226 FXUS07 KWBC 311900 PMD30D Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 300 PM EDT Fri Oct 31 2025 30-DAY OUTLOOK DISCUSSION FOR NOVEMBER 2025 As of the end of October 2025, a La Nia Advisory remains in effect as the latest weekly Nio 3.4 index stood at -0.6 degrees Celsius and upper ocean heat content in the equatorial Pacific continues to be below normal. Meanwhile an active Madden Juilan Oscillation (MJO) signal is present in the Maritime Continent and is expected to propagate to the Western Pacific by early to mid November (corresponding to phases 5 and 6 in Wheeler-Hendon (WH) phase space). Thereafter, uncertainty is high as to if this signal will propagate further into WH phase 7 by the end of November. During the latter half of October, the North Atlantic Oscillation has been predominantly negative while the Pacific North America (PNA) has been mostly positive. The Arctic Oscillation (AO) has been more variable, oscillating between the negative and positive phases. Composites derived from these tropical (ENSO and MJO) and extratropical (NAO, PNA, and AO) drivers generally support above normal 500-hPa mean heights across much of the western and central Contiguous United States (CONUS) and near to below normal heights across much of the Eastern Seaboard. Mean below normal heights are generally favored off the coast of Southeast Alaska. Uncertainty is high across the remainder of Alaska as MJO and ENSO composites mostly oppose each other. All composites generally agree on strong ridging in the eastern North Atlantic southeast of Greenland. Dynamical model guidance from the ECMWF, GEFS, and Canadian ensemble means are generally supportive of the statistical composites. The first week of November is predicted to feature a deep trough over the Gulf of Alaska, downstream ridging in the western CONUS, and a pair of troughs over the Mississippi Valley and near Atlantic Canada. As the week progresses, deep troughing is forecast to persist over the Gulf of Alaska and impinge on the West Coast of the CONUS. Above normal heights are then forecast to overspread the central CONUS as the trough over the Mississippi Valley departs. As we approach the middle of November, CPCs 8-14 day outlook features above normal heights across the western half of the CONUS, below normal heights across the Northeast, and below normal heights across most of Alaska (particularly southwestern parts of the state). Finally, during the second half of November, CPCs Weeks 3-4 Outlook favors a transition to above normal heights across much of the East and a continuation of below-normal heights across much of Alaska. Above normal mean temperatures are favored across the western and central CONUS as 500-hPa heights are favored to be above normal during much of the month across these regions. Probabilities of above normal temperatures exceed 60 percent across parts of the Central Rockies and adjacent Great Basin as temperatures are forecast to be upwards of 10 to 15 degrees Fahrenheit above average during the first week of November. In addition, CPCs 6-10 day and week-2 outlooks indicate that above normal temperatures are likely to continue across this area until at least mid-November, which further increases confidence in above normal temperatures. Confidence is much lower across the Eastern Seaboard as a variable pattern is favored with troughing early in the month potentially giving way to near or even above normal heights as the month progresses. Due to this potential transitional pattern, equal chances (EC) of below, near, or above normal temperatures are forecast across most of the Eastern Seaboard. Alaska is also an area where forecast confidence is low. Statistical guidance from natural analog composites favor below normal temperatures across much of the state. Below normal temperatures are also supported by predicted below normal heights depicted by dynamical guidance across most of the state (particularly southwestern areas) during much of the month. However, at the surface, dynamical model guidance generally favors a warmer solution, particularly across southeastern parts of the state. Additionally, sea surface temperatures (SSTs) are currently above normal adjacent to the south and west coasts of Alaska, which reduces chances of below normal temperatures in coastal areas. Due to conflicting statistical and dynamical model guidance, EC is forecast across most of western and central Alaska. A slight tilt toward above normal temperatures is indicated for Southeast Alaska and much of the eastern Mainland, consistent with CPCs 6-10 day and week-2 outlooks. An active pattern is favored across much of the West Coast of the CONUS and southeastern Alaska. Short term guidance as well as CPCs 6-10, week-2, and weeks 3-4 outlooks all favor above normal precipitation for most of these areas. Some locations along the West Coast (particularly near the Bay Area) are forecast to receive upward of 33 to 50 percent of the normal monthly totals in the first week of