PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 830AM EDT THURSDAY JUL 17 2014 30-DAY OUTLOOK DISCUSSION FOR AUGUST 2014 RECENT OCEANIC CONDITIONS ACROSS THE TROPICAL PACIFIC CONTINUE TO SUPPORT THE FAVORED TRANSITION FROM ENSO-NEUTRAL TO EL NINO LATER THIS SUMMER. HOWEVER, THE ATMOSPHERE REMAINS SOMEWHAT DECOUPLED WITH THE RELATIVELY WARM SEA SURFACE TEMPERATURES (SST) AND THE SUBSURFACE WARMTH OF THE TROPICAL PACIFIC. THESE OBSERVATIONS SUGGESTS THAT THE ENSO PHASE IS STILL NEUTRAL. IT NOW APPEARS THAT THE PREDICTED EL NINO MAY PEAK AT WEAK TO MODERATE STRENGTH BY LATE AUTUMN/EARLY WINTER, COMPARED TO PREVIOUS EXPECTATIONS OF FAVORED MODERATE INTENSITY PEAKING DURING THE SAME PERIOD. DURING THE PAST FEW WEEKS, POSITIVE SST ANOMALIES PERSISTED (THOUGH WEAKENED SLIGHTLY) IN THE EASTERN EQUATORIAL PACIFIC, AND ANOMALIES ARE CLOSE TO ZERO IN THE CENTRAL PACIFIC (180W-150W). THE LATEST WEEKLY SST DEPARTURE IN THE EAST-CENTRAL PACIFIC (NINO 3.4 REGION) IS +0.3C. THE OCEANIC HEAT CONTENT (SUBSURFACE TEMPERATURE ANOMALIES IN THE UPPERMOST 300-METERS OF THE EASTERN AND CENTRAL EQUATORIAL PACIFIC) DECLINED FAIRLY RAPIDLY IN THE LAST FEW MONTHS, AND ANOMALIES ARE NOW CLOSE TO ZERO. DURING THIS SAME PERIOD, THE LARGE RESERVOIR OF SUBSURFACE WARMTH OVER THE CENTRAL AND EASTERN EQUATORIAL PACIFIC HAS DIMINISHED SIGNIFICANTLY IN COVERAGE AND MAGNITUDE, AND IS NOW CONFINED FROM ABOUT 145W-85W, AND EXTENDS DOWN TO A DEPTH OF ABOUT 75 METERS. DURING THE PAST 30-DAYS, TROPICAL RAINFALL WAS SLIGHTLY ABOVE-AVERAGE IN INDONESIA AND THE WESTERN EQUATORIAL PACIFIC, AND LOW-LEVEL (850-HPA) WINDS WERE NEAR LONG-TERM AVERAGES ACROSS MOST OF THE EQUATORIAL PACIFIC. MONTHLY MEAN TEMPERATURES FOR AUGUST 2014 ARE FAVORED TO BE ABOVE-NORMAL ACROSS THE SOUTHERN HALVES OF BOTH THE LOWER GREAT PLAINS AND MISSISSIPPI VALLEY, THE SOUTHEAST, TENNESSEE VALLEY, AND MUCH OF THE MID-ATLANTIC REGION, AS WELL AS IN THE PACIFIC NORTHWEST, MOST OF NEVADA AND CALIFORNIA, AND ALASKA. BELOW-NORMAL MONTHLY MEAN TEMPERATURES ARE MOST LIKELY OVER PORTIONS OF THE NORTHERN GREAT PLAINS, UPPER MISSISSIPPI VALLEY, AND UPPER GREAT LAKES REGION. THIS OUTLOOK IS BASED PRIMARILY ON RECENT RUNS OF THE CFS DYNAMICAL MODEL, NMME, IMME, AND THEIR CONSTITUENT CLIMATE MODELS. IT IS ALSO BASED ON, TO A LESSER DEGREE, THE CAS, SMLR, CCA, AND OCN STATISTICAL TOOLS, AS WELL AS SOIL MOISTURE CONSIDERATIONS. AREAS OF DIMINISHED