Skip Navigation Links www.nws.noaa.gov 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center
 
 

CPC Search
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

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
   Hawaiian
   Tools


More Outlooks
    0.5mn SON 2014
    1.5mn OND 2014
    2.5mn NDJ 2014
    3.5mn DJF 2014
    4.5mn JFM 2015
    5.5mn FMA 2015
    6.5mn MAM 2015
    7.5mn AMJ 2015
    8.5mn MJJ 2015
    9.5mn JJA 2015
   10.5mn JAS 2015
   11.5mn ASO 2015
   12.5mn SON 2015
    0.5mn Sep 2014


Tools Used (see Discussion for explanation)
   CCA
   OCN
   CMP
   SMT
   POE
 
HOME> Outlook Maps>Seasonal Forecast Discussion
 
PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THURSDAY AUG 21 2014

SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS

THE MAIN FACTORS THAT USUALLY INFLUENCE THE SEASONAL CLIMATE OUTLOOK INCLUDE:
1) EL NINO AND LA NINA - WHICH TOGETHER COMPRISE EL NINO/SOUTHERN OSCILLATION
OR ENSO. IMPACTS OF THESE EVENTS ARE SUMMARIZED BY SEPARATING 3-MONTH
OBSERVATIONS FROM 3 OR MORE DECADES INTO EL NINO, NEUTRAL, AND LA NINA SETS,
AVERAGING EACH SEPARATELY, AND THEN COMPUTING ANOMALIES. THESE ARE CALLED "ENSO
COMPOSITES", WHICH ARE USED AT TIMES TO SUBJECTIVELY MODIFY THE FORECAST.
2) TRENDS - APPROXIMATED BY THE OCN TOOL AS THE DIFFERENCE BETWEEN THE MOST
RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN
LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGICAL PERIOD (1981-2010).
3) THE MADDEN-JULIAN OSCILLATION (MJO) - AFFECTS CLIMATE VARIABILITY WITHIN
SEASONS.
4) THE NORTH ATLANTIC OSCILLATION (NAO) AND THE PACIFIC - NORTH AMERICAN (PNA)
PATTERNS - WHICH AFFECT ANOMALY PATTERNS ESPECIALLY DURING THE COLD SEASONS.
THESE PHENOMENA ARE CONSIDERABLY LESS PREDICTABLE ON A SEASONAL TIMESCALE THAN
ENSO.
5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE
VARIABILITY AFFECTING THE TROPICS AND THE NORTH PACIFIC AND NORTH AMERICAN
REGIONS, BUT WHICH VARIES ON A MUCH LONGER TIMESCALE THAN ENSO.
6) PERSISTENTLY DRY OR WET SOILS IN THE SPRING AND SUMMER AND SNOW AND ICE
COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS
AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM.
7) STATISTICAL FORECAST TOOLS - CANONICAL CORRELATION ANALYSIS (CCA), SCREENING
MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOGUE (CA) AND ENSEMBLE CCA
(ECCA).
8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM
(CFS). AN EXPERIMENTAL MODEL FORECAST SYSTEM, THE NATIONAL MULTI-MODEL
ENSEMBLE, COMPRISED OF SEVERAL MODELS AND DESIGNATED NMME, MAY ALSO BE USED
EXPERIMENTALLY AND SUBJECTIVELY UNTIL IT IS INCLUDED INTO THE CONSOLIDATION. AN
INTERNATIONAL MULTI-MODEL ENSEMBLE DESIGNATED IMME IS ALSO AVAILABLE.
9) CONSOLIDATION (CON) - AN OBJECTIVE, SKILL-WEIGHTED COMBINATION OF THE OCN,
CCA, SMLR, ECCA, AND CFS FORECASTS IS USED AS A FIRST GUESS IN PREPARING THE
FORECAST MAPS. THIS TECHNIQUE MAKES OPTIMUM USE OF THE KNOWN SKILL OF FORECAST
TOOLS.

CURRENT ATMOSPHERIC AND OCEANIC OBSERVATIONS SUGGEST A TRANSITION FROM
ENSO-NEUTRAL TO EL NINO CONDITIONS IS UNDERWAY, THOUGH THERE CONTINUES TO BE
CONFLICTING INDICATIONS AND SIGNIFICANT UNCERTAINTY AS TO HOW STRONG THIS EL
NINO MAY GET. A MAJORITY OF DYNAMICAL AND STATISTICAL MODEL PREDICTIONS OF
EAST-CENTRAL EQUATORIAL PACIFIC SEA SURFACE TEMPERATURES (SSTS) FAVOR A WEAK EL
NINO, PEAKING DURING THE LATE AUTUMN AND EARLY WINTER IN THE NORTHERN
HEMISPHERE.

