913  
FXUS07 KWBC 211231  
PMD30D  
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830 AM EDT THU JUN 21 2018  
 
30-DAY OUTLOOK DISCUSSION FOR JULY 2018  
 
THE JULY 2018 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED ON DYNAMICAL  
MODEL GUIDANCE, STATISTICAL TOOLS, CURRENT SOIL MOISTURE CONDITIONS, AND  
POTENTIAL INFLUENCES FROM MODES OF TROPICAL VARIABILITY. ENSO IS NOT A FACTOR  
IN THESE OUTLOOKS SINCE IT IS IN A NEUTRAL STATE AND IS PREDICTED TO REMAIN  
NEUTRAL.  
 
THE MADDEN-JULIAN OSCILLATION (MJO) IS NOT LIKELY TO PLAY A SIGNIFICANT ROLE,  
AS TELECONNECTIONS TO MID-LATITUDE CIRCULATION FEATURES FROM MJO RELATED  
CONVECTION IS TYPICALLY WEAK DURING JULY. THE PREDICTED EVOLUTION OF THE MJO IS  
NOT ONE CONDUCIVE TO THE MJO SUPPORTING TROPICAL CYCLONE DEVELOPMENT IN THE  
EASTERN PACIFIC OR THE ATLANTIC. GIVEN THE PREDICTED STATE OF ENSO AND MJO,  
HIGHER FREQUENCY MODES THAT ARE NOT PREDICTABLE ON MONTHLY TIME SCALES ARE  
LIKELY TO INFLUENCE TROPICAL CYCLONE FORMATIONS, AND THE RESULTANT POTENTIAL  
FOR LARGE MOISTURE INFLUXES INTO THE FORECAST DOMAIN.  
 
MODEL OUTLOOKS FROM THE NMME SUITE, MORE RECENT RUNS FROM THE CFS, AND TRENDS  
FAVOR ABOVE NORMAL TEMPERATURES ACROSS THE WESTERN CONUS, WHERE THE HIGHEST  
ODDS FOR ABOVE NORMAL TEMPERATURES ARE DEPICTED IN THE OFFICIAL OUTLOOK. OVER  
PORTIONS OF THE HIGH PLAINS AND GREAT PLAINS, MANY MODELS INDICATE AN AREA  
WHERE NEAR OR BELOW NORMAL TEMPERATURES ARE FAVORED, WHICH IS IN OPPOSITION TO  
TRENDS, SO EQUAL CHANCES (EC) IS DEPICTED. CURRENT SOIL MOISTURE CONDITIONS AND  
DYNAMICAL MODEL OUTPUT ALSO FAVOR ABOVE NORMAL TEMPERATURES OVER THE CENTRAL  
PLAINS AS WELL AS THE MIDDLE AND LOWER MISSISSIPPI VALLEYS. FURTHER EAST,  
ESPECIALLY ACROSS THE NORTHEAST, TRENDS ALSO CONTRIBUTE TO THE SIGNAL FOR ABOVE  
NORMAL TEMPERATURES. ACROSS THE SOUTHEAST, SOME MODELS HAVE LITTLE TO NO SIGNAL  
FOR TEMPERATURE DEVIATIONS, SO EC IS INDICATED IN THE OFFICIAL OUTLOOK. ACROSS  
ALASKA, TRENDS FAVOR ABOVE NORMAL TEMPERATURES THOUGH MODEL OUTPUTS SHOW A  
WEAKNESS ACROSS EASTERN ALASKA. THE OUTLOOK FAVORS ABOVE NORMAL TEMPERATURES  
OVER WESTERN AND SOUTHERN ALASKA, WHERE MODEL OUTPUT, TRENDS, AND RECENT SST  
OBSERVATIONS ALIGN.  
 
THE PRECIPITATION OUTLOOK IS LESS CERTAIN THAN THE TEMPERATURE OUTLOOK,  
ESPECIALLY OVER THE GREAT PLAINS. MOST OF THE MODELS FROM THE NMME SUITE AND  
THE RECENT CFS RUNS DEPICT A STRONG DRY SIGNAL OVER THE CARIBBEAN AND A STRONG  
WET SIGNAL OVER THE CENTRAL TROPICAL PACIFIC. MOST OF THE MODELS INDICATE A  
SIGNAL FOR ABOVE NORMAL PRECIPITATION OVER THE SOUTHWEST AND INTO THE CENTRAL  
ROCKIES, WHICH IS CONSISTENT WITH SOME NORTHWARD MOISTURE TRANSPORT OUT OF THE  
EAST PACIFIC, AND AN ACTIVE START TO THE SOUTHWEST MONSOON. THE DRY SIGNAL FROM  
THE CARIBBEAN EXTENDS INTO THE GREAT PLAINS, IMPLYING LESS NORTHWARD MOISTURE  
TRANSPORT FROM THE LOWER LATITUDES. THIS SIGNAL CONFLICTS WITH TRENDS FOR  
PORTIONS OF THE LOWER MISSISSIPPI VALLEY, SO PROBABILITIES ARE MUTED COMPARED  
TO MODEL OUTPUTS. MODEL HINDCASTS REVEAL LITTLE SKILL IN THE CENTRAL AND  
NORTHERN PLAINS AND TRENDS ARE WEAK IN THOSE AREAS, SO NO SIGNAL FOR EITHER  
WETTER OR DRIER THAN NORMAL CONDITIONS IS DEPICTED IN THE OUTLOOK. TRENDS IN  
THE NORTHEAST FOR THE CORE SUMMER MONTHS FAVOR WETTER CONDITIONS, WHILE RECENT  
CFS OUTPUT SUGGESTS BELOW NORMAL PRECIPITATION FOR THE NORTHEAST, WITH THAT  
SIGNAL FADING OVER THE MID-ATLANTIC. BOTH TRENDS AND MODEL GUIDANCE FAVOR BELOW  
NORMAL PRECIPITATION FOR THE PACIFIC NORTHWEST. ABOVE AVERAGE PRECIPITATION IS  
FAVORED FOR NORTHERN AND WESTERN ALASKA INCLUDING THE ALEUTIANS, SUPPORTED BY  
MODEL GUIDANCE. ACROSS EASTERN ALASKA, UNCERTAINTY IS GREATER, SO EQUAL CHANCES  
IS INDICATED.  
 
FORECASTER: MATTHEW ROSENCRANS  
 
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 SAT JUNE 30 2018  
 
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.  

 
 
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