566 FXUS07 KWBC 311901 PMD30D Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 300 PM EDT Fri Jul 31 2026 30-DAY OUTLOOK DISCUSSION FOR AUG 2026 As of the end of July 2026, an El Niño Advisory, meaning that El Niño conditions are present and expected to continue, remains in effect. The latest weekly observed sea surface temperatures (SSTs) in the Niño 3.4 region were 1.4 degrees Celsius above average, which is consistent with the upper end of a moderate strength El Niño. Meanwhile, the Madden Julian Oscillation (MJO) is weakening and is predicted to further weaken in the short term as it moves into the Indian Ocean, and enters into a period of destructive interference with El Niño. However, recent dynamical model guidance indicates the potential for re-intensification of the MJO signal in the Western Pacific (Phase 6 in Wheeler-Hendon space) toward the middle of August. Recent trends for the month of August generally support above normal mid-level heights across the West, Southern Plains, and Southeastern Alaska, while below normal heights have been observed in northwestern Alaska. Dynamical model guidance from the European Centre for Medium-Range Weather Forecasts (ECMWF) and the Global Ensemble Forecast System (GEFS) generally support above normal mid-level heights across most of the Lower 48 states throughout much of the month of August. However, a trough forecast over southern Canada may graze parts of the Northern Plains and Great Lakes early in the month before settling across the Northeast by the middle of the Month. Cyclonic mid-level flow is generally favored over central Mainland Alaska early in the month before potentially retrograding toward the western or southwestern Mainland by mid-month. The main contributors to the updated monthly outlook for August were dynamical model guidance, official National Weather Service (NWS) short and extended range forecasts for days 1-7, week-2, and weeks 3-4, the background El Niño state, MJO, trends, and antecedent conditions such as soil moisture and nearshore SSTs. Above normal temperatures are favored for the western and southern two-thirds of the Contiguous United States (CONUS). Confidence is high (greater than 50 percent chance) for above normal temperatures across much of the Southern Plains, where El Niño composites, trend, and dynamical model guidance all support increased warmth. Confidence is also high (greater than 50 percent chance) for above normal temperatures across coastal California due to a combination of predicted mid-level ridging and observed above normal SSTs in nearshore waters. Confidence is low across from the Northern Plains and Great Lakes, where El Niño composites are generally less supportive of anomalous warmth. Equal chances (EC) of above, near, and below normal temperatures are indicated for these areas. Additionally, dynamical model guidance predicts a progression of a mid-level trough across southern Canada during the early to middle parts of August. This trough may graze the northern tier of the CONUS before potentially settling over the Northeast by Mid-Month. Due to the potential for anomalous troughing across the Northeast during mid to late August coupled with below normal observed nearshore SSTs, EC is indicated across the northeastern CONUS, marking a reduction in above normal temperature probabilities relative to the mid-month outlook. Confidence is also low across Alaska, due to mixed signals among statistical and dynamical model guidance. As such, elevated chances of above normal temperatures are limited to extreme eastern sections of the Mainland as well as Southeast Alaska. Predicted cyclonic mid-level flow as well as observed below normal nearshore SSTs adjacent to the South Coast and above normal sea ice to the north of the state preclude favoring above normal temperatures across the remainder of the state. Above normal precipitation is favored across a large portion of the Southwest and Great Basin, as dynamical model guidance is in good agreement on a renewed push of monsoonal moisture into the region from south to north. Confidence has increased for below normal precipitation across the southern Plains, as El Niño composites, trend, and dynamical model guidance are all converging on a drier solution. Confidence is low across much of the eastern CONUS due to very weak signals among dynamical model guidance such as the ECMWF ensemble. Moreover, a slow moving frontal boundary early in August reduces chances of below normal precipitation across the southeastern CONUS, resulting in a removal of enhanced below normal probabilities depicted in the mid-month outlook in favor of EC across the region. A slight tilt toward above normal precipitation was introduced to parts of the Northeast, due to support from ECMWF ensemble precipitation output and consistent with the potential for a prolonged period of cyclonic mid-level flow mid to late month. A slight tilt toward below normal precipitation is indicated for the coastal Pacific Northwest and Southeast Alaska broadly consistent with NWS 6-10 day and week-2 outlooks as well as recent trends. Above normal precipitation is favored for much of western and northern Mainland Alaska due to strong trends as well as the potential for a prolonged period of mid-level cyclonic flow as depicted by dynamical model guidance. ******************************************************************************* ****** Previous mid-month discussion below ****** ******************************************************************************* The outlooks for August 2026 are issued against the backdrop of an El Niño Advisory, meaning that El Niño conditions are present and expected to continue. The latest weekly observed sea surface temperatures (SSTs) in the Niño 3.4 region were 1.3 degrees Celsius above normal, consistent with an El Niño of moderate strength. Meanwhile, the eastward progression of the Madden Julian Oscillation (MJO) is currently stalled, but is expected to resume before