Prognostic Discussion for Long-Lead Seasonal Outlooks 
NWS Climate Prediction Center College Park MD 
830 AM EST Thu Jan 16 2025 
 
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS 
 
The most recent El Niño Southern Oscillation (ENSO) discussion has now stated 
that we are under a La Niña Advisory and that La Niña conditions are present. 
Equatorial sea surface temperatures (SSTs) are below-average in the central and 
east-central Pacific Ocean, with SST departures in the Niño3.4 region reaching 
-0.7 degrees Celsius in the past week. La Niña conditions are expected to 
persist through February-April (FMA) 2025 with a 59% chance, with a 60% chance 
of a transition to ENSO-neutral during March-May (MAM) 2025. This La Niña is 
predicted to be weak, with the majority of guidance favoring SSTs in the 
Niño3.4 region around -0.5 degrees Celsius. Conversely, chances of a strong La 
Niña are near zero. Though we still expect the canonical La Niña impacts in the 
upcoming few seasons, there may be more variability within the season given the 
forecasted weakness of the event. 
 
The FMA 2025 Temperature Outlook remains very similar to last month, and favors 
below normal temperatures stretching from the northwestern Contiguous United 
States (CONUS) to the Northern Plains, as well as southeastern Alaska. Above 
normal temperatures are forecast over the southern tier of the CONUS and along 
the East Coast into New England, and over northern Alaska. The highest 
probabilities of above normal temperatures reach 50 to 60% over parts of the 
Southwest, southern Texas, the southern Gulf States, and Florida. The FMA 
Precipitation Outlook is similar in pattern to last month, which was and is a 
pattern that is canonical of La Niña in FMA. Above normal precipitation is 
favored over the Northwest, the Great Lakes, Ohio Valley, parts of the Upper 
and Middle Mississippi Valley, Interior Northeast, and western and northern 
Alaska. Below normal precipitation is indicated over the Southwest, Central 
Plains, the Gulf Coast, and southern Mid-Atlantic. Though similar to last 
month, probabilities are increased over the Southwest and Ohio Valley regions 
where we typically see strong La Niña teleconnections now that La Niña 
conditions are present. 
 
Equal Chances (EC) of above, near, and below normal temperatures or 
precipitation are indicated where there is model and/or tool disagreement, 
forecast probabilities for each category are similar, and temperatures or 
precipitation are expected to be close to the climatological distribution. 
 
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 
 
La Niña conditions recently emerged, with below-average SSTs observed across 
the central and east-central Pacific ocean, above-normal SSTs in the western 
Pacific, and near-normal SSTs in the eastern Pacific. The latest weekly Niño 
indices ranged from 0.3 degrees Celsius in the Niño 1+2 region, and -0.7 
degrees Celsius in the Niño 3.4 and 4 regions. The below normal SSTs have 
persisted in the central and east-central equatorial Pacific Ocean for at least 
the last 4 weeks. Negative subsurface temperature anomalies reached a minimum 
in late December, but have persisted overall since, and recently expanded to 
the central Pacific Ocean. Over the past 30 days, low-level wind anomalies were 
easterly from the western to central equatorial Pacific Ocean, and upper-level 
wind anomalies were westerly across the east-central and eastern equatorial 
Pacific Ocean. Finally, convection has been suppressed near the Date Line with 
enhanced convection over Indonesia. These collectively reflect a La Niña, and 
as such, a La Niña advisory is now in effect. 
 
The Madden-Julian Oscillation (MJO) became incoherent during early January, but 
more recent observations of the Realtime Multivariate MJO (RMM) index show a 
regain in amplitude over the Western Hemisphere, with the MJO slow to resume 
its eastward propagation. However, for the upcoming forecast period over the 
next few weeks, dynamical models  are unanimous in favoring a high amplitude MJO 
event propagating from the Western Hemisphere and across the Indian Ocean. 
Though perhaps more relevant to the monthly forecast, the forecasted MJO may 
constructively interfere with the emerging low frequency base state, 
potentially strengthening the La Niña conditions later this winter. 
 
