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Official 90-day Outlooks are issued once each month near mid-month at 8:30am Eastern Time. Please consult the schedule of 30 & 90-day outlooks for exact release dates.

Text Discussions
   90day Prognostic
   30day Prognostic

More Outlooks
    0.5mn ASO 2019
    1.5mn SON 2019
    2.5mn OND 2019
    3.5mn NDJ 2019
    4.5mn DJF 2019
    5.5mn JFM 2020
    6.5mn FMA 2020
    7.5mn MAM 2020
    8.5mn AMJ 2020
    9.5mn MJJ 2020
   10.5mn JJA 2020
   11.5mn JAS 2020
   12.5mn ASO 2020
    0.5mn Aug 2019

Tools Used (see Discussion for explanation)
HOME> Outlook Maps>Seasonal Forecast Discussion
Prognostic Discussion for Long-Lead Seasonal Outlooks 
NWS Climate Prediction Center College Park MD
830 AM EDT Thu Jul 18 2019


The August-September-October (ASO) 2019 temperature outlook indicates that
above normal seasonal mean temperatures are most likely for the western third
of the CONUS, the Southern Plains and Southeast, the Northeast, and all of
Alaska. The highest probabilities for above normal temperatures are over
western areas of Alaska and the Pacific Northwest, as well as much of the
Southwest, New England, and the Florida Peninsula.

The August-September-October (ASO) 2019 precipitation outlook indicates that
above normal seasonal total precipitation is most likely for areas of western
Alaska and the High Plains and northern Great Plains.

Equal Chances (EC; white areas) of below, near, and above normal seasonal mean
temperatures or seasonal total precipitation amounts are where the likelihoods
for these three categories are similar to their climatological probabilities.
Review of subsequent seasonal outlooks and the scientific forecast basis for
all outlooks are given below.

Note: For Graphical Displays of the Forecast Tools Discussed Below See:


Currently weak El Nino conditions persist but are expected to transition to
ENSO neutral conditions within the next two months. Near average sea surface
temperatures (SSTs) with some smaller scale anomalies are observed from 140W to
the coast of South America, and large-scale warmer than average SSTs are
observed in the central and west Pacific. The latest weekly Nino 3.4 SST
anomaly is +0.4 degree C, while the latest Nino 4 SST anomaly is +0.9 degree C,
indicating the current gradient in equatorial SSTs from east to west. A large
area of cooler than average subsurface water at depths of 100-200 meters in the
west Pacific and from just below the surface to 100 meters depth in the east
Pacific has persisted in the last two months, while warmer than average water
persists from the surface to depths of 100 meters from 160E to 130W longitude.
Oceanic heat content, determined from near equatorial Pacific Ocean temperature
anomalies from the surface to a depth of 300 meters from the Date Line to 100W,
has decreased to near zero anomaly in July. Low-level wind anomalies were near
average over the tropical Pacific Ocean, and upper-level wind anomalies were
westerly over the far eastern Pacific Ocean. Collectively, these oceanic and
atmospheric conditions represent a continuation of weak El Nino conditions in

Other boundary conditions relevant to the seasonal outlook are soil moisture
anomalies and, in some areas, near-coastal SSTs. Widespread and persistent
above normal precipitation for most of the CONUS during spring resulted in
positive soil moisture anomalies for many areas of the central and eastern
CONUS. Sea ice coverage for the Arctic is at record low amounts and SSTs are
well above normal near the west coast of Alaska.


There is a significant split on the ENSO outlook between dynamical and
statistical models. Statistical models, including the Canonical Correlation
Analysis, Constructed Analog and Markov models, persist in predicting warming
central and eastern Pacific SSTs though Boreal autumn into winter and likely El
Nino conditions, while a consensus of dynamical models from the North American
Multi-Model Ensemble (NMME) predicts a return to near average SSTs over the
central and eastern Pacific in the next couple months and on average some
warming of SSTs by winter. Most of the dynamical models indicate either a weak
El Nino or ENSO neutral. Both statistical and dynamical model forecasts predict
a low probability that a La Nina will develop by next winter. The probability
of average Nino 3.4 region SST anomalies above +0.5 Celsius and El Nino
conditions increase through autumn and are elevated from climatology to near 40
percent by winter (DJF), but fall short of 50 percent in both the CPC SST
Consolidation of statistical and dynamical models and the official CPC/IRI
consensus ENSO outlook, indicating that neutral ENSO conditions are now more
likely for autumn and winter with probabilities of near 50 percent.


