PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300 PM EST SUN JAN 31 2016 30-DAY OUTLOOK DISCUSSION FOR FEBRUARY 2016 THE UPDATE OF THE FEBRUARY 2016 FORECAST AT THE VERY END OF JANUARY IS BASED PRIMARILY ON DYNAMICAL MODEL PREDICTION THAT TAKE INTO ACCOUNT THE INITIAL STATE OF THE ATMOSPHERE AT THE PRESENT TIME. THIS GENERALLY YIELDS HELPFUL INFORMATION FOR THE FIRST SEVERAL DAYS OF THE MONTH. SPECIFIC TOOLS CONSULTED FOR THIS PURPOSE ARE THE GFS, GEFS AND CFS, WPC'S LATEST DAY 1-7 FORECAST FOR QPF AND ALSO YESTERDAY'S WEEK 2 FORECAST AND THE EXPERIMENTAL WEEK 3 AND 4 FORECAST MADE JUST 2 DAYS AGO. THE LONG LEAD FORECAST FOR FEBRUARY MADE AT MID-MONTH NEEDS ONLY MINOR ADJUSTMENT FOR TEMPERATURE. FOR PRECIPITATION THE ADJUSTMENT IS SOMEWHAT LARGER. THE CANONICAL ENSO RESPONSE FOR PRECIPITATION OVER THE US DOES NOT APPEAR TO BE FIRMLY IN PLACE FOR THE FIRST 2 WEEKS AT LEAST. FOR BOTH TEMPERATURE AND PRECIPITATION THE ADJUSTMENTS ARE MAINLY IN TERMS OF PROBABILITY. PATTERN CHANGES ARE RELATIVELY SMALL AND NO 2-CLASS CHANGES. A PRECIPITATION EVENT CURRENTLY UNDERWAY IN SOUTHERN CALIFORNIA WILL PRODUCE A NARROW STRIPE OF PRECIPITATION FROM SOUTHERN CALIFORNIA TO THE GREAT LAKES BUT IN NONE OF THESE AREAS WILL THIS SYNOPTIC EVENT BE ENOUGH TO FORCE THE MONTHLY TOTAL IN THE ABOVE MEDIAN TERCILE. PROBABILITIES FOR BELOW MEDIAN HAVE BEEN REDUCED IN THE GREAT LAKES AREA, WHILE PROBABILITY FOR ABOVE MEDIAN PRECIPITATION HAVE BEEN PUSHED NORTHWARD IN UTAH AND COLORADO. WE REDUCED THE PROBABILITY FOR ABOVE MEDIAN PRECIPITATION IN TEXAS AND SOUTHERN NEW MEXICO AND ARIZONA BECAUSE CFS, WHICH COMBINES THE WELL PREDICTED EARLY SYNOPTIC EVENTS WITH THE CLIMATE SIGNAL IN THE REMAINDER OF THE MONTH, PREDICTS LITTLE PRECIPITATION IN THOSE AREAS. IN OTHER AREAS THE PRECIPITATION FORECAST IS UNCHANGED FROM MID-JANUARY. AS FOR TEMPERATURE WE REDUCED THE PROBABILITY FOR ABOVE NORMAL ACROSS THE NORTHERN TIER EAST OF THE DAKOTAS SOMEWHAT BECAUSE AFTER A MILD START A COLD AIR OUTBREAK IN THE 2ND WEEK SEEMS LIKELY. BASED ON CFS WE EXTENDED THE BELOW NORMAL AREA ACROSS THE SOUTH SLIGHTLY INTO COLORADO. IN OTHER AREAS THE TEMPERATURE FORECAST IS UNCHANGED FROM MID-JANUARY. MESSAGE AT MID-MONTH WAS: THE ONGOING, STRONG EL NINO IS THE IMPORTANT DRIVER OF CLIMATE FORECASTS OVER NORTH AMERICA, ESPECIALLY IN FEBRUARY. PLEASE SEE THE ENSO DIAGNOSTIC DISCUSSION AT: HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/ENSO_ADVISORY/ FOR A MORE DETAILED ANALYSIS OF SEA SURFACE TEMPERATURES ACROSS THE EQUATORIAL PACIFIC. THE CURRENT EVENT IS AMONG THE STRONGEST ON RECORD AND IS FORECAST TO REMAIN