Prognostic Discussion for Long-Lead Seasonal Outlooks 
NWS Climate Prediction Center College Park MD 
830 AM EDT Thu Mar 20 2025 
 
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS 
 
The April-May-June (AMJ) 2025 seasonal outlook favors above-normal temperatures 
for the southern half and eastern one-third of the contiguous U.S. (CONUS) as 
well as for the Alaska Peninsula and adjacent areas of the southern Mainland 
and eastern Aleutians. The greatest odds are forecast in the Southwest, 
southern Plains and bottom two thirds of the Florida Peninsula. Below-normal 
seasonal mean temperatures are most likely for a small area of west-central 
Alaska. 
 
For precipitation, the AMJ 2025 outlook forecasts elevated probabilities for 
below-normal seasonal total precipitation amounts for much of the western U.S. 
and the central and southern High and Great Plains. The highest odds are 
centered just north of the Four Corners region. Above-normal precipitation is 
favored for the southern Great lakes and Ohio Valley. In Alaska, above-normal 
precipitation is most likely for the northern and much of the western areas of 
the state while drier-than-normal conditions are favored for coastal 
south-central Alaska. 
 
Equal Chances (EC) of above, near, and below normal temperatures or 
precipitation are indicated where forecast information is in considerable 
disagreement or climate signals  are weak or show little historical forecast 
skill. In these areas, the odds of all three categories are similar to 
climatological probabilities. 
 
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 
 
Although a La Nina advisory remains active, oceanic conditions consistent with 
La Nina have weakened during February 2025, and ENSO neutral is favored to 
develop within the next 1-2 months. Atmospheric conditions in the tropical 
Pacific Ocean, however, still remain reasonably consistent with a La Nina event 
and likely persist into and through the month of April. Suppressed convection 
remains in place near the Date Line along the equator with enhanced convection 
to the west near the Maritime continent. Low-level wind anomalies remain 
anomalously easterly in the west-central Pacific with cyclonic circulations 
evident north and south of the equator in the east-central Pacific. 
 
The latest monthly average sea surface temperatures (SSTs) remain negative 
(less than -0.5 degrees C) from about 160E to 140W in the equatorial Pacific 
Ocean. The latest weekly Nino SST indices vary widely from the Nino4 to Nino1+2 
region. Although the Nino4 index remains at -0.4 degrees C, Nino3.4, Nino3 and 
Nino1+2 currently range from +0.3 to +1.3 degrees C. 
 
An active MJO is forecast to continue shifting eastward from the Indian Ocean 
across Indonesia to the western Pacific over the next few weeks well into 
April.  If the event evolves as forecast, there may be some cooling of 
equatorial west-central and central SSTs and Nino indices due to a potential 
increase in Trade winds as the enhanced convection phase shifts eastward. 
 
In addition, a Sudden Stratospheric Warming (SSW) event occurred on March 9-10, 
2025 with recent forecasts of potential coupling between the stratosphere and 
troposphere during April which may impact temperatures during the first month 
of the seasonal outlook period especially for Alaska and parts of the western 
CONUS. 
 
With respect to land surface states, drought conditions are evident for many 
parts of the CONUS with areas in southern California, the Southwest, Texas, the 
north-central High Plains and parts of the Eastern Seaboard experiencing severe 
to exceptional drought (D2-D4 in the U.S. Drought Monitor). Moreover, below 
normal snowfall occurred this past from the northern Plains to the Great Lakes 
to the Northeast. 
 
PROGNOSTIC DISCUSSION OF SST FORECASTS 
 
Forecasts of equatorial Pacific Ocean SSTs (i.e. Nino3.4 index), are similar in 
indicating a continuation of decreasing negative values approaching near zero 
Nino3.4 index anomaly through the spring and summer seasons. The suite of NMME 
and C3S dynamical model guidance and their ensemble mean forecasts are quite 
consistent in forecasting ENSO neutral conditions through JAS 2025 with Nino3.4 
index values within a range from -0.5 degrees C to effectively zero anomaly. A 
few members forecast slightly positive values over this period. 
 
The CPC Nino3.4 SST consolidation forecast that includes some statistical 
models as well is consistent with the above, but diverges in the late summer 
and autumn toward predictions of increasingly more negative Nino3.4 index 
anomalies. These anomalies minimize during early winter 2025-2026 in weak La 
Nina territory but with very high forecast spread. 
 
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS 
 
Lingering potential impacts from La Nina are considered for the AMJ 2025 season 
as was consideration of impacts from the recent SSW and current active MJO - 
noting influence is front loaded within the season especially in April. Soil 
moisture conditions contributed to modifying probabilities in several areas of 
the CONUS as was the deficit in current snow cover and depth in some northern 
areas. 
 
Participant members and and ensemble means from the NMME and C3S dynamical 
model guidance suites contribute to the outlooks as does statistical and hybrid 
forecast tools such as CBaM. Temperature trends  which are strongly positive 
(except for the north central U.S. in AMJ) for much of the CONUS for many leads 
from Spring into autumn 2025, played a considerable role in many of the 
outlooks. 
 
The ENSO-OCN statistical guidance was followed from late autumn 2025 through 
the remainder of the forecast leads into 2026. The ENSO condition is 
approximated by the CPC Nino3.4 SST consolidation forecast - noting large 
spread and uncertainty given forecasts of ENSO initiating at this time of the 
year. Odds are only slightly modified in these cas es. 
 
