959
FXUS07 KWBC 301900
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT THU APR 30 2026
30-DAY OUTLOOK DISCUSSION FOR MAY 2026
THE UPDATED MAY TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED ON THE LATEST
DYNAMICAL MODELS, WPC TEMPERATURE AND PRECIPITATION FORECASTS DURING THE FIRST
WEEK OF THE MONTH, THE CPC 8-14 DAY TEMPERATURE AND PRECIPITATION OUTLOOKS, AND
THE WEEK 3-4 MODEL OUTPUT (VALID MAY 15-28). SOIL MOISTURE WAS ALSO A FACTOR IN
THE UPDATED MAY OUTLOOKS. THE MADDEN-JULIAN OSCILLATION (MJO) STRENGTHENED
DURING EARLY APRIL WITH AN EASTWARD PROPAGATION OVER THE WESTERN HEMISPHERE. BY
LATE APRIL, THE MJO SHIFTED EAST TO AFRICA AND THE WESTERN INDIAN OCEAN. A
ROBUST MJO OVERSPREADING THE INDIAN OCEAN AND ITS POTENTIAL INFLUENCE LATER IN
MAY WAS A CONSIDERATION IN THE UPDATED TEMPERATURE OUTLOOK. ENSO-NEUTRAL
CONDITIONS ARE PRESENT WITH EL NINO LIKELY TO EMERGE DURING MAY-JUNE-JULY.
FOLLOWING AN UNUSUALLY WARM EARLY SPRING FOR THE SOUTH-CENTRAL AND EASTERN
CONTIGUOUS U.S. (CONUS), A MAJOR PATTERN CHANGE WAS WELL UNDERWAY BY THE END OF
APRIL AS A HIGHLY AMPLIFIED 500-HPA TROUGH HAS DEVELOPED OVER EASTERN NORTH
AMERICA. A COUPLE OF STRONG COLD FRONTS FOR THIS TIME OF YEAR ARE FORECAST TO
USHER IN COOLER-THAN-NORMAL TEMPERATURES FROM THE GREAT PLAINS TO THE EAST
COAST THROUGH THE FIRST TEN DAYS OF THE MONTH. UNSEASONABLY COOL TEMPERATURES
THROUGH AT LEAST EARLY MAY RESULTS IN THE UPDATED OUTLOOK LEANING TOWARDS
BELOW-NORMAL TEMPERATURES ACROSS PARTS OF THE EASTERN CORN BELT, GREAT LAKES,
AND NORTHEAST. THE GEFS AND ECENS DEPICT THE EASTERN NORTH AMERICA TROUGH
DEAMPLIFYING AND PROGRESSING TO THE EAST BY MID-MAY WITH ANOMALOUS MID-LEVEL
RIDGING EXPANDING TO THE GREAT PLAINS. THE WEEK 3-4 GEFS AND ECENS, VALID FROM
MAY 15-28, ARE IN GOOD AGREEMENT WITH A BROAD 500-HPA RIDGE AND POSITIVE HEIGHT
ANOMALIES THROUGHOUT THE LOWER 48 STATES. THESE MODEL SOLUTIONS ALSO FAVOR A
FLIP FROM BELOW TO ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE EAST-CENTRAL
CONUS DURING MID-MAY WHICH WOULD BE CONSISTENT WITH THE MJO CURRENTLY ENTERING
THE INDIAN OCEAN. THIS PREDICTED VARIABLE TEMPERATURE PATTERN DURING MAY
SUPPORTS SMALLER PROBABILITIES (< 50%) FOR BELOW AND ABOVE-NORMAL TEMPERATURES
ALONG WITH EQUAL CHANCES (EC) OF BELOW, NEAR, OR ABOVE-NORMAL TEMPERATURES
ACROSS THE EASTERN THIRD OF THE CONUS. FARTHER TO THE WEST, ABOVE-NORMAL
TEMPERATURES ARE MORE LIKELY TO PREVAIL DURING MOST IF NOT ALL OF THE MONTH.
THE LARGEST ABOVE-NORMAL TEMPERATURE PROBABILITIES (> 60%) ARE FORECAST FOR THE
PACIFIC NORTHWEST WITH TEMPERATURES AVERAGING 10 TO 15 DEGREES F ABOVE NORMAL
DURING THE FIRST WEEK OF MAY. PROBABILITIES ARE LOWER ACROSS THE DESERT
SOUTHWEST AS MODEL SOLUTIONS REMAIN CONSISTENT THAT A COUPLE OF SOUTHERN STREAM
SHORTWAVE TROUGHS CROSS THIS REGION EARLY IN THE MONTH. IN ADDITION TO THE
PREDICTED LONGWAVE PATTERN AND DYNAMICAL MODEL TEMPERATURE TOOLS, DRY TOPSOIL
SUPPORTS THE INCREASED CHANCE OF ABOVE-NORMAL TEMPERATURES FROM THE OKLAHOMA
AND TEXAS PANHANDLES NORTH THROUGH WESTERN KANSAS AND NEBRASKA. DUE IN PART TO
NEARBY BELOW-NORMAL SEA SURFACE TEMPERATURE ANOMALIES, THE MAY OUTLOOK
CONTINUES TO SLIGHTLY FAVOR BELOW-NORMAL TEMPERATURES FOR SOUTHWESTERN ALASKA
AND THE ALASKA PENINSULA. BASED ON A MODEL CONSENSUS, ABOVE-NORMAL TEMPERATURES
ARE SLIGHTLY FAVORED ACROSS NORTHERN TO EASTERN ALASKA.
