, OR ABOVE MEDIAN PRECIPITATION 
AMOUNTS FOR MOST SEASONS. THERE IS SOME TENDENCY FOR DRY LATE SUMMER CONDITIONS 
IN THE PACIFIC NORTHWEST, AND ENHANCED CHANCES FOR ABOVE MEDIAN PRECIPITATION 
IN PARTS OF THE SOUTHEASTERN CONUS.  THESE SIGNALS ARE EVIDENT IN THE CON 
FORECAST.  EARLY FALL PRECIPITATION TRENDS FAVOR THE ABOVE MEDIAN CATEGORY FOR 
PARTS OF THE CENTRAL HIGH PLAINS. LONG TERM PRECIPITATION TRENDS ELEVATE THE 
CHANCES OF BELOW MEDIAN PRECIPITATION IN THE SOUTHEASTERN STATES FOR THE DJF 
2010-2011 AND JFM 2011 OUTLOOKS.

NOTE - AREAS OF UNCERTAINTY THAT FORMERLY WERE LABELED CL (CLIMATOLOGICAL 
PROBABILITIES) ARE NOW LABELED EC (EQUAL CHANCES).

FORECASTER: ANTHONY ARTUSA

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 FEB 18 2010

1971-2000 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 17, 2001 
FORECAST RELEASE.

$$