140
FXUS05 KWBC 201331
PMD90D
PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830 AM EST THU FEB 20 2025
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS
LA NIñA CONDITIONS ARE PRESENT OVER THE CENTRAL AND EAST-CENTRAL EQUATORIAL
PACIFIC, ACCOMPANIED BY BELOW-AVERAGE SEA SURFACE TEMPERATURES (SSTS) IN THIS
AREA. THE LATEST WEEKLY SST DEPARTURE IN THE NIñO 3.4 REGION IS -0.3 DEGREES
CELSIUS. LA NIñA CONDITIONS ARE EXPECTED TO PERSIST THROUGH FEBRUARY-APRIL
(FMA) 2025 WITH A 59% CHANCE, WITH A 66% CHANCE OF A TRANSITION TO ENSO-NEUTRAL
DURING MARCH-MAY (MAM) 2025. THIS LA NIñA IS PREDICTED TO BE WEAK AND
RELATIVELY SHORT-LIVED, WITH THE MAJORITY OF GUIDANCE FAVORING SSTS IN THE NIñO
3.4 REGION AROUND -0.5 DEGREES CELSIUS. THOUGH WE STILL EXPECT THE CANONICAL LA
NIñA IMPACTS THROUGH THE MAM SEASON, AND POSSIBLY INTO THE APRIL-JUNE (AMJ)
SEASON, THERE MAY BE MORE VARIABILITY WITHIN THE SEASON GIVEN THE FORECASTED
WEAKNESS OF THE EVENT.
THE MAM 2025 TEMPERATURE OUTLOOK REMAINS VERY SIMILAR TO LAST MONTH, AND FAVORS
BELOW NORMAL TEMPERATURES STRETCHING FROM THE NORTHWESTERN CONTIGUOUS UNITED
STATES (CONUS) TO THE NORTHERN PLAINS, AS WELL AS SOUTHEASTERN AND SOUTHCENTRAL
ALASKA. ABOVE NORMAL TEMPERATURES ARE FORECAST OVER THE SOUTHERN TIER OF THE
CONUS AND MUCH OF THE EASTERN CONUS. ABOVE NORMAL TEMPERATURES ARE ALSO
FORECAST OVER NORTHERN AND WESTERN ALASKA. THE HIGHEST PROBABILITIES OF ABOVE
NORMAL TEMPERATURES REACH 50 TO 60% OVER PARTS OF THE SOUTHWEST, SOUTHERN
TEXAS, THE SOUTHERN GULF STATES INCLUDING FLORIDA, AND SOUTHERN GEORGIA. THE
MAM PRECIPITATION OUTLOOK IS SIMILAR IN PATTERN TO LAST MONTH, WHICH WAS AND IS
A PATTERN THAT IS CANONICAL OF LA NIñA IN MAM. ABOVE NORMAL PRECIPITATION IS
FAVORED OVER THE NORTHWEST, THE GREAT LAKES AND INTERIOR NORTHEAST, OHIO AND
TENNESSEE VALLEYS, PARTS OF THE MISSISSIPPI VALLEY, AND WESTERN AND NORTHERN
ALASKA. BELOW NORMAL PRECIPITATION IS INDICATED OVER THE SOUTHWEST, MUCH OF THE
GREAT PLAINS, THE GULF COAST, AND THE SOUTHERN COAST OF MAINLAND ALASKA.
EQUAL CHANCES (EC) OF ABOVE, NEAR, AND BELOW NORMAL TEMPERATURES OR
PRECIPITATION ARE INDICATED WHERE THERE IS MODEL AND/OR TOOL DISAGREEMENT,
FORECAST PROBABILITIES FOR EACH CATEGORY ARE SIMILAR, AND TEMPERATURES OR
PRECIPITATION ARE EXPECTED TO BE CLOSE TO THE CLIMATOLOGICAL DISTRIBUTION.
