PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 
300PM EST SATURDAY JAN 31 2015 
 
30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2015 
 
THE FEBRUARY 2015 MONTHLY OUTLOOK INCORPORATES GUIDANCE FROM THE NCEP CLIMATE 
FORECAST SYSTEM (CFS), THE NCEP GLOBAL ENSEMBLE FORECAST SYSTEM (GEFS) 
CALIBRATED USING RETROSPECTIVE FORECASTS FOR 1985-2010 GENERATED BY THE NOAA 
EARTH SYSTEM RESEARCH LABORATORY (ESRL), AND THE NORTH AMERICAN ENSEMBLE 
FORECAST SYSTEM (NAEFS, A MULTI-MODEL ENSEMBLE THAT COMBINES BIAS-CORRECTED 
OUTPUT FROM THE NCEP GEFS AND THE ENVIRONMENT CANADA ENSEMBLE PREDICTION 
SYSTEM). THE FEBRUARY OUTLOOK ALSO CONSIDERS GFS AND ECMWF TEMPERATURE AND 
PRECIPITATION FORECASTS FOR VARIOUS TIME SCALES OUT TO ONE MONTH IN ADVANCE. 
 
THE UPDATED OUTLOOK FOR FEBRUARY 2015 IS SIGNIFICANTLY DIFFERENT FROM THE 
PREVIOUS 0.5-MONTH LEAD OUTLOOK ISSUED ON JANUARY 15. THIS IS DUE TO LARGE 
DIFFERENCES BETWEEN THE VARIOUS DYNAMICAL MODEL INPUTS, AND THE CONTINUING 
UNCERTAINTY REGARDING POSSIBLE ENSO IMPACTS. 
 
THE TEMPERATURE OUTLOOK FOR FEBRUARY 2015 PREDICTS ENHANCED CHANCES OF 
ABOVE-NORMAL MEAN TEMPERATURES FOR THE NORTHERN HALF OF THE GREAT PLAINS, AND 
ALL AREAS WEST OF THE CONTINENTAL DIVIDE, WITH PROBABILITIES FOR RELATIVE 
WARMTH EXCEEDING 50-PERCENT IN THE GREAT BASIN. ABOVE-NORMAL MEAN TEMPERATURES 
ARE ALSO FAVORED ALONG THE ALASKA COAST FROM PRINCE WILLIAM SOUND IN 
SOUTH-CENTRAL ALASKA TO KETCHIKAN IN THE FAR SOUTHERN PANHANDLE. MOST OF THE 
MODELS AND TOOLS SUPPORT THESE AREAS. WITH THE MOST RECENT MODEL GUIDANCE FOR 
THE REMAINDER OF ALASKA CONFLICTING WITH THE AVAILABLE GUIDANCE FROM TWO WEEKS 
AGO, IT WAS NECESSARY TO CHANGE THE ALASKA TEMPERATURE OUTLOOK SIGNIFICANTLY, 
FROM ENHANCED ODDS OF ABOVE-NORMAL TEMPERATURES TO EQUAL CHANCES (EC). THERE 
ARE ENHANCED ODDS OF BELOW-NORMAL TEMPERATURES FOR MUCH OF THE EASTERN THIRD OF 
THE CONUS. THIS PREDICTION IS ALSO WELL SUPPORTED BY MOST TOOLS, AND IS 
CONSISTENT WITH THE IDEA OF A PERSISTENT, LARGE-SCALE TROUGH DOMINATING THE 
MID-TROPOSPHERIC CIRCULATION IN THE EAST. THE PREVIOUSLY ISSUED AREAS OF 
FAVORED BELOW-NORMAL TEMPERATURES (SOUTHERN PLAINS) AND ABOVE-NORMAL 
TEMPERATURES (FLORIDA) HAVE BEEN REMOVED IN FAVOR OF EC, DUE TO WEAK AND/OR 
CONFLICTING SIGNALS AMONG THE MODELS. 
 
