653
FXUS05 KWBC 181331
PMD90D
PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830 AM EST THU JAN 18 2024
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS
EL NIñO CONDITIONS CONTINUE WITH EQUATORIAL SEA SURFACE TEMPERATURES (SSTS)
ABOVE AVERAGE ACROSS THE CENTRAL AND EASTERN EQUATORIAL PACIFIC OCEAN. THE
ATMOSPHERIC RESPONSE ACROSS THE GLOBAL TROPICS IS CONSISTENT WITH THE ONGOING
EL NIñO. EL NIñO IS FORECAST TO PERSIST THROUGH MARCH-APRIL-MAY WITH A
TRANSITION TO ENSO-NEUTRAL CONDITIONS LATER IN THE SPRING AND SUMMER.
THE FEBRUARY-MARCH-APRIL (FMA) 2024 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL
TEMPERATURES ACROSS THE PACIFIC NORTHWEST, NORTHERN TO CENTRAL CALIFORNIA,
PARTS OF THE GREAT BASIN, NORTHERN ROCKIES, NORTHERN GREAT PLAINS, GREAT LAKES,
AND NORTHEAST. THE HIGHEST FORECAST CONFIDENCE FOR ABOVE-NORMAL TEMPERATURES
EXISTS FOR THE PACIFIC NORTHWEST AND MUCH OF ALASKA. BELOW-NORMAL TEMPERATURE
PROBABILITIES ARE SLIGHTLY ELEVATED ACROSS SOUTHEASTERN NEW MEXICO AND WESTERN
TO CENTRAL TEXAS. NEAR-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE
SOUTHEAST.
THE FMA 2024 PRECIPITATION OUTLOOK DEPICTS ELEVATED PROBABILITIES FOR
ABOVE-NORMAL PRECIPITATION FOR SOUTHERN CALIFORNIA, THE DESERT SOUTHWEST, THE
CENTRAL TO SOUTHERN PLAINS, THE SOUTHEAST, AND MUCH OF THE EAST COAST. THE
SOUTHEAST IS THE MOST LIKELY AREA TO HAVE ABOVE-NORMAL PRECIPITATION.
ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED FOR PARTS OF SOUTHERN ALASKA AND THE
NORTH SLOPE OF ALASKA. BELOW-NORMAL PRECIPITATION IS FAVORED FOR THE PACIFIC
NORTHWEST AND FROM THE GREAT LAKES SOUTH TO THE OHIO VALLEY.
AREAS DEPICTED IN WHITE AND LABELED “EQUAL-CHANCES” OR “EC” ARE REGIONS WHERE
CLIMATE SIGNALS ARE WEAK, AND SO THERE ARE EQUAL CHANCES FOR EITHER ABOVE-,
NEAR- OR BELOW-NORMAL SEASONAL MEAN TEMPERATURES OR TOTAL PRECIPITATION AMOUNTS.
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
ABOVE-AVERAGE SSTS PERSIST ACROSS THE EQUATORIAL CENTRAL AND EASTERN PACIFIC.
WEEKLY OBSERVED SST ANOMALIES IN THE NIñO 3.4 REGION ARE AT +1.9 DEGREES
CELSIUS. SUBSURFACE TEMPERATURE ANOMALIES (AVERAGED FROM 180-100W AND 0-300
METERS) ARE AT +1.0 DEGREES CELSIUS WHICH IS A DECREASE FROM A PEAK OF +1.5
DEGREES CELSIUS IN LATE NOVEMBER. THIS SLIGHT DECREASE IS DUE TO AN EXPANSION
OF NEGATIVE SUBSURFACE TEMPERATURE ANOMALIES EASTWARD TO 150W, BUT THESE
NEGATIVE ANOMALIES REMAIN AT A DEPTH OF 100 METERS. FROM DECEMBER 16, 2023 TO
JANUARY 10, 2024, POSITIVE OLR ANOMALIES (SUPPRESSED CONVECTION AND
PRECIPITATION) CONTINUE OVER THE PHILIPPINES, INDONESIA, AND NORTHERN
AUSTRALIA. NEGATIVE OLR ANOMALIES (ENHANCED CONVECTION AND PRECIPITATION) WERE
OBSERVED AROUND THE DATE LINE AND EXTEND THROUGH THE EASTERN TROPICAL PACIFIC,
MOSTLY TO THE NORTH OF THE EQUATOR. LOW-LEVEL (850-HPA) WIND ANOMALIES WERE
WESTERLY OVER THE EAST-CENTRAL EQUATORIAL PACIFIC AND EASTERLY ACROSS THE FAR
WESTERN PACIFIC. UPPER-LEVEL (200-HPA) WIND ANOMALIES WERE EASTERLY OVER THE
EASTERN EQUATORIAL PACIFIC. THESE ATMOSPHERIC AND OCEANIC CONDITIONS REFLECT A
CONTINUATION OF EL NIñO. THE MADDEN-JULIAN OSCILLATION (MJO) REMAINS ACTIVE AND
