237  
FXUS07 KWBC 211231  
PMD30D  
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830 AM EDT THU MAY 21 2020  
 
30-DAY OUTLOOK DISCUSSION FOR JUNE 2020  
 
THE JUNE 2020 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED PRIMARILY ON  
DYNAMICAL MODEL GUIDANCE, STATISTICAL TOOLS, AND CURRENT SOIL MOISTURE  
CONDITIONS. ENSO-NEUTRAL CONDITIONS ARE CURRENTLY PRESENT ACROSS THE TROPICAL  
PACIFIC, AND THE CONSENSUS FORECAST INDICATES THAT ENSO-NEUTRAL CONDITIONS ARE  
LIKELY TO REMAIN IN PLACE THROUGHOUT THE MONTH OF JUNE AND INTO THE NEXT  
SEVERAL SEASONS. SSTS HAVE COOLED ACROSS MOST OF THE EQUATORIAL TROPICAL  
PACIFIC DURING THE LAST SEVERAL WEEKS AND ARE NEAR OR BELOW AVERAGE OVER THE  
EASTERN EQUATORIAL PACIFIC. THE MADDEN-JULIAN OSCILLATION OR MJO HAS RECENTLY  
BECOME ACTIVE WITH CONVECTION CENTERED OVER THE INDIAN OCEAN. DYNAMICAL MODEL  
FORECASTS, INCLUDING THE NCEP CFSV2, INDICATE THAT THE MJO IS EXPECTED TO  
REMAIN ACTIVE AND PROPAGATE ACROSS THE MARITIME CONTINENT INTO THE WESTERN  
PACIFIC OCEAN, POTENTIALLY INFLUENCING THE CLIMATE OVER NORTH AMERICA IN THREE  
TO FOUR WEEKS FROM THE PRESENT TIME. STATISTICAL TOOLS SHOW THAT THE ACTIVE MJO  
IN THE CURRENT PHASE WILL POTENTIALLY ENHANCE THE CHANCES OF BELOW NORMAL  
TEMPERATURES ACROSS MUCH OF THE EASTERN CONUS AND ABOVE NORMAL TEMPERATURES FOR  
PARTS OF THE WESTERN CONUS IN EARLY JUNE. THE TRANSIENT MJO IMPACT WILL  
POTENTIALLY INFLUENCE JUNE MONTHLY AVERAGE TEMPERATURES AND INCREASE THE  
UNCERTAINTY IN THE JUNE OUTLOOK. ABSENT A SIGNAL FROM ENSO, THE JUNE  
TEMPERATURE OUTLOOK IS SOMEWHAT IMPACTED BY DECADAL TIME SCALE TEMPERATURE  
TRENDS, MODERATED BY SHORTER TIMESCALE CLIMATE IMPACTS, INCLUDING SOIL MOISTURE  
FEEDBACKS. IF THE MJO OR RELATED ATMOSPHERIC KELVIN WAVE PROPAGATES EASTWARD  
OVER THE WESTERN HEMISPHERE DURING EARLY JUNE, THIS WOULD PROVIDE A FAVORABLE  
LARGE SCALE ENVIRONMENT FOR TROPICAL CYCLONE DEVELOPMENT ACROSS THE NORTHWEST  
CARIBBEAN AND SOUTHERN GULF OF MEXICO AND MAY IMPACT PRECIPITATION FOR PARTS OF  
THE SOUTHEASTERN CONUS.  
 
