PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300PM EST TUESDAY DEC 31 2013 30-DAY OUTLOOK DISCUSSION FOR JANUARY 2014 THE UPDATED TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JANUARY 2014 ARE BASED PRIMARILY ON THE MOST RECENT CFS GUIDANCE, DYNAMICAL MODEL RUNS OUT TO TWO WEEKS, THE WPC DAYS 1-7 PRECIPITATION FORECAST, CPC'S 6-10 AND 8-14 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, AND THE EXPECTATION OF ENSO-NEUTRAL CONDITIONS. SIGNIFICANT CHANGES ARE DEEMED NECESSARY TO THE 0.5-MONTH LEAD OUTLOOK. THE UPDATED JANUARY 2014 TEMPERATURE OUTLOOK FAVORS ELEVATED ODDS OF ABOVE-NORMAL MEAN TEMPERATURES OVER INTERIOR CALIFORNIA, THE SOUTHWESTERN CONUS, FLORIDA, AND NORTHERN AND WESTERN ALASKA. ODDS FOR BELOW-NORMAL MEAN TEMPERATURES ARE ELEVATED FROM THE NORTHERN HIGH PLAINS EASTWARD ACROSS THE MIDWEST, GREAT LAKES REGION, AND OHIO VALLEY. IT IS THOUGHT THAT SURGES OF UNSEASONABLY COLD ARCTIC AIR COULD REACH THE NORTHEAST AND MID-ATLANTIC COASTS, AFFECTING THE BIG CITIES ALONG THE I-95 CORRIDOR. HOWEVER, THESE OUTBREAKS ARE EXPECTED TO BE FAIRLY SHORT-LIVED NEAR THE COAST, AND IT APPEARS THAT EQUAL CHANCES MAY BE THE BEST BET THERE. THE AREA OF BELOW-NORMAL TEMPERATURES INDICATED OVER THE SOUTHERN COAST OF ALASKA (EXCLUDING THE ALEUTIANS) ON THE 0.5-MONTH LEAD OUTLOOK DID NOT HAVE MUCH SUPPORT FROM THE CURRENT MODEL RUNS AND WAS THEREFORE REMOVED. ELSEWHERE, CLIMATE SIGNALS ARE EITHER WEAK OR CONFLICTING, SO EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-NORMAL TEMPERATURES ARE FAVORED. THE UPDATED JANUARY 2014 PRECIPITATION OUTLOOK INDICATES ENHANCED ODDS OF ABOVE-MEDIAN PRECIPITATION FOR MONTANA, THE ALASKA PANHANDLE, AND SOUTHWESTERN ALASKA. ODDS FOR BELOW-MEDIAN PRECIPITATION ARE ENHANCED OVER CALIFORNIA AND THE SOUTHWESTERN CONUS. THE AREA OF BELOW-MEDIAN PRECIPITATION INDICATED BY THE 0.5-MONTH LEAD OUTLOOK OVER THE GULF COAST STATES DOES NOT HAVE MUCH SUPPORT FROM THE LATEST MODEL RUNS AND WAS THEREFORE REMOVED. ELSEWHERE, CLIMATE SIGNALS ARE EITHER WEAK OR CONFLICTING, SO EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-MEDIAN PRECIPITATION AMOUNTS ARE FAVORED. --------------------- THE PREVIOUS MONTHLY OUTLOOK DISCUSSION RELEASED DECEMBER 19 IS SHOWN BELOW: --------------------- 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. THE NEXT MONTHLY OUTLOOK...FOR FEB ... WILL BE ISSUED ON THU JAN 16 2014 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$