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FXUS07 KWBC 181331
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST THU DEC 18 2025
30-DAY OUTLOOK DISCUSSION FOR JANUARY 2026
THE JANUARY 2026 MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS ARE CONSTRUCTED
BY CONSIDERING THE LA NIñA BASE STATE, AS WELL AS DYNAMICAL CLIMATE MODELS AND
INTEGRATED STATISTICAL TOOLS. EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) REMAIN
BELOW AVERAGE ACROSS THE CENTRAL AND EAST-CENTRAL PACIFIC OCEAN, WITH SST
DEPARTURES IN THE NIñO 3.4 REGION REACHING -0.7 DEGREES C. THESE BELOW-AVERAGE
SSTS HAVE PERSISTED SINCE SEPTEMBER 2025, AND WE ARE FIRMLY WITHIN WEAK LA NIñA
TERRITORY. FURTHERMORE, ATMOSPHERIC ANOMALIES OVER THE TROPICAL PACIFIC OCEAN
ARE CONSISTENT WITH LA NIñA, CONSEQUENTLY, WE EXPECT LA NIñA TELECONNECTIONS
DURING JANUARY 2026. IN CONTRAST, THE MADDEN-JULIAN OSCILLATION (MJO) REMAINS
MORE UNCERTAIN, AS MODELS SUGGEST DESTRUCTIVE INTERFERENCE FROM A STRONG KELVIN
WAVE MAY HINDER ITS RE-EMERGENCE. THE JANUARY 2026 OUTLOOKS ARE PRIMARILY
SHAPED BY THE LA NIñA BACKGROUND STATE, DYNAMICAL CLIMATE MODELS, LOCAL SST
ANOMALIES, SEA ICE, AND LAND SURFACE CONDITIONS (WHERE APPROPRIATE). AN
EXPERIMENTAL MULTIPLE LINEAR REGRESSION (MLR) TOOL WHICH ESTIMATES THE
INFLUENCES OF THE EL NIñO SOUTHERN OSCILLATION (ENSO), MJO, AND DECADAL TRENDS
IS UTILIZED, AS IS A CONSOLIDATION THAT INCLUDES INFLUENCE OF ENSO, DECADAL
TRENDS, AND CALIBRATED NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) OUTPUT. WEEKS
3-4 FORECASTS FROM THE GLOBAL ENSEMBLE FORECAST SYSTEM VERSION 12 (GEFSV12),
THE EUROPEAN CENTRE FOR MEDIUM-RANGE WEATHER FORECASTS (ECMWF), AND COUPLED
FORECAST SYSTEM VERSION 2 (CFSV2) MODELS THAT COVER THE PERIOD TO ABOUT
MID-JANUARY WERE ALSO CONSIDERED. IMPACTS FROM THE MJO, ALONG WITH LAND SURFACE
VARIABLES SUCH AS SNOW COVER, WILL BE RE-EVALUATED AT THE END OF THE MONTH FOR
THE UPDATED VERSION OF THIS OUTLOOK.
THE JANUARY 2026 TEMPERATURE OUTLOOK FEATURES INCREASED CHANCES OF BELOW-NORMAL
TEMPERATURES FOR MUCH OF MAINLAND ALASKA, ALL OF SOUTHEAST ALASKA, AND
STRETCHING FROM THE NORTHERN ROCKIES TO THE UPPER MISSISSIPPI VALLEY.