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
A WEAK LA NIñA CONTINUES OVER THE CENTRAL AND EAST-CENTRAL PACIFIC OCEAN, WITH
BELOW-AVERAGE SSTS OBSERVED ACROSS THIS REGION, AND THE LATEST WEEKLY NIñO 3.4
INDEX AT -0.3 DEGREES CELSIUS. THE LATEST WEEKLY NIñO INDICES INCLUDED +0.9
DEGREES CELSIUS IN THE NIñO 1+2 REGION, +0.1 IN NIñO 3, AND -0.7 DEGREES
CELSIUS IN NIñO 4. THE BELOW-AVERAGE SSTS HAVE PERSISTED IN THE CENTRAL AND
EAST-CENTRAL EQUATORIAL PACIFIC OCEAN FOR AT LEAST THE LAST TWO MONTHS.
NEGATIVE SUBSURFACE TEMPERATURE ANOMALIES REACHED A MINIMUM IN LATE DECEMBER,
BUT HAVE PERSISTED OVERALL SINCE, AND EXPANDED TO THE CENTRAL PACIFIC OCEAN.
OVER THE PAST 30 DAYS, LOW-LEVEL WIND ANOMALIES WERE EASTERLY FROM THE WESTERN
TO CENTRAL EQUATORIAL PACIFIC OCEAN, AND UPPER-LEVEL WIND ANOMALIES WERE
WESTERLY ACROSS THE CENTRAL AND EAST-CENTRAL EQUATORIAL PACIFIC OCEAN ON THE
SOUTHERN FLANK OF A LARGE CYCLONIC CIRCULATION OVER THE PACIFIC. FINALLY,
TROPICAL CONVECTION HAS BEEN SUPPRESSED NEAR THE DATE LINE WITH ENHANCED
CONVECTION OVER INDONESIA. THESE ATMOSPHERIC AND OCEANIC INDICATORS
COLLECTIVELY REFLECT LA NIñA.
THE MADDEN-JULIAN OSCILLATION (MJO) MADE A NEAR-CIRCUMNAVIGATION OF THE GLOBAL
TROPICS DURING THE PAST 40 DAYS, WITH THE MOST RECENT OBSERVATIONS OF THE
REALTIME MULTIVARIATE MJO (RMM) INDEX SHOWING THE ENHANCED PHASE NEAR THE
INTERFACE BETWEEN RMM PHASES 7 AND 8 (NEAR THE INTERFACE BETWEEN THE EASTERN
AND WESTERN HEMISPHERES), WITH RELATIVELY MODEST AMPLITUDE OUTSIDE THE UNIT
CIRCLE. FOR THE NEXT WEEK OR SO, DYNAMICAL MODEL RMM FORECASTS FAVORED A SLOWED
AND ERRATIC EVOLUTION OF THE MJO SIGNAL. BEYOND THIS TIME HOWEVER, FORECASTS
DEPICT A MORE CANONICAL EASTWARD PROPAGATION OF THE MJO THAT REACHES THE INDIAN
OCEAN TOWARDS THE BEGINNING OF MARCH. FORECASTS OF THE MJO INDEX ARE GENERALLY
CONSIDERED TO BE MORE RELEVANT TO THE MONTHLY OUTLOOK.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE DYNAMICAL MODELS IN THE COLUMBIA CLIMATE SCHOOL INTERNATIONAL RESEARCH
INSTITUTE FOR CLIMATE AND SOCIETY (IRI) PLUME CONTINUE TO PREDICT A WEAK AND A
SHORT DURATION LA NIñA. WEAK LA NIñA CONDITIONS ARE EXPECTED TO PERSIST THROUGH
FMA 2025 AND THEN TRANSITION TO ENSO-NEUTRAL. THE IRI DYNAMICAL MODEL AVERAGE
AND SEVERAL OF THE MODELS OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME)
PREDICT AN EARLIER TRANSITION TO ENSO-NEUTRAL IN JFM 2025. THE CPC ENSO
FORECAST TEAM FAVORS A WEAK LA NIñA THROUGH FMA, BUT THERE IS ALSO A 41 PERCENT
CHANCE OF ENSO-NEUTRAL EMERGING IN THIS SEASON.
