141 FXUS05 KWBC 161231 PMD90D Prognostic Discussion for Long-Lead Seasonal Outlooks NWS Climate Prediction Center College Park MD 830 AM EDT Thu Apr 16 2026 SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS Current oceanic and atmospheric observations reveal the transition from La Nina to ENSO-neutral is now complete. Another transition, this time from ENSO-Neutral to El Nino, is expected to occur during the May-Jun-Jul (MJJ) 2026 season (61 percent chance), with El Nino likely to persist through at least the end of 2026. The May-Jun-Jul (MJJ) 2026 temperature outlook favors above-normal seasonal mean temperatures for much of the contiguous U.S. (CONUS) with the exception of parts of the northern Plains, Upper Mississippi Valley, and Great Lakes region. A tilt toward above-normal temperatures is also forecast across Alaska. The highest probabilities (60-70 percent) of above- normal temperatures are forecast for areas of the northern and central Great Basin and Rockies. The MJJ 2026 precipitation outlook depicts modestly enhanced probabilities of below-normal seasonal precipitation amounts from the Pacific Northwest and northern and central portions of the Intermountain West and Rockies southeastward across parts of the central Great Plains. Below-normal precipitation is also favored for most of Southeast Alaska. Above normal precipitation is favored for most of western Alaska, the vicinity of the Lower Four Corners region, and most of the Atlantic Coast states into the eastern Gulf region. Equal chances (EC) are forecast for areas where probabilities for each category of seasonal mean temperatures and seasonal accumulated precipitation amounts are expected 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 During March, ENSO-neutral conditions emerged, accompanied by near-average sea-surface temperatures (SSTs) in the central and east-central equatorial Pacific. During the May-Jun-Jul (MJJ) 2026 season, El Nino is likely to emerge (61 percent chance) and persist through at least the end of this year. The latest weekly Nino 3.4 index value is -0.3 deg C. The equatorial subsurface temperature index (averaged from 180 to 100W) increased for the 5th consecutive month, with above-average subsurface temperatures extending across the entire Pacific to a depth of at least 250-300 meters. Westerly wind anomalies were observed over the western equatorial Pacific at low levels (850-hPa) and were evident over the eastern Pacific at high levels (200-hPa). Convection was near-average over the Date Line, with suppressed convection over western Indonesia. Collectively, the coupled ocean-atmosphere system reflected ENSO-neutral conditions. PROGNOSTIC DISCUSSION OF SST FORECASTS Nearly all SST anomaly forecasts for the Nino 3.4 region favor the development of an El Nino within the next few months, though there are significant differences regarding the predicted maximum intensity of such an event. The CPC SST Consolidation Nino 3.4 forecast reaches the threshold anomaly value of El Nino (+0.5 deg C) during the AMJ season, peaks at +1.2 deg C (a "moderate El Nino") during OND 2026, and gradually tapers off after that, returning to ENSO-neutral by FMA 2027. The error bars associated with the consolidation become quite large by the onset of autumn 2026, so this also must be taken into account. The CFSv2 curve has the greatest slope of the Consolidation constituents, rapidly peaking near +2.1 deg C (a "very strong" El Nino) by OND 2026. The NMME and IMME/C3S ensemble averages pass through the El Nino threshold value of +0.5 deg C prior to May. CPC's official ENSO Probabilities chart favors ENSO-neutral through the AMJ season (80 percent chance), with El Nino favored to become the dominant phase of ENSO during MJJ (61 percent chance). The odds for a warm event rapidly climb to near 90 percent by JAS and persist through at least NDJ 2026-27. CPC ENSO Strength Probabilities (issued in April 2026) depict odds near 50 percent that the RONI (Relative Oceanic Nino Index) will rise into either the strong (+1.5C <= RONI < +2.0C) or very strong (RONI >= +2.0C) categories during NDJ 2026. El Nino is likely because of increasing subsurface temperature anomalies across the entire near-equatorial Pacific, and recent westerly wind anomalies over the western Pacific that triggered oceanic Kelvin waves and downwelling. An important caveat with this outlook is the necessity of continued westerly wind anomalies across the equatorial Pacific Ocean during the Northern Hemisphere summer