PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300 PM EDT FRI JUN 30 2017 30-DAY OUTLOOK DISCUSSION FOR JULY 2017 THE UPDATE TO THE JULY MONTHLY OUTLOOK IS MADE USING THE LATEST GUIDANCE FROM THE CFS AND ECMWF DYNAMICAL MODELS FOR THE FULL MONTH, AS WELL AS ADDITIONAL DYNAMICAL MODEL FORECASTS, FROM THE NCEP GEFS AND ENVIRONMENT CANADA ENSEMBLE PREDICTION SYSTEMS, FOR THE FIRST TWO WEEKS OF JULY. THE CFS AND ECMWF FORECASTS FOR THE MONTH OF JULY INDICATE ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MOST OF THE WESTERN HALF OF THE CONUS, AS WELL AS ALONG THE GULF AND ATLANTIC COASTS AND FOR NEW ENGLAND. THE GREATEST PROBABILITIES FOR ABOVE NORMAL TEMPERATURES EXCEED 60 PERCENT OVER PARTS OF MONTANA. EQUAL CHANCES OF ABOVE AND BELOW NORMAL IS INDICATED FOR THE PACIFIC COAST, WHERE WEAKER ANOMALIES ARE FORECAST BY BOTH THE CFS AND ECMWF MONTHLY FORECASTS AND SHORT RANGE FORECASTS. EQUAL CHANCES OF ABOVE AND BELOW NORMAL TEMPERATURES IS ALSO INDICATED FOR MUCH OF THE MISSISSIPPI AND OHIO VALLEYS, WHERE TROUGHING IS PREDICTED FOR MUCH OF THE MONTH BY AVAILABLE MODELS. ABOVE NORMAL TEMPERATURES ARE LIKELY FOR NORTHERN ALASKA, THE ALEUTIAN ISLANDS, AND ALONG THE WEST COAST OF THE STATE, AS INDICATED IN MODEL FORECASTS FOR THE FIRST COUPLE WEEKS OF JULY, AS WELL AS THE MONTHLY FORECAST FROM THE ECMWF MODEL. THE UPDATE TO THE JULY PRECIPITATION OUTLOOK HAS CHANGED SOMEWHAT FROM THE PRIOR HALF-MONTH LEAD OUTLOOK. MODEL FORECASTS FROM WEEK 1 AND WEEK 2, AS WELL AS MONTHLY FORECASTS FROM THE ECMWF AND CFS MODELS, ALL INDICATE BELOW NORMAL PRECIPITATION IS MOST LIKELY FOR PARTS OF WASHINGTON STATE AND ALONG THE CANADIAN BORDER INTO THE NORTHERN PLAINS, DUE TO A PREDICTED RIDGE CENTERED OVER THIS REGION. THIS REPRESENTS A CHANGE FROM THE HALF-MONTH LEAD JULY OUTLOOK, WHEN ABOVE NORMAL PRECIPITATION WAS INDICATED BY MODEL FORECASTS FROM THE CFS AND NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) FOR PARTS OF MONTANA AND NORTH DAKOTA. LIKELY ABOVE NORMAL PRECIPITATION FOR THE WESTERN GULF COAST REGION, AS INDICATED IN THE MONTHLY OUTLOOK FROM MID-JUNE, IS NOW MORE LIKELY TO BE LOCATED FURTHER EAST OVER THE CENTRAL AND EASTERN GULF COAST, AS WELL AS EXTENDING NORTHWARD INTO THE CENTRAL MISSISSIPPI AND OHIO VALLEYS AND ACROSS MUCH OF THE SOUTHEAST. ABOVE MEDIAN PRECIPITATION FOR THIS REGION IN THE UPDATE TO THE JULY OUTLOOK IS SUPPORTED BY BOTH THE DYNAMICAL MODEL GUIDANCE FOR WEEK 1 AND WEEK 2, AS WELL AS THE JULY PRECIPITATION FORECASTS FROM THE ECMWF AND CFS MODELS. ABOVE NORMAL PRECIPITATION