PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD 300 PM EDT SAT JUN 30 2018 30-DAY OUTLOOK DISCUSSION FOR JULY 2018 THE UPDATED TEMPERATURE AND PRECIPITATION OUTLOOKS, VALID FOR JULY 2018, REFLECT THE LATEST MODEL GUIDANCE AND OUTLOOK PRODUCTS FROM THE VARIOUS NCEP CENTERS. THE TEMPERATURE OUTLOOK FOR JULY HAS CHANGED CONSIDERABLY OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. A PREDICTED COLDER THAN NORMAL START TO THE MONTH IS LIKELY TO RESULT IN AN OVERALL COOLER THAN NORMAL MONTH FOR THE NORTHERN ROCKIES, WHILE THE SIGNAL FOR WARMTH OVER MUCH OF THE PACIFIC NORTHWEST HAS BEEN REMOVED. FOR THE PACIFIC NORTHWEST, NORTHERN CALIFORNIA AND PORTIONS OF THE GREAT BASIN, EARLY COOL TEMPERATURES ASSOCIATED WITH TROUGHING ALOFT ARE LIKELY TO GIVE WAY TO WARMER TEMPERATURES LATER IN THE MONTH, SO THAT INCREASES THE UNCERTAINTY. THE COOLER TEMPERATURES PREDICTED OVER THE PACIFIC NORTHWEST ARE LINKED TO THE SAME AIR MASS AND PREDICTED TROUGHING THAT COULD INFLUENCE THE ALASKA PANHANDLE, SO UNCERTAINTY THERE INCREASED ENOUGH TO WARRANT A CHANGE FROM ABOVE NORMAL TO EQUAL CHANCES. SIGNALS FOR WARMTH FROM THE SOUTHERN PLAINS TO THE NORTHEAST REMAIN, THOUGH WITH MORE CERTAINTY, SO PROBABILITIES ARE INCREASED, ESPECIALLY OVER THE NORTHEAST WHERE A VERY WARM START TO THE MONTH WILL NOT LIKELY BE OVERCOME BY A PREDICTED MODERATION LATER IN THE MONTH. OVER THE SOUTHERN PLAINS, CURRENT AND PREDICTED DRY CONDITIONS ARE LIKELY TO CONTRIBUTE TO ABOVE NORMAL TEMPERATURES. THE UNCERTAINTY OVER THE PACIFIC NORTHWEST RESULTED IN THE REMOVAL OF MUCH OF THE SIGNAL FOR BELOW NORMAL PRECIPITATION, WHICH IS NOW FURTHER NORTHWEST AND INFLUENCING THE ALASKA PANHANDLE AND SOUTHERN ALASKA. MOISTURE FLOWING INTO THE SOUTHWEST IS LIKELY RELATED TO ONGOING AND PREDICTED TROPICAL CYCLONE ACTIVITY LEADING TO MULTIPLE GULF SURGES, MODELS HAVE BEEN DEPICTING THIS SIGNAL FOR MANY DAYS NOW. THE SIGNAL FOR DRYNESS IN THE SOUTHERN PLAINS REMAINS, THOUGH IT SHIFTED A BIT FURTHER NORTHWEST AS RAINS ARE PREDICTED DURING THE FIRST WEEK OF JULY FROM EASTERN TEXAS TO GEORGIA MITIGATE CHANCES FOR BELOW NORMAL PRECIPITATION THERE. MODERATE PRECIPITATION EARLY IN JULY IS FORECAST FOR SOUTHEASTERN NEW MEXICO TO PORTIONS OF OKLAHOMA, THEN THE REST OF THE MONTH LOOKS TO TILT DRIER, SO THERE IS QUITE A BIT OF UNCERTAINTY FROM SOUTHEASTERN NEW MEXICO TO OKLAHOMA, AND FOR ARKANSAS. SIGNALS FOR BELOW NORMAL PRECIPITATION FOR THE NORTHEAST CONTINUE, LINKED TO EARLY MONTH DRYNESS AND PREDICTED RIDGING OVER THE GREAT LAKES FOR MOST OF THE MONTH. ----------------- PREVIOUS DISCUSSION FOLLOWS ----------------- 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. THE NEXT MONTHLY OUTLOOK...FOR AUG ... WILL BE ISSUED ON THU JUL 19 2018 THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD. $$