THE TEMPERATURE OUTLOOK FOR SEPTEMBER-OCTOBER-NOVEMBER (SON) 2014 INDICATES
ELEVATED ODDS OF ABOVE-NORMAL MEAN TEMPERATURES ACROSS THE WESTERN CONUS, THE
ATLANTIC COAST STATES AS FAR SOUTH AS NORTHERN FLORIDA, AND MOST OF ALASKA.
BELOW-NORMAL MEAN TEMPERATURES ARE FAVORED FROM CENTRAL PORTIONS OF THE GREAT
PLAINS SOUTHWEST INTO CENTRAL NEW MEXICO.

THE SON 2014 PRECIPITATION OUTLOOK CALLS FOR SLIGHTLY ENHANCED PROBABILITIES OF
BELOW-MEDIAN PRECIPITATION ACROSS PORTIONS OF THE PACIFIC NORTHWEST. ELEVATED
CHANCES FOR ABOVE-MEDIAN PRECIPITATION AMOUNTS ARE FORECAST FROM SOUTHERN
CALIFORNIA AND EASTERN NEVADA EASTWARD ACROSS THE CENTRAL AND SOUTHERN ROCKIES,
THE CENTRAL AND SOUTHERN GREAT PLAINS, AND WESTERN PORTIONS OF THE MIDDLE AND
LOWER MISSISSIPPI VALLEY. THE ODDS FOR ABOVE-MEDIAN PRECIPITATION ARE ALSO
ENHANCED OVER SOUTHERN FLORIDA AND MOST OF SOUTHERN ALASKA.

IN AREAS WHERE THE LIKELIHOODS OF SEASONAL MEAN TEMPERATURES AND SEASONAL
ACCUMULATED PRECIPITATION AMOUNTS ARE SIMILAR TO CLIMATOLOGICAL PROBABILITIES,
EQUAL CHANCES (EC) IS SHOWN.

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

ATMOSPHERIC AND OCEANIC CONDITIONS IN THE PACIFIC BASIN INDICATE THAT A
TRANSITION TO AN EL NINO CONTINUES, THOUGH THERE ARE CONFLICTING INDICATIONS
AND CONSIDERABLE UNCERTAINTY REGARDING THE PEAK STRENGTH OF THIS PREDICTED WARM
EVENT. THE LATEST WEEKLY OBSERVATIONS SHOW SST ANOMALIES OF +0.0 DEGREES C IN
THE NINO 3.4 REGION, +0.4C IN NINO 4, +0.5C IN NINO 3, AND +1.2C IN NINO 1+2.
SUB-SEASONAL VARIABILITY ACROSS THE TROPICS HAS SLOWED THE TRANSITION TO EL
NINO IN RECENT WEEKS. THE SPATIAL DISTRIBUTION OF TROPICAL CONVECTION DURING
THE PAST 30-DAYS IN THE WESTERN AND CENTRAL PACIFIC IS NOT CONSISTENT WITH AN
EL NINO. ALTHOUGH THERE HAVE BEEN SOME AREAS OF SUPPRESSED CONVECTION OVER THE
MARITIME CONTINENT REGION, IT HAS NOT BEEN A MORE COHERENT AND STABLE PATTERN
OF SUPPRESSED CONVECTION. IN ADDITION, SUPPRESSED CONVECTION IS ALSO ALONG (BUT
MOSTLY SOUTH OF) THE EQUATOR IN THE VICINITY OF THE DATE LINE, WHICH IS NOT
CONSISTENT WITH A DEVELOPING WARM EVENT. LOW-LEVEL (850-HPA) WINDS WERE
NEAR-AVERAGE ACROSS MOST OF THE EQUATORIAL PACIFIC DURING THIS SAME PERIOD.

THE EXTRATROPICAL PACIFIC (POLEWARD OF 20N) CURRENTLY PROJECTS ONTO A POSITIVE
PDO PATTERN, THOUGH SIGNIFICANTLY LESS THAN LAST MONTH, WITH THE CURRENT PDO
INDEX VALUE AT +0.70. THE STATE OF THE NORTHERN ATLANTIC OCEAN IS ALSO A BIT
DIFFERENT THAN IN RECENT YEARS, WITH THE MOST RECENT INDEX VALUE OF THE AMO
BEING SLIGHTLY MORE POSITIVE THAN THAT FROM LAST MONTH.

