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. 
$$