Prognostic Discussion for Long-Lead Seasonal Outlooks 
NWS Climate Prediction Center College Park MD 
830 AM EDT Thu May 21 2026 
 
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS 
 
El Nino Southern Oscillation (ENSO)-neutral conditions continued through 
mid-May, but positive sea surface temperature (SST) anomalies have increased 
across the central and eastern Pacific Ocean during the spring. El Nino is 
likely to emerge soon (82% chance in May-June-July) and continue through the 
Northern Hemisphere winter 2026-27 (96% chance in December 2026-February 2027). 
 
The June-July-August (JJA) Temperature Outlook favors above-normal temperatures 
throughout the West, much of the Great Plains, Lower Mississippi Valley, and 
East. The highest forecast confidence for above-normal temperatures is across 
the Pacific Northwest. Above-normal temperatures are also favored for a 
majority of Alaska. 
 
The JJA Precipitation Outlook depicts elevated above-normal precipitation 
probabilities for parts of the Southwest, Great Basin, Central to Southern 
Rockies, and the Northeast. The outlook leans towards below-normal 
precipitation along the western Gulf Coast, along with portions of the Northern 
Great Plains and Upper Mississippi Valley. Above-normal precipitation is 
favored for western and northern Alaska. 
 
Areas depicted in white and labeled "Equal-Chances" or "EC" are regions where 
climate signals  are weak, and so there are equal chances for either above-, 
near- or below-normal seasonal mean temperatures or total precipitation amounts. 
 
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 
 
Weekly observed SST departures in the Nino 3.4 region are +0.5 degrees C and 
have increased steadily since March. From April 19 to May 16, equatorial SSTs 
were above-average (at or more than 0.5 degrees C) across the central and 
eastern Pacific Ocean. By mid-May, equatorial subsurface temperature anomalies 
were more than +2 degrees C between 100 and 150 meters at depth, near the Date 
Line. During late April through mid-May, negative outgoing longwave radiation 
(OLR) anomalies (enhanced convection and precipitation) was observed north of 
the equator near the Date Line. Above-average OLR (suppressed convection and 
precipitation) was observed over Indonesia, the Philippines, and south of the 
equator near the Date Line. Low-level (850-hPa) winds were close to average 
across most of the equatorial Pacific Ocean, while upper-level (200-hPa) wind 
anomalies were westerly over the central and east-central Pacific. 
 
The Madden-Julian Oscillation (MJO) briefly stalled over the Indian Ocean 
during early May and became less coherent. However, the MJO recently began to 
resume its eastward propagation to the Maritime Continent. Dynamical model 
forecasts are in good agreement that a robust MJO propagates east over the West 
Pacific and eventually shifts to the Western Hemisphere by early June. 
 
PROGNOSTIC DISCUSSION OF SST FORECASTS 
 
The CPC SST consolidation forecast for Nino 3.4 depicts SST anomalies 
increasing through the summer and reaching +1.5 degrees C (strong El Nino 
threshold) by Sep-Oct-Nov. A majority of the North American Multi-Model 
Ensemble Members (NMME) along with the ECMWF model also indicate a strong El 
Nino by the fall. Later in the 2026-27 winter, the CPC SST consolidation 
forecast depicts anomalies decreasing but remaining above +0.5 degrees C 
through Feb-Mar-Apr 2027. As of May 14, the CPC ENSO outlook indicates that El 
Nino is likely to emerge soon (82% chance in May-Jun-Jul) and continue through 
Dec 2026-Feb 2027 (96% chance). By the late fall and early winter 
(October-November-December), there is near a 2 in 3 chance of a strong El Nino. 
 
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS 
 
The Temperature and Precipitation Outlooks for JJA 2026 were based on dynamical 
models such as the North American Multi-Model Ensemble (NMME) and the 
Copernicus (C3S) multi-model ensemble system. A Calibration, Bridging, and 
Merging (CBaM) version of the NMME was also used in the outlooks. Soil moisture 
influence along with its constructed analog were factors in the JJA temperature 
and precipitation outlooks An objective, historical skill-weighted 
consolidation that includes the NMME along with statistical tools such as the 
SST-based Constructed Analog and the ENSO-OCN was used through Oct-Nov-Dec. 
Beyond that time, the consolidation only includes statistical tools. Long-term 
climate trends  were considered for all leads, but were relied upon most during 
the 2027 spring and summer. 
 
