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FXUS07 KWBC 301900
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT FRI JUN 30 2023
30-DAY OUTLOOK DISCUSSION FOR JULY 2023
THE UPDATED TEMPERATURE AND PRECIPITATION OUTLOOKS FOR JULY 2023 ARE UPDATED TO
REFLECT RECENT MODEL GUIDANCE AND INCORPORATE THE LATEST OFFICIAL OUTLOOKS FROM
THE WEATHER PREDICTION CENTER(WPC) FOR WEEK-1, AND THOSE FROM THE CLIMATE
PREDICTION CENTER (CPC) FOR FURTHER LEADS. EL NIñO IS STILL PRESENT IN THE
EQUATORIAL PACIFIC, AND LIKELY TO REMAIN IN PLACE FOR THE ENTIRE MONTH. THE
ACTIVE PHASE OF THE MADDEN JULIAN OSCILLATION (MJO) IS OVER THE INDIAN OCEAN,
BUT OF LOW AMPLITUDE AND UNLIKELY TO HAVE A MAJOR IMPACT OUTSIDE OF INFLUENCE
ON TROPICAL CYCLONE FORMATIONS POTENTIALLY LATER IN THE MONTH. EARLY MONTH
SIGNALS ARE LIKELY TO DRASTICALLY CHANGE THE SOIL MOISTURE ANOMALY PATTERNS
OVER THE COTERMINOUS UNITED STATES (CONUS), SO THE ANALOGS BASED ON THOSE
ANOMALIES ARE NOT HEAVILY WEIGHTED.
FOR THE TEMPERATURE OUTLOOK, THE LARGEST CHANGES FROM THE MID-MONTH OUTLOOK TO
THE UPDATED OUTLOOK EXTEND FROM THE NORTHERN AND CENTRAL ROCKIES TO HIGH
PLAINS, AND ACROSS SOUTHERN ALASKA. THE OUTLOOK OVER THE NORTHERN AND CENTRAL
ROCKIES AND HIGH PLAINS NOW FAVORS BELOW-NORMAL TEMPERATURES, LARGELY
INFLUENCED BY THE FORECAST CONDITIONS EARLY IN THE MONTH (DAYS 1-14). THE
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE DECREASED OVER THE MISSISSIPPI
AND OHIO RIVER VALLEYS, REFLECTIVE OF THE LATEST OFFICIAL OUTLOOKS AND MODEL
GUIDANCE. SOME TOOLS INDICATE ABOVE-NORMAL TEMPERATURES OVER CALIFORNIA AND
NEVADA, WHILE OTHERS INDICATE NEAR OR BELOW-NORMAL TEMPERATURES IN THE SECOND
HALF OF THE MONTH, SO EQUAL CHANCES OF ABOVE, NEAR, OR BELOW NORMAL
TEMPERATURES (EC) IS INDICATED FOR THOSE AREAS OF DISAGREEMENT AMONG THE TOOLS.
ACROSS SOUTHERN MAINLAND ALASKA AND THE ALASKA PENINSULA, TROUGHING DURING THE
FIRST HALF OF THE MONTH COULD TIP TEMPERATURES TO THE BELOW-NORMAL CATEGORY,
THOUGH SOME MODERATION IS LIKELY IN THE SECOND HALF OF THE MONTH.
THE PRECIPITATION OUTLOOK FOR ALASKA HAS CHANGED TO FAVORING ABOVE-NORMAL
PRECIPITATION FROM THE ALASKA PENINSULA NORTHWARD ACROSS WESTERN ALASKA TO THE
BROOKS RANGES AND ALONG THE NORTHERN COAST. THIS IS MAINLY A SIGNAL EARLY IN
THE MONTH, BUT DOES REMAIN WITH WEAK PROBABILITIES THROUGH THE ENTIRE MONTH.
OVER THE CONUS, THE MONSOON RAINS ARE STILL EXPECTED TO BE BELOW NORMAL.
