490 FXUS05 KWBC 201331 PMD90D Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EST Thu Nov 20 2025 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS La Nia conditions continue with sea surface temperatures (SSTs) below average across the central and eastern equatorial Pacific Ocean. La Nia is slightly favored to persist through December-January-February but is likely to remain weak. A transition to ENSO-neutral conditions is expected by early spring 2026. The December-January-February (DJF) 2025-26 Temperature Outlook favors above-normal temperatures across much of the East Coast, Southeast, Gulf Coast, Texas, the Southwest, and California. The DJF Temperature Outlook leans towards below-normal temperatures from the Upper Mississippi Valley and Northern to Central Great Plains west to parts of the Pacific Northwest. An increased chance of below (above)-normal temperatures is forecast for southeastern (northwestern) Alaska. The DJF Precipitation Outlook depicts elevated below-normal precipitation probabilities for portions of the Mid-Atlantic, Southeast, Gulf Coast, Texas, the Southwest, and California. Above-normal precipitation is favored from the Upper Mississippi Valley and Great Lakes south to the Ohio Valley along with the Northern Great Plains, Northern Rockies, and parts of the Pacific Northwest. An increased chance of below (above)-normal precipitation is forecast for southeastern (northwestern) Alaska. 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 Weekly observed sea surface temperatures (SSTs) in the Nio 3.4 region are below average throughout the central and eastern equatorial Pacific. The latest weekly SST departure, centered on November 12, is -0.7 degrees C. The negative SST anomalies recently expanded eastward across the equatorial Pacific to the South American coast. Since the beginning of September, subsurface temperature anomalies (averaged from 180-100W and 0-300 meters depth) have remained negative with little change in magnitude. From October 17 to November 11, negative outgoing longwave radiation (OLR) anomalies (enhanced convection and precipitation) continued over Indonesia, Southeast Asia, the Philippines, and parts of northern Australia. Conversely, positive OLR anomalies (suppressed convection and precipitation) were observed at and near the Date Line. Low-level (850-hPa) wind anomalies were easterly from the western to the east-central equatorial Pacific Ocean, while upper-level (200-hPa) wind anomalies were westerly over most of the equatorial Pacific. These atmospheric and oceanic conditions reflect La Nia conditions. The Madden-Julian Oscillation (MJO) slowed and weakened during mid-November as it destructively interfered with the La Nia background state. Dynamical model Realtime Multivariate MJO (RMM) forecasts depict a strengthening MJO with eastward propagation over the West Pacific from late November to the beginning of December. The extratropical response, associated with a West Pacific MJO, favors an amplifying 500-hPa ridge (trough) over Alaska (west-central CONUS) by the end of November which would promote anomalous cold to shift southeast into the lower 48 states. PROGNOSTIC DISCUSSION OF SST FORECASTS The CPC SST consolidation forecast for Nio 3.4 depicts La Nia conditions persisting through at least DJF as the SST anomaly remains near -0.5 degrees C. The dynamical models and the Constructed Analog are in good agreement that SSTs become closer to average by later in the winter or early next spring. The International Multimodel Ensemble (C3S) members depict a similar timing of when the transition to ENSO-neutral conditions happens. The CPC ENSO outlook indicates that La Nia is favored to persist through DJF before a transition to ENSO-neutral conditions during January-February-March. ENSO-neutral is strongly favored (near or more than a 70 percent chance) through the 2026 spring. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS The Temperature and Precipitation Outlooks for DJF 2025-26 were based on La Nia composites, expectations for periods of a negative Arctic Oscillation, the North American Multi-Model Ensemble (NMME), and the Copernicus (C3S) multi-model ensemble system. A Calibration, Bridging, and Merging (CBaM) version of the NMME was also considered. An objective, historical skill-weighted consolidation that includes the NMME along with statistical tools such as the SST-based Constructed Analog and the ENSO-OCN was used through April-May-June 2026. Beyond that time, the consolidation only includes statistical tools. Long-term climate trends were considered for all leads, but were relied upon most during the summer and fall 2026. PROGNOSTIC DISCUSSION OF OUTLOOKS - DJF 2025 TO DJF 2026 TEMPERATURE The DJF Temperature Outlook was based largely on La Nia composites, the calibrated NMME where it is more skillful over previous winter seasons, and the consolidation tool. High-latitude blocking has been quite prevalent since mid-October with the Arctic Oscillation (AO) in a negative phase for much of the past month. The GEFS and ECENS favor a persistence of a negative AO into the beginning of December. The Madden-Julian Oscillation is forecast to strengthen and propagate east over the West Pacific (phase 7). This MJO evolution can lead to an amplifying mid-level ridge over Alaska and an outbreak of anomalously cold temperatures shifting southeast from the north-central to eastern CONUS. Due to a persistent negative AO and an expected MJO influence, early December is likely to be colder-than-normal across the Midwest and the December outlook depicts elevated below-normal temperature probabilities for this region. This favored colder-than-normal forecast for December was a factor in expanding the slight lean towards