IS ALSO INDICATED BY DYNAMICAL MODEL FORECASTS FOR WESTERN ALASKA THROUGHOUT THE MONTH OF JULY. THE ORIGINAL HALF-MONTH LEAD FORECAST DISCUSSION RELEASED ON JUNE 15TH IS BELOW: SEA SURFACE TEMPERATURES (SSTS) ARE SLIGHTLY ABOVE AVERAGE ACROSS THE EQUATORIAL PACIFIC. THE MOST RECENT THREE-MONTH MEAN TEMPERATURE ANOMALY FOR THE NINO 3.4 REGION IS +0.4 DEGREES CELSIUS. UPPER-OCEAN TEMPERATURES ARE FROM 0.5 TO 1 DEGREE C ABOVE AVERAGE TO DEPTHS OF ABOUT 100 TO 150 METERS ACROSS THE EQUATORIAL PACIFIC, HOWEVER, THE TOTAL HEAT CONTENT OF THE EQUATORIAL PACIFIC BETWEEN THE SURFACE AND 300 METERS DEPTH HAS DECREASED AFTER PEAKING IN EARLY MAY. NEGATIVE OUTGOING LONGWAVE RADIATION (OLR) ANOMALIES, INDICATING ENHANCED ATMOSPHERIC CONVECTION, WERE OBSERVED NEAR INDONESIA, WHILE POSITIVE ANOMALIES, INDICATING SUPPRESSED CONVECTION, WERE OBSERVED WEST OF THE DATE LINE. LOW-LEVEL WINDS AT 850-HPA AND UPPER-LEVEL WINDS AT 200-HPA HAVE BEEN NEAR LONG-TERM AVERAGES OVER THE EQUATORIAL PACIFIC. THESE ATMOSPHERIC AND OCEAN ANOMALIES INDICATE THE PERSISTENCE OF ENSO-NEUTRAL CONDITIONS. DYNAMICAL MODELS SUCH AS THE CFS AND THE CONSENSUS OF NMME MODELS INDICATE A DECREASE IN THE LIKELIHOOD OF EL NINO CONDITIONS DEVELOPING IN THE NEXT FEW MONTHS RELATIVE TO FORECASTS MADE LAST MONTH. THE CPC CONSOLIDATION OF FORECASTS FROM THE CFS AND THREE STATISTICAL MODELS (CONSTRUCTED ANALOG, MARKOV AND CANONICAL CORRELATION ANALYSIS) FOR THE NINO 3.4 SST INDICATES LESS THAN A 50% PROBABILITY OF ANOMALIES GREATER THAN +0.5C THROUGH 2017 INTO THE BEGINNING OF 2018. THE CPC/IRI CONSENSUS ENSO FORECAST INDICATES SLIGHTLY GREATER THAN A 50% PROBABILITY OF CONTINUING ENSO NEUTRAL CONDITIONS INTO EARLY 2018. THE MADDEN-JULIAN OSCILLATION, AS INDICATED BY THE RMM INDICES, WAS RECENTLY ACTIVE OVER THE WESTERN HEMISPHERE, HOWEVER, DYNAMICAL MODEL FORECASTS DO NOT PREDICT A COHERENT MJO SIGNAL AFTER THE NEXT COUPLE WEEKS. TROPICAL-EXTRATROPICAL TELECONNECTIONS DO NOT PLAY A ROLE IN THE CURRENT MONTHLY FORECAST. WITHOUT THE INFLUENCE OF SIGNIFICANT CLIMATE MODELS OF VARIABILITY DURING THE NEXT MONTH, THE JULY TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED PRIMARILY ON FORECASTS FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME), WITH PARTICULAR FOCUS ON THE FORECASTS OF THE NCEP CLIMATE FORECAST SYSTEM (CFS), AND SOME ATTENTION TO AREAS WHERE THE INFLUENCE OF DECADAL TIMESCALE CLIMATE TRENDS IS GREATER. THE AVERAGE TEMPERATURE ANOMALY FORECAST FROM THE NMME FOR NORTH AMERICA INDICATES POSITIVE ANOMALIES OVER ALMOST THE