CONFIDENCE INCLUDE THE FOUR CORNERS MONSOON REGION (WHERE THE CFS IN PARTICULAR PREDICTS ENHANCED ODDS OF BELOW-NORMAL TEMPERATURES, AS OPPOSED TO THE EUROPEAN AND OTHER CLIMATE MODELS WHICH FAVOR NEAR OR EVEN ABOVE-NORMAL TEMPERATURES), AND NORTHERN ALASKA. IN THIS LATTER AREA, RECENT RUNS OF THE CFS APPEAR TO BE TOO COLD, ESPECIALLY GIVEN THE ANOMALOUSLY LOW ICE COVER OBSERVED OVER THE BEAUFORT SEA. IN AREAS WHERE CLIMATE SIGNALS ARE WEAK AND/OR UNRELIABLE, EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-NORMAL MONTHLY MEAN TEMPERATURES IS INDICATED. PRECIPITATION FOR AUGUST 2014 IS ANTICIPATED TO BE ABOVE-MEDIAN OVER MUCH OF THE INTERIOR WEST. BELOW-MEDIAN PRECIPITATION AMOUNTS ARE SLIGHTLY FAVORED FOR MOST OF THE GULF COAST REGION, AND PORTIONS OF GEORGIA AND SOUTH CAROLINA. THE OUTLOOK IS BASED PRIMARILY ON THE SAME TOOLS NOTED ABOVE FOR TEMPERATURE. FOR THE SOUTHWEST, IT IS CONSISTENT WITH THE EXPECTATION OF BOTH AN ENHANCED MONSOON AND AN ENHANCED EASTERN PACIFIC HURRICANE SEASON. IN THE NORTHERN HIGH PLAINS AND NORTHERN ROCKIES, IT IS MOST LIKELY DUE TO FRONTAL ACTIVITY. PERHAPS THE MOST UNCERTAIN PART OF THIS FORECAST IS THE ANTICIPATED REGION OF FAVORED BELOW-MEDIAN RAINFALL OVER THE GULF COAST STATES AND ADJACENT PORTIONS OF GEORGIA AND SOUTH CAROLINA. THE CFS AND IMME SUPPORT SOME EXTENSION OF THIS AREA OF RELATIVE DRYNESS THROUGH NORTH CAROLINA AND PARTS OF THE MID-ATLANTIC REGION, WHILE THE NMME INCLUDES ONLY TEXAS AND LOUISIANA. THIS IS COMPLICATED BY WHAT APPEARS TO BE THE EARLY STAGES OF A FLASH DROUGHT TRYING TO DEVELOP FROM ALABAMA AND THE FLORIDA PANHANDLE NORTHEASTWARD INTO SOUTHWESTERN VIRGINIA. THE PRECIPITATION FORECAST FOR THE UPCOMING 7-DAYS CALLS FOR SIGNIFICANT RAINFALL (RANGING FROM 0.5 TO 4 INCHES) TO OCCUR ACROSS THE GULF COAST REGION AND SOUTHEAST, WHICH MAY (AT LEAST TEMPORARILY) HELP TO OFFSET THE RAPIDLY DETERIORATING SOIL MOISTURE CONDITIONS NOW SETTING UP IN THE SOUTHEAST. THE OFFICIAL CPC PRECIPITATION OUTLOOK IS THOUGHT TO BE A REASONABLE COMPROMISE BETWEEN VARIOUS COMPETING FACTORS. IN AREAS WHERE CLIMATE SIGNALS ARE WEAK AND/OR UNRELIABLE, EQUAL CHANCES (EC) OF BELOW-, NEAR-, AND ABOVE-MEDIAN PRECIPITATION AMOUNTS IS INDICATED. 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: 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 AUG WILL BE ISSUED ON THU JULY 31 2014 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$