PROGNOSTIC DISCUSSION OF OUTLOOKS - JJA 2026 TO JJA 2027 
 
TEMPERATURE 
 
The highest forecast confidence for above-normal temperatures (probabilities 
more than 60%) during Jun-Jul-Aug (JJA) is across the Pacific Northwest where 
there is excellent agreement among dynamical models  and consistent with favored 
below-normal precipitation. In addition, El Nino summers tend to be 
warmer-than-normal. Based on a consensus of dynamical models  and statistical 
tools, enhanced above-normal temperature probabilities (greater than 40%) 
cover the remainder of the western contiguous U.S. (CONUS), much of the Central 
to Southern Great Plains, and extend from the Southeast north to southern New 
England. Equal chances (EC) of below, near, or above-normal temperatures are 
forecast for the Midwest where a more variable temperature pattern is expected 
this summer and the warmer dynamical model output is offset by the colder El 
Nino composites. Although the CBaM version of the NMME depicts elevated 
below-normal temperature probabilities for parts of the Midwest, a lean towards 
below-normal temperatures was not introduced until the Jul-Aug-Sep (JAS) 
outlook as there are signs that June could be warmer-than-normal. Dynamical 
model output and El Nino composites favor above-normal temperatures throughout 
Alaska, except for the North Slope. Although the June outlook leans on the 
colder side for coastal southwestern Alaska and the Alaska Peninsula, elevated 
above-normal temperature probabilities (33-40%) are forecast across these areas 
during the three-month period of JJA. 
 
Later in the summer and into the early fall, including Jul-Aug-Sep and 
Aug-Sep-Oct, the outlook slightly favors below-normal temperatures for parts of 
the Midwest based on El Nino influences historically. Given the increasing 
chance of a strong El Nino by next winter, above-normal temperature 
probabilities were increased to more than 50% across the northern tier of the 
CONUS, from the Pacific Northwest east to the Northern Great Plains, during 
Dec-Jan-Feb 2026-27. EC was maintained for the southern tier of the CONUS 
through next winter which is consistent with the SST-Constructed Analog tool. 
By the late spring and following summer of 2027, decadal trends  were the major 
factor in those temperature outlooks. 
 
PRECIPITATION 
 
Similar to previous forecast reasoning with low soil moisture favoring enhanced 
heating and a robust start to the Monsoon along with good dynamical model 
agreement and consistency, the JJA outlook favors above-normal precipitation 
for much of the Southwest. Dynamical model output has trended wetter farther to 
the north into the Central Rockies, and this is consistent with El Nino summers 
historically. Therefore, the JJA outlook depicts elevated above-normal 
precipitation probabilities as far north as Wyoming with the largest 
probabilities (> 40%) centered over the Four Corners. Surrounding this enhanced 
Monsoon signal, below-normal precipitation is favored for parts of the Pacific 
Northwest, Northern to Central Great Plains, and Upper Mississippi Valley 
during JJA. This favored dryness has support from a number of tools including 
the NMME, SST-Constructed Analog, and decadal trends . In addition, soil 
moisture is low for Nebraska, southern South Dakota, and parts of Minnesota 
where there is a significant positive correlation between low May soil moisture 
and below-normal precipitation during JJA. Forecast confidence for a particular 
category of precipitation (below, near, or above) is lower for the remainder of 
the Great Plains and Midwest as the NMME trended notably wetter compared to one 
month ago. The JJA outlook leans slightly towards below-normal precipitation 
along the western Gulf Coast based on composites and dynamical model output. 
For the eastern CONUS, many of the tools lean on the wetter side but vary 
regionally. Therefore, the JJA precipitation outlook relied upon the 
consolidation with a slight lean (33-40% chance) towards above-normal 
precipitation across the Northeast. Based on the NMME, elevated above-normal 
precipitation probabilities are forecast across western and northern Mainland 
Alaska. El Nino summers tend to be drier for southern Alaska, but the JJA 
outlook calls for equal chances of below, near, or above-normal precipitation 
since last month's outlook favored above-normal precipitation. 
 
Starting in Jul-Aug-Sep (JAS) and continuing through Sep-Oct-Nov, elevated 
above-normal precipitation probabilities are forecast for southern California 
due to the likelihood of an active East Pacific hurricane season and its 
associated influence on precipitation. A dry signal in El Nino composites peaks 
in JAS throughout the south-central CONUS and the precipitation outlook 
followed this historical guidance. Given the increasing chance of a strong El 
Nino by the late fall, the Mid-Atlantic is favored to have above-normal 
precipitation beginning in Oct-Nov-Dec. Compared to last month, above-normal 
precipitation probabilities were increased across the southern tier of the 
CONUS during the late fall and 2026-27 winter, now exceeding 60% for parts of 
the Southeast. El Nino composites also supported a couple of areas with favored 
below-normal precipitation across parts of the Midwest and Northern Rockies. EC 
is forecast for nearly all of the West Coast during the winter 2026-27 due to 
the weak signal from the ENSO-OCN tool. By the summer of 2027, the 
precipitation outlook is based on decadal trends . 
 
FORECASTER: Brad Pugh 
 
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 Cas e 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 Jun 18 2026 
 
 
1991-2020 base period means were implemented effective with the May 20, 2021 
forecast release. 
$$