PROGNOSTIC DISCUSSION OF SST FORECASTS

MOST STATISTICAL AND DYNAMICAL MODELS CONTINUE TO SUGGEST THAT AN EL NINO WILL
EMERGE WITHIN THE NEXT 3-6 WEEKS. A GENERAL CONSENSUS FAVORS A WEAK WARM EVENT
(ONI RANGING BETWEEN +0.5C AND +0.9C), PEAKING DURING THE LATE AUTUMN AND EARLY
WINTER, WHILE A FEW SOLUTIONS FAVOR A MODERATE EVENT. THE CFS IS AMONG THE
WARMEST OF PREDICTIONS, WITH THE CFS ENSEMBLE MEAN PEAKING IN LATE AUTUMN AND
EARLY WINTER AT MODERATE STRENGTH (+1.2C), WITH MOST INDIVIDUAL MEMBERS RANGING
FROM ABOUT +0.8C TO +1.5C, WITH A GRADUAL DECLINE OF SST ANOMALIES THROUGH
WINTER AND EARLY SPRING. THE CPC CONSOLIDATION (CPC CON) FORECASTS A MAXIMUM
SST ANOMALY OF ABOUT +0.8C (WEAK EL NINO) IN NDJ 2014/15, DECREASING IN
MAGNITUDE TO BORDERLINE NEUTRAL CONDITIONS (+0.5C) BY FMA 2015. THE NMME
PREDICTS A BORDERLINE EL NINO (+0.5C) BY SEPTEMBER, AND SLOWLY INCREASING TO A
MAXIMUM VALUE OF +1.0 (BORDERLINE MODERATE EL NINO) BY LATE WINTER. THE IMME
SST ANOMALY PLUME IS SIMILAR TO THE NMME PLUME, EXCEPT IT TOPS OUT AROUND +0.8C
(WEAK EL NINO) BY LATE WINTER.

PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS

THE TEMPERATURE AND PRECIPITATION OUTLOOKS WERE MADE CONSIDERING EL NINO
CONDITIONS TO BE A FACTOR IN AUTUMN AND WINTER. GUIDANCE FROM THE CFS AS WELL
AS THE NMME AND IMME AND THEIR ASSOCIATED COMPONENTS CONTRIBUTED TO THE
OUTLOOKS FROM SON THROUGH NDJ 2014, ESPECIALLY WHERE THEIR ANOMALIES AGREED
WITH COMPOSITES FROM DEVELOPING WARM ENSO EVENTS. FROM DJF 2014/15 THROUGH FMA
2015, LESS WEIGHT WAS PLACED ON THE DYNAMICAL INPUTS SUCH AS THE CFS, NMME, AND
IMME, AND MORE ON TRADITIONAL ENSO COMPOSITES. THE DYNAMICAL SOLUTIONS APPEAR
TO BE TOO WARM OVER MOST OF THE CONUS GIVEN THE EXPECTATION OF A WEAK EL NINO
DURING THE WINTER, AND AREAS OF COVERAGE AND PROBABILITIES WERE REDUCED
ACCORDINGLY FROM THE PREVIOUS MONTH'S SET OF OUTLOOKS VALID FROM DJF TO FMA.
FROM MAM TO SON 2015, THE TEMPERATURE OUTLOOKS ARE BASED PRIMARILY ON THE
CONSOLIDATION (CON) TOOL WHICH INCORPORATES HISTORICAL TEMPERATURE TRENDS,
WHILE FOR PRECIPITATION, MOST INDICATIONS WERE EITHER WEAK OR CONFLICTING,
FAVORING A FORECAST OF EC. THE EXCEPTIONS FOR PRECIPITATION INCLUDED JJA AND
JAS 2015, WHERE DRIER TRENDS ARE FAVORED IN THE CENTRAL INTERMOUNTAIN REGION.


PROGNOSTIC DISCUSSION OF OUTLOOKS - SON 2014 TO SON 2015

TEMPERATURE

THE SON THROUGH NDJ 2014-15 TEMPERATURE OUTLOOKS INDICATE ELEVATED
PROBABILITIES OF ABOVE-NORMAL SEASONAL MEAN TEMPERATURES FOR NEARLY ALL OF
ALASKA. ELEVATED PROBABILITIES OF ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE
ALSO FORECAST FOR MUCH OF THE WEST, AND ATLANTIC COAST STATES AS FAR SOUTH AS
NORTHERN FLORIDA (SON), WITH THE PREDICTED TRANSITION TO ABOVE-NORMAL
TEMPERATURES ACROSS THE NORTHERN HALF OF THE CONUS BY NDJ. BELOW-NORMAL
SEASONAL MEAN TEMPERATURES ARE FAVORED FROM CENTRAL PORTIONS OF THE GREAT
PLAINS SOUTHWEST INTO CENTRAL NEW MEXICO. THESE EARLY LEAD OUTLOOKS ARE BASED
PRIMARILY ON THE CFS, NMME, IMME, CON, IRI, AND ENSO COMPOSITES. THE AREA OF
PREDICTED BELOW-NORMAL TEMPERATURES IS BASED ON COMPOSITES OF THE CURRENT PHASE
OF THE PDO AND DEVELOPING WARM EVENTS, AND THE SMLR. FROM DJF 2014/15 THROUGH
FMA 2015, THE SAME TOOLS NOTED ABOVE WERE CONSIDERED, WITH A GREATER EMPHASIS
ON ENSO COMPOSITES (THOUGH WITH DIMINISHED COVERAGE AND PROBABILITIES DEEMED
MORE APPROPRIATE FOR AN EXPECTED WEAK WARM EVENT). THESE OUTLOOKS INDICATE THE
ANTICIPATED EXPANSION OF BELOW-NORMAL TEMPERATURES ACROSS FLORIDA AND THE GULF
COAST, CONSISTENT WITH AN ENHANCED SUBTROPICAL JET STREAM. THE MAM 2015 OUTLOOK
FAVORS THE WINDING DOWN OF THE PREDICTED EL NINO, WHILE ALL SUBSEQUENT LEADS
ARE BASED ALMOST ENTIRELY ON THE CON AND LONG-TERM TEMPERATURE TRENDS.

