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FXUS05 KWBC 151231
PMD90D
PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830 AM EDT THU JUN 15 2023
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS
EL NIñO CONDITIONS ARE PRESENT AND EQUATORIAL SEA SURFACE TEMPERATURES (SSTS)
ARE ABOVE AVERAGE ACROSS THE CENTRAL AND EASTERN EQUATORIAL PACIFIC OCEAN. EL
NIñO IS EXPECTED TO STRENGTHEN AND PERSIST THROUGH THE WINTER 2023-24.
THE JULY-AUGUST-SEPTEMBER (JAS) 2023 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL
SEASONAL MEAN TEMPERATURES ACROSS A MAJORITY OF THE U.S. THE HIGHEST
PROBABILITIES (MORE THAN 50 PERCENT) OF ABOVE-NORMAL TEMPERATURES ARE FORECAST
ACROSS PARTS OF CALIFORNIA, THE PACIFIC NORTHWEST, GREAT BASIN, SOUTHWEST, GULF
COAST, AND EAST. THE JAS PRECIPITATION OUTLOOK DEPICTS ELEVATED PROBABILITIES
OF BELOW-NORMAL PRECIPITATION FOR PARTS OF THE SOUTHWEST, PACIFIC NORTHWEST,
AND GREAT LAKES, WHILE ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF THE
GREAT PLAINS, PARTS OF THE MIDDLE TO LOWER MISSISSIPPI VALLEY, NORTHERN
ROCKIES, AND FLORIDA PENINSULA. EQUAL CHANCES (EC) ARE FORECAST IN AREAS WHERE
THE LIKELIHOOD OF SEASONAL MEAN TEMPERATURES OR SEASONAL ACCUMULATED
PRECIPITATION AMOUNTS ARE EXPECTED TO BE SIMILAR TO CLIMATOLOGICAL
PROBABILITIES.
BASIS AND SUMMARY OF THE CURRENT LONG-LEAD OUTLOOKS
NOTE: FOR GRAPHICAL DISPLAYS OF THE FORECAST TOOLS DISCUSSED BELOW SEE:
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/TOOLS/BRIEFING
CURRENT ATMOSPHERIC AND OCEANIC CONDITIONS
OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC REFLECT EL
NIñO CONDITIONS. THE OBSERVED WEEKLY SSTS, CENTERED ON JUNE 7, FEATURE POSITIVE
ANOMALIES THROUGHOUT THE EQUATORIAL PACIFIC WITH THE LARGEST ANOMALIES OF MORE
THAN +1 DEGREE C GENERALLY EAST OF 140°W. THE LATEST WEEKLY SST DEPARTURE FOR
THE NIñO 3.4 REGION IS AT +0.9 DEGREES C. EQUATORIAL UPPER-OCEAN HEAT ANOMALIES
(AVERAGED BETWEEN 180 TO 100 °W AND 0-300M DEPTH) REMAIN STRONGLY POSITIVE.
FROM MAY 13 TO JUNE 7, LOW-LEVEL (850-HPA) WESTERLY WIND ANOMALIES WERE
OBSERVED ACROSS THE WESTERN EQUATORIAL PACIFIC. CONSISTENT WITH EL NIñO
CONDITIONS, NEGATIVE OLR ANOMALIES (ENHANCED CONVECTION) WERE LOCATED EAST OF
PAPUA NEW GUINEA AND ALSO NEAR THE EQUATOR ACROSS THE EASTERN PACIFIC. POSITIVE
OLR ANOMALIES (SUPPRESSED CONVECTION) WERE OBSERVED THROUGHOUT MUCH OF
SOUTHEAST ASIA AND INDONESIA.
ALTHOUGH THE REAL-TIME MULTIVARIATE (RMM) INDEX DEPICTS A WEAK MADDEN-JULIAN
OSCILLATION (MJO) PROPAGATING EAST FROM THE INDIAN OCEAN TO THE MARITIME
CONTINENT DURING EARLY JUNE, THE 200-HPA VELOCITY POTENTIAL FIELD FEATURES A
COHERENT AND MORE ROBUST MJO. DYNAMICAL MODEL FORECASTS INDICATE THAT THE MJO
IS LIKELY TO CONTINUE PROPAGATING EAST TO THE WESTERN HEMISPHERE BY LATE JUNE.