HURRICANE BEATRIZ COULD TRIGGER A MONSOON MOISTURE SURGE DURING THE FIRST HALF
OF JULY ACROSS THE SOUTHWEST, SO PROBABILITIES ARE MITIGATED COMPARED TO SOME
MODEL GUIDANCE. STRONGER SIGNALS FOR ABOVE-NORMAL PRECIPITATION ARE LOCATED
OVER THE CENTRAL GREAT PLAINS AND MIDDLE MISSISSIPPI VALLEY DUE TO PREDICTED
RAINS IN THE FIRST WEEK EXCEEDING THE THRESHOLD FOR THE BELOW NORMAL CATEGORY
ON THE MONTHLY TIMESCALE. SMALL PORTIONS OF TEXAS ARE ALSO LIKELY TO EXCEED
THAT THRESHOLD DURING THE FIRST WEEK OF JULY. DURING THE REMAINDER OF THE
MONTH, AN ACTIVE STORM TRACK IS FORECAST FROM THE NORTHERN ROCKIES TO THE OHIO
VALLEY AND NORTHEAST, WHICH LEADS TO ENHANCED PROBABILITIES OF ABOVE-NORMAL
PRECIPITATION IN THOSE REGIONS.
---- PREVIOUS DISCUSSION FROM MID-JUNE RELEASE FOLLOWS -----
THE JULY 2023 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED ON THE NORTH
AMERICAN MULTI-MODEL ENSEMBLE (NMME), CPC'S STATISTICAL TOOLS, CONSOLIDATIONS
OF THOSE INPUTS, THE COPERNICUS (C3S) MODEL SYSTEMS DATA FOR JULY, THE WEEK 3-4
MODEL SOLUTIONS, AND ANTECEDENT SOIL MOISTURE CONDITIONS. AN EL NIñO ADVISORY
WAS RECENTLY ISSUED, THOUGH THE OCEAN-ATMOSPHERE COUPLING IS NOT YET STRONG
ENOUGH TO CONTRIBUTE MAJORLY TO THE VARIABILITY OVER ALASKA AND THE CONTIGUOUS
UNITED STATES (CONUS) DURING JULY. THE MADDEN-JULIAN OSCILLATION (MJO) REMAINS
ACTIVE WITH ITS ENHANCED PHASE OVER THE MARITIME CONTINENT. THE MJO IS FORECAST
TO WEAKEN BY MANY OF THE GLOBAL MODELS. TYPICALLY IN JULY, THE MAIN PATHWAY OF
MJO RELATED INFLUENCE ON THE MID-LATITUDE CIRCULATION PATTERN IS THROUGH
MODULATION OF TROPICAL CYCLONE ACTIVITY. AN MJO CONTRIBUTING TO A RELATIVE
BURST IN EAST PACIFIC TROPICAL CYCLONE ACTIVITY COULD RESULT IN MOISTURE SURGES
INTO THE SOUTHWEST, AND LATER MORE TROPICAL CYCLONE ACTIVITY IN THE ATLANTIC,
THOUGH JULY IS RELATIVELY A QUIET TIME OF YEAR FOR TROPICAL ACTIVITY IN THE
ATLANTIC.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM THE FOUR CORNERS REGION, ACROSS THE
CENTRAL AND SOUTHERN GREAT PLAINS, THE SOUTHEAST, AND THE NORTHEAST. THE
HIGHEST ODDS ARE ACROSS THE RIO GRANDE VALLEY AND THE NORTHEAST, WHERE NMME AND
STATISTICAL TOOL OUTPUTS ARE ALIGNED. FROM SOUTHERN CALIFORNIA TO THE GREAT
BASIN, NORTHERN ROCKIES AND PORTIONS OF THE NORTHERN GREAT PLAINS, THE NMME AND
C3S SOLUTIONS WERE MUCH COOLER THAN THE STATISTICAL TOOLS, AND RECENT SOIL
MOISTURE CONDITIONS ARE QUITE ANOMALOUS IN THOSE REGIONS, SO UNCERTAINTY IS