ABOVE-NORMAL TEMPERATURES ARE MORE LIKELY FOR THE SOUTHERN TIER OF THE
CONTIGUOUS UNITED STATES (CONUS), COVERING MUCH OF THE SOUTHWEST, FOUR CORNERS,
SOUTHERN PLAINS, SOUTHEAST, AND MID-ATLANTIC. EQUAL CHANCES (EC) OF ABOVE-,
NEAR-, AND BELOW-NORMAL TEMPERATURES ARE FORECAST FOR WESTERN AND NORTHERN
ALASKA, THE NORTHWEST, MUCH OF NORTHERN AND CENTRAL CALIFORNIA, THE CENTRAL
PLAINS, GREAT LAKES, AND NEW ENGLAND. A MID-LEVEL HEIGHT PATTERN TYPICAL OF LA
NIñA HAS BEEN ESTABLISHED AND IS FORECAST TO PERSIST INTO AT LEAST MID-JANUARY
PER WEEK 3-4 DYNAMICAL MODELS. A BLOCKING HIGH HAS BEEN A SIGNIFICANT FEATURE
OVER THE NORTH PACIFIC AND ALEUTIANS, WITH DOWNSTREAM MID-LEVEL LOW PRESSURE
RESIDING OVER EASTERN ALASKA AND PORTIONS OF THE NORTHWEST. ABOVE-AVERAGE
MID-LEVEL HEIGHTS COVER MUCH OF THE SOUTHERN TIER AND EASTERN CONUS. THE
PATTERN REFLECTED IN THE JANUARY 2026 TEMPERATURE OUTLOOKS IS CONSISTENT WITH
LA NIñA EXPECTATIONS, THOUGH IT HAS BEEN MODIFIED BASED ON AVAILABLE GUIDANCE.
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE HIGHEST OVER SOUTHEAST ALASKA
AND ADJACENT AREAS OF SOUTHEASTERN MAINLAND ALASKA, REACHING 50 TO 60%, GIVEN
CONSISTENCY AMONG VARIOUS TOOLS. MONTHLY FORECASTS FOR ALASKA FROM NMME, C3S,
AND CFSV2 ALIGN WITH SHORTER-TERM WEEK 3-4 FORECASTS IN FAVORING THESE COOLER
CONDITIONS. PROBABILITIES ARE ALSO ENHANCED, REACHING 50 TO 60%, OVER SOUTHERN
NEW MEXICO, TEXAS, LOUISIANA, AND FLORIDA. THIS IS DRIVEN BY STRONG AGREEMENT
BETWEEN DYNAMICAL MODELS AND HIGHER-PROBABILITY SIGNALS IN THE SHORTER-TERM
WEEK 3-4 FORECASTS.
WHILE DECADAL TRENDS AND CERTAIN TOOLS LIKE THE CFSV2 TILT TOWARD ABOVE-NORMAL
TEMPERATURES OVER THE NORTHERN COAST OF ALASKA, EC IS INDICATED BECAUSE EARLY
TO MID-JANUARY IS FORECAST TO BE AT LEAST SLIGHTLY BELOW-NORMAL, AND SEA ICE IS
PRESENT ALONG THE COAST. SIMILARLY, WHILE LA NIñA OFTEN BRINGS BELOW-NORMAL
TEMPERATURES TO THE NORTHERN TIER OF THE CONUS, SOMETIMES INCLUDING THE
NORTHWEST, THE NMME, C3S, AND CFSV2 MONTHLY OUTLOOKS ARE GENERALLY ABOVE-NORMAL
ALONG THE WESTERN THIRD OF THE COUNTRY. FURTHERMORE, SHOULD THE MJO BECOME MORE
COHERENT, IT COULD INTRODUCE MORE VARIABILITY, SUCH AS COOLER TEMPERATURES IN
THE WEST, THOUGH THIS INFLUENCE IS CURRENTLY HIGHLY UNCERTAIN. EC IS THUS
FAVORED OVER MUCH OF THE WEST AND NORTHWEST AS WE CANNOT DISCOUNT THE
POSSIBILITY OF COOLER AIR EXTENDING FURTHER WEST AND SOUTH.
SIMILARLY, MODELS ARE WARM OVER THE CENTRAL CONUS, HOWEVER, IT IS NOT UNHEARD
OF DURING JANUARY AND LA NIñA YEARS TO SEE COLD AIR INTRUSIONS REACH FURTHER
SOUTH, AS SUCH WE TILT TOWARD EC OVER THE CENTRAL CONUS AND WILL RE-ASSESS IN
THE MONTHLY UPDATE. IN ADDITION, UNCERTAINTY IS HIGH IN THE CENTRAL CONUS IN A
CONSOLIDATION OF STATISTICAL TOOLS (WHICH INCLUDE INFLUENCE OF TREND AND ENSO),
AND NMME, WHICH ADDS TO OUR UNCERTAINTY HERE. FINALLY, GUIDANCE WAS MIXED AND
INCONSISTENT OVER THE GREAT LAKES AND NEW ENGLAND, WHICH ALSO LED TO A TILT
TOWARD EC. BECAUSE THIS LA NIñA IS CURRENTLY WEAK, INCREASED VARIABILITY AND
UNCERTAINTY ARE POSSIBLE FOR SOME REGIONS, WHICH ALSO SUPPORTS EC.