THE MJO IS LIKELY TO CONSTRUCTIVELY INTERFERE WITH EL NIñO DURING THE LATTER
HALF OF JUNE AND IS EXPECTED TO PROVIDE AN INCREASINGLY FAVORABLE LARGE-SCALE
ENVIRONMENT FOR TROPICAL CYCLONE DEVELOPMENT ACROSS THE EAST PACIFIC FROM LATE
JUNE INTO THE BEGINNING OF JULY. HOWEVER, THE MJO WAS NOT A FACTOR IN THE
SEASONAL OUTLOOKS.
NEGATIVE SST ANOMALIES HAVE PERSISTED ACROSS THE EASTERN BERING SEA SINCE THE
BEGINNING OF MAY, WHILE SSTS ARE NEAR AVERAGE ALONG MUCH OF THE WEST COAST. THE
NORTHERN GULF OF MEXICO COOLED RECENTLY WITH NEAR OR BELOW-NORMAL SSTS OBSERVED
DURING EARLY JUNE. POSITIVE SST ANOMALIES STRENGTHENED ACROSS THE EASTERN
TROPICAL ATLANTIC SINCE MAY.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE CPC SST CONSOLIDATION FOR THE NIñO 3.4 REGION INDICATES AN INCREASE IN THE
MAGNITUDE OF POSITIVE ANOMALIES THIS SUMMER AND FALL TO AROUND +1 DEGREE C,
FOLLOWED BY A DECLINE TO MORE NEUTRAL ENSO CONDITIONS DURING SPRING 2024. THE
CFSV2 DEPICTS A STRONG EL NIñO BY ASO, WHILE THE NORTH AMERICAN MULTI-MODEL
ENSEMBLE (NMME) KEEPS THE ANOMALIES BELOW 1.5 DEGREES C. THE STATISTICAL TOOLS
VARY WITH THE STRENGTH OF THE EL NIñO DURING THE NEXT SIX MONTHS. AS OF EARLY
JUNE, NOAA’S CPC FORECAST CALLS FOR MORE THAN A 90 PERCENT CHANCE OF EL NIñO
PERSISTING THROUGH JFM 2024 WITH A 56 PERCENT CHANCE OF A STRONG EL NIñO (> 1.5
DEGREES C) DURING NDJ 2023.
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS
TOOLS USED FOR THE SEASONAL OUTLOOKS INCLUDED DYNAMICAL MODEL GUIDANCE SUCH AS
THE NMME, THE CALIBRATION, BRIDGING, AND MERGING (CBAM) POST-PROCESSING OF THE
NMME, AND THE COPERNICUS CLIMATE CHANGE SERVICE (C3S) SEASONAL MODEL
CONTRIBUTIONS. IN ADDITION, THE CONSOLIDATION TOOL, WHICH INCLUDES NMME INPUT
AND VARIOUS STATISTICAL TOOLS, WAS USED. CURRENT SOIL MOISTURE CONDITIONS WERE
A CONSIDERATION ACROSS THE MIDWEST AND CORN BELT IN THE JAS TEMPERATURE
OUTLOOK. EL NIñO TEMPERATURE AND PRECIPITATION COMPOSITES WERE RELIED UPON FROM
JAS 2023 THROUGH JFM 2024 AND THESE COMPOSITES WERE WEIGHED MOST HEAVILY FROM
NDJ 2023-24 THROUGH JFM 2024. DECADAL TRENDS IN TEMPERATURE AND PRECIPITATION
WERE A FACTOR AT ALL TIME LEADS BUT RELIED UPON THE MOST, BEGINNING IN THE
SPRING 2024.