THE JUNE TEMPERATURE OUTLOOK CALLS FOR ENHANCED PROBABILITIES FOR ABOVE NORMAL  
TEMPERATURES FOR ALL OF ALASKA WITH PROBABILITIES EXCEEDING 50 PERCENT FOR  
SOUTHWESTERN AREAS OF THE STATE, WHERE NEARBY SEA SURFACE TEMPERATURES ARE  
ABOVE AVERAGE. THE WEEK 3-4 TEMPERATURE OUTLOOK INDICATES LIKELY ABOVE NORMAL  
AVERAGE TEMPERATURES FOR THE FIRST HALF OF JUNE FOR ALASKA, AND DYNAMICAL MODEL  
FORECASTS FROM THE CFS AS WELL AS THE NMME SUPPORT ABOVE NORMAL TEMPERATURES  
FOR THE MONTH. ABOVE NORMAL TEMPERATURES ARE ALSO LIKELY FOR THE MONTH OF JUNE  
FOR THE WESTERN CONUS, PRIMARILY TO THE WEST OF THE CONTINENTAL DIVIDE,  
SUPPORTED BY DYNAMICAL MODEL FORECASTS FROM THE CFS AND NMME, AND SIMILAR IN  
EXTENT TO PREDICTED LIKELY ABOVE NORMAL TEMPERATURES IN THE FIRST HALF OF JUNE  
BY THE CPC WEEK 3-4 OUTLOOK. PROBABILITIES EXCEED 50 PERCENT FOR MUCH OF THE  
GREAT BASIN AND SOUTHWEST REGIONS, WHERE THE SIGNAL DUE TO DECADAL TEMPERATURE  
TRENDS IS GREATER. UNCERTAINTY INCREASES ACROSS MUCH OF THE CENTRAL AND EASTERN  
CONUS, DUE IN PART TO THE INFLUENCE OF SHORTER TIMESCALE CLIMATE SIGNALS SUCH  
AS THE MJO. A LARGE AREA OF EQUAL CHANCES OF BELOW, NEAR OR ABOVE NORMAL  
TEMPERATURES IS INDICATED FOR THE MONTH OF JUNE FROM THE NORTHERN AND CENTRAL  
PLAINS ACROSS THE UPPER AND CENTRAL MISSISSIPPI VALLEYS, WHERE THERE IS GREATER  
ENSEMBLE SPREAD AMONG INDIVIDUAL MODELS OF THE NMME. TEMPERATURES FOR THE MONTH  
OF JUNE MAY ALSO BE MODERATED ACROSS THIS AREA BY CURRENT POSITIVE SOIL  
MOISTURE ANOMALIES AND AN ABOVE NORMAL PRECIPITATION FORECAST. PROBABILITIES OF  
ABOVE NORMAL TEMPERATURES INCREASE FOR THE GULF COAST STATES AS WELL AS THE  
EASTERN SEABOARD AND NORTHEAST REGIONS, SUPPORTED BY DYNAMICAL MODEL FORECASTS  
INCLUDING THE CFS AND NMME MODELS. MODELS CONSISTENTLY SHOW A HIGH PROBABILITY  
OF ABOVE NORMAL TEMPERATURES FOR THE SOUTHERN FLORIDA PENINSULA WHERE THE  
PROBABILITY OF ABOVE NORMAL TEMPERATURES EXCEEDS 50 PERCENT. ABOVE NORMAL  
TEMPERATURES FOR THE NORTHEAST REGION ARE ALSO SUPPORTED BY LARGER POSITIVE  
DECADAL TEMPERATURE TRENDS FOR THIS REGION.  
 
THE JUNE PRECIPITATION OUTLOOK CALLS FOR ENHANCED PROBABILITIES OF BELOW NORMAL  
PRECIPITATION FOR WESTERN AREAS OF THE STATES OF WASINGTON AND OREGON,  
SUPPORTED BY DYNAMICAL MODEL FORECASTS INCLUDING NMME PROBABILITY FORECASTS,  
WHERE SEASONAL CLIMATE SIGNALS INDICATE A BROADER AREA OF LIKELY BELOW NORMAL  
PRECIPITATION. HOWEVER, DYNAMICAL MODELS INDICATE UNCERTAINTY IS GREATER IN THE  
INDIVIDUAL MONTH OF JUNE. PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE  
ENHANCED OVER A LARGE AREA OF THE EASTERN CONUS STRETCHING FROM EASTERN AREAS  
OF THE GREAT PLAINS ACROSS THE CENTRAL AND LOWER MISSISSIPPI VALLEYS AND THE  
SOUTHEAST REGION TO THE SOUTHERN ATLANTIC COAST, SUPPORTED BY PROBABILITY  
FORECASTS FROM THE NMME. DYNAMICAL MODELS, INCLUDING THE CFS, INDICATE AN  
ACTIVE GULF OF MEXICO IN JUNE. SKILL IN PRECIPITATION FORECASTS IS LIMITED BUT  
A CLEAR SIGNAL IS APPARENT IN DYNAMICAL MODELS FOR A LARGE AREA OF THE EASTERN  
CONUS. MODELS ARE LESS CONSISTENT FOR THE NORTHEAST REGION JUNE PRECIPITATION  
FORECAST WHERE EQUAL CHANCES OF BELOW, NEAR AND ABOVE NORMAL PRECIPITATION IS  
INDICATED. DYNAMICAL MODEL FORECASTS FROM THE NMME INDICATE MUCH OF THE  
PRECIPITATION SIGNAL OVER ALASKA IS ALONG THE SOUTHERN COAST, WHERE  
PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE INCREASED.  
 
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 JUN WILL BE ISSUED ON SUN MAY 31 2020  
 
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.  

 
 
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