THE PRECIPITATION OUTLOOK FOR FEBRUARY 2015 FAVORS ABOVE-MEDIAN PRECIPITATION 
ALONG THE ALASKA COAST FROM ABOUT PRINCE WILLIAM SOUND TO KETCHIKAN, AND ALONG 
THE PACIFIC NORTHWEST COAST AS FAR SOUTH AS NORTHWESTERN CALIFORNIA. 
ABOVE-MEDIAN PRECIPITATION IS ALSO FAVORED ACROSS A PORTION OF THE SOUTHEASTERN 
CONUS. THERE IS NEARLY UNANIMOUS AGREEMENT AMONG THE VARIOUS CLIMATE MODELS FOR 
THE FIRST AREA MENTIONED. WHILE THE SECOND AREA (SOUTHEASTERN CONUS) DOES HAVE 
SOME OBJECTIVE SUPPORT, IT ALSO COINCIDES WITH THE PREDICTED SOUTHERN PORTION 
OF THE EASTERN CONUS TROUGH, ON AVERAGE, AND IS THE MOST LIKELY LOCATION TO 
RECEIVE PRECIPITATION. THE AREA OF FAVORED ABOVE-MEDIAN PRECIPITATION FROM 
SOUTHERN CALIFORNIA EASTWARD TO THE SOUTHERN GREAT PLAINS WITH THE PREVIOUS 
OUTLOOK WAS REMOVED DUE TO WEAK AND/OR CONFLICTING INDICATIONS AMONG THE LATEST 
MODEL GUIDANCE. THE SAME IS TRUE FOR THE AREA OF FAVORED BELOW-MEDIAN 
PRECIPITATION OVER THE INTERIOR NORTHWEST AND NORTHERN ROCKIES. 
 
IN AREAS WHERE CLIMATE SIGNALS ARE WEAK OR CONFLICTING, SUCH THAT THE 
LIKELIHOODS OF MONTHLY MEAN TEMPERATURES OR MONTHLY ACCUMULATED PRECIPITATION 
AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS 
INDICATED. 
 
------- THE PREVIOUS DISCUSSION, ISSUED JANUARY 15, FOLLOWS BELOW -------- 
 
THE FEBRUARY 2015 OUTLOOK REFLECTS A FAIRLY HIGH AMOUNT OF UNCERTAINTY, GIVEN 
SIGNIFICANT DIFFERENCES AMONG VARIOUS CLIMATE MODELS, AND THE CONTINUED LACK OF 
A ROBUST ATMOSPHERIC RESPONSE TO THE NEAR- TO ABOVE-AVERAGE EQUATORIAL PACIFIC 
SSTS. 
 
DURING THE PAST 4 WEEKS, EQUATORIAL SEA-SURFACE TEMPERATURES (SST) WERE 
ABOVE-AVERAGE ACROSS MOST OF THE PACIFIC, THOUGH THE ANOMALIES HAVE RECENTLY 
WEAKENED. THE LATEST WEEKLY NINO 3.4 INDEX IS +0.4 C. POSITIVE SUBSURFACE 
TEMPERATURE ANOMALIES HAVE PERSISTED ACROSS MOST OF THE CENTRAL AND EASTERN 
EQUATORIAL PACIFIC SINCE MID-NOVEMBER, TO A DEPTH OF 50-100 METERS. WHILE 
OCEANIC INDICATORS FAVOR AN EL NINO, ATMOSPHERIC INDICATORS CONTINUE TO FAVOR 
ENSO-NEUTRAL CONDITIONS. DURING THE PAST 30-DAYS, ENHANCED CONVECTION AND 
PRECIPITATION HAS BEEN OBSERVED OVER INDONESIA, THE PHILIPPINES, NORTHERN 
AUSTRALIA, AND THE WESTERN PACIFIC. SUPPRESSED CONVECTION AND PRECIPITATION WAS 
OBSERVED NEAR THE DATE LINE. LOW-LEVEL (850-HPA) WINDS WERE NEAR-AVERAGE ACROSS 
MOST OF THE EQUATORIAL PACIFIC. THE CONVECTION AND LOW-LEVEL WIND PATTERNS ARE 
NOT CONSISTENT WITH AN EL NINO. COLLECTIVELY, THE OCEANIC AND ATMOSPHERIC 
INDICATORS SUPPORT THE CONTINUATION OF ENSO-NEUTRAL CONDITIONS. THIS CONTINUED 
LACK OF COUPLING BETWEEN THE OCEAN AND ATMOSPHERE SUGGESTS THAT THE WINDOW OF 
OPPORTUNITY FOR A WEAK WARM EVENT IS RAPIDLY NARROWING. THERE IS AN 
APPROXIMATELY 50-60 PERCENT CHANCE OF EL NINO CONDITIONS DURING THE NEXT TWO 
MONTHS, AFTER WHICH ENSO-NEUTRAL IS FAVORED. 
 