November alone. For these reasons, above normal precipitation is favored along much of the West Coast and adjacent Northern Rockies northward to Southeast Alaska and adjacent areas of the southeastern Mainland. Conversely, below normal precipitation is more likely across most of the southern CONUS. Confidence for below normal precipitation is highest across the Southwest and adjacent areas of the Southern High Plains as anomalous ridging is forecast to prevail for much of the month. Despite predicted rainfall during the first week of the month across parts of the Southeast and Gulf Coast, a slight tilt toward below normal precipitation is indicated for the month as a whole as a transition to a drier pattern is favored in CPCs weeks 3-4 outlooks. This slight tilt toward dry is extended northward to the Mid-Atlantic as surface high pressure dominates early in the month in the wake of a departing storm system. A slight tilt toward above normal precipitation is indicated for much of the Northeast, consistent with CPCs 6-10 day, week-2, and weeks 3-4 outlooks. ****************************************************************************** ***** Previous mid-month discussion below ***** ****************************************************************************** The November 2025 outlooks are issued against the backdrop of a La Nia Advisory and the potential emergence of an enhanced Madden Julian Oscillation (MJO) signal. La Nia conditions are present and favored to persist through the month of November and beyond. Natural analog composites derived from a nearest neighbor analysis of the past 12 months of equatorial Pacific Sea Surface Temperature (SST) and Upper Ocean Heat anomalies are supportive of anomalous mid-level troughing along the Eastern Seaboard with above normal heights more likely for much of the central and western Contiguous United States (CONUS) and northern Alaska. Meanwhile, the magnitude of the Real-time Multivariate based Madden Julian Oscillation (MJO) index has been weak since early September but is showing signs of emerging in the Indian Ocean. Both the Global Ensemble Forecast System (GEFS) and the European Centre for Medium Range Weather Forecasts (ECMWF) predict this emerging MJO event to strengthen and approach the Western Pacific by the start of November. Composite analysis of Western Pacific MJO events is suggestive of anomalous ridging over much of the western and central CONUS early followed by potential troughing across the Northern Plains later in the month (if the MJO signal continues its eastward propagation). Recent analysis of extratropical indices show that the Arctic Oscillation (AO) and the North Atlantic Oscillation (NAO) have been mostly positive in early October while the Pacific North America (PNA) index has largely been negative. All three of these extratropical indices are currently in the process of switching phases to the opposite sign from that observed earlier in the month. Composites derived from analysis of the recent evolution of these extratropical indices favor above normal mid-level heights across the higher latitudes of the Western Hemisphere in November, consistent with the negative phase of both the AO and NAO and ridging over the southeast, suggestive of a return to a negative PNA. Combined natural analog composites derived from the recent evolution of tropical and extratropical indices depict a 500-hPa flow pattern dominated by above normal heights across much of the higher latitudes of the Western Hemisphere and below normal heights farther to the south across the northeastern CONUS during the month of November. Weakly above normal heights are illustrated across the Lower Mississippi Valley and much of the western CONUS. Meanwhile, trends during the last 15 years favor above normal heights across most of Alaska as well as most of the central and eastern CONUS, with the exception of the Northern Tier. SSTs are currently above normal adjacent to the Western and Central Gulf Coast, Southern Florida, the Northeast, California, and much of the south and west coasts of Mainland Alaska. Arctic Sea Ice extent is currently below normal but not at record low levels. Natural analog composites, trends, and 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) form the basis of the November outlooks. The latest CPC Weeks 3-4 Outlooks and associated ensemble guidance from the European Centre for Medium Range Weather Forecasts (ECMWF), Global Ensemble Forecast System (GEFS), and the CFS also contributed. Antecedent conditions such as extratropical SSTs, sea ice extent, and snow cover anomalies were also considered where appropriate. Above normal temperatures are favored for most of the western and central CONUS, with the exception of the Northern Tier. This tilt toward above normal temperatures is consistent with La Nia composites, dynamical model guidance from the NMME, C3S, and CFSv2, as well as the official CPC Weeks 3-4 temperature outlooks. Probabilities of above normal temperatures exceed 