WAS STRONG ENOUGH TO RAPIDLY WEAKEN THE POSITIVE PHASE OF THE INDIAN OCEAN
DIPOLE AND ALSO ENHANCE THE CONVECTION ACROSS THE WESTERN MARITIME CONTINENT
DURING EARLY JANUARY. THE GEFS AND ECMWF MODELS ARE IN EXCELLENT AGREEMENT THAT
THE MJO PROPAGATES EASTWARD TO THE WEST PACIFIC DURING LATE JANUARY. BY THE END
OF THE MONTH AND HEADING INTO FEBRUARY, THE MJO IS LIKELY TO CONSTRUCTIVELY
INTERFERE WITH EL NIñO.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE CPC SST CONSOLIDATION FORECAST FOR NIñO 3.4 DEPICTS DECREASING POSITIVE
ANOMALIES BY THE SPRING, AND IT IS TYPICAL FOR EL NIñO TO PEAK IN STRENGTH
DURING THE WINTER. DYNAMICAL AND STATISTICAL MODELS ARE IN GOOD AGREEMENT THAT
A TRANSITION TO ENSO-NEUTRAL CONDITIONS OCCURS EITHER IN THE SPRING OR BY THE
EARLY SUMMER. THE CPC ENSO OUTLOOK INDICATES A LIKELY TRANSITION TO
ENSO-NEUTRAL DURING APRIL-MAY-JUNE WITH INCREASING CHANCES OF LA NIñA FROM THE
SUMMER INTO THE FALL. BY AUGUST-SEPTEMBER-OCTOBER, THERE IS MORE THAN A 60
PERCENT CHANCE OF LA NIñA.
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS
THE TEMPERATURE AND PRECIPITATION OUTLOOKS FOR FMA 2024 WERE BASED ON DYNAMICAL
MODEL GUIDANCE SUCH AS THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME),
INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), AND STATISTICAL TOOLS SUCH AS THE
GLOBAL SST-BASED CONSTRUCTED ANALOG (CA) AND ENSO-OCN. THE OBJECTIVE,
HISTORICAL SKILL-WEIGHTED CONSOLIDATION WAS A MAJOR TOOL USED IN THE OUTLOOKS,
AND THAT INCLUDES THE ENSO-OCN TOOL AND A COMPLETE SUITE OF STATISTICAL AND
DYNAMICAL TOOL COMBINATIONS. EL NIñO COMPOSITES WERE USED PRIMARILY DURING FMA
AND TO A LESSER EXTENT THROUGH MAM AS THE ATMOSPHERIC RESPONSE TO EL NIñO IS
EXPECTED TO DIMINISH LATER IN THE SPRING. LA NIñA COMPOSITES WERE CONSIDERED
BEGINNING DURING THE SUMMER AND USING THESE COMPOSITES, MODIFICATIONS WERE MADE
TO THE LATE FALL 2024 AND WINTER 2024-2025 OUTLOOKS. LONG-TERM CLIMATE TRENDS
WERE CONSIDERED FOR ALL LEADS, BUT WERE RELIED UPON MOST FROM THE SUMMER 2024
THROUGH FMA 2025.
PROGNOSTIC DISCUSSION OF OUTLOOKS - FMA 2024 TO FMA 2025
TEMPERATURE
ELEVATED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES DURING FMA 2024 ARE
FORECAST ACROSS THE NORTHERN TIER OF THE CONTIGUOUS U.S. (CONUS) AND ALASKA
WHICH IS SUPPORTED BY THE CALIBRATED NMME, CONSOLIDATION TOOL, AND EL NIñO
COMPOSITES. THE LARGEST PROBABILITIES (ABOVE 50 PERCENT) FOR ABOVE-NORMAL
TEMPERATURES ARE FORECAST FOR MUCH OF OREGON, WASHINGTON, AND NORTHERN IDAHO
WHERE THE TELECONNECTION TO EL NIñO HAS ITS STRONGEST CORRELATION. ABOVE-NORMAL
TEMPERATURE PROBABILITIES ARE LIMITED TO BELOW 40 PERCENT ACROSS THE NORTHERN
GREAT PLAINS AND PARTS OF THE UPPER MIDWEST DUE TO UNCERTAINTY ON THE ARCTIC
OSCILLATION (AO) PHASE. A PERSISTENT -AO COULD PROMOTE A MAJOR ARCTIC AIR
OUTBREAK WHICH COULD SKEW THE SEASONAL MEAN TEMPERATURE TOWARDS AT LEAST THE
MIDDLE TERCILE FOR THESE AREAS. IN ADDITION, THE MADDEN-JULIAN OSCILLATION HAS
REMAINED ACTIVE SINCE NOVEMBER 2023. IF THE MJO REMAINS ACTIVE AND RESULTS IN
SUBSEASONAL PATTERN CHANGES, THAT WOULD ALSO LEAD TO LOWER FORECAST CONFIDENCE.