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS
DYNAMICAL MODEL FORECASTS FROM THE NMME, THE COUPLED FORECAST SYSTEM MODEL
VERSION 2 (CFSV2), AND THE COPERNICUS (C3S) MULTI-MODEL ENSEMBLE SYSTEM WERE
USED EXTENSIVELY FOR THE FIRST SIX LEADS WHEN THEY ARE AVAILABLE, AS WAS THE
OBJECTIVE, HISTORICAL SKILL WEIGHTED CONSOLIDATION AND CALIBRATION, BRIDGING,
AND MERGING (CBAM) GUIDANCE, THAT COMBINES BOTH DYNAMICAL AND STATISTICAL
FORECAST INFORMATION.
ADDITIONALLY, THE OFFICIAL ENSO FORECAST FAVORS A WEAK LA NIñA THROUGH FMA
2025. THIS ANTICIPATED WEAK LA NIñA SIGNAL PLAYED A ROLE IN THE CONSTRUCTION OF
THESE OUTLOOKS. COMPOSITES DERIVED FROM NEAREST NEIGHBOR STATISTICAL ANALYSIS
OF RECENTLY OBSERVED TROPICAL PACIFIC SST AND EQUATORIAL HEAT ANOMALIES WERE
UTILIZED WHERE APPROPRIATE. AT LATER LEADS, DECADAL TRENDS IN TEMPERATURE AND
PRECIPITATION WERE INCREASINGLY RELIED UPON IN CREATING THE SEASONAL OUTLOOKS.
PROGNOSTIC DISCUSSION OF OUTLOOKS - MAM 2025 TO MAM 2026
TEMPERATURE
THE MAM 2025 TEMPERATURE OUTLOOK IS VERY SIMILAR TO THE LEAD 2 PREDICTION OF
MAM 2025 RELEASED IN JANUARY 2025. MODELS CONTINUE TO REFLECT A LA NIñA
TEMPERATURE PATTERN, AND THOUGH THE TELECONNECTION TYPICALLY WEAKENS IN MAM
COMPARED TO THE PREVIOUS SEASON (FMA), THERE ARE LIKELY TO BE LAGGED IMPACTS OF
THE LA NIñA. AN IMPORTANT CAVEAT IS THAT WITH A WEAK LA NIñA WE MAY SEE PERIODS
OF INCREASED VARIABILITY WITHIN THE SEASON. ABOVE NORMAL TEMPERATURES ARE
FAVORED FOR MUCH OF THE SOUTHERN AND EASTERN CONUS, WHILE BELOW NORMAL
TEMPERATURES ARE FAVORED FOR THE NORTHWEST TO THE NORTHERN PLAINS. OVER ALASKA,
BELOW NORMAL TEMPERATURES ARE INDICATED FOR SOUTHEASTERN AND SOUTHCENTRAL
PORTIONS OF THE STATE, TRANSITIONING TO ABOVE NORMAL TEMPERATURES OVER WESTERN
AND NORTHERN PORTIONS OF THE STATE. THE ABOVE NORMAL TEMPERATURES OVER NORTHERN
ALASKA, AND THE SOUTHWESTERN AND EASTERN CONUS, ARE FURTHER SUPPORTED BY ABOVE
NORMAL TRENDS. EC, DUE TO WEAK OR CONFLICTING SIGNALS AMONG TOOLS, IS FORECAST
FOR A SIGNIFICANT FRACTION OF THE LOWER 48 STATES AND PORTIONS OF ALASKA.