PROGNOSTIC DISCUSSION OF OUTLOOKS - JAS 2023 TO JAS 2024
TEMPERATURE
ABOVE-NORMAL TEMPERATURES ARE FAVORED THROUGHOUT A MAJORITY OF THE U.S. DURING
JAS WITH THE HIGHEST PROBABILITIES (ABOVE 50 PERCENT) FORECAST FOR MUCH OF THE
WEST, GULF COAST, AND EAST, CONSISTENT WITH DYNAMICAL MODEL GUIDANCE AND
DECADAL TRENDS. ALTHOUGH THE JULY OUTLOOK DEPICTS EQUAL CHANCES (EC) OF BELOW,
NEAR, OR ABOVE-NORMAL TEMPERATURES FOR THE INTERIOR WEST, THE ENHANCED
PROBABILITIES (GREATER THAN 50 PERCENT) FOR THIS REGION DURING JAS ARE
JUSTIFIED FOR A THREE-MONTH PERIOD WITH SUPPORT FROM THE CONSOLIDATION TOOL AND
DECADAL TRENDS. BASED ON THE CBAM AND AN EXPECTATION OF A WEAK MONSOON,
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES EXCEED 60 PERCENT ACROSS ARIZONA.
COMPARED TO THE PREVIOUS OUTLOOK, ABOVE-NORMAL TEMPERATURE PROBABILITIES WERE
INCREASED ACROSS THE CORN BELT AND GREAT LAKES DUE TO A NOTABLE WARMING TREND
IN THE NMME FROM LAST MONTH ALONG WITH LOW SOIL MOISTURE HEADING INTO JULY.
BASED ON THE LATEST NMME, LOWER PROBABILITIES (33 TO 40 PERCENT) ARE FORECAST
FOR COASTAL CENTRAL TO SOUTHERN CALIFORNIA. EC IS FORECAST ACROSS THE
NORTH-CENTRAL CONUS WHERE LARGE DIFFERENCES EXIST AMONG THE NMME, CBAM, AND EL
NIñO COMPOSITES. THE CONSOLIDATION TOOL AND EL NIñO COMPOSITES SUPPORT
INCREASED ABOVE-NORMAL TEMPERATURE PROBABILITIES ACROSS MUCH OF ALASKA,
ALTHOUGH EC IS FORECAST FOR NORTHERN MAINLAND ALASKA WHERE THE WARM SIGNAL IS
WEAKER AMONG THE STATISTICAL TOOLS. ABOVE-NORMAL TEMPERATURES REMAIN THE MOST
LIKELY OUTCOME THROUGHOUT MUCH OF THE U.S. FROM ASO TO OND 2023. BEGINNING IN
NDJ 2023-24 THROUGH JFM 2024, PREDICTED EL NIñO CONDITIONS RESULT IN ENHANCED
CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE NORTHERN TIER OF THE CONUS
WITH AN INCREASING COVERAGE OF EC ACROSS CALIFORNIA, THE SOUTHWEST, SOUTHERN
GREAT PLAINS, AND LOWER MISSISSIPPI VALLEY. DURING THE WINTER 2023-24,
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE EAST BASED ON THE STATISTICAL
CONSOLIDATION. DURING THE SPRING AND SUMMER 2024, THE TEMPERATURE OUTLOOK IS
CONSISTENT WITH DECADAL TRENDS.
PRECIPITATION
FOLLOWING THIS PAST WINTER AND SPRING WITH ABOVE-NORMAL SNOWFALL ACROSS THE
WEST AND CURRENT SOIL MOISTURE ABOVE THE 70TH PERCENTILE, A SLUGGISH START TO
THE MONSOON IS LIKELY FOR THE SOUTHWEST DURING JULY. BASED ON GOOD MODEL
CONTINUITY AND AGREEMENT, FORECAST CONFIDENCE IS RELATIVELY HIGH FOR A WEAK
MONSOON AND THEREFORE, BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS THE
SOUTHWEST DURING JAS. CONSISTENT WITH A PREDICTED WEAKER MONSOON AND SUPPORTED
BY THE NMME AND EL NIñO COMPOSITES, ELEVATED CHANCES FOR ABOVE-NORMAL
PRECIPITATION ARE FORECAST FOR MUCH OF THE GREAT PLAINS EXTENDING WEST TO THE
NORTHERN ROCKIES. GIVEN THE STRONG DRY SIGNAL APPARENT AMONG THE STATISTICAL
TOOLS ACROSS ONTARIO AND BORDERING GREAT LAKES, THE JAS OUTLOOK LEANS TOWARDS
BELOW-NORMAL PRECIPITATION ACROSS MOST OF MICHIGAN AND NORTHEASTERN WISCONSIN.