WHILE SOME REGIONS IN THE JANUARY TEMPERATURE OUTLOOK REMAIN UNCERTAIN DUE TO
THE VARIABILITY OF WEAK LA NIñA TELECONNECTIONS, THE PRECIPITATION PATTERN IS
MORE CONSISTENT ACROSS VARIOUS TOOLS, CLOSELY RESEMBLING THE EXPECTED LA NIñA
SIGNATURE. ABOVE-NORMAL PRECIPITATION IS FAVORED FOR THE NORTHWEST, NORTHERN
ROCKIES, GREAT LAKES, AND MUCH OF THE OHIO AND MIDDLE MISSISSIPPI VALLEYS.
WESTERN ALASKA ALSO LEANS ABOVE-NORMAL. DRIER CONDITIONS ARE MORE LIKELY ACROSS
THE SOUTHWEST, SOUTHERN PLAINS, AND MUCH OF THE SOUTHEAST. A WEAK TILT TOWARD
BELOW-NORMAL PRECIPITATION IS ALSO INDICATED OVER MUCH OF THE SOUTHERN COAST OF
MAINLAND ALASKA AND ALL OF SOUTHEAST ALASKA. WHILE THE NMME AND C3S FAVOR
BELOW-NORMAL PRECIPITATION UP MUCH OF THE WEST COAST, REACHING INTO THE
NORTHWEST IN SOME MODELS, RECENT FORECASTS FROM CFSV2 TILT ABOVE-NORMAL FOR THE
MONTH OF JANUARY OVER THE NORTHWEST. MOREOVER, WEEK 3 AND WEEK 4 DYNAMICAL
MODELS FORECAST AT LEAST 40 TO 50% CHANCES OF ABOVE-NORMAL PRECIPITATION OVER
THE NORTHWEST. AS SUCH, WE HAVE MINIMIZED THE REGION OF BELOW-NORMAL
PRECIPITATION FORECAST BY SOME OF THE MULTI-MODEL ENSEMBLES, CONFINING IT MORE
TO SOUTHEASTERN CALIFORNIA. GIVEN THE UNCERTAINTY REGARDING HOW FAR SOUTH THE
MOISTURE MAY REACH, MUCH OF CALIFORNIA IS DESIGNATED AS EC. ABOVE-NORMAL
PRECIPITATION IS ALSO INDICATED FOR THE GREAT LAKES, OHIO VALLEY, AND PARTS OF
THE MIDDLE AND LOWER MISSISSIPPI VALLEYS AND THE TENNESSEE VALLEY , WHICH IS A
TYPICAL LA NIñA SIGNATURE. THESE TWO AREAS OF ABOVE-NORMAL PRECIPITATION ARE
CONNECTED BY A WEAK (33 TO 40%) CHANCE OF ABOVE-NORMAL PRECIPITATION THAT IS
SUPPORTED BY THE NMME AND C3S. THE BELOW-NORMAL PRECIPITATION FAVORED OVER THE
SOUTHERN TIER IS CONSISTENT WITH MODELS AND LA NIñA, THOUGH SOME UNCERTAINTY
EXISTS OVER PARTS OF TEXAS AND LOUISIANA AS IT IS CURRENTLY UNCLEAR HOW FAR
SOUTH ANY ABOVE-NORMAL PRECIPITATION MIGHT REACH. FINALLY, OVER ALASKA, DECADAL
TRENDS AND LA NIñA SUPPORT THE FORECAST FOR BELOW-NORMAL PRECIPITATION OVER THE
SOUTHERN COAST OF THE MAINLAND AND SOUTHEAST ALASKA, WHILE DYNAMICAL MODELS
LIKE THE NMME, C3S, AND CFSV2 FAVOR ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE
WESTERN MAINLAND.
FORECASTER: JOHNNA INFANTI
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 FEB ... WILL BE ISSUED ON THU JAN 15 2026.
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
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