PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY JUN 19 2014 30-DAY OUTLOOK DISCUSSION FOR JULY 2014 THE JULY OUTLOOK IS BASED ON EVOLVING ENSO CONDITIONS, SOIL MOISTURE, AND SEA SURFACE TEMPERATURE (SST) ANOMALIES, AS WELL AS GUIDANCE FROM NUMERICAL CLIMATE PREDICTION MODELS. EL NINO IS FORECAST TO DEVELOP DURING THE NEXT SEVERAL MONTHS, WITH THE LATEST CONSENSUS CPC/IRI FORECAST PLACING PROBABILITIES OF EL NINO OVER 70% FOR JAS. THE CURRENT NORTH PACIFIC SSTS PROJECT QUITE STRONGLY ONTO THE POSITIVE PHASE OF THE PDO (INDEX VALUE OF +1.80). IT IS REASONABLE TO EXPECT THIS BOUNDARY FORCING TO PERSIST THROUGH JULY GIVEN THE CURRENTLY FAVORED EMERGENCE OF EL NINO CONDITIONS. RECENT SOIL MOISTURE OBSERVATIONS INDICATE ANOMALOUSLY WET CONDITIONS ACROSS MUCH OF THE NORTHERN ROCKIES AND THE GULF COAST, WITH DRY SOILS OBSERVED FROM THE MIDWEST TO THE SOUTHERN GREAT PLAINS, SOUTHWEST AND CALIFORNIA. THE LATEST CFS FORECAST FAVORS ANOMALOUS RIDGING OVER WESTERN NORTH AMERICA, EXPANDING EASTWARD OVER THE EASTERN TWO-THIRDS OF THE CONUS THROUGH THE MIDDLE OF JULY. CONSTITUENTS OF THE NMME (NATIONAL MULTI-MODEL ENSEMBLE) EXHIBITED A HIGH LEVEL OF AGREEMENT FOR SURFACE PARAMETERS. THE STATISTICAL TOOLS WERE GENERALLY IN GOOD AGREEMENT WITH THE DYNAMICAL TOOLS AS WELL, ALTHOUGH THE EXACT PLACEMENT OF FEATURES WAS SLIGHTLY DIFFERENT. NUMERICAL GUIDANCE, CORRELATIONS BETWEEN THE PDO AND RECENT TEMPERATURES, AND MUCH DRIER THAN NORMAL SOILS SUPPORT ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MOST OF THE WEST, WEST OF THE CONTINENTAL DIVIDE. MOST OF THE DYNAMICAL MODEL GUIDANCE AND SOME OF THE STATISTICAL TOOLS INDICATED ENHANCED ODDS FOR BELOW-NORMAL TEMPERATURES ACROSS THE NORTHERN GREAT PLAINS, WITH SOME INPUTS FAVORING BELOW-NORMAL TEMPERATURES ACROSS THE GREAT LAKES AS WELL. ENSO COMPOSITES ALSO HIGHLIGHT A SLIGHT TILT TOWARD BELOW-NORMAL TEMPERATURES ACROSS THE FRONT RANGE OF THE CENTRAL ROCKIES AND PORTIONS OF THE HIGH PLAINS. A STRONGER SUBTROPICAL RIDGE DEVELOPING LATER IN JULY (WEEK3/4 GUIDANCE FROM CFS) IS LIKELY TO CONTRIBUTE TO ABOVE-NORMAL TEMPERATURES ACROSS THE SOUTH-CENTRAL AND SOUTHEAST CONUS. THE ODDS FOR ABOVE-NORMAL TEMPERATURES ARE CONSTRAINED OVER THE SOUTHEAST AS THE CONSTRUCTED ANALOG FROM SOIL MOISTURE (CAS) CONTRADICTS THE DYNAMICAL GUIDANCE. THE STATISTICAL AND DYNAMICAL TOOLS INDICATE NEAR OR ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR ALASKA, WITH ABOVE-NORMAL SSTS IN THE NORTH PACIFIC LIKELY A CONTRIBUTING FACTOR. THE PRECIPITATION OUTLOOK CALLS FOR ENHANCED ODDS OF ABOVE-MEDIAN PRECIPITATION ALONG MOST OF THE ROCKIES. DYNAMICAL GUIDANCE AND ENSO COMPOSITES KEYED TO EL-NINO CONDITIONS INDICATE THE HIGHEST PROBABILITIES FOR ABOVE-MEDIAN PRECIPITATION ACROSS THE CENTRAL AND NORTHERN ROCKIES. CCA AND CON OUTPUT ALSO INDICATE ABOVE-MEDIAN PRECIPITATION ACROSS THE NORTHERN ROCKIES, ALTHOUGH CORRELATIONS BETWEEN THE PDO AND PRECIPITATION DO NOT SHOW A STRONG SIGNAL EITHER WAY ACROSS THE NORTHERN ROCKIES. CORRELATIONS WITH THE PDO AND COMPOSITES BASED ON EL NINO DO SHOW DRY CONDITIONS ACROSS SOUTHERN ARIZONA, SO THE AREA OF ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION DOES NOT INCLUDE SOUTHERN ARIZONA. DYNAMICAL MODEL GUIDANCE IS NEARLY UNANIMOUS IN CALLING FOR NEAR TO BELOW-MEDIAN PRECIPITATION FROM THE GULF COAST AND LOWER MISSISSIPPI VALLEY TO SOUTHERN PORTIONS OF THE MIDWEST. ANOMALOUS RIDGING LINKED TO ABOVE-NORMAL SSTS OVER THE NORTH PACIFIC FAVORS BELOW-MEDIAN PRECIPITATION FOR THE ALASKAN PANHANDLE, AS INDICATED BY MOST MODELS IN THE NMME AND IMME. 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: MATTHEW ROSENCRANS 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 JUL WILL BE ISSUED ON MON JUNE 30 2014 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$