PROGNOSTIC DISCUSSION OF SST FORECASTS 
 
The dynamical models  in the Columbia Climate School International Research 
Institute for Climate and Society (IRI) plume continue to predict a weak and a 
short duration La Niña. La Niña conditions are expected to persist through FMA 
2025 with a 59% chance, transitioning to ENSO-neutral likely during MAM 2025 
with a 60% chance. Dynamical models  predict a weak La Niña, with the Niño3.4 
index less than -0.5 degrees Celsius. The above mentioned MJO may add some 
uncertainty to the strength of the La Niña later in the winter if there is 
constructive interference, though we still expect the La Niña to be on the 
weaker side. 
 
 
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS 
 
Dynamical model forecasts from the North American Multi-Model Ensemble (NMME), 
the Coupled Forecast System Model Version 2 (CFSv2), and the Copernicus (C3S) 
multi-model ensemble system were used extensively for the first six leads when 
they are available, as was the objective, historical skill weighted 
consolidation and Calibration, Bridging, and Merging (CBaM) guidance, that 
combines both dynamical and statistical forecast information. 
 
Additionally, La Niña conditions emerged and the official ENSO forecast favors 
a weak La Niña through FMA 2025. This anticipated weak La Niña signal played a 
role in the construction of these outlooks. Composites derived from nearest 
neighbor statistical analysis of recently observed tropical Pacific SST and 
Equatorial heat anomalies were utilized where appropriate. At later leads, 
decadal trends  in temperature and precipitation were increasingly relied upon 
in creating the seasonal outlooks. 
 
 
PROGNOSTIC DISCUSSION OF OUTLOOKS - FMA 2025 TO FMA 2026 
 
TEMPERATURE 
 
The FMA 2025 Temperature Outlook is very similar to the lead 2 prediction of 
FMA 2025 released in December 2024. Models remained in agreement on the overall 
forecasted pattern of temperature, and given the now emergent La Niña 
conditions, reflect a La Niña pattern in temperature. Above-normal temperatures 
are favored for much of the southern CONUS and East Coast, while below normal 
temperatures are forecast for the Northwest to the Northern Plains. Over 
Alaska, below normal temperatures are indicated for the Southeast, 
transitioning to above normal temperatures over the Northwest. The above normal 
temperatures over northern Alaska, the Southwest, and East Coast are further 
supported by above normal trends . Overall, this pattern is canonical of La Niña 
during FMA, though we note that with a weak La Niña we may see periods of 
variability within the season. EC, due to weak or conflicting signals  among 
tools, is forecast for much of California, parts of the Great Basin, the 
Central Rockies and Plains, the western Great Lakes, and central and 
southwestern Alaska. 
 
Though the La Niña is forecast to weaken throughout MAM 2025, there are likely 
to be lagged impacts of the La Niña lasting through at least the season. In 
addition, despite the teleconnection typically weakening in MAM vs. FMA, we 
still expect some lasting impacts in key regions for La Niña impacts. As such, 
the MAM forecast also resembles a typical La Niña pattern, and changes are not 
significant from last month's prediction to this month. Below normal 
temperatures are maintained over southeastern Alaska, and the Northwest to the 
Northern Plains, while above normal temperatures stretch from the Southwest 
across the southern tier of the CONUS and up the East Coast, as well as 
northern Alaska. 
 