ENTIRETY OF THE U.S. INCLUDING THE CONUS AND ALASKA. COUNTS OF ENSEMBLE MEMBERS FROM ALL OF THE MODELS INDICATES GREATER THAN 40% IN THE ABOVE NORMAL TERCILE IN ALMOST ALL OF THE U.S., EXCEPT NORTHERN ALASKA, THE NORTHWEST CONUS, AND A FEW SCATTERED SMALLER REGIONS IN THE EASTERN CONUS. PROBABILITY ANOMALY CORRELATION (PAC) CALIBRATED PROBABILITY FORECASTS INDICATE A COHERENT PATTERN OF LIKELY ABOVE NORMAL TEMPERATURES OVER MOST REGIONS, WITH REDUCED PROBABILITIES AND LOWER POTENTIAL SKILL OVER NORTHERN ALASKA, THE PACIFIC NORTHWEST, AND PARTS OF THE EASTERN CONUS CENTERED AROUND THE CENTRAL MISSISSIPPI VALLEY. RELYING ON THESE DYNAMICAL MODEL FORECASTS FROM THE NMME AND CFS, THE JULY TEMPERATURE OUTLOOK INDICATES INCREASED LIKELIHOOD OF ABOVE NORMAL TEMPERATURES FOR ALL REGIONS OF ALASKA AND THE CONUS EXCEPT FOR PARTS OF THE NORTHWEST, WHERE EQUAL CHANCES OF ABOVE, NEAR AND BELOW NORMAL TEMPERATURES IS INDICATED. PROBABILITIES EXCEED 50% OVER A LARGE AREA OF THE SOUTHWEST CONUS, WHERE DECADAL TRENDS HAVE A SIGNIFICANT INFLUENCE ON DYNAMICAL MODEL FORECASTS, AS WELL AS IN PARTS OF MAINE, TEXAS, FLORIDA AND ALASKA. THE JULY PRECIPITATION OUTLOOK RELIES PRIMARILY ON PAC CALIBRATED PROBABILITY FORECASTS FROM THE NMME, AND TO SOME EXTENT, THE MOST RECENT RUNS OF THE CFS AT THE TIME OF THE FORECAST. CALIBRATED FORECASTS FROM THE NMME HAVE LARGE AREAS WHERE PROBABILITIES ARE NEAR EQUAL CHANCES FOR ABOVE, NEAR AND BELOW MEDIAN, INDICATING IN PART THE LOW SKILL OF MONTHLY PRECIPITATION FORECASTS INITIALIZED MORE THAN A HALF MONTH BEFORE JULY. LIMITED AREAS OF INCREASED PROBABILITIES IN THE JULY PRECIPITATION OUTLOOK ARE ALSO A RESULT OF WEAK PRECIPITATION TRENDS AND A LACK OF FORCED CLIMATE SIGNALS FOR MOST REGIONS. THE GREATEST SIGNALS FOR ABOVE MEDIAN PRECIPITATION ARE INDICATED TO BE IN THE WESTERN GULF COAST REGION, A SMALL AREA OF EASTERN MONTANA AND WESTERN NORTH DAKOTA, AND SOUTHWESTERN REGIONS OF ALASKA, INCLUDING THE ALEUTIAN ISLANDS. IN THESE AREAS, PROBABILITIES ARE GENERALLY WEAK AND ONLY EXCEED 40% IN SOME AREAS. A GREATER PROBABILITY OF BELOW MEDIAN PRECIPITATION IS INDICATED FOR PARTS OF THE GREAT BASIN AND CENTRAL ROCKIES. THOUGH THE SIGNAL FOR BELOW MEDIAN PRECIPITATION IN THE WEST IS WEAK IN THE NMME PROBABILITY FORECASTS, A LARGER AREA OF GREATER PROBABILITIES FOR BELOW MEDIAN IS SUPPORTED BY THE RECENT RUNS OF THE CFS. FORECASTER: DAN COLLINS 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 AUG ... WILL BE ISSUED ON THU JUL 20 2017 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$