PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EST THURSDAY DEC 19 2013

30-DAY OUTLOOK DISCUSSION FOR JANUARY 2014

RECENT OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC OCEAN 
CONTINUE TO SUPPORT ENSO NEUTRAL CONDITIONS. SEA SURFACE TEMPERATURE (SST) 
ANOMALIES ARE CLOSE TO ZERO ACROSS THE EAST-CENTRAL EQUATORIAL PACIFIC (NINO 
3.4 REGION). SLIGHTLY POSITIVE SST ANOMALIES WERE OBSERVED IN THE WESTERN 
PORTION OF THE BASIN (NINO 4 REGION), WITH THE LATEST WEEKLY SST DEPARTURE OF 
+0.2 DEG C. IN CONTRAST, SLIGHTLY NEGATIVE SST ANOMALIES WERE OBSERVED NEAR THE 
SOUTH AMERICAN COAST (NINO 1+2 REGION), WITH THE LATEST WEEKLY SST DEPARTURE OF 
-0.2 DEG C. NEAR-EQUATORIAL SUBSURFACE HEAT CONTENT (TO A DEPTH OF 300 METERS) 
HAS AVERAGED CLOSE TO A HALF-DEGREE C ABOVE NORMAL DURING NOVEMBER AND THE 
FIRST HALF OF DECEMBER. LOW-LEVEL EASTERLY WIND ANOMALIES CONTINUED OVER THE 
WESTERN EQUATORIAL PACIFIC, WHILE UPPER-LEVEL WESTERLY WIND ANOMALIES WERE 
EVIDENT OVER THE CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC. LARGE SCALE 
CONVECTIVE ACTIVITY OVER PARTS OF INDONESIA AND THE FAR WESTERN PACIFIC 
CONTINUE TO BE ENHANCED, WHILE CONVECTION OVER THE CENTRAL PACIFIC REMAINS 
SUPPRESSED.  TAKEN COLLECTIVELY, THE OCEANIC AND ATMOSPHERIC OBSERVATIONS ARE 
CONSISTENT WITH ENSO NEUTRAL CONDITIONS. STATISTICAL AND DYNAMICAL MODELS 
PREDICT SST'S IN THE ENSO SENSITIVE REGION OF THE EAST-CENTRAL PACIFIC TO BE 
NEAR NORMAL FOR AT LEAST THE NEXT FEW MONTHS, SUGGESTING THAT THE ENSO STATE 
WILL REMAIN NEUTRAL DURING JANUARY 2014.  

THERE ARE CONFLICTING INDICATIONS FOR CLIMATIC ANOMALIES OVER THE UNITED STATES 
FOR THE JANUARY OUTLOOK. THIS OUTLOOK IS BASED IN LARGE PART ON ENSO-NEUTRAL
CONDITIONS, PROBABILISTIC FORECASTS FROM THE CFS, NMME, IMME, AND LONG TERM 
TRENDS. THE MJO HAS BEEN GENERALLY WEAK AND THERE IS HIGH UNCERTAINTY IN ITS 
FUTURE EVOLUTION.

THE JANUARY 2014 TEMPERATURE OUTLOOK INDICATES ELEVATED ODDS FOR ABOVE-NORMAL 
MONTHLY MEAN TEMPERATURES FROM NEAR THE CENTRAL AND SOUTHERN PACIFIC COAST 
SOUTHEASTWARD ACROSS THE CENTRAL AND SOUTHERN ROCKIES AND THE SOUTHERN HALF OF 
THE GREAT PLAINS, CONTINUING EASTWARD ACROSS THE LOWER MISSISSIPPI VALLEY AND 
GULF COAST STATES TO GEORGIA AND FLORIDA. ODDS FOR ABOVE-NORMAL TEMPERATURES 
ARE ALSO ELEVATED OVER NORTHERN ALASKA. THESE AREAS ARE BASED LARGELY ON RECENT 
TRENDING OF CFS PROBABILISTIC TEMPERATURE FORECASTS, AND IMME FORECASTS. ODDS 
FOR BELOW-NORMAL MEAN TEMPERATURES ARE ENHANCED OVER MONTANA, DUE PRIMARILY TO 
NEGATIVE PACIFIC DECADAL OSCILLATION (PDO) COMPOSITES USING DATA FROM THE PAST 
30 YEARS. ODDS ARE ALSO TILTED TOWARDS BELOW-NORMAL MEAN TEMPERATURES ALONG THE 
SOUTHERN COAST OF ALASKA, FROM KODIAK ISLAND TO KETCHIKAN. THIS HAS SUPPORT 
FROM VARIOUS NMME INPUTS AND RECENT TRENDING TOWARD NEAR-BELOW NORMAL SSTS. 
ELSEWHERE, CLIMATE SIGNALS ARE EITHER WEAK OR CONFLICTING, SO EQUAL CHANCES 
(EC) OF BELOW-, NEAR-, AND ABOVE-NORMAL TEMPERATURES ARE FAVORED.
  
THE JANUARY 2014 PRECIPITATION OUTLOOK INDICATES ELEVATED CHANCES FOR 
ABOVE-MEDIAN PRECIPITATION AMOUNTS FOR THE NORTHERN HIGH PLAINS AND NORTHERN 
ROCKIES, MUCH OF NORTHERN AND WESTERN ALASKA, AND THE ALASKAN PANHANDLE. THESE 
AREAS ARE SUPPORTED BY RECENT PROBABILISTIC FORECASTS OF THE CFS, THE NMME, AND 
THE IMME. ODDS FOR BELOW-MEDIAN PRECIPITATION AMOUNTS ARE ELEVATED OVER 
CALIFORNIA AND MUCH OF NEVADA, AND FROM TEXAS EASTWARD ACROSS THE GULF COAST 
STATES TO GEORGIA AND FLORIDA. THESE AREAS HAVE SOME SUPPORT FROM THE CFS, 
NMME, IMME, AND THE CCA. ELSEWHERE, CLIMATE SIGNALS ARE EITHER WEAK OR 
CONFLICTING, SO EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-MEDIAN 
PRECIPITATION AMOUNTS ARE FAVORED.

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 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.



AN UPDATED MONTHLY OUTLOOK... FOR JAN WILL BE ISSUED ON TUE DECEMBER 31 2013


THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.

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