043 FXUS05 KWBC 151231 PMD90D Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EDT Thu Oct 15 2026 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS The ongoing El Nino event continues to strengthen, and an El Nino advisory remains in effect and is favored to continue through Spring 2027. The seasonal outlooks for the upcoming winter and spring are heavily influenced by this very strong event. The Temperature Outlook for Nov-Dec-Jan (NDJ) 2026-2027 favors above-normal seasonal mean temperatures for eastern Alaska, the northern tier and western third of the contiguous U.S. (CONUS), south Florida, and the Ohio Valley and mid-Atlantic regions. The highest odds of warmer than normal conditions are located over Southeast Alaska, the upper Mississippi Valley and Great Lakes. Near-normal seasonal average temperatures are favored for much of the Southeast. There is an elevated likelihood of above-normal seasonal precipitation amounts for much of California, the Southwest, the Central and Southern Plains, the Lower Mississippi Valley, the Southeast and along the eastern seaboard. The greatest likelihood for wetter than normal conditions is forecast for the Southeast and Florida. Below-normal precipitation is favored for much of interior Alaska, the Northern Rockies and High Plains, and parts of the Great lakes region. Equal chances (EC, white areas) are forecast for areas where probabilities for each category of seasonal mean temperatures and accumulated precipitation amounts are forecast 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 El Nino conditions are strongly in place in the tropical Pacific Ocean as shown by both oceanic and atmospheric indicators. Above-average relative sea surface temperature anomalies (SSTs) exist along the equator from just east of the Date Line (160 E) to the South America coast. Large positive SST anomalies of greater than +2.0 degrees C are depicted eastward of 160 W along the equator with areas of +4.0 degrees C present off the South America coast to 120 W. Below-average SSTs are present in the western Pacific and in the typical horseshoe pattern both north and south of the equatorial extension of warmer water along the equator. The latest weekly values of the Nino3.4, Nino3 and Nino1+2 SST indexes are +2.4, +3.4 and +4.4 degrees C respectively. Considerable remaining fuel is present for further strengthening of this El Nino event as a large reservoir of above-normal ocean temperatures continues to be indicated from 170 W to the South America coast and to a depth of greater than 200 m. The atmosphere has strongly responded to these ongoing ocean conditions as early as this summer as shown by the highly anomalous tropical cyclone seasons in the central and eastern Pacific (well above) and Atlantic (well below) basins. There is greatly enhanced (suppressed) convection over the central and eastern Pacific (Indonesia and western Pacific). Low level (850-hPa) westerly wind anomalies are large and indicate a substantial weakening of the normal trade winds. At upper levels (200-hPa), easterly wind anomalies with anti-cyclonic circulations north and south of the equator in the central Pacific are present, indicative of a strong, maturing El Nino episode. A review of the northern hemisphere snow cover extent shows a highly variable pattern with the most substantial anomalies being areas of below-average coverage in north-central Asia and northern Canada. The Quasi-Biennial Oscillation (QBO) is currently in its westerly phase and is forecast to remain so throughout the winter into Spring 2027. The negative phase of the Pacific Decadal Oscillation (PDO) remains in place when viewing the latest observations. PROGNOSTIC DISCUSSION OF SST FORECASTS The CPC objective, skill weighted consolidation and North American Multi-Model Ensemble (NMME) relative Nino3.4 SST outlooks forecast a further increase in the relative Nino3.4 index value to near +3.0 and +3.5 degrees C respectively with a general peak in anomalous values during the NDJ 2026-2027 season. The official CPC ENSO Outlook forecasts high probabilities (80%) for at least a strong El Nino event to continue through the Jan-Feb-Mar (JFM) 2027 season and favors an El Nino event of any strength to continue through the Mar-Apr-May (MAM) 2027. ENSO neutral is then favored through May-Jun-Jul (MJJ) 2027. Thereafter, the CPC consolidated SST forecasts potential La Nina conditions during autumn 2027. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS The current El Nino event, associated conditions and potential impacts are a primary driver in the seasonal outlook package through the Spring 2027 season with close inspection of some of the historically strong El Nino events. Other physical subseasonal to seasonal (S2S) climate drivers considered in preparing the outlooks are the QBO, ENSO relationship with the stratospheric polar vortex (winter seasons), coastal SSTs in some areas and the negative phase of the Pacific Decadal Oscillation (PDO). The NMME and Copernicus Climate System (C3S) dynamical model ensemble prediction systems and their participant models are utilized, as well as several statistical and hybrid forecast tools and long-term temperature and precipitation trends. Experimental National Centers for Environmental Prediction (NCEP) Seasonal Forecast System (SFS) model guidance and an internal Machine Learning forecast system targeting the S2S time scale are also consulted. PROGNOSTIC DISCUSSION OF OUTLOOKS - NDJ 2026 TO NDJ 2027 TEMPERATURE The NDJ 2026-2027 Temperature Outlook favors above-normal seasonal mean temperatures for eastern Alaska, the western third of the CONUS, the northern tier from the Pacific Northwest eastward to include the Midwest and much of the East, and southern Florida. The highest odds for warmer than normal conditions are forecast for southeastern Mainland and Southeast Alaska, the Pacific Northwest to the northern Plains, Great Lakes and interior Northeast. This is consistent with typically observed conditions during strong El Nino events. Statistical, hybrid and dynamical model guidance is very consistent across the board for this favored outcome. There is more uncertainty in seasonal mean temperatures across the southern tier of the CONUS. Near-normal temperatures