BASED ON THE LATEST NMME, SLIGHTLY ELEVATED PROBABILITIES FOR ABOVE-NORMAL
PRECIPITATION ARE FORECAST ACROSS THE FLORIDA PENINSULA. ALTHOUGH RECENT
DYNAMICAL MODEL OUTPUT BACKED OFF ON THE DRY SIGNAL ACROSS THE PACIFIC
NORTHWEST, STATISTICAL TOOLS SUPPORT A CONTINUATION OF FAVORED BELOW-NORMAL
PRECIPITATION FOR PARTS OF OREGON AND WASHINGTON. ALSO, THIS IS CONSISTENT WITH
AN INCREASING DRY SIGNAL, ASSOCIATED WITH EL NIñO, DURING THE FALL SEASON.
ALTHOUGH DECADAL TRENDS SUPPORT ABOVE-NORMAL PRECIPITATION FOR THE MID-ATLANTIC
DURING JAS, EC IS FORECAST FOR THIS REGION DUE TO THE DRIER EL NIñO COMPOSITES
AND THE ABSENCE OF A WET SIGNAL IN THE NMME. GIVEN INCONSISTENT MODEL OUTPUT
THE PAST TWO MONTHS AND CONFLICTING SIGNALS AMONG THE TOOLS, EC IS ALSO
FORECAST FOR MUCH OF ALASKA DURING JAS. HOWEVER, BELOW-NORMAL PRECIPITATION IS
SLIGHTLY FAVORED FOR PARTS OF WESTERN MAINLAND ALASKA BASED ON THE NMME.
PRECIPITATION OUTLOOKS DURING THE FALL 2023 THROUGH THE WINTER 2023-24 RELIED
UPON EL NIñO COMPOSITES AND THE CONSOLIDATION TOOL WITH AN INCREASED CHANCE OF
ABOVE (BELOW)-NORMAL PRECIPITATION ACROSS THE SOUTHERN (NORTHERN) TIER OF THE
CONUS. THE LARGEST PROBABILITIES (50 PERCENT FOR ABOVE) ARE FORECAST ACROSS
PARTS OF THE SOUTHEAST FROM NDJ 2023-24 THROUGH JFM 2024 BASED ON A STRONG,
RELIABLE WET SIGNAL ASSOCIATED WITH EL NIñO. DURING THE SPRING AND SUMMER 2023,
THE PRECIPITATION OUTLOOKS ARE BASED MOSTLY ON DECADAL TRENDS.
FORECASTER: BRAD PUGH
THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1991 AND 2020, FOLLOWING
THE WORLD METEROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3
COMPLETE DECADES AS THE CLIMATIC 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.
FOR A DESCRIPTION OF OF THE STANDARD FORECAST TOOLS - THEIR SKILL- AND THE
FORECAST FORMAT PLEASE SEE OUR WEB PAGE AT
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/LONG_RANGE/TOOLS.HTML
(USE LOWER CASE LETTERS)
INFORMATION ON THE FORMATION OF SKILL OF THE CAS FORECASTS MAY BE FOUND AT:
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/SOILMST_MONITORING/US/OUTLOOK/OUTLOOK.SHTM
L
(USE LOWERCASE LETTERS)
NOTES - THESE CLIMATE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR
VALID PERIOD. WITHIN ANY GIVEN VALID PERIOD OBSERVATIONS AND SHORT AND MEDIUM
RANGE FORECASTS SHOULD BE CONSULTED.
THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE ISSUANCE OF THE NEW SET NEXT
MONTH ON JUL 20 2023
1991-2020 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 20, 2021
FORECAST RELEASE.
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