PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300PM EDT SATURDAY MAY 31 2014 30-DAY OUTLOOK DISCUSSION FOR JUNE 2014 THE MONTHLY OUTLOOK FOR JUNE IS LITTLE CHANGED COMPARED TO THE 0.5 MONTH LEAD FORECAST ISSUED A COUPLE OF WEEKS AGO. IN GENERAL, THE LONGWAVE PATTERN FORECAST BY THE CFS EARLIER IN THE MONTH SEEMS REASONABLE, AND ITS LATEST OUTLOOK FOR JUNE REFLECTS AS MUCH. POSITIVE HEIGHT ANOMALIES ARE FORECAST ACROSS THE FAR NORTHEASTERN PACIFIC EXTENDING INTO NORTHWESTERN NORTH AMERICA. THIS IS SUPPORTED BY MEDIUM-RANGE FORECASTS FROM THE GFS AND ECMWF WHICH NOW EXTEND THROUGH THE SECOND FULL WEEK OF JUNE. FURTHERMORE, THIS IS SUPPORTED BY THE CFS, THE ECMWF WEEKLY FORECAST SYSTEM, AND THE JMA WEEKLY FORECAST SYSTEM, FOR THE MONTHLY AVERAGE. THERE IS A TRANSIENT WARMUP FORECAST ACROSS MUCH OF THE EASTERN CONUS EARLY IN THE MONTH, WHICH LEADS TO A SOMEWHAT LARGE AREA OF EQUAL CHANCES DEPICTED, MOSTLY DUE TO UNCERTAINTY IN HOW PERSISTENT COOL CONDITIONS MAY BE HEADING TOWARD MID-MONTH AND BEYOND. HOWEVER, BELOW-NORMAL TEMPERATURES ARE FAVORED ACROSS PARTS OF THE NORTHERN TIER OF THE CONUS, WHERE MODEL GUIDANCE HAS BEEN THE MOST CONSISTENT OVER THE PAST FEW WEEKS. HEAVY PRECIPITATION EARLY IN THE PERIOD ACROSS MUCH OF THE CENTRAL-EASTERN CONUS SUPPORTS THE 0.5 MONTH LEAD PRECIPITATION OUTLOOK ACROSS MUCH OF THE CONUS. HOWEVER, HEAVY RAIN IS FORECAST FARTHER NORTH ACROSS PARTS OF THE GREAT LAKES, LEADING TO THE REMOVAL OF THE AREA OF BELOW-MEDIAN PRECIPITATION DEPICTED IN THE EARLIER OUTLOOK. NEAR-TO-BELOW MEDIAN PRECIPITATION IS EXPECTED OVER THAT REGION FOR THE MIDDLE AND LATTER PORTIONS OF THE MONTH. THERE IS INCREASED CONFIDENCE THAT THE MEAN MID-LEVEL RIDGE WILL BE STRONGER THAN NORMAL OVER PARTS OF THE SOUTHWEST, ESPECIALLY HEADING TOWARD THE MIDDLE OF THE MONTH. THIS ALLOWS FOR ENHANCED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ACROSS PARTS OF SOUTH TEXAS. BELOW-NORMAL SSTS IN THE GULF OF MEXICO STILL FAVOR BELOW-NORMAL TEMPERATURES ALONG THE IMMEDIATE COAST, THOUGH ABOVE-NORMAL TEMPERATURES ARE FAVORED TO THE NORTHWEST OF THAT REGION. DUE TO INCREASED CONFIDENCE IN THE AVERAGE ANOMALOUS NORTHERLY MID-LEVEL FLOW ACROSS THE NORTHWESTERN COAST OF NORTH AMERICA, ENHANCED PROBABILITIES OF BELOW-MEDIAN PRECIPITATION ARE DEPICTED SOUTHWARD FROM THE ALASKAN PANHANDLE TO THE PACIFIC NORTHWEST. THE AREA FAVORING ABOVE-NORMAL TEMPERATURES OVER FLORIDA HAS BEEN REMOVED AS SSTS HAVE DECREASED CONSIDERABLY AROUND THE PENINSULA IN THE PAST TWO WEEKS. SSTS HAVE INCREASED OFF THE WEST COAST RECENTLY, FURTHER SUPPORTING INCREASED ODDS OF ABOVE-NORMAL TEMPERATURES IN THAT REGION. PREVIOUS DISCUSSION: THE MONTHLY OUTLOOK FOR JUNE 2014 IS BASED ON FACTORS THAT INFLUENCE CLIMATIC CONDITIONS SUCH AS THE ENSO STATE, 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 AT OVER 65% FOR JJA. THE CURRENT NORTH PACIFIC SSTS PROJECT QUITE STRONGLY ONTO THE POSITIVE PHASE OF THE PDO, A RARE FEAT FOR THIS TIME OF YEAR CONSIDERING THE PRECEDING ENSO NEUTRAL CONDITIONS. THIS WELL-KNOWN HORSESHOE STRUCTURE IN NORTH PACIFIC SST ANOMALIES IS LIKELY IN RESPONSE TO PERSISTENT EXTRATROPICAL ATMOSPHERIC FORCING DURING THE COLD SEASON, NAMELY, A NEGATIVE PHASE OF THE WEST PACIFIC/NORTH PACIFIC OSCILLATION. IT IS REASONABLE TO EXPECT THIS BOUNDARY FORCING TO PERSIST THROUGH THE WARM SEASON CONSIDERING THE SEASONAL WEAKENING OF THE ATMOSPHERIC CIRCULATION, THE EMERGING EL NINO, AND THE CONSENSUS OF CLIMATE MODEL FORECASTS. IN THE ATLANTIC, PERSISTENT FORCING FROM THE POSITIVE PHASE OF THE NAO HAS PRODUCED A COLD TRIPOLE, WITH BELOW-AVERAGE SSTS IN PARTS OF