PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 
300PM EST TUESDAY JAN 31 2012 
 
30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2012 
 
THE UPDATE TO THE FEBRUARY MONTHLY FORECAST IS MADE USING THE LATEST GUIDANCE 
FROM NUMERICAL WEATHER PREDICTION (NWP) MODELS FOR THE FIRST TWO WEEKS OF THE 
MONTH AS WELL AS THE LATEST FEBRUARY TEMPERATURE AND PRECIPITATION FORECASTS 
FROM THE CLIMATE FORECAST SYSTEM VERSION 2 (CFSV2). FOR THE FIRST TWO WEEKS OF 
FEBRUARY, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM (NAEFS) BIAS-CORRECTED 
TEMPERATURE AND PRECIPITATION FORECASTS FROM THE COMBINED MULTI-MODEL ENSEMBLES 
OF NCEP AND ENVIRONMENT CANADA PROVIDED ADDITIONAL GUIDANCE. 
 
OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE TROPICAL PACIFIC BASIN CONTINUE 
TO INDICATE LA NINA CONDITIONS AS OF THE END OF JANUARY. THE LATEST SEA SURFACE 
TEMPERATURE (SST) OBSERVATIONS SHOW ANOMALIES COLDER THAN -1.0 C ACROSS MUCH OF 
THE CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC OCEAN, INCLUDING THE NINO 3.4 
REGION, WHILE IN JANUARY A SLIGHT SST WARMING WAS OBSERVED IN THE EASTERN 
EQUATORIAL PACIFIC. TEMPERATURE AND PRECIPITATION COMPOSITES OF HISTORICAL LA 
NINA EVENTS WERE USED TO MODIFY THE PRIOR AND UPDATED FEBRUARY OUTLOOKS. 
 
THE UPDATED FEBRUARY TEMPERATURE OUTLOOK IS SIMILAR TO THE PRIOR FEBRUARY 
OUTLOOK, INDICATING ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOR 
MUCH OF THE CONTIGUOUS U.S. EAST OF THE ROCKY MOUNTAINS, WITH THE EXCEPTIONS OF 
THE SOUTHERN FLORIDA PENINSULA AND NORTHERN NEW ENGLAND. RECENT MODEL GUIDANCE 
WAS USED TO EXPAND THIS AREA INTO THE NORTHERN PLAINS. AN AREA OF ENHANCED 
CHANCES OF BELOW NORMAL TEMPERATURES IN THE PACIFIC NORTHWEST HAS BEEN REMOVED 
IN THE UPDATE WHERE IT CONFLICTS WITH THE LATEST CFSV2 AND NAEFS FORECASTS. 
 
THE UPDATED FEBRUARY PRECIPITATION OUTLOOK IS ALSO SIMILAR TO THE PRIOR 
FEBRUARY OUTLOOK, INDICATING ENHANCED PROBABILITIES OF ABOVE MEDIAN 
PRECIPITATION FROM THE CENTRAL MISSISSIPPI VALLEY TO THE EASTERN GREAT LAKES 
REGION, AND ENHANCED PROBABILITIES OF BELOW MEDIAN PRECIPITATION ACROSS THE 
SOUTHERN U.S. FROM CALIFORNIA TO THE SOUTH ATLANTIC COAST. USING THE LATEST 
MODEL GUIDANCE AN AREA OF INCREASED CHANCES OF ABOVE MEDIAN PRECIPITATION IN 
THE PACIFIC NORTHWEST HAS BEEN REMOVED AND THE AREA OF BELOW MEDIAN 
PRECIPITATION HAS BEEN EXPANDED TO THE BORDER OF CALIFORNIA AND OREGON. 
PRECIPITATION EXPECTED FOR TEXAS AND THE GULF COAST IN THE SHORT RANGE 
FORECASTS RESULTS IN A REDUCTION IN THE PROBABILITY OF BELOW MEDIAN 
PRECIPITATION IN THAT REGION, THOUGH BELOW MEDIAN MONTHLY TOTAL PRECIPITATION 
REMAINS MOST LIKELY. 
 
BELOW IS THE DISCUSSION FROM THE HALF-MONTH LEAD MONTHLY OUTLOOK FOR FEBRUARY, 
2012. 
 
OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE TROPICAL PACIFIC BASIN INDICATE 
WEAK TO MODERATE LA NINA CONDITIONS AT THE CURRENT TIME. THE LATEST SEA SURFACE 
TEMPERATURE (SST) OBSERVATIONS SHOW ANOMALIES OF -1.0 C ACROSS MUCH OF THE 
CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC OCEAN TO -2.0 C NEAR THE DATE LINE 
WITH ANOMALIES OF -0.5 C EXTENDING EASTWARD TO THE SOUTH AMERICAN COAST. 
SUBSURFACE TEMPERATURE OBSERVATIONS SHOW A LARGE VOLUME OF BELOW NORMAL 
TEMPERATURE ANOMALIES FOR THE CENTRAL AND EASTERN NEAR-EQUATORIAL PACIFIC OCEAN 
TO A DEPTH OF MORE THAN 150 METERS. ANOMALOUSLY COLD SUBSURFACE WATER IS AN 
INDICATION THAT THE CURRENT LA NINA EVENT WILL PERSIST, AT LEAST INTO THE 
BOREAL SPRING. MONTHLY MEAN ATMOSPHERIC CONDITIONS OVER THE TROPICAL PACIFIC 
OCEAN ARE CONSISTENT WITH ONGOING LA NINA CONDITIONS, INCLUDING SUPPRESSED 
CONVECTION AROUND THE DATE LINE NEAR THE EQUATOR OVER THE CENTRAL PACIFIC, 
ENHANCED LOW-LEVEL EASTERLY WIND ANOMALIES OVER THE WESTERN TROPICAL PACIFIC 
OCEAN, AND UPPER-LEVEL WESTERLY WIND ANOMALIES OBSERVED OVER MOST OF THE 
PACIFIC BASIN. CONVECTION AND PRECIPITATION HAS BEEN ENHANCED OVER THE MARITIME 
CONTINENT. LA NINA IS EXPECTED TO HAVE AN IMPACT ON THE MONTHLY MEAN 
TEMPERATURE AND PRECIPITATION PATTERNS OVER NORTH AMERICA IN THE MONTH OF 
FEBRUARY 2012. THE ARCTIC OSCILLATION (AO) HAS BEEN POSITIVE FOR MUCH OF THE 
LAST FEW MONTHS AND IS FORECAST TO BE POSITIVE IN FEBRUARY BY THE CFSV2 MODEL, 
THOUGH THE SKILL OF AO FORECASTS IS NOT BELIEVED TO BE HIGH. 
 
THE TEMPERATURE OUTLOOK FOR FEBRUARY 2012 INDICATES ENHANCED PROBABILITIES OF 
ABOVE NORMAL TEMPERATURES FOR A LARGE AREA OF THE UNITED STATES FROM THE 
SOUTHWEST ACROSS THE CENTRAL AND SOUTHERN GREAT PLAINS, INCLUDING SOUTHERN 
PORTIONS OF THE GREAT LAKES REGION AND MOST OF THE MISSISSIPPI VALLEY, AND 
ALONG THE EAST COAST FROM THE MID-ATLANTIC AND SOUTHERN NEW ENGLAND TO FLORIDA. 
GREATEST PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE FOR THE SOUTHEAST 
REGION. PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ENHANCED FOR WESTERN 
PORTIONS OF THE PACIFIC NORTHWEST, THE ALEUTIANS, SOUTHERN ALASKA AND THE 
ALASKAN PANHANDLE, EXCLUDING THE NORTH SLOPE OF ALASKA. EQUAL CHANCES (EC) OF 
BELOW, NEAR, AND ABOVE NORMAL TEMPERATURES ARE PREDICTED OVER A LARGE PORTION 
OF THE WESTERN UNITED STATES INCLUDING CALIFORNIA, THE CENTRAL AND NORTHERN 
ROCKIES AND THE NORTHERN PLAINS. THE FEBRUARY TEMPERATURE OUTLOOK WAS MADE 
CONSIDERING COMPOSITES OF TEMPERATURE ANOMALIES FROM HISTORICAL LA NINA EVENTS, 
THE CFSV2 MODEL FORECASTS, AND MODEL FORECASTS FROM THE NATIONAL MULTI-MODEL 
ENSEMBLE (NMME). THE CFSV2 TEMPERATURE FORECAST APPEARS TO BE INFLUENCED BY A 
CONTINUING LA NINA AND A POSITIVE ARCTIC OSCILLATION (AO). THE AREA OF 
INCREASED CHANCES FOR ABOVE NORMAL TEMPERATURES EXTENDS FURTHER INTO THE 
NORTHERN U.S. AND THE NORTHEAST THAN INDICATED IN LA NINA COMPOSITES, AS 
PREDICTED BY THE DYNAMICAL MODELS. 
 
