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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.

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More Outlooks
    0.5mn MJJ 2017
    1.5mn JJA 2017
    2.5mn JAS 2017
    3.5mn ASO 2017
    4.5mn SON 2017
    5.5mn OND 2017
    6.5mn NDJ 2017
    7.5mn DJF 2017
    8.5mn JFM 2018
    9.5mn FMA 2018
   10.5mn MAM 2018
   11.5mn AMJ 2018
   12.5mn MJJ 2018
    0.5mn May 2017


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
830 AM EDT THU APR 20 2017

SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS

THE MAY-JUNE-JULY (MJJ) 2017 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL
TEMPERATURES FOR MUCH OF THE FORECAST DOMAIN. FOR THE CONTIGUOUS U.S.,
ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE MOST LIKELY FOR THE PACIFIC COASTAL
STATES AND ACROSS THE SOUTHWEST REGION AND THE CENTRAL AND SOUTHERN PLAINS INTO
THE EASTERN U.S., WITH THE GREATEST ODDS INDICATED FOR PARTS OF THE SOUTHWEST,
THE GULF COAST AND ATLANTIC COASTAL REGIONS. ABOVE-NORMAL TEMPERATURES ARE ALSO
FAVORED FOR MUCH OF ALASKA.

THE MJJ 2017 PRECIPITATION OUTLOOK INDICATES ENHANCED PROBABILITIES OF
ABOVE-MEDIAN PRECIPITATION FOR AREAS OF THE ROCKY MOUNTAINS AND JUST EAST, FROM
CENTRAL MONTANA SOUTHWARD INCLUDING WYOMING, COLORADO AND NEW MEXICO, AS WELL
AS FOR WESTERN AREAS OF THE GULF COAST, AND FOR EASTERN INTERIOR REGIONS OF
ALASKA. BELOW-MEDIAN SEASONAL PRECIPITATION AMOUNTS ARE FAVORED FOR THE WESTERN
AND CENTRAL GREAT LAKES REGION.

EQUAL CHANCES (EC) ARE FORECAST OVER AREAS WHERE ODDS OF ABOVE-, BELOW-, OR
NEAR-NORMAL SEASONAL MEAN TEMPERATURES AND SEASONAL ACCUMULATED PRECIPITATION
AMOUNTS ARE EXPECTED TO BE 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

OCEANIC AND ATMOSPHERIC OBSERVATIONS ACROSS THE EQUATORIAL PACIFIC AS A WHOLE
INDICATE ENSO-NEUTRAL CONDITIONS ARE CONTINUING. A RESIDUAL, SMALL AREA OF
SLIGHTLY BELOW NORMAL SEA SURFACE TEMPERATURES (SSTS) REMAINS IN PROXIMITY TO
THE DATE LINE, FROM LAST WINTER'S LA NINA, BUT IN AREAS TO THE WEST AND EAST
ALONG THE EQUATOR, SSTS ARE NOW ABOVE AVERAGE. THE HEAT CONTENT ANOMALY OF THE
UPPER-OCEAN LAYERS, TO A DEPTH OF 300 METERS, SUMMED ACROSS THE BASIN FROM THE
DATE LINE TO 100W IS NOW NEAR ZERO AFTER DECREASING FROM POSITIVE HEAT CONTENT
ANOMALIES DURING FEBRUARY AND MARCH.

IN THE ATMOSPHERE OVER THE PAST MONTH, EASTERLY WIND ANOMALIES CONTINUED TO BE
OBSERVED OVER THE CENTRAL AND WESTERN TROPICAL PACIFIC. OVER THE SAME PERIOD,
MEASUREMENTS OF TROPICAL CONVECTION INDICATED CONTINUED SUPPRESSED CONVECTION
IN THE CENTRAL PACIFIC AND CONTINUING ENHANCED CONVECTION OVER MUCH OF THE
MARITIME CONTINENT. THIS ANOMALOUS CONVECTION PATTERN APPEARS TO BE A RESIDUAL
OF THE WEAK LA NINA EVENT THAT HAS OTHERWISE ENDED.