THE MONTHLY PACIFIC DECADAL OSCILLATION (PDO) INDEX FOR DECEMBER 2014 IS +2.51, 
WHICH IS THE HIGHEST DECEMBER VALUE OF RECORD (SINCE 1900). REGRESSIONS OF 
FEBRUARY TEMPERATURE ON DECEMBER PDO VALUES SUPPORT A RELATIVELY COLD PATTERN 
FOR MUCH OF THE CONUS EAST OF THE ROCKIES. THE MADDEN JULIAN OSCILLATION IS 
CURRENTLY ACTIVE, WITH THE ENHANCED CONVECTIVE PHASE CENTERED OVER THE WESTERN 
PACIFIC, AND SUPPRESSED CONVECTIVE PHASES OVER THE INDIAN OCEAN AND IN THE 
WEST-CENTRAL PACIFIC NEAR THE DATE LINE. DURING THE NEXT TWO WEEKS, THE 
ENHANCED PHASE OF THE MJO IS PREDICTED TO SHIFT EASTWARD INTO THE WESTERN 
HEMISPHERE, AND DECREASE IN AMPLITUDE. LAGGED COMPOSITES ON THE MJO FAVOR A 
COOLING DOWN FOR MUCH OF THE CONUS DURING WEEK 2. IT IS DIFFICULT TO SAY HOW 
MUCH OF A ROLE THE MJO MAY PLAY IN INFLUENCING U.S. CLIMATE IN FEBRUARY. 
 
CFS AND ECMWF DYNAMICAL MODEL GUIDANCE FOR THE WEEK 3 AND WEEK 4 PERIODS DEPICT 
A MODERATING TREND IN SURFACE TEMPERATURES ACROSS THE CENTRAL AND EASTERN 
CONUS. THESE MODELS ARE ALSO VERY PERSISTENT IN PREDICTING ABOVE-AVERAGE MEAN 
TEMPERATURES ACROSS THE WESTERN CONUS AND ALASKA. AN ASSORTMENT OF CLIMATE 
MODELS FOR FEBRUARY 2015 PREDICT A FAIRLY WIDE RANGE OF POSSIBLE OUTCOMES. THE 
NATIONAL MULTI-MODEL ENSEMBLE (NMME) AND THE INTERNATIONAL MULTI-MODEL ENSEMBLE 
(IMME) FORECAST ENHANCED CHANCES OF ABOVE-AVERAGE MEAN TEMPERATURES IN ALASKA, 
THE WESTERN CONUS, AND TO A MODEST DEGREE, PARTS OF THE SOUTHEAST. THEY ALSO 
ANTICIPATE ENHANCED CHANCES OF BELOW-AVERAGE MEAN TEMPERATURES IN PARTS OF 
TEXAS. THE INDIVIDUAL MODEL INPUTS TO THE NMME ALL AGREE ON THE PREDICTED 
RELATIVE WARMTH IN ALASKA, AND WITH ONE EXCEPTION, THEY ALSO AGREE ON THE 
WARMTH OVER THE WESTERN CONUS. HOWEVER, FOR REMAINING AREAS OF THE CONUS, 
TEMPERATURE SIGNALS AMONG THE VARIOUS MODELS ARE EITHER WEAK OR CONFLICTING, 
SUGGESTING LITTLE PREDICTIVE SIGNAL FOR TEMPERATURE ANOMALIES. THE OFFICIAL 
FEBRUARY 2015 TEMPERATURE OUTLOOK THEREFORE FAVORS ABOVE-AVERAGE TEMPERATURES 
IN ALASKA, THE WESTERN CONUS, AND FLORIDA, AND BELOW-AVERAGE TEMPERATURES IN 
TEXAS. 
 