THE PRECIPITATION OUTLOOK FOR FEBRUARY 2012 INDICATES ENHANCED PROBABILITIES OF 
BELOW MEDIAN PRECIPITATION AMOUNTS ACROSS THE SOUTHERN UNITED STATES FROM 
CENTRAL AND SOUTHERN CALIFORNIA ACROSS MUCH OF THE DESERT SOUTHWEST, SOUTHERN 
ROCKIES, SOUTHERN PLAINS, SOUTHERN PORTIONS OF THE GULF COAST STATES, AND THE 
SOUTHERN ATLANTIC COAST REGION. THE PROBABILITY OF BELOW MEDIAN PRECIPITATION 
AMOUNTS ARE GREATEST ALONG THE GULF COAST. 
 
INCREASED PROBABILITIES OF ABOVE MEDIAN PRECIPITATION AMOUNTS ARE PREDICTED 
FROM THE CENTRAL MISSISSIPPI AND OHIO VALLEYS NORTHWARD INTO THE GREAT LAKES 
REGION AS WELL AS FOR A SMALL PORTION OF THE PACIFIC NORTHWEST AND FOR THE 
SOUTHERN ALASKAN PANHANDLE. EQUAL CHANCES (EC) FOR BELOW, NEAR, AND ABOVE 
MEDIAN PRECIPITATION ARE INDICATED OVER REMAINING AREAS OF THE UNITED STATES IN 
THE FEBRUARY OUTLOOK WHERE THERE ARE NO STRONG CLIMATE SIGNALS OR FORECASTS 
HAVE LOWER SKILL. THE FEBRUARY PRECIPITATION OUTLOOK WAS BASED ON FORECASTS 
FROM THE CFSV2 AND OTHER DYNAMICAL MODEL FORECASTS FROM THE NMME, WITH 
CONSIDERATION OF LA NINA COMPOSITES OF PRECIPITATION ANOMALIES FOR HISTORICAL 
LA NINA EVENTS. 
 
THE MAIN FACTORS WHICH 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 3 OR MORE DECADES INTO EL 
NINO, NEUTRAL, AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN COMPUTING 
ANOMALIES.  THESE ARE CALLED "COMPOSITES", 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 ARCTIC OSCILLATION (AO), THE SIMILAR NORTH ATLANTIC OSCILLATION (NAO) 
AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE 
ANOMALY PATTERN ESPECIALLY DURING THE COLD SEASONS AND ARE IN GENERAL 
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 TOOLS - CANONICAL CORRELATION ANALYSIS (CCA), SCREENING 
MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOGUE (CA) AND ENSEMBLE CCA 
(ECCA). 
8) DYNAMICAL FORECAST MODELS - INCLUDING THE GFS (FOR ZERO-LEAD UPDATE 
FORECASTS), THE NCEP CLIMATE FORECAST SYSTEM (CFS). THE UPGRADED VERSION OF THE 
CFS (CFSV2) BECAME OPERATIONAL IN LATE MARCH OF 2011. BOTH VERSIONS OF CFS ARE 
CURRENTLY RUN IN PARALLEL.  AN EXPERIMENTAL FORECAST SYSTEM, THE NATIONAL 
MULTI-MODEL ENSEMBLE, COMPRISED OF SEVERAL DYNAMICAL MODELS AND DESIGNATED 
NMME, MAY ALSO BE USED. 
 
 
FORECASTER: DAN COLLINS 
 
 
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 16 2012 
 
 
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. 
 
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