The temperature and precipitation outlooks were based primarily on dynamical
model guidance from the NMME and statistical model guidance which includes a
statistical forecast of the linear impacts of ENSO combined with decadal
climate trends based on the CPC SST Consolidation forecast for Nino 3.4.
Potential impacts from El Nino conditions were considered for the seasonal
outlook for the DJF 2019-2020 through FMA 2020 seasons, due to the slightly
elevated probability of El Nino and low probability of La Nina. Soil moisture
conditions were considered for the earliest leads as were coastal SST
anomalies. Several statistical and dynamical models , as well as hybrid
statistical-dynamical models, along with an objective consolidation of several
forecast tools, were also examined in preparation of the seasonal outlooks.
Decadal climate trends were considered for all leads but encompass a greater
fraction of the forced climate signal in longer leads, as the uncertainty
increases and signal decreases in predictable interannual climate variability.



The ASO 2019 through DJF 2019-2020 seasonal mean temperature outlooks utilize
the predictability of several climate phenomena, including potential ENSO
conditions and impacts, anomalous land surface conditions and sea surface
temperatures, and decadal timescale climate variability or trends . Calibrated
NMME forecasts based on probability anomaly correlation (or PAC) and a
statistical-dynamical hybrid model combining calibrated NMME temperature
forecasts with statistically bridged impacts from NMME Nino 3.4 forecasts
(known as calibration, bridging and merging or CBaM) indicate that
probabilities of below and above normal temperatures are nearly equal during
ASO over much of the northern central CONUS from the Northern Plains into the
upper and central Mississippi Valley. Some individual model forecasts for ASO
from the NMME and monthly NMME forecasts indicate the potential for below
normal temperatures for much of this region, especially in August 2019. Above
average soil moisture anomalies and an above normal precipitation outlook for
ASO 2019 also favor lower probabilities of above normal temperatures for much
of the central CONUS. Supported by both the PAC calibrated NMME and CBAM
forecasts, the outlooks for SON 2019 through DJF 2019-2020 indicate greater
than climatological probabilities of above normal temperatures for all of the
CONUS and Alaska. Probabilities of above normal are greater for the western
CONUS and Alaska, where decadal climate trends are a strong influence on
seasonal mean temperatures. Dynamical model forecasts from the NMME and in CBAM
also indicate greater probabilities for the west than the eastern CONUS,
influenced by both decadal temperature trends and the impacts of above normal
SSTs in the central and western tropical Pacific. The probabilities of above
normal temperatures exceed 70 percent for western and northern Alaska in the
outlook for ASO and SON 2019, where well above normal SSTs are predicted to
persist and observed sea ice has been substantially below normal in autumn in
recent decades.

The forecasts for JFM 2020 and beyond are largely unchanged from the seasonal
outlook last month, relying primarily on signals due to multi-decadal climate
trends. Above normal temperatures are likely for all of Alaska and most of the
CONUS, except for some areas of the northern central CONUS, where equal chances
of below, near and above normal temperatures are indicated, due to weak climate
trends. This area expands from JFM 2020 through JAS 2020 and is not included in
the outlook for ASO 2020, when decadal trends are most widespread.


For the ASO 2019 precipitation outlook, above normal precipitation is forecast
for western Alaska, as well as northern and southern coastal regions of Alaska,
following NMME and CBAM model guidance. This forecast of above normal
precipitation for much of Alaska persists through all leads with some
variations in regions, as it is related to signals from decadal climate trends
and above normal sea surface temperatures. Following NMME and CBAM model
guidance, above normal precipitation is also likely for most of the Northern
and Central Plains in ASO 2019. Some of the signal for above normal
precipitation persists for parts of the Great Plains into SON 2019, while a
signal for above normal precipitation increases across much of the Southwest in
SON 2019 and persists for parts of the region through JFM 2020. Above normal
precipitation is also likely for western regions of the Gulf Coast for NDJ and
DJF 2019-2020. Some of the signal for above normal precipitation arises from
forecasts for a warmer than normal tropical Pacific Ocean, despite the greater
chance of ENSO neutral conditions than El Nino development. Minimal changes
were made to the outlooks for FMA 2020 forward as no climate forecasts for
these leads have changed since last month. The outlooks for AMJ through ASO
2020 indicate likely above normal precipitation over parts of the eastern
CONUS, while likely below normal precipitation is indicated for parts of the
Northwest in JJA through ASO 2020, due to multi-decadal precipitation trends .


The Climatic normals are based on conditions between 1981 and 2010, 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
(Use Lower Cas e Letters)
Information on the formation of skill of the CAS forecasts may be found at:
(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 Aug 15 2019

1981-2010 base period means were implemented effective with the May 19, 2011
forecast release.

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Page last modified: January 17, 2006
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