PROGNOSTIC DISCUSSION OF SST FORECASTS

THE CPC NINO 3.4 SST CONSOLIDATION FORECAST, WHICH INCLUDES CANONICAL
CORRELATION ANALYSIS (CCA), CONSTRUCTED ANALOG (CA), AND MARKOV STATISTICAL
FORECASTS, ALONG WITH THE CFS DYNAMICAL MODEL, PREDICTS A MEDIAN TEMPERATURE
ANOMALY OF +0.4C FOR THE COMING SEASONS FROM APPROXIMATELY MJJ THROUGH OND
2017, WITH EL NINO AS MOST LIKELY FROM LATE SUMMER THROUGH AUTUMN. A
CONSIDERABLE DIFFERENCE BETWEEN THE CFS AND THE STATISTICAL GUIDANCE APPEARS IN
THE CONSOLIDATION, HOWEVER, WITH THE CFS FORECASTING A RAPID INCREASE IN SSTS
EARLY IN THE OUTLOOK PERIOD AND EL NINO CONDITIONS BEGINNING WITH THE MJJ 2017
SEASON, WHILE THE CA STATISTICAL FORECAST EXCEEDS THE +0.5C THRESHOLD FOR EL
NINO STARTING IN JAS 2017, AND THE CCA AND MARKOV MODELS REMAIN IN ENSO NEUTRAL
THROUGHOUT THE FORECAST PERIOD.  THIS SEPARATION BETWEEN THE STATISTICAL AND
DYNAMICAL MODELS IS ALSO DEPICTED BY THE LATEST IRI NINO3.4 SST FORECAST PLUME.
MOREOVER, FORECASTS FROM THE DYNAMICAL SUITE OF MODELS FROM THE NMME ALSO
INDICATE A MORE RAPID INCREASE IN NINO 3.4 SST DURING THE SPRING AND SUMMER
MONTHS. THE LATEST OFFICIAL ENSO OUTLOOK FROM CPC/IRI INDICATES ENSO-NEUTRAL
CONDITIONS ARE LIKELY TO CONTINUE THROUGH AT LEAST THE NORTHERN HEMISPHERE
SPRING WITH INCREASING ODDS FOR THE DEVELOPMENT OF EL NINO CONDITIONS AS AUTUMN
APPROACHES WITH PROBABILITIES FOR EL NINO OF ABOUT 50% FROM ASO 2017 CONTINUING
THROUGH NDJ 2017. THE CONSENSUS FORECAST INDICATES THE LIKELIHOOD OF A REPEAT
LA NINA EVENT TO BE VERY SMALL DURING THIS FORECAST PERIOD.

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

THE PRIMARY TOOLS USED FOR THIS SET OF SEASONAL OUTLOOKS INCLUDED BOTH
STATISTICAL AND DYNAMICAL MODEL FORECAST GUIDANCE, AND IN PARTICULAR AT LONGER
LEADS, DECADAL TEMPERATURE AND PRECIPITATION TRENDS. THE DYNAMICAL MODEL
GUIDANCE FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND ITS INDIVIDUAL
MODELS, INCLUDING THE NCEP CFS, WERE IMPORTANT CONTRIBUTORS TO THE OUTLOOKS
THROUGH SON 2017. ANTECEDENT SOIL MOISTURE AND SNOWPACK ANOMALIES IN CERTAIN
REGIONS ALSO IMPACTED THE OUTLOOKS, PRIMARILY AT EARLY LEADS. LIKELY
ENSO-NEUTRAL CONDITIONS IN EARLY SEASONS, LEADS TO RELIANCE PRIMARILY ON THE
DYNAMICAL MODEL FORECASTS, WHILE THE INCREASING CHANCE OF EL NINO IN LATE
SUMMER AND AUTUMN WAS CONSIDERED IN THE TEMPERATURE AND PRECIPITATION OUTLOOKS
INTO WINTER SEASONS.

PROGNOSTIC DISCUSSION OF OUTLOOKS - MJJ 2017 TO MJJ 2018

TEMPERATURE

THE LATEST MJJ AND JJA 2017 TEMPERATURE OUTLOOKS INDICATE ABOVE-NORMAL
TEMPERATURES ARE MOST LIKELY FOR MUCH OF THE FORECAST DOMAIN, WITH THE
EXCEPTION OF PARTS OF THE NORTHERN ROCKIES AND NORTHERN PLAINS. THE CHANCES OF
ABOVE-NORMAL SEASONAL MEAN TEMPERATURES ARE SLIGHTLY ENHANCED FOR MUCH OF THE
PACIFIC NORTHWEST, BUT THE PROBABILITY OF ABOVE-NORMAL TEMPERATURES IS
MODERATED BY RECENT POSITIVE SNOW AND SOIL MOISTURE ANOMALIES. ABOVE-NORMAL
TEMPERATURES ARE PARTICULARLY ENHANCED FOR A REGION STRETCHING FROM THE
SOUTHWEST, EASTWARD ACROSS THE CENTRAL AND SOUTHERN PLAINS INTO THE EASTERN
U.S. THE GREATEST PROBABILITIES EXCEED 50% FOR PARTS OF THE SOUTHWEST AND ALONG
THE GULF AND ATLANTIC COASTS, FOLLOWING THE CALIBRATED PROBABILISTIC GUIDANCE
FROM THE NMME. NEGATIVE SOIL MOISTURE ANOMALIES IN THE SOUTHEAST REGION ALSO
CONTRIBUTE TO THE LIKELIHOOD OF ANOMALOUS WARMTH. DECADAL CLIMATE TRENDS ALSO
SUPPORT THE OUTLOOK AND ARE A COMPONENT OF THE DYNAMICAL MODEL GUIDANCE. THESE
FORECAST TOOLS ALSO SUPPORT ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES
FOR ALASKA.

