PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830 AM EDT THU JUN 15 2017

30-DAY OUTLOOK DISCUSSION FOR JULY 2017

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.



AN UPDATED MONTHLY OUTLOOK... FOR JUL WILL BE ISSUED ON FRI JUNE 30 2017


THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.

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