months, which is not assured. PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS Physical subseasonal to seasonal (S2S) climate drivers considered in this set of outlooks include anomalous land surface states, in particular ongoing drought conditions as well as deficits in snowpack across the western CONUS. Correlations between current (April) soil moisture and MJJ temperature and precipitation were considered, as were ENSO composites and regressions. Though El Nino development is possible during JJA, actual impacts are more likely to arise by JAS. This also allows for the passage of the so-called Spring Predictability Barrier, a period of less-skillful SST anomaly forecasts. This "barrier" may be related to an annual reset or transition period of the global ocean-atmosphere system. El Nino composites and regressions are more likely to be reliable from JAS onwards through late autumn. The NMME and Copernicus Climate Suite (C3S) dynamical model ensemble systems and their participant models are utilized as well as experimental output from a beta version of the Seasonal Forecast System (SFS, future system to replace the CFSv2). Standard statistical forecast tools, objective, skill weighted consolidation guidance, and long term temperature and precipitation trends contributed strongly to the outlooks at various leads and locations. In particular, the constructed analog anchored to SST (CA-SST) and a companion anchored to soil moisture anomalies (CAS) played a somewhat larger role than normal in this set of outlooks. The Calibrated, Bridging, and Merging (CBaM) tool was also used. PROGNOSTIC DISCUSSION OF OUTLOOKS - MJJ 2026 TO MJJ 2027 TEMPERATURE The MJJ 2026 temperature outlook favors above-normal seasonal mean temperatures for much of the CONUS, and all of Alaska, consistent with most model guidance. Maximum temperature probabilities of 60-70 percent are depicted over northern and central portions of the Intermountain West and Rockies. The elevated chances of above-normal temperatures over the West are supported by most of the available models and tools (including the SFS Beta), as well as trends. The widespread anomalous warmth correlates well with below-normal soil moisture, snow pack deficits, and natural analogs which are anchored on Pacific SSTs. The analogs use a nearest neighbor analysis and 12 months of SST observations, assigning equal weight to each of the four Nino regions. Over the interior Southeast, a secondary maximum for above-normal temperatures is favored (50-60 percent). The calibrated NMME, CBaM, CFSv2, ENSO-OCN and statistical and final consolidation tools support this secondary maximum, in addition to very low soil moisture profiles currently in place over that region. Elsewhere, from portions of the northern Great Plains eastward across the Upper Mississippi Valley and Great Lakes region, Equal Chances (EC) of above-, near-, and below-normal temperatures are favored. This broad region of favored EC is where many models and tools support very weak temperature signals or conflicting indications. It is also consistent with the idea of (favored) soon-to-emerge El Nino conditions, with non-warmth favored during the summer months. During the next three seasons (JJA, JAS, and ASO) the signal for anomalous warmth over much of the CONUS remains dominant, especially over the western half of the Lower 48 states, Gulf Coast states, and East Coast states. Above-normal temperature chances are greatest over the West and the Northeast. This is backed by the CBaM and many of the other tools. With the expectation of a soon-to-develop El Nino, below-normal temperatures are slightly favored in JAS and ASO generally from the Middle Mississippi Valley into the central Great Lakes area. This cool preference is based largely on ENSO regression relationships. Temperature relationships with soil moisture were also considered through these seasons. In Alaska, areas south of the Brooks Range are favored to be relatively warm, while the North Slope varies from different spatial coverages of above-normal temperatures to EC. Moving into the autumn months, the maps begin to assume the shape of familiar El Nino composites, with the southern CONUS transitioning from favored above-normal temperatures to widespread EC, while the northern CONUS retains the anomalous warmth. This pattern broadly persists throughout DJF 2026-27 and JFM 2027, the height of the winter season. El Nino also tilts the odds towards above-normal temperatures throughout Alaska during this