DESPITE THE INCREASED UNCERTAINTY RELATED TO THE AO AND MJO, ABOVE-NORMAL
TEMPERATURES REMAIN THE MOST LIKELY OUTCOME ACROSS THE NORTH-CENTRAL CONUS
GIVEN THE ONGOING EL NIñO. BASED ON EL NIñO COMPOSITES AND THE ENSO-OCN TOOL
ALONG WITH CONTINUITY FROM PREVIOUS OUTLOOKS, BELOW-NORMAL TEMPERATURE
PROBABILITIES ARE ELEVATED ACROSS SOUTHEASTERN NEW MEXICO AND WESTERN TO
CENTRAL TEXAS. THE EXPECTATION OF A HIGHLY VARIABLE TEMPERATURE PATTERN DURING
FMA ALONG WITH SUPPORT FROM THE CONSOLIDATION TOOL LEADS TO NEAR-NORMAL
TEMPERATURES BEING FAVORED FOR MUCH OF THE SOUTHEAST. EQUAL CHANCES (EC) FOR
BELOW, NEAR, OR ABOVE-NORMAL TEMPERATURES ARE FORECAST FOR PARTS OF THE
SOUTHERN TIER OF THE CONUS DUE TO CONFLICTING AND/OR WEAK SIGNALS AMONG THE
STATISTICAL AND DYNAMICAL TOOLS. LONG-TERM TRENDS BECAME THE MAJOR FACTOR IN
THE TEMPERATURE OUTLOOK DURING THE SUMMER. GIVEN THE INCREASING CHANCE OF LA
NIñA BY THE LATE SUMMER AND FALL, LA NIñA TEMPERATURES COMPOSITES WERE ALSO
CONSIDERED.
PRECIPITATION
THE FMA PRECIPITATION OUTLOOK IS CONSISTENT WITH EL NIñO COMPOSITES AND
STRONGLY FAVORS ABOVE-NORMAL PRECIPITATION ACROSS THE SOUTHEAST WITH
BELOW-NORMAL PRECIPITATION MORE LIKELY FROM THE OHIO VALLEY NORTH TO THE GREAT
LAKES. BASED ON GOOD AGREEMENT AMONG STATISTICAL AND DYNAMICAL TOOLS, THE
LARGEST PROBABILITIES (MORE THAN 60 PERCENT) FOR ABOVE-NORMAL PRECIPITATION ARE
FORECAST ACROSS NORTH-CENTRAL FLORIDA. SLIGHTLY ELEVATED ABOVE-NORMAL
PRECIPITATION PROBABILITIES EXTEND NORTH ALONG THE EAST COAST TO SOUTHERN NEW
ENGLAND AND ALSO WESTWARD TO PARTS OF THE GREAT PLAINS, BASED ON EL NIñO
COMPOSITES AND THE IMME. DYNAMICAL MODELS AND STATISTICAL TOOLS SUPPORT
INCREASED BELOW-NORMAL PRECIPITATION PROBABILITIES ACROSS THE PACIFIC NORTHWEST
AND NORTHERN INTERMOUNTAIN WEST. ALTHOUGH THE NMME TRENDED DRIER FROM ITS
DECEMBER MODEL RUN THROUGHOUT THE SOUTHWEST AND CALIFORNIA, ABOVE-NORMAL
PRECIPITATION IS FAVORED FOR THESE AREAS DUE TO SUPPORT FROM THE CONSOLIDATION
TOOL AND EL NIñO COMPOSITES. BASED ON THE CONSOLIDATION TOOL, NMME, AND
ENSO-OCN, INCREASED ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE FORECAST FOR
MUCH OF SOUTHERN ALASKA AND THE NORTH SLOPE OF ALASKA.
THE MARCH-APRIL-MAY PRECIPITATION OUTLOOK MAINTAINED CONTINUITY FROM THE
PREVIOUS MONTH WITH EL NIñO EXPECTED TO HAVE A LINGERING INFLUENCE INTO AT
LEAST THE EARLY SPRING. BY APRIL-MAY-JUNE (AMJ), THE NMME DEPICTS AN INCREASING
DRY SIGNAL ACROSS THE SOUTHERN GREAT PLAINS AND THE AMJ OUTLOOK FOLLOWED THIS
MODEL GUIDANCE. MINOR ADJUSTMENTS WERE MADE TO SUBSEQUENT THREE-MONTH PERIODS
THROUGH THE SUMMER, CONSISTENT WITH THE UPDATED NMME, CONSOLIDATION, AND
LONG-TERM TRENDS. GIVEN THE INCREASING CHANCE OF LA NIñA BY THE LATE SUMMER AND
FALL, LATER OUTLOOKS WERE TILTED TOWARDS LA NIñA PRECIPITATION COMPOSITES.
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 FEB 15 2024
1991-2020 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 20, 2021
FORECAST RELEASE.
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