SHIFTING INTO AMJ 2025, IMPACTS OF LA NIñA ARE EXPECTED TO WANE AS ENSO NEUTRAL
BECOMES INCREASINGLY LIKELY. BELOW NORMAL TEMPERATURES OVER ALASKA AND THE
NORTHWEST INTO THE PLAINS DIMINISH IN FAVOR OF EC ALONG MUCH OF THE NORTHERN
TIER OF THE CONUS AND SOUTHEASTERN ALASKA. ABOVE NORMAL TEMPERATURES ARE
MAINTAINED AND/OR EXPANDED OVER PARTS OF THE WESTERN CONUS, SOUTHEAST, THE
EASTERN QUARTER OF THE CONUS, AND WESTERN AND NORTHERN ALASKA GIVEN MODEL
AGREEMENT AMONG NMME AND C3S. THIS PATTERN IS GENERALLY MAINTAINED THROUGH
SEPTEMBER-NOVEMBER (SON) 2025 WITH THE SUPPORT OF DYNAMICAL CLIMATE MODELS AND
DECADAL TRENDS, WITH THE LEAST COVERAGE OF EC FORECAST OVER THE UPPER HALF OF
THE MISSISSIPPI VALLEY DURING JUNE-AUGUST (JJA). SOMEWHAT LARGER AREAS OF EC
ARE DEPICTED OVER ALASKA DURING THE JULY-SEPTEMBER (JAS) THROUGH SON SEASONS
WHERE GUIDANCE HAD WEAK OR CONFLICTING SIGNALS. OCTOBER-DECEMBER (OND) 2025 AND
NOVEMBER-JANUARY (NDJ) 2025-2026 FEATURE SLIGHTLY ABOVE NORMAL TEMPERATURES
ACROSS MUCH OF THE CONUS AND ALASKA GIVEN RECENT DECADAL TRENDS. THE ABOVE
NORMAL TEMPERATURES DIMINISH AND SHIFT TO THE EAST COAST BY DECEMBER-FEBRUARY
(DJF) 2025-2026, WITH SOME INDICATION OF ABOVE NORMAL TEMPERATURES OVER THE
SOUTHWEST IN FMA 2026, AND A SLIGHT TILT TOWARD BELOW NORMAL OVER PARTS OF THE
NORTHERN PLAINS AND NORTHWEST IN JANUARY-MARCH (JFM) 2026. THE LAST 3 LEADS OF
THIS FORECAST HAVE LARGE AREAS OF EC GIVEN COMPARATIVELY LOWER CONFIDENCE AT
THESE LONGER LEAD TIMES.
PRECIPITATION
THE MAM 2025 PRECIPITATION OUTLOOK REFLECTS THE EXPECTED LA NIñA TELECONNECTION
OVER THE CONUS. ABOVE NORMAL PRECIPITATION IS FAVORED OVER THE NORTHWEST, GREAT
LAKES, INTERIOR NORTHEAST, OHIO AND TENNESSEE VALLEYS, PORTIONS OF THE
MISSISSIPPI VALLEY, AND NORTHERN AND WESTERN ALASKA. BELOW NORMAL PRECIPITATION
IS INDICATED FOR THE SOUTHWEST, MUCH OF THE GREAT PLAINS, THE GULF COAST, AND
THE SOUTHERN COAST OF MAINLAND ALASKA. THIS PRECIPITATION PATTERN IS VERY
SIMILAR TO LAST MONTH’S LEAD 2 OUTLOOK FOR MAM, WITH ONLY RELATIVELY MINOR
ADJUSTMENTS RENDERED TO THE DEPICTION. EC IS INDICATED OVER A SIGNIFICANT
FRACTION OF THE LOWER 48 STATES AND MUCH OF ALASKA SOUTH OF THE BROOKS RANGE.
