862 FXUS07 KWBC 171231 PMD30D Prognostic Discussion for Monthly Outlook NWS Climate Prediction Center College Park MD 830 AM EDT Thu Sep 17 2026 30-DAY OUTLOOK DISCUSSION FOR OCT 2026 The October 2026 Temperature and Precipitation Outlooks are based on the: North American Multi-Model Ensemble (NMME) and International Multi-Model Ensemble (IMME), consolidation (dynamical and statistical tools), and El Nino composites. Due to the strong and dominant El Nino, the Madden-Julian Oscillation (MJO) was not a factor in the October forecast. The West Pacific is likely to remain active with a number of tropical cyclones (TCs) heading into October. If a TC recurves northeastward into the higher latitudes of the North Pacific, it could disrupt the downstream longwave pattern which increases forecast uncertainty. Although soil moisture has a declining influence on surface temperatures during the fall, the intensifying drought conditions with low soil moisture will have a warming effect on surface temperatures across the Southern Great Plains, Ozarks region, Lower Mississippi Valley, and parts of the Southeast. The October Temperature Outlook generally used the consolidation tool as a guide, which represents a combination of dynamical model output and statistical tools which include impacts from the phase of the El Nino Southern Oscillation (ENSO) and long-term trend. Above-normal temperatures are favored along the West Coast and for much of the central and eastern Contiguous U.S. (CONUS). The equal chances (EC) of below, near, or above-normal temperatures across the interior West is due to conflicting signals between the cooler El Nino composites and warmer dynamical models. The outlook leans slightly towards above normal (33-40% chance) across parts of Arizona and New Mexico based on the long-term trend. Above-normal temperature probabilities are increased to more than 50% for the Lower Mississippi Valley given the intensifying drought and low soil moisture having a warming effect heading into October. The other area with higher forecast confidence is southeastern Alaska with the calibrated NMME and IMME depicting greater than a 50% chance of above-normal temperatures. The lack of sea ice supports above-normal temperatures for the North Slope of Alaska. The increased chance that a recurving TC in the West Pacific affects the longwave pattern downstream over North America is a source of forecast uncertainty, limiting the coverage of above-normal temperature probabilities exceeding 50 percent. During the first half of October, the GEFS and ECMWF models are in good agreement with a 500-hPa trough near the West Coast and anomalous mid-level ridging over the eastern two-thirds of the CONUS. This longwave pattern would yield a relatively wet start to the month for the Southwest. On the monthly time scale, the CFS model along with the NMME and IMME support elevated above-normal precipitation probabilities from the Southwest eastward to the Central to Southern Great Plains and parts of the Gulf Coast. This favored wetness also extends west to include southern California due to good model consistency from past daily CFS model runs and the likelihood of a continued active East Pacific hurricane season. Although El Nino composites would support the October outlook leaning on the drier side for the Pacific Northwest and Northern Intermountain West, EC is forecast for these areas due to a lack of support from the calibrated dynamical model output and the ENSO-OCN tool. Elsewhere across the lower 48 states, EC is also forecast with generally weak signals among the tools at this time lead. Based on model guidance favoring above-normal precipitation during the first half of the month along with the IMME on the monthly time scale, elevated above-normal precipitation probabilities (33-40%) are forecast across parts of southeastern Alaska and coastal southern Alaska. FORECASTER: Brad Pugh 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. An updated monthly outlook... for Oct will be issued on Wed September 30 2026 These outlooks are based on departures from the 1991-2020 base period. $$