IN AREAS WITHOUT SUBSTANTIAL AND RELIABLE CLIMATE SIGNALS, EQUAL CHANCES OF
BELOW-, NEAR- AND ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE INDICATED.

PRECIPITATION

THROUGH AUTUMN 2014, THERE ARE FAIRLY STRONG AND CONSISTENT INDICATIONS FROM
THE CFS, NMME, AND IMME FOR ABOVE-MEDIAN PRECIPITATION AMOUNTS VARYING
THROUGHOUT PORTIONS OF SOUTHERN CALIFORNIA, THE SOUTHWEST, CENTRAL AND SOUTHERN
PORTIONS OF BOTH THE ROCKIES AND GREAT PLAINS, AND CENTRAL AND SOUTHERN
PORTIONS OF THE MISSISSIPPI VALLEY. ABOVE-MEDIAN PRECIPITATION AMOUNTS ARE ALSO
ENHANCED OVER FLORIDA AND SOUTHERN ALASKA. THIS IS ALSO CONSISTENT WITH THE
EARLY STAGES OF AN EL NINO. ENHANCED ODDS OF BELOW-MEDIAN PRECIPITATION ARE
INDICATED OVER THE NORTHWEST, BASED LARGELY ON THE CFS MODEL (BUT ALSO TO SOME
EXTENT ON THE IMME AND IRI). AS SEASONS PROGRESS INTO WINTER, THE OUTLOOKS
REFLECT THE PRECIPITATION PATTERNS ASSOCIATED WITH EL NINO EVENTS, WITH
ABOVE-MEDIAN PRECIPITATION AMOUNTS FAVORED THROUGHOUT MUCH OF THE SOUTHERN
CONUS IN ASSOCIATION WITH AN EXPECTED ACTIVE SOUTHERN STREAM, AND A TENDENCY
FOR BELOW-MEDIAN AMOUNTS NEAR THE OHIO RIVER VALLEY AND ALSO IN PARTS OF THE
NORTHERN ROCKIES. BOTH THE SPATIAL COVERAGE AND PROBABILITIES HAVE BEEN
DIMINISHED SOMEWHAT FROM THE PREVIOUS SET OF OUTLOOKS VALID FOR THESE SAME
TARGET SEASONS. AS NOTED ABOVE, THESE ADJUSTMENTS WERE MADE TO BETTER ACCOUNT
FOR AN EXPECTED WEAK EL NINO. THE PRECIPITATION OUTLOOK FOR MAM 2015 AND BEYOND
SHOW EQUAL CHANCES FOR BELOW-, NEAR- AND ABOVE-MEDIAN SEASONAL ACCUMULATED
PRECIPITATION THROUGHOUT THE CONUS AND ALASKA, WITH ONE EXCEPTION. FOR THE
SEASONS OF JJA AND JAS 2015, HISTORICAL PRECIPITATION TRENDS FAVOR DRYNESS
ACROSS PORTIONS OF THE CENTRAL INTERMOUNTAIN REGION.

FORECASTER: ANTHONY ARTUSA

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
HTTP:/WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/90DAY/DISC.HTML
(USE LOWER CASE LETTERS)
INFORMATION ON THE FORMATION OF SKILL OF THE CAS FORECASTS MAY BE FOUND AT:
HTTP://WWW.CPC.NCEP.NOAA.GOV/SOILMST/FORECASTS.HTML (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 SEP 18 2014


1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011
FORECAST RELEASE.
$$

NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5200 Auth Road
Camp Springs, Maryland 20746
Climate Prediction Center Web Team
Page last modified: January 17, 2006
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act
About Us
Career Opportunities