STRONG IN FEBRUARY. PRETTY MUCH ALL TOOLS SHOW THE ENSO IMPACT. THE MADDEN-JULIAN OSCILLATION IS A POTENTIAL CONTRIBUTOR TO THE VARIABILITY OVER NORTH AMERICA BUT IS CURRENTLY WEAK. MOST OUTLOOKS SHOW IT WILL STRENGTHEN SO IF THIS HAPPENS IT WILL BE CONSIDERED IN THE UPDATE. DYNAMICAL MODEL OUTPUTS, INCLUDING THE NMME AND CFS, PLAYED A ROLE IN THE OUTLOOKS. IN THE TEMPERATURE FIELDS, MOST OF THE MODELS IN THE NMME SUITE INDICATE PATTERNS CONSISTENT WITH THE EL NINO REGRESSIONS OR COMPOSITES, WITH SOME SMALL SPATIAL SHIFTS. THE NMME AND CFS MODEL OUTLOOKS FOR PRECIPITATION ARE ALSO CONSISTENT WITH CANONICAL, EL NINO COMPOSITES AND CORRELATION MAPS. GUIDANCE FROM THE CFS HAS BEEN CONSISTENT AND ALIGNS WELL WITH CORRELATION MAPS OF FEBRUARY PRECIPITATION WITH NINO3.4 VALUES. THOSE CORRELATIONS IMPLY ABOVE MEDIAN PRECIPITATION ACROSS THE SOUTHERN TIER OF THE CONUS, ALONG MUCH OF THE WEST COAST, AND SOUTHERN PORTIONS OF THE MID-ATLANTIC. THE CFS FORECAST USED AT MID-MONTH IS BASED ON 40 MEMBERS PUT TOGETHER BY LAGGED FORECASTING. AS WE GET CLOSER TO THE UPDATE ON JANUARY 31 2016 A CFS ENSEMBLE USING ONLY FORECAST RUNS OF THE LAST 24 HOURS IS USED SO AS TO GIVE PROPER IMPORTANCE TO THE ATMOSPHERIC INITIAL CONDITIONS AS SHORT LEADS. AT THIS TIME WE ARE PREDICTING MAINLY THE CLIMATE SIGNAL. ENHANCED ODDS FOR ABOVE NORMAL TEMPERATURES (UP TO 50%) ARE PREDICTED ALONG THE WEST COAST AND THE NORTHERN STATES ALL THE WAY TO NEW ENGLAND AND THE NORTHERN MID-ATLANTIC. MUCH OF ALASKA IS PREDICTED TO HAVE ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES, EXCEPT ALONG ITS WEST COAST WHERE EQUAL CHANCES (EC) IS FAVORED. THE ALASKA PANHANDLE HAS 50% CHANCE FOR THE ABOVE NORMAL TERCILE. ELEVATED CHANCES FOR BELOW NORMAL TEMPERATURES ARE INDICATED ONLY IN TEXAS AND ALONG THE GULF COAST. ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS CALIFORNIA, THE SOUTHWEST, CENTRAL/SOUTHERN GREAT PLAINS, GULF COAST STATES, PARTS OF THE EAST COAST AND ALSO SOUTHERN COASTAL ALASKA. THE HIGHEST PROBABILITIES (UP TO 60 PERCENT) FOR ABOVE-MEDIAN PRECIPITATION ARE FORECAST ACROSS THE FLORIDA PENINSULA. FEBRUARY TYPICALLY HAS THE STRONGEST SIGNAL DURING EL NINO. BELOW-MEDIAN PRECIPITATION IS FAVORED ACROSS THE NORTHERN ROCKIES, PARTS OF THE NORTHERN GREAT PLAINS, GREAT LAKES, THE OHIO VALLEY AND MUCH OF ALASKA EXCEPT ITS SOUTHERN COAST. THE DRY SIGNAL ACROSS THE OHIO VALLEY PEAKS TYPICALLY IN FEBRUARY DURING EL NINO. 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: HUUG VAN DEN DOOL 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 18 2016 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$