are favored for the Southeast and northern Florida where a mixture of outcomes is indicated by forecast guidance and where near-normal conditions have been observed during some of the historically strong El Nino events of the past. Similarly, large spread and varying forecast outcomes in forecast tools and during strong El Nino events supports the forecast of Equal Chances (EC) for either above-, near- or below-normal seasonal mean temperatures over the Southwest and parts of the southern Plains. The evolution of the Temperature Outlooks from Dec-Jan-Feb (DJF) 2026-2027 through MAM 2027 maintain the NDJ forecast pattern in large order and are consistent with strong El Nino events through these seasons with additional attention paid to some of the historically strong events. Some exceptions include a slight shift eastward and southward for the forecast area of near-normal temperatures in the Southeast and Florida. This near-normal area ends by the Feb-Mar-Apr (FMA) 2027 season. An important note about the Southeast CONUS including Florida, is that the dynamical model guidance from ensemble systems are highlighting elevated odds (in some cases quite strongly) for below-normal temperatures as the seasons progress and this maximizes during the JFM and FMA seasons. It is felt that the dynamical model guidance is too sensitive to forecast above-normal precipitation and overestimating cooler daytime temperatures - especially during the second half of the winter season. In contrast, the statistical guidance favors near- to above-normal temperatures for these seasons. This guidance factors in positive long-term temperature trends that are likely amplified by warmer-than-normal nighttime temperatures driven by increased moisture, cloudiness and precipitation. During the FMA and MAM 2027 seasons, there is enough consensus in statistical, hybrid and dynamical model guidance for parts of the Southwest CONUS to favor below-normal temperatures in this area. This signal is also observed in some of the very strong El Nino events of the past, to varying degrees. Another change over these seasons is a slight lowering of probabilities for above-normal temperatures in the northern Plains during FMA to Apr-May-Jun (AMJ) 2027. Two additional considerations when preparing the outlook include (1) how the current easterly phase of the QBO may impact the strength of the stratospheric polar vortex (SPV) and (2) the ongoing negative phase of the PDO. This winter, the QBO is forecast to be in its westerly phase and expected to continue through the extended winter months. The SPV is typically stronger and more stable under westerly QBO and El Nino conditions, both of which will be in place this winter. The potential prospects of a more stable SPV slightly decreases the odds for Sudden Stratospheric Warming (SSW) events or other undulations that may lead to negative Arctic Oscillation (AO) periods. This is supportive of above-normal temperatures in mid-latitude areas in general and consistent with the forecast of above-normal temperatures across the northern and eastern CONUS. It is somewhat difficult to ascertain the potential influence of the negative phase of the PDO given the very strong El Nino events of 1997-1998 and 2015-2016 both occurred during the positive phase of the PDO. Although the PDO is in its negative phase, it is felt that given the very strong El Nino event that its influence during the winter seasons may be minimal. The outlooks from AMJ 2027 onwards are based on the ENSO-OCN forecast tool which is based on the "perfect prog" forecast from the CPC SST consolidation (ENSO component) and long term temperature trends (Optimal Climate Normal). PRECIPITATION For the NDJ 2026-2027 Precipitation Outlook, there is an elevated likelihood of above-normal seasonal precipitation amounts for much of California and the Southwest, the central and southern Plains, and the Southeast and along the Eastern Seaboard. Below-normal precipitation is favored for the northern Rockies and parts of the Great Lakes as well as much of western and central interior Alaska. Anticipated impacts related to the ongoing El Nino event primarily inform the forecast. Additional attention to the historically strong El Nino events of the past show considerable wetness observed across much of the CONUS and extended well north along the Eastern Seaboard. Dynamical model guidance across ensemble prediction systems is in very good agreement with this premise. Above-normal precipitation in the Southeast is one of the most reliable signals from El Nino events and dynamical model guidance shows very high probabilities for wetter than average conditions in this region. Odds for above-normal precipitation exceed 70% for some areas in the extreme Southeast and northern Florida through the JFM 2027 season and decrease slowly through AMJ 2027. An enhanced and southward and eastward shifted Pacific Jet supports elevated probabilities for above-normal precipitation for much of the West Coast including areas extending as far north as the Oregon coast. The forecast probabilities across the West Coast and Southwest are somewhat lower than the Southeast CONUS due to a greater range of potential outcomes as indicated by statistical and dynamical model guidance. Moving through the winter and spring 2027 seasons, the areas of favored below-normal precipitation over the northern Rockies and Great Lakes remain generally consistent with a gradual slight northward shift and these areas become combined by the MAM 2027 season. The Pacific Jet is shifted southward and eastward during El Nino events and so the storm track and associated precipitation tends to be located south of most of mainland Alaska. Thus, below-normal precipitation is favored for much of mainland Alaska. Dynamical model guidance and statistical forecast tools are in strong agreement for drier than normal conditions for this area through the FMA 2027 season. Similar to temperature, the precipitation outlooks after AMJ 2027 are based on the ENSO-OCN forecast tool and tend toward slight La Nina impacts at the very last leads during autumn 2027. FORECASTER: Jon Gottschalck 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 Nov 19 2026 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$