LA NIñA TYPICALLY LEADS TO A WETTER NORTHERN CALIFORNIA AND DRIER SOUTHERN
CALIFORNIA, HOWEVER, THE IMPACTS OF LA NIñA CAN GENERALLY BE QUITE VARIABLE
OVER CENTRAL PARTS OF THE WEST COAST. IN ADDITION, THE WEAKNESS OF THIS EVENT
MAY ADD ADDITIONAL UNCERTAINTY TO THE PRECIPITATION PATTERN, AS SUCH,
PROBABILITIES ARE WEAK AND EC IS INDICATED OVER MUCH OF CALIFORNIA. MODELS HAD
SOME DISAGREEMENT OVER THE NORTHERN PLAINS, WITH EVERY FORECAST CATEGORY
OBTAINING SOME SUPPORT FROM THE ARRAY OF MODEL SOLUTIONS, THUS EC IS FAVORED
OVER THE NORTHERN PLAINS AS WELL. WHILE LA NIñA TYPICALLY CAN LEAD TO BELOW
NORMAL PRECIPITATION OVER THE EAST COAST, THE LOCATION OF THE JET STREAM AND
ASSOCIATED STORM TRACK OVER THE GREAT LAKES AND INTERIOR MID-ATLANTIC DURING A
LA NIñA CAN BE VARIABLE. SHOULD IT SHIFT MORE TO THE EAST, THERE MAY BE MORE
PRECIPITATION OVER THE EAST COAST, WHILE SHIFTING MORE TO THE WEST MAY LEAD TO
LESS PRECIPITATION. GIVEN THE WEAKNESS OF THE LA NIñA LEADING TO POTENTIALLY
MORE VARIABILITY IN THE TELECONNECTION PATTERN VS. DURING A STRONG LA NIñA, EC
IS FAVORED OVER THE NORTHEASTERN COAST. SIMILARLY TO TEMPERATURE, WE EXPECT
SOME LAGGED IMPACTS OF THE LA NIñA WELL INTO MAM 2025, AND THE FORECASTED
PRECIPITATION PATTERN REMAINS SIMILAR TO THE EXPECTED LA NIñA TELECONNECTION
PATTERN INTO THIS SEASON.
AS THE FORECAST PROGRESSES THROUGH LATER LEADS AND INTO FALL/WINTER 2025, ENSO
GUIDANCE BECOMES LESS OF A PLAYER IN THIS FORECAST, AND DECADAL PRECIPITATION
TRENDS ARE RELIED ON MORE. BELOW NORMAL PRECIPITATION SHIFTS NORTHWARD FROM ITS
MORE SOUTHWESTERN ORIENTATION IN MAM THROUGH OND 2025. ABOVE NORMAL
PRECIPITATION SHIFTS FROM THE GREAT LAKES, OHIO VALLEY, AND MID-ATLANTIC TOWARD
THE EAST COAST THROUGH SON. FROM MAY-JULY (MJJ) THROUGH SON, THE TILT TOWARDS
ABOVE NORMAL PRECIPITATION OVER THE EAST COAST STATES IS RELATED TO THE
INCREASED CLIMATOLOGICAL INFLUENCE OF TROPICAL CYCLONES, AS WELL AS TRENDS. IN
ALASKA, ABOVE NORMAL PRECIPITATION OVER NORTHWESTERN PORTIONS OF THE STATE IS
FAVORED TO EXPAND TO THE SOUTH AND EAST AS THE FORECAST PERIOD PROGRESSES.
STATISTICAL GUIDANCE IS INCREASINGLY RELIED UPON FOR LATER LEADS, FOR EXAMPLE
NDJ 2025-2026 AND ON, AND SMALL, RELATIVELY WEAK REGIONS OF ABOVE NORMAL
PRECIPITATION ARE FAVORED FOR THE SOUTHEAST THAT SHIFT NORTHWARD TO THE END OF
THE FORECAST PERIOD (MAM 2026). ABOVE NORMAL PRECIPITATION IS ALSO FAVORED OVER
PARTS OF THE NORTHERN CONUS, WHILE BELOW NORMAL PRECIPITATION BEGINS TO MAKE AN
APPEARANCE OVER THE SOUTHWEST LATE NEXT WINTER. ABOVE NORMAL PRECIPITATION
PROBABILITIES PERSIST OVER ALASKA THOUGH THE REMAINDER OF THE PERIOD, THOUGH
SHIFT FROM COVERING MUCH OF THE STATE IN OND TO THE NORTH AND EAST IN NDJ AND
DJF 2025-2026, TO THE WEST IN JFM, FMA, AND MAM 2026.
FORECASTER: ANTHONY ARTUSA
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 MAR 20 2025
1991-2020 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 20, 2021
FORECAST RELEASE.
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