50 percent for much of the Southern Plains and Southwest, where dynamical model guidance and CPCs Weeks 3-4 outlooks show the most support. Confidence is much lower across the Northern Tier as the NMME and CFSv2 show little or no above normal temperature signals for the Pacific Northwest and Northern Rockies. Additionally, composites from the predicted enhanced MJO signal in the Western Pacific are suggestive of a potential cold air outbreak across the Northern Plains during the month of November. Combined natural analog composites from the current evolution of tropical and extratropical indices are suggestive of a mean negative AO pattern in November. Composites from a combined negative AO and La Nia state favor colder than normal conditions across the Northern Plains, which are at odds with dynamical model guidance such as the C3S. For these reasons Equal Chances (EC) of above, near, or below normal temperatures are posted for the Northern Tier from the Pacific Northwest, Northern Rockies, Northern Plains, and Upper Mississippi Valley. Uncertainty is also high across the eastern third of the CONUS as La Nia composites depict a weak or even cold signal across parts of the East. Moreover, combined natural analogs from the current evolution of tropical and extratropical drivers are supportive of anomalous troughing, particularly over the Northeast. This reduced confidence is supported by the NMME, which has a weak temperature signal across much of the Eastern Seaboard and from CPCs Weeks 3-4 outlooks, which has EC across much of the Southeast. For these reasons, EC is forecast for most of the Eastern Seaboard, Appalachians, Great Lakes, and parts of the Ohio Valley. A slight tilt toward above normal temperatures are indicated for parts of southern Florida owing largely to observed above normal SSTs in adjacent waters. Despite the anomalous troughing suggested by natural analog composites across the Northeast, a slight tilt toward above normal temperatures is indicated for areas of Northern New England. This modest tilt toward above normal temperatures was posted due to support from recent trends, above normal observed SSTs in the adjacent Atlantic, and the CPC Weeks 3-4 outlooks. Confidence is low across Alaska as forecast guidance is mixed at best. Dynamical model guidance is inconsistent with the NMME offering a weak signal across almost the entire state with a tilt toward cold forecast for inland areas of the northwestern Mainland while the C3S and CFSv2 are more supportive of warmth across most of the state. As a result, the final consolidation of dynamical and statistical guidance does not present much in the way of a coherent pattern across much of the state. A slight tilt toward above normal temperatures is posted for southwestern and northwestern parts of the state, consistent with above normal SSTs in adjacent waters and observed below normal sea ice extent. One of the more confident aspects in the precipitation outlook for the month of November is the prospect of a drier than normal pattern across the Southeast and adjacent areas. The NMME, C3S, and CFSv2, and La Nia composites are all supportive of dryness across the Southeast and much of the Mid Atlantic. As a result, below normal precipitation is favored across much of the East, with the greatest confidence across much of the Southeast. A second area where below normal precipitation is favored is across much of the Southwest and Southern High Plains due to good agreement among dynamical guidance. Below normal precipitation probabilities were kept more modest across the Southwest/Southern High Plains than the Southeast as support from statistical guidance is not as robust. Conversely, above normal precipitation is favored for the Northern Plains and adjacent areas of the Central Plains and Upper Mississippi Valley. These areas have among the strongest above normal precipitation signals in the combined natural analog composites. Additionally the final consolidation shows a wet signal from the Northern High Plains to the Central Plains. The most confident above normal precipitation area (greater than 40 percent chance) corresponds to this signal in the final consolation combined with natural analog composites. The area of favored above normal precipitation extends westward from here to include the Pacific Northwest and Northern California due largely to La Nia Composites. Most of this area of favored above normal precipitation is also consistent with the CPC Weeks 3-4 Outlooks. As was the case with temperature, the precipitation forecast for Alaska is low confidence as the NMME has virtually no signal at all for the entire state. Despite this uncertainty, an area of modestly enhanced probabilities of above normal precipitation was posted for the northwestern Mainland, consistent with the final consolidation. 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 Dec ... will be issued on Thu Nov 20 2025 These outlooks are based on departures from the 1991-2020 base period. $$