period, with somewhat higher probabilities favored over southern sections of the state. Moving through late winter and early spring 2027, the official temperature outlooks begin to carve out a large area of EC across the north-central states, with a return to relatively warm temperatures over the southern CONUS, as favored by the ENSO-OCN tool and the statistical consolidation. Longer-term trends generally favor warmer-than-normal temperatures in Alaska during this period. PRECIPITATION The MJJ 2026 precipitation outlook modestly favors above-normal precipitation over most of the Atlantic Coast states, extending into the eastern Gulf Coast region. This has the support of CBaM, CFSv2, the final consolidation, C3S, NCAR_CCSM4, CMCC, and the 15-year OCN trend tool. Wetter-than-normal conditions are also favored in the Lower Four Corners region, with the expectation of a fairly robust monsoon. What precipitation falls in the month of July is forecast to carry the MJJ season as a whole, as May and June tend to be rather dry in the Desert Southwest. Below-normal precipitation is favored from the Pacific Northwest and northern Intermountain region east-southeastward across the northern and central Rockies, and the Central Plains. Approximately one-half of the available precipitation guidance leans towards this scenario, in addition to historical trends for this time of year (though trends do not favor the eastern extension of the relative dryness into the Central Plains). In Alaska, above-normal precipitation is favored for most of the western half of the state, with below-normal slightly favored over much of Southeast Alaska. This is consistent with most of the precipitation guidance. Elsewhere, which includes much of Eastern Alaska and much of the CONUS, EC is favored. During the next two seasons (JJA and JAS), relative dryness is favored across parts of the far Northwest, the Central and Southern Plains, and (by JAS) Florida. For the Northwest, long-term trends favor relative dryness quite strongly, as do the statistical and final consolidation forecasts. These same tools favor below-normal precipitation over the Central and Southern Plains in JJA, in addition to the uncalibrated NMME, uncalibrated C3S, CFSv2, and the expectation of continuing drought. In ASO 2026, the C3S and OCN trend tool are primary supporters of the below-normal precipitation favored over the Northwest, and Central and Southern Plains. Areas of above-normal precipitation are favored throughout much of the Four Corners region during the JJA, JAS, and ASO seasons, in expectation of a fairly robust monsoon setup. Above-normal precipitation is also favored over the southern Mid-Atlantic and interior Southeast during these same seasons, well supported by the OCN trend tool. Another consideration towards the end of the summer is that tropical cyclone (TC) activity normally gets disrupted over the western Atlantic Ocean and Caribbean Sea by increased 200-hPa wind speeds associated with El Nino. This is why the area of favored above-normal precipitation has been nudged inland away from the Southeast coast. Moving into the autumn months, the precipitation outlooks begin to take on the familiar resemblance of El Nino composites. The canonical dichotomy of anomalous wetness across much of the southern tier of the CONUS and expanding areas of anomalous dryness across the northern tier become better established by late fall and winter. The two primary regions of favored dryness include the northwestern CONUS (with the signal becoming more concentrated inland across the Northwest by winter), and over the Great Lakes/Ohio Valley by the same period. By late winter, all that remains (in an anomalous sense) is a fairly small region of favored above-normal precipitation over the Southeast, which then varies in aerial extent during the remaining seasons of this outlook period. In Alaska, above-normal precipitation amounts are favored over most areas south of the Brooks Range through the summer and autumn months. By DJF 2026-27 and JFM 2027, El Nino composites favor a thin sliver of relative wetness along the immediate southern coast of Alaska. EC is deemed the most likely precipitation outcome during FMA 2027, with historical trends favoring a return of above-normal precipitation chances to the North Slope and environs during the spring months. 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 May 21 2026 1991-2020 base period means were implemented effective with the May 20, 2021 forecast release. $$