FOR PRECIPITATION, THE NMME, IMME, AND CFS PREDICT ENHANCED ODDS OF 
ABOVE-MEDIAN PRECIPITATION FROM SOUTHERN CALIFORNIA EASTWARD ACROSS THE 
SOUTHWEST, SOUTHERN ROCKIES, AND SOUTHERN GREAT PLAINS, WITH THE HIGHER 
PROBABILITIES IN NEW MEXICO AND TEXAS. THESE SAME MODELS ALSO ANTICIPATE 
ELEVATED ODDS OF BELOW-MEDIAN PRECIPITATION ACROSS PARTS OF THE PACIFIC 
NORTHWEST AND NORTHERN ROCKIES. THESE PREDICTED CLIMATE ANOMALIES HAVE 
REASONABLE SUPPORT FROM A MAJORITY OF THE CLIMATE MODELS WHICH CONSTITUTE THE 
NMME. SOME MODELS ALSO FORECAST A TILT IN THE ODDS TOWARD DRYNESS NEAR THE 
GREAT LAKES/OHIO VALLEY REGION, AND WETNESS ALONG THE SOUTH-CENTRAL AND 
SOUTHEASTERN ALASKA COAST, BUT THEY APPEAR TO BE EITHER TOO WEAK OR DISAGREE 
SUBSTANTIALLY IN PREDICTED LOCATION TO BE USED RELIABLY. THE OFFICIAL FEBRUARY 
2015 PRECIPITATION OUTLOOK THEREFORE FAVORS ABOVE-MEDIAN PRECIPITATION FROM 
SOUTHERN CALIFORNIA EASTWARD TO TEXAS, AND BELOW-MEDIAN PRECIPITATION IN THE 
PACIFIC NORTHWEST AND NORTHERN ROCKIES. 
 
IN AREAS WHERE CLIMATE SIGNALS ARE WEAK OR CONFLICTING, SUCH THAT THE 
LIKELIHOODS OF MONTHLY MEAN TEMPERATURES OR MONTHLY ACCUMULATED PRECIPITATION 
AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS 
INDICATED. 
 
THE MAIN FACTORS THAT USUALLY INFLUENCE THE MONTHLY CLIMATE OUTLOOK INCLUDE: 
1) EL NINO AND LA NINA - WHICH COMPRISE ENSO. IMPACTS OF THESE EVENTS ARE 
SUMMARIZED BY SEPARATING 3-MONTH OBSERVATIONS FROM THREE OR MORE DECADES INTO 
EL NINO, NEUTRAL AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN 
COMPUTING ANOMALIES. THESE ARE CALLED "COMPOSITES" AND 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 - CALLED THE MADDEN JULIAN OSCILLATION 
(MJO) - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS. 
4) THE ARCTIC OSCILLATION (AO), THE SIMILAR NORTH ATLANTIC OSCILLATION (NAO), 
AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE 
ANOMALY PATTERN ESPECIALLY DURING BOREAL WINTER AND ARE GENERALLY CONSIDERED TO 
HAVE LOW PREDICTABILITY. 
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 MODELS - CANONICAL CORRELATION ANALYSIS (CCA), 
SCREENING MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOG (CA), AND 
ENSEMBLE CCA (ECCA). 
8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM 
VERSION 2 (CFS) AND FOR THE ZERO-LEAD UPDATE FORECASTS THE NCEP GLOBAL ENSEMBLE 
FORECAST SYSTEM (GEFS).  AN EXPERIMENTAL FORECAST SYSTEM, THE NATIONAL 
MULTI-MODEL ENSEMBLE (NMME), COMPRISED OF SEVERAL DYNAMICAL MODELS IS ALSO USED. 
 
 
FORECASTER: ANTHONY ARTUSA 
 
 
THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, FOLLOWING 
THE WORLD METEOROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3 
COMPLETE DECADES AS THE CLIMATE 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. 
 
 
 
THE NEXT MONTHLY OUTLOOK...FOR MAR ... WILL BE ISSUED ON THU FEB 19 2015 
 
 
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. 
 
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