HIGHER THERE COMPARED TO OTHER PARTS OF THE FORECAST DOMAIN. TRENDS (OPTIMAL
CLIMATE NORMALS) IN THOSE REGIONS ALSO SHOW PATTERNS OPPOSITE OF MANY OTHER
TOOLS, SO OCN ARE DISCOUNTED IN FAVOR OF EQUAL CHANCES OF ABOVE-, NEAR-, AND
BELOW-NORMAL TEMPERATURES (EC). MANY TOOLS INDICATED WEAK PROBABILITIES ACROSS
THE GREAT PLAINS AND CORN BELT, BUT THE RECENT SOIL MOISTURE ANALOGS FAVORED
ABOVE-NORMAL TEMPERATURES. SUMMER MONTHS ARE WHEN THAT PREDICTOR HAS THE
STRONGEST RELATIONSHIP, SO A SLIGHT TILT TOWARD ABOVE-NORMAL TEMPERATURES WAS
MAINTAINS ACROSS MUCH OF THE GREAT PLAINS AND CORN BELT. ACROSS ALASKA, MOST
MODELING SYSTEMS AND STATISTICAL TOOLS FAVORED ABOVE-NORMAL TEMPERATURES, WITH
THE HIGHEST ODDS ACROSS THE SOUTHERN PORTIONS OF MAINLAND ALASKA. RECENT
BELOW-NORMAL SEA SURFACE TEMPERATURES (SSTS) AND LATE SEASON SEA ICE BREAKUP
MITIGATE ODDS NEAR THE WEST COAST OF ALASKA.
A WEAKENED MONSOON DURING JULY ACROSS EASTERN ARIZONA AND NEW MEXICO IS
PREDICTED IN MANY OF THE NMME INPUT SYSTEMS AND SOME OF THE STATISTICAL TOOLS,
SO THAT SIGNAL MAKES IT INTO THE FINAL CONSOLIDATION. AGAIN, TRENDS ARE SHOWING
OPPOSITE SIGNALS ACROSS THE GREAT BASIN AND PORTIONS OF THE ROCKIES, SO
FORECAST PROBABILITIES ARE A BIT MUTED, AND THE TRENDS ARE LARGELY DISCOUNTED.
NMME OUTPUT FAVORS ABOVE-NORMAL PRECIPITATION ACROSS THE RIO GRANDE WHILE
STATISTICAL TOOLS HAVE A SIGNAL FURTHER EAST, SO THE OFFICIAL OUTLOOK IS A
COMPROMISE BETWEEN THOSE TWO. UPPER-LEVEL HEIGHT ANOMALIES FROM THE NMME IMPLY
A STRONG SUBTROPICAL RIDGE, WHICH WOULD FAVOR ABOVE-NORMAL PRECIPITATION FROM
THE SOUTHERN GREAT PLAINS NORTHWARD AND INTO THE MID-ATLANTIC. THE MID-LATITUDE
PORTION OF THE NMME SIGNAL WOULD ALSO FAVOR A STORM TRACK ACROSS THE NORTHERN
GREAT PLAINS AND INTO THE OHIO RIVER VALLEY, SO ABOVE-NORMAL PRECIPITATION IS
FAVORED ACROSS THOSE TWO REGIONS. THE NMME HAS STRONG SIGNALS FOR BELOW-NORMAL
PRECIPITATION ACROSS NORTHERN MAINLAND ALASKA, WITH A WEAK STORM TRACK FURTHER
SOUTH. MANY OF THE STATISTICAL TOOLS HAVE LOW SKILL DURING JULY IN ALASKA, AND
THE COUPLING TO THE TROPICS IS NOT INFLUENTIAL IN ALASKA DURING THE SUMMER, SO
THE NMME HAD A LARGER INFLUENCE ON THE OUTLOOK.
FORECASTER: MATTHEW ROSENCRANS
THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1991 AND 2020, 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 2023
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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