THE TROPICAL ATLANTIC AS WELL AS IN THE NORTHERN PART OF THE BASIN. IN FACT, PROJECTING THE RECENTLY OBSERVED (FMA) SST ANOMALIES NEAR NORTH AMERICA (160E-360, 10S-70N) ONTO SSTS OVER THE PAST 35 YEARS REVEALS THAT SUCH A STRUCTURE HAS NOT BEEN AS STRONGLY OBSERVED SINCE THE EARLY 1990S. THERE WERE A FEW RECENT DEVELOPING EL NINO YEARS (2002, 2004, 2009) THAT PROJECT WEAKLY ONTO THE CURRENT STATE. RECENT SOIL MOISTURE OBSERVATIONS INDICATE ANOMALOUSLY WET CONDITIONS ACROSS MUCH OF THE NORTHERN ROCKIES AND THE EASTERN GULF COAST, WITH DRY SOILS OBSERVED ACROSS MUCH OF THE CENTRAL-SOUTHERN PLAINS AND POINTS SOUTHWEST. THE LATEST CFSV2 FAVORS ANOMALOUS RIDGING OVER NORTHWESTERN NORTH AMERICA, WHILE THE STATISTICAL GUIDANCE BASED ON SSTS FAVORS A MEAN RIDGE POSITION FARTHER EAST OVER CENTRAL NORTH AMERICA. GIVEN THE CONSISTENCY OF THE CFSV2 AND SUPPORT FROM THE OTHER NUMERICAL GUIDANCE, THE FORMER SOLUTION IS FAVORED. ADDITIONALLY, THE FORECAST 700-HPA WAVE TRAIN EMANATING FROM THE ENHANCED CONVECTION OVER THE PACIFIC IN THE CFSV2 SEEMS REASONABLE, THOUGH NOT UNANIMOUSLY OBSERVED IN PRIOR DEVELOPING EL NINO EVENTS. NUMERICAL GUIDANCE AND RELATIVELY DRY SOILS SUPPORT THE ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS PARTS OF THE SOUTHERN PLAINS. THIS OUTLOOK LEANED ON THE NEAR-UNANIMITY OF THE DYNAMICAL GUIDANCE FAVORING BELOW-NORMAL TEMPERATURES EXTENDING FROM THE NORTHERN ROCKIES EASTWARD. THE FORECAST FOR THE NORTHERN ROCKIES IS FURTHER SUPPORTED BY ABOVE-AVERAGE SOIL MOISTURE IN THAT REGION. BELOW-NORMAL TEMPERATURES ARE FAVORED ACROSS PARTS OF THE WESTERN GULF COAST DUE TO BELOW-NORMAL SSTS IN THE WESTERN GULF. THIS IS FURTHER SUPPORTED BY SOME STATISTICAL GUIDANCE AS WELL AS EXTENDED RANGE (WEEK 3/4) NUMERICAL GUIDANCE. ABOVE-NORMAL TEMPERATURES ARE FAVORED OVER THE WEST COAST AND ALASKA WHERE SSTS ARE EXPECTED TO BE ABOVE NORMAL. THE DYNAMICAL GUIDANCE REMAINS IN VERY GOOD AGREEMENT ON THIS TEMPERATURE RESPONSE. THE PRECIPITATION OUTLOOK IS REASONABLY CONFIDENT FOR A 0.5 MONTH LEAD MONTHLY OUTLOOK. STATISTICAL GUIDANCE AND DYNAMICAL TOOLS ARE IN VERY GOOD AGREEMENT ON THE ENHANCED PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FAVORED ACROSS PARTS OF THE WESTERN PLAINS AND CENTRAL ROCKIES. THE EASTWARD EXTENSION TO THE SOUTHEAST COAST IS SUPPORTED BEST BY THE ECMWF AND STATISTICAL TOOLS. THERE IS A LARGE DEGREE OF UNCERTAINTY ACROSS THE WESTERN GULF COAST, WHERE THE CFSV2 HAS PERSISTENTLY FORECAST BELOW-MEDIAN RAINFALL FOR JUNE. IN OPPOSITION TO THIS, THE IMME AND SOME STATISTICAL TOOLS SUPPORT NEAR- OR ABOVE-MEDIAN PRECIPITATION IS THIS REGION. LARGE UNCERTAINTY EXISTS IN BOTH THE TEMPERATURE AND PRECIPITATION OUTLOOKS ACROSS THE SOUTHWESTERN CONUS. THE STATISTICAL GUIDANCE, BASED LARGELY ON SSTS AND THE DEVELOPING EL NINO, SUPPORT THE HIGHEST PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION FARTHER NORTH WHERE THEY ARE INDICATED ON THE OUTLOOK MAP. HOWEVER, SOME DYNAMICAL GUIDANCE, LED BY THE CFSV2, INDICATES HIGH PROBABILITIES OF ABOVE-MEDIAN PRECIPITATION IN THE SOUTHWESTERN U.S., LIKELY AIDED BY THE INCREASE IN TROPICAL MOISTURE FLOWING NORTHWARD OUT OF THE NORTHEAST PACIFIC. THIS WOULD BE UNUSUAL FOR THIS EARLY IN THE SEASON AND HAS BEEN LARGELY DISCOUNTED IN THE JUNE OUTLOOK. IF THIS SOLUTION COMES TO BEAR, HOWEVER, THIS WOULD LIKELY HAVE A COOLING EFFECT ON TEMPERATURES IN THAT REGION. 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: STEPHEN BAXTER 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 JUL ... WILL BE ISSUED ON THU JUN 19 2014 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$