SHORT TERM CLIMATE MODEL FORECASTS FOR THE BEGINNING OF MAY AND WEAKER SIGNALS
IN THE SEASONAL MODEL GUIDANCE FOR PARTS OF THE NORTHERN ROCKIES INTO THE
NORTHERN PLAINS RESULTS IN AN AREA OF EQUAL CHANCES (EC) OVER THESE REGIONS.

LITTLE CHANGE WAS MADE TO PREVIOUS OUTLOOKS FOR REMAINING SEASONS THROUGH 2017
INTO THE FIRST HALF OF 2018. ENHANCED PROBABILITIES OF ABOVE-NORMAL
TEMPERATURES ARE INDICATED THROUGHOUT THE FORECAST DOMAIN THROUGH DJF
2017-2018. FROM THE JFM THROUGH MJJ 2018 SEASONS, REGIONS OF ENHANCED
PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOLLOW STATISTICAL GUIDANCE,
PRIMARILY RESULTING FROM DECADAL CLIMATE TRENDS.

HIGH PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR THE NORTH
SLOPE OF ALASKA DURING SON AND OND 2017 DUE TO DECADAL TRENDS IN THE SEASONAL
CYCLE OF SEA ICE.

PRECIPITATION

FOR PRECIPITATION, THE MJJ AND JJA 2017 OUTLOOKS INDICATE ABOVE-MEDIAN
PRECIPITATION FOR AREAS OF THE ROCKY MOUNTAINS AND JUST TO THE EAST, FROM
CENTRAL MONTANA SOUTHWARD INCLUDING PARTS OF WYOMING, UTAH, COLORADO AND NEW
MEXICO, AS WELL AS FOR WESTERN AREAS OF THE GULF COAST, AND FOR EASTERN
INTERIOR REGIONS OF ALASKA. BELOW-MEDIAN SEASONAL PRECIPITATION AMOUNTS ARE
FAVORED FOR THE WESTERN AND CENTRAL GREAT LAKES REGION. THE OUTLOOKS FOR THE
MJJ THROUGH SON 2017 SEASONS ARE PRIMARILY BASED ON WEAK SIGNALS THAT APPEAR IN
CALIBRATED PROBABILISTIC GUIDANCE FROM THE NMME. ELEVATED CHANCES FOR
ABOVE-MEDIAN PRECIPITATION CONTINUE FOR AREAS IN THE CENTRAL AND NORTHERN
ROCKIES AND NORTHERN HIGH PLAINS FOR JJA AND JAS 2017, AND FOR THE CENTRAL
ROCKIES FOR ASO AND SON 2017. FROM ASO THROUGH OND 2017, INCREASING CHANCES FOR
EL NINO CONDITIONS AND DYNAMICAL MODEL FORECASTS OF GREATER THAN AVERAGE SSTS
IN THE EASTERN TROPICAL PACIFIC LEAD TO A SOUTHWARD SHIFT OF THIS REGION OF
LIKELY ABOVE-MEDIAN PRECIPITATION INTO THE SOUTHWEST CONUS INCLUDING SOUTHERN
CALIFORNIA AND ARIZONA IN OND 2017.

FOR LATE AUTUMN AND WINTER, FROM NDJ 2017-2018 THROUGH JFM 2018, THE LOW
PROBABILITY OF A LA NINA AND ELEVATED CHANCES FOR A POSSIBLE EL NINO RESULT IN
REMOVAL OF A SIGNAL FOR DRIER THAN NORMAL CONDITIONS FROM THE DECADAL CLIMATE
TRENDS FOR THE SOUTHWEST. FOLLOWING FMA 2018, WEAK SIGNALS DUE TO DECADAL
TRENDS IN PRECIPITATION ARE INDICATED, INCLUDING BELOW-MEDIAN PRECIPITATION FOR
PARTS OF THE SOUTHWEST BEGINNING WITH THE FMA 2018 SEASON AND ABOVE-MEDIAN
PRECIPITATION IN THE NORTHERN-CENTRAL CONTIGUOUS U.S. BEGINNING WITH MAM 2018.

FORECASTER: DAN COLLINS

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/LONG_RANGE/TOOLS.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/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 MAY 18 2017


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

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