gradually disorganizing in late July. This weakening MJO may destructively interfere with the background El Niño state as it approaches the Indian Ocean near the beginning of August. In the extratropics, the Arctic Oscillation (AO) has been positive in early July but has trended to near zero in recent days. After a brief dip, the North Atlantic Oscillation (NAO) has returned to the positive phase, while the Pacific North American (PNA) index has trended negative. A nearest neighbor analysis of the recent evolution of the El Niño Southern Oscillation (ENSO), the MJO, and extratropical indices all played a role in the August Outlooks, with the greatest weight placed on ENSO impacts, due to large uncertainties in the MJO and extratropical signals. Antecedent conditions, such as extratopical SSTs and soil moisture conditions, were also considered where appropriate as were recent temperature and precipitation trends. Dynamical guidance from the Copernicus Climate Change Service (C3S), North American Multi-Model Ensemble (NMME), the Couple Forecast System Version 2 (CFSv2), and the Forecast Consolidation Tool (CON) (which includes both dynamical model input and statistical guidance), also were significant contributors to the August outlooks, as was consistency with the most recent Weeks 3-4 Outlooks, which now extends through the first week of August. Above normal temperatures are favored for the eastern and south-central Contiguous United States (CONUS), the West Coast, the northwestern CONUS, and most of Alaska. Confidence is high (greater than 50 percent chance) for above normal temperatures across the Southeast and southern Mid-Atlantic, where above normal SSTs in adjacent waters as well as dry soils favor warmer temperatures. Dynamical models such as the NMME and C3S also support above normal temperatures there. Above normal temperatures are also favored (greater than 40 percent chance) across the Southern Plains, consistent with ENSO composites and trends. A tilt toward warmer then normal conditions (33 to 50 percent chance) extends northward along the East Coast due to support from NMME and C3S guidance. Similarly, there is a 33 to 50 percent chance of above normal temperatures for the northwestern CONUS due to strong dynamical model support. However, due to lack of statistical guidance support and below normal SSTs off the Pacific Northwest coast, enhanced above normal temperature probabilities were kept modest. A tilt toward above normal temperatures (33 to 40 percent chance) also extends southward along the California Coast as SSTs off the California Coast lean above normal. Below normal temperatures are favored (33 to 40 percent chance) for the Northern Plains due to a strong cold signal from natural detrended ENSO analogs with support from constructed analogs from soil moisture (CAS). However, probabilities were kept modest due to a lack of dynamical model support. Equal chances of above, below, and near normal temperatures (EC) are indicated for much of the interior southwestern CONUS, as cooler detrended ENSO composites and the prospects of above normal cloudiness and precipitation conflict with warmer dynamical model guidance. Above normal temperatures are weakly favored for most of Alaska south of the North Slope, consistent with the NMME. Natural ENSO analogs favor warmth across southwestern Mainland Alaska and Southeast Alaska, however, below normal SSTs along much of the South Coast kept above normal temperature probabilities muted. EC is indicated for the North Slope of Alaska, as sea ice extent north of the state is currently above normal. Above normal precipitation chances are elevated across two main axes across the CONUS. The first axis is across much of the west associated with the potential for an enhanced monsoon. This wet signal has support from the C3S and CFSv2 as well as from ENSO composites and natural analogs (except southern areas). Additionally, the most recent Weeks 3-4 Outlooks tilt wet across the Southwest and adjacent Great Basin. As such above normal precipitation is favored (33 to 50 percent chance) across much of the Great Basin, Southwest, Central and Northern Rockies, and Northern High Plains. The second axis where above normal precipitation is favored (33 to 40 percent chance) extends from the Northern Plains to the Middle Mississippi Valley. These elevated probabilities of above normal precipitation have support from ENSO composites and MJO natural analogs as well as the CAS tool. Probabilities were kept modest due to weak signals from dynamical model guidance. Below normal precipitation is favored (33 to 50 percent chance) across parts of the Southeast and southern Mid-Atlantic, due to support from detrended ENSO composites, MJO natural analogs, and observed below normal soil moisture. A slight tilt (33 to 40 percent chance) toward below normal precipitation is also indicated for the Great Lakes region, with support from MJO and extratropical natural analogs as well as the CON. Confidence is low across the Southern Plains as ENSO composites, trend, and to some extent, dynamical model guidance conflicts with strong wet signals from MJO and extratropical natural analogs. Due to this conflicting guidance, EC has been issued for this region. A slight tilt (33 to 40 percent chance) toward below normal precipitation is indicated for parts of the Pacific Northwest and Southeast Alaska, due to support from trend, the NMME, CFSv2, and the latest Weeks 3-4 Outlooks. Probabilities were kept muted in these areas due to lack of ENSO support. Above normal precipitation is favored (33 to 50 percent chance) across most of Mainland Alaska and the Alaska Peninsula, due to strong support from trend and ENSO. However, due to lack of dynamical model support, probabilities were kept modest. FORECASTER: Scott Handel 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 Sep ... will be issued on Thu Aug 20 2026 These outlooks are based on departures from the 1991-2020 base period. $$