THE UPDATED MAY PRECIPITATION OUTLOOK RELIES PRIMARILY ON THE MODEL
PRECIPITATION FORECASTS THROUGH THE FIRST TWO WEEKS OF THE MONTH. DURING THE
LATTER HALF OF MAY, THE GEFS AND ECENS EITHER DIVERGE OR DEPICT WEAK SIGNALS
FOR PRECIPITATION. A STATIONARY FRONT ALONG WITH AT LEAST TWO SHORTWAVE TROUGHS
WITHIN THE SOUTHERN STREAM FAVOR ABOVE-NORMAL PRECIPITATION FROM TEXAS EAST TO
THE WESTERN GULF COAST, LOWER MISSISSIPPI VALLEY, AND PARTS OF THE SOUTHEAST.
PROBABILITIES EXCEED 40% IN PORTIONS OF SOUTHEASTERN TEXAS, LOUISIANA, AND
SOUTHWESTERN MISSISSIPPI WHERE THE WPC 7-DAY QPF HAS AROUND 2 INCHES OF
PRECIPITATION. DOWNSTREAM OF A 500-HPA TROUGH AXIS THAT IS FORECAST TO PERSIST
THROUGH MID-MAY AND CONSISTENT WITH THE 8-14 DAY OUTLOOK, ABOVE-NORMAL
PRECIPITATION IS SLIGHTLY FAVORED FOR EASTERN MAINE. ALTHOUGH A NUMBER OF TOOLS
LEAN ON THE WETTER SIDE FOR MORE OF THE SOUTHEAST AND NEW ENGLAND EARLY IN THE
MONTH, HIGH UNCERTAINTY DURING THE LATER HALF OF MAY PRECLUDES FAVORING
ABOVE-NORMAL PRECIPITATION. THE LARGE ABOVE-NORMAL PRECIPITATION PROBABILITIES
(> 60%) ACROSS SOUTHERN NEW MEXICO AND THE EL PASO AREA ARE RELATED TO THE
LIKELIHOOD THAT PRECIPITATION DURING THE FIRST WEEK OF MAY REACHES THE UPPER
TERCILE FOR THE MONTH IN A CLIMATOLOGICALLY DRIER AREA. A DRY START TO THE
MONTH AND THE EXPECTATION THAT ANOMALOUS 500-HPA RIDGING EXPANDS EASTWARD TO
THE NORTH-CENTRAL CONUS BY MID-MAY FAVORS BELOW-NORMAL PRECIPITATION ACROSS THE
PACIFIC NORTHWEST, MUCH OF THE NORTHERN ROCKIES, NORTHERN TO CENTRAL GREAT
PLAINS, AND UPPER MISSISSIPPI VALLEY. DUE TO WEAK AND CONFLICTING MODEL
GUIDANCE, EC IS FORECAST THROUGHOUT ALASKA.
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PREVIOUS DISCUSSION RELEASED ON APRIL 16 BELOW
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THE MAY 2026 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED ON THE: NORTH
AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND INTERNATIONAL MULTI-MODEL ENSEMBLE
(IMME), CONSOLIDATION (COMBINATION OF STATISTICAL AND DYNAMICAL MODEL TOOLS),
SOIL MOISTURE INFLUENCE AND ITS CONSTRUCTED ANALOG, AND DECADAL TRENDS. THE
MADDEN-JULIAN OSCILLATION (MJO) STRENGTHENED DURING EARLY APRIL AND DYNAMICAL
MODELS HAVE REMAINED CONSISTENT SINCE LAST WEEK THAT A ROBUST MJO PROPAGATES
EASTWARD FROM THE WEST PACIFIC TO THE INDIAN OCEAN DURING THE LATTER HALF OF
APRIL. THIS MJO EVOLUTION AND ITS POTENTIAL INFLUENCE ON THE MID-LATITUDE
CIRCULATION PATTERN WAS CONSIDERED IN THE TEMPERATURE OUTLOOK. ENSO-NEUTRAL
CONDITIONS ARE PRESENT WITH EL NINO LIKELY TO EMERGE DURING MAY-JUNE-JULY.
THE NMME AND IMME SUPPORT AN INCREASED CHANCE OF ABOVE-NORMAL TEMPERATURES FOR
THE WESTERN CONTIGUOUS U.S. (CONUS), MUCH OF THE GREAT PLAINS, AND SOUTHEAST.