Following MAM and shifting into April-June (AMJ) 2025, impacts of La Niña begin 
to wane as ENSO neutral conditions are forecast to prevail. Below normal 
temperatures over Alaska and the Northwest into the Plains diminish in favor of 
EC along much of the northern tier of the CONUS and southeastern Alaska. Above 
normal temperatures are maintained and expanded over parts of the Western 
CONUS, Southeast, along the Eastern quarter of the CONUS, and western and 
northern Alaska given model agreement among NMME and C3S. This pattern is 
generally maintained through September-November (SON) 2025 with the support of 
dynamical climate models and decadal trends . However, July-September (JAS) 
through SON feature larger areas of EC over the central CONUS and parts of 
Alaska where guidance had weak or conflicting signals . October-December (OND) 
2025 and November-January (NDJ) 2025-2026 feature slightly above normal 
temperatures across much of the CONUS and Alaska given recent decadal trends . 
The above normal temperatures diminish and shift to the East Coast by 
December-February (DJF) 2025-2026, with some indication of above normal 
temperatures over the Southwest in FMA 2026, and a slight tilt toward below 
normal over parts of the Northern Plains and Northwest in January-March (JFM) 
2026. The last 3 leads of this forecast have large areas of EC given 
comparatively lower confidence at these longer lead times. 
 
PRECIPITATION 
 
The FMA 2025 Precipitation Outlook is very typical of the La Niña 
teleconnection over the CONUS. Above normal precipitation is favored over the 
Northwest, Great Lakes, Ohio Valley, Upper and Middle Mississippi Valley, 
interior Northeast, and northern and western Alaska. Below normal precipitation 
is indicated for the Southwest, Central and Southern Plains, the Gulf Coast, 
the southern East Coast, and southern Alaska. This precipitation pattern is 
very similar to last month’s FMA forecast, however, probabilities are increased 
over the Southwest and Ohio Valley regions given good agreement among tools as 
well as the La Niña. EC is indicated over much of California, excepting the 
slight tilt toward above normal (below normal) precipitation over the northern 
(southern) part of the state, as well as the Northern Plains and coastal 
Northeast. La Niña typically leads to a wetter northern California and drier 
southern California, however, the impacts of La Niña can generally be quite 
variable over central parts of the West Coast. In addition, the weakness of 
this event may add additional uncertainty to the precipitation pattern, as 
such, probabilities are weak and EC is indicated over much of California. 
Models had some disagreement over the Northern Plains, with some tilting more 
wet and others toward near-normal, thus EC is favored over the Northern Plains 
as well. While La Niña typically can lead to below normal precipitation over 
the east coast, the location of the stormtrack over the Lakes and interior 
Mid-Atlantic during a La Niña can be variable. Should it shift more to the 
east, there may be more precipitation over the east coast, while shifting more 
to the west may lead to less precipitation. Given the weakness of the La Niña 
leading to potentially more variability in the teleconnection pattern vs. 
during a strong La Niña, EC is favored over the Northeastern coast. Similarly 
to temperature, we expect some lagged impacts of the La Niña into MAM 2025, and 
the forecasted precipitation pattern remains similar into this season. 
 
As the forecast progresses through later leads and into Fall/Winter 2025, ENSO 
guidance becomes less of a player in this forecast, and decadal precipitation 
trends are relied on more. Below normal precipitation shifts northward from its 
more southwestern orientation in MAM through OND 2025. Above normal 
precipitation shifts from the Great Lakes, Ohio Valley, and Mid-Atlantic toward 
the East Coast through SON. Above normal precipitation over northwestern 
Alaska, expands to the South and East as the forecast period progresses. 
Statistical guidance is increasingly relied upon for later leads, for example 
NDJ 2025-2026 and on, and small, relatively weak regions of above normal 
precipitation are favored for the Southeast that shift northward to the end of 
the forecast period (FMA 2026). Above normal precipitation is also favored over 
parts of the northern CONUS, while below normal precipitation begins to make an 
appearance over the Southwest late next winter. Above normal precipitation 
probabilities persist over Alaska though the remainder of the period, though 
shift from covering much of the state in OND to the north and east in NDJ and 
DJF 2025-2026, to the west in JFM and FMA 2026. 
 
 
FORECASTER: Johnna Infanti 
 
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 Feb 20 2025 
 
 
1991-2020 base period means were implemented effective with the May 20, 2021 
forecast release. 
$$