below southeastward compared to the DJF outlook released in October. In addition to the negative AO and MJO influences, the stratospheric polar vortex is forecast to become stretched and displaced off the North Pole. Although a major sudden stratospheric warming (SSW) is not forecast by the GEFS, the ECMWF ensemble mean from November 18 depicts a slight reversal of 10-hPa zonal winds at 60N consistent with a SSW, which could prolong the negative AO. A SSW would be very rare for this time of year. Even if a SSW does not occur during late November, this may set the stage for additional polar vortex disruptions and a major SSW with impacts to the troposphere later this winter. Temperatures are expected to be highly variable along and north of the 40th parallel this winter which is typical during La Nia. The DJF outlook leans towards below-normal temperatures from the Upper Mississippi Valley and Northern to Central Great Plains west to the Northern Rockies and parts of the Pacific Northwest where below-normal temperatures occur most frequently during La Nia winters and there is additional support from the consolidation tool. The calibrated NMME supports an increased chance of above-normal temperatures for much of California, the Southwest, Rio Grande Valley, Gulf Coast, Southeast, Mid-Atlantic, and southern New England. Due to good agreement and consistency among the tools, the highest forecast confidence in the DJF Temperature Outlook is for above-normal temperatures (50-60 percent chance) across the Florida Peninsula and parts of the Southwest. In between the favored above across the southern tier and below farther to the north, equal chances of below, near, or above-normal temperatures are forecast as these areas are expected to have the most temperature variability this winter. The Alaska Temperature Outlook is quite consistent with La Nia composites and dynamical models which call for an increased chance of below (above)-normal temperatures for southeastern (northwestern) Alaska. The January-February-March (JFM) and February-March-April Temperature Outlooks hedged slightly colder than the dynamical model guidance across the Great Plains due to the potential for additional periods of a negative AO phase and at least one Arctic air outbreak in January and/or February. It should be noted that probabilities for below or above-normal temperatures are less than 50 percent throughout the forecast domain during JFM as forecast confidence is tempered due to the expectation of a highly variable pattern within this three-month period. By April-May-June, above-normal temperatures become the most likely category for a majority of the lower 48 states and Alaska, and then the entire forecast domain is favored to have above-normal temperatures during September-October-November consistent with long-term trends. PRECIPITATION The DJF precipitation outlook is consistent with La Nia composites as the southern tier of the CONUS is typically drier-than-normal with above-normal precipitation more likely for the Northern Rockies, Northern Great Plains, Upper Mississippi Valley, and from the Great Lakes south to the Ohio and Tennessee Valleys. Despite a wet signal in La Nia composites for western parts of Oregon and Washington, equal chances (EC) for below, near, or above-normal precipitation are forecast based on the NMME and consolidation tool. Compared to the previous month's release, below-normal precipitation probabilities were decreased to below 40 percent for southern California and the Southwest as the SST-Constructed Analog has a wetter signal for these areas. Also, the unusually wet October and November decrease forecast confidence that below-normal precipitation will verify during DJF. The highest confidence in below-normal precipitation across the southern tier of the CONUS exists for portions of the Southeast where drier-than-normal winters are very reliable during La Nia. Below-normal precipitation probabilities decrease to the south across the Florida Peninsula due in part to the drier winter climatology. Elevated below-normal precipitation probabilities extend northward to the Mid-Atlantic as the primary storm track is expected to be farther to the west across the Ohio Valley. This favored winter storm track results in enhanced above-normal precipitation probabilities for the Ohio Valley. It is typical to have a tight gradient between above and below normal precipitation from the Tennessee Valley south to the Gulf Coast during La Nia winters. Based on La Nia composites and good model agreement, the largest above-normal precipitation probabilities (more than 50 percent) are forecast across the Northern Rockies and Northern High Plains. Good model consistency supports an increased chance of above-normal precipitation for western Mainland Alaska. Overall the precipitation tools have trended wetter for southeastern Alaska where now the DJF outlook only slightly leans towards the drier side. Although a transition to ENSO-neutral conditions is likely to occur during January-February-March 2026, a La Nia influence on the mid-latitude circulation pattern and anomalous precipitation is expected to linger through the late winter or even early spring. Therefore, the JFM and February-March-April Precipitation Outlooks are similar to La Nia composites with minor adjustments based on the NMME, C3S, and consolidation. Later in the spring and into the summer 2026, the coverage of EC increases due to weak and/or conflicting signals among forecast guidance. At the longer lead times, long-term trends were used to identify any areas with either favored below or above-normal precipitation. 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 Dec 18 2025 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$