THE LARGEST ABOVE-NORMAL TEMPERATURE PROBABILITIES (GREATER THAN 50%) ARE
FORECAST FOR THE PACIFIC NORTHWEST WHERE THE CALIBRATED NMME AND IMME HAVE THE
STRONGEST WARM SIGNAL AND THERE IS ALSO SUPPORT FROM THE STATISTICAL TOOLS. IN
ADDITION, THE LARGER PROBABILITIES ARE CONSISTENT WITH THE EXPECTATION FOR A
DRIER-THAN-NORMAL MAY. RECENT HEAVY PRECIPITATION HAS MOISTENED TOPSOIL FROM
EASTERN OKLAHOMA SOUTHWARD INTO CENTRAL TEXAS. THE GEFS AND ECENS FAVOR A
CONTINUATION OF THE WET PATTERN FOR THESE AREAS WITH AN EXPANSION EASTWARD INTO
THE LOWER MISSISSIPPI VALLEY BY THE END OF APRIL. DUE TO THE LIKELIHOOD THAT
TOPSOIL IS NEUTRAL TO WET HEADING INTO MAY AND TOOLS FAVOR ABOVE-NORMAL
PRECIPITATION FOR THE MONTH, ABOVE-NORMAL TEMPERATURE PROBABILITIES FROM THE
DYNAMICAL MODELS ARE REDUCED ACROSS MUCH OF THE SOUTH-CENTRAL CONUS. FARTHER TO
THE EAST, DRIER TOPSOIL AND THE CONSOLIDATION TOOL LEAD TO AN INCREASED CHANCE
OF ABOVE-NORMAL TEMPERATURES FOR THE SOUTHEAST. THE CURRENT WEST PACIFIC MJO
(PHASE 7) WOULD FAVOR AN AMPLIFIED 500-HPA TROUGH DEVELOPING OVER THE EASTERN
CONUS BY THE END OF APRIL WHICH MAY RESULT IN A RELATIVELY COOL START TO MAY
FOR THE MIDWEST, NORTHEAST, AND MID-ATLANTIC. HOWEVER, IF THE MJO PROPAGATES
BACK TO THE INDIAN OCEAN, THEN ABOVE-NORMAL TEMPERATURES COULD RETURN TO THESE
AREAS LATER IN MAY. DUE TO THIS EXPECTED VARIABLE TEMPERATURE PATTERN DURING
THE MONTH AND A WEAKER WARM SIGNAL AMONG THE DYNAMICAL MODELS, EQUAL CHANCES
(EC) OF BELOW, NEAR, OR ABOVE-NORMAL TEMPERATURES ARE FORECAST FROM THE MIDDLE
AND UPPER MISSISSIPPI VALLEY EAST TO THE MID-ATLANTIC AND NORTHEAST. ELEVATED
ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE FORECAST FOR EASTERN ALASKA.
HOWEVER, THE OUTLOOK HEDGED COLDER ACROSS SOUTHWESTERN ALASKA WITH EC FORECAST
DUE TO THE WEEK 3-4 GEFS AND ECENS FAVORING NEAR TO BELOW NORMAL EARLY IN THE
MONTH. LARGE NEGATIVE SST ANOMALIES LED TO THE OUTLOOK LEANING SLIGHTLY ON THE
COLDER SIDE ALONG COASTAL SOUTHWESTERN ALASKA AND THE ALASKA PENINSULA.
BASED ON THE NMME, IMME, AND CONSOLIDATION, BELOW-NORMAL PRECIPITATION IS
FAVORED FOR PARTS OF SOUTHEASTERN ALASKA, THE PACIFIC NORTHWEST, AND THE GREAT
BASIN. CONVERSELY, THESE FORECAST TOOLS SUPPORT THE OUTLOOK LEANING ON THE
WETTER SIDE ACROSS SOUTHWESTERN ARKANSAS, SOUTHEASTERN OKLAHOMA, CENTRAL TO
EASTERN TEXAS, AND MOST OF LOUISIANA. MANY OF THE DYNAMICAL MODELS, ESPECIALLY
THE ECMWF, ALONG WITH TRENDS FAVOR A WETTER MAY ACROSS THE SOUTHEAST. HOWEVER,
EQUAL CHANCES (EC) OF BELOW, NEAR, OR ABOVE-NORMAL PRECIPITATION ARE FORECAST
FOR THIS REGION AS THE WET MODEL SIGNAL WAS OFFSET BY A CORRELATION BETWEEN DRY
APRIL SOIL MOISTURE AND BELOW-NORMAL PRECIPITATION DURING MAY. AS OF MID-APRIL,
SOIL MOISTURE IS BELOW THE 5TH PERCENTILE THROUGHOUT THE SOUTHEAST AND WILL
LIKELY DECLINE FURTHER DURING THE NEXT WEEK WITH SUMMERLIKE HEAT AND AN
INCREASING WATER DEMAND. A LARGE COVERAGE OF EC IS ALSO FORECAST ACROSS A
MAJORITY OF ALASKA AND THE LOWER 48 STATES DUE TO HIGH UNCERTAINTY AT THIS TIME
LEAD WITH A MONTHLY PRECIPITATION OUTLOOK ALONG WITH LOW PREDICTABILITY IN
FORECASTING ANOMALOUS CONVECTIVE PRECIPITATION THROUGHOUT THE CENTRAL AND
EASTERN CONUS.
FORECASTER: BRAD PUGH
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 JUN ... WILL BE ISSUED ON THU MAY 21 2026
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
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