PROGNOSTIC DISCUSSION OF OUTLOOKS - AMJ 2025 TO AMJ 2026 
 
TEMPERATURE 
 
The preparation of the AMJ 2025 temperature outlook considered a number of 
factors including potential residual La Nina impacts, available dynamical model 
guidance, latest land surface states (soil moisture departures and anomalous 
snow cover and depth) and long term temperature trends . In addition, some 
consideration is given to the recent SSW and ongoing MJO event. Above-normal 
temperatures are favored for nearly all of the southern tier and eastern 
one-third of the U.S. Overwhelmingly consistent and strong warmer than normal 
signals from the NMME and C3S dynamical model guidance, other statistical 
forecast tools, quite dry land surface conditions and strong positive long term 
temperature trends  support the highest forecast odds for the interior West, 
Southwest and southern Plains. 
 
Below-normal SSTs currently observed off the coast of southern California are 
the basis for the EC forecast for the small region along the coast in this 
area. 
 
Potential early season impacts from a residual La Nina signal, the SSW (Pacific 
Northwest), the MJO (north central U.S.), negative long term temperature trends  
 (April, north central U.S.) and CBaM hybrid guidance offset warmer than 
average forecast signals  from anomalous dry and snow free land surface states 
and dynamical model guidance. So EC is forecast from the Pacific Northwest to 
the northern Plains. The above-normal probabilities from the models seems to be 
considerably overdone in this region given all the factors at play and may 
suffer from substantial positive temperature bias related to long term trends  
and anomalously dry land surface states at these latitudes this time of year. 
 
For Alaska, only small tilts away from climatological probabilities are 
forecast for west central Alaska on the cooler than normal side supported by 
early season impacts from the SSW event and some dynamical model guidance 
including the ECMWF system. Warmer than normal conditions are favored for the 
Alaska Peninsula region. 
 
From the May-Jun-Jul (MJJ) 2025 season to early autumn, the majority of 
forecast tools including dynamical and statistical model guidance, long-term 
positive temperature trends , and expansive anomalously dry land surface states 
support increasing odds and coverage for above normal temperatures to the 
Aug-Sep-Oct (ASO) season. Over this multi-season period, the highest likelihood 
for above-normal temperatures is forecast for the western U.S., southern Plains 
and Gulf coast. 
 
The temperature outlooks from ASO 2025 through Feb-Mar-Apr (FMA) 2026 are based 
on the ENSO-OCN forecast guidance which utilizes the favored ENSO phase and 
magnitude and long-term temperature trends  as viewed by OCN. 
 
For Alaska, the temperature outlooks from MJJ 2025 through ASO 2025 are 
primarily supported by dynamical and statistical model guidance and favor 
above-normal temperatures for the majority of the state. Subsequent leads from 
SON 2025 are based mainly on long term temperature trends  especially for SON 
and OND 2025 and FMA and MAM 2026. 
 
PRECIPITATION 
 
For the AMJ 2025 precipitation outlook, below-normal precipitation is most 
likely for much of the western U.S from northern California and the Central 
Great Basin eastward to include much of the Rockies, Southwest and parts of the 
central and southern Plains. The greatest likelihood for deficient seasonal 
precipitation amounts is forecast for the south-central Rockies and adjacent 
areas of the Central Great Basin. Both dynamical and statistical forecast 
guidance is nearly unanimous with this below-normal precipitation forecast with 
additional support from negative (drier) long term precipitation trends . Drier 
than normal conditions are also favored for south-central coastal Alaska. 
 
Above-normal precipitation is favored for much of western and northern Alaska 
and for parts of the southern Great Lakes and Ohio Valley. Potential residual 
La Nina impacts early in the season and dynamical model guidance is the primary 
support for these highlighted regions. 
 
There was considerable forecast tool disagreement for the Southeast U.S. and 
Gulf coast so EC is forecast in this region. 
 
For the MJJ 2025 through SON 2025 seasons, below-normal precipitation is most 
likely to continue across much of the western U.S. at the start and then slowly 
shift eastward to include the northern and central Plains and later the Upper 
Midwest by ASO 2025 before fading by OND 2025. Consistent and strong signals  
for below-normal precipitation from the NMME and C3S model guidance and 
negative long term precipitation trends  are the basis for the forecast 
evolution. 
 
With respect to enhanced wetness, positive (wetter) long term precipitation 
trends and C3S dynamical model guidance elevate the probabilities for 
above-normal precipitation along the entire eastern seaboard from MJJ 2025 to 
primarily the lower Atlantic seaboard by SON 2025. Below normal winter 
precipitation and so drier than normal land surface states and expectations of 
above-normal temperatures during the Spring favors more efficient heating in 
the Southwest with the potential for an early onset and/or more robust than 
normal monsoon circulation. So above-normal precipitation is favored for an 
area in the Southwest from MJJ 2025 through ASO 2025 maximizing in likelihood 
and forecast coverage in JAS 2025. 
 
A change from the preceding set of outlooks released in February is the 
forecast of favored above-normal precipitation for much of Alaska primarily 
based on a change in dynamical model guidance. The NMME and C3S systems are 
considerably wetter for Alaska this month so adjustments are made to the 
current set of outlooks. 
 
The precipitation outlooks from OND 2025 through Feb-Mar-Apr (FMA) 2026 are 
based on the ENSO-OCN forecast guidance which utilizes the favored ENSO phase 
and magnitude and long-term precipitation trends  taken from OCN. 
 
FORECASTER: Jon Gottschalck 
 
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 Apr 17 2025 
 
 
1991-2020 base period means were implemented effective with the May 20, 2021 
forecast release. 
$$