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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 DJF 2018
    1.5mn JFM 2019
    2.5mn FMA 2019
    3.5mn MAM 2019
    4.5mn AMJ 2019
    5.5mn MJJ 2019
    6.5mn JJA 2019
    7.5mn JAS 2019
    8.5mn ASO 2019
    9.5mn SON 2019
   10.5mn OND 2019
   11.5mn NDJ 2019
   12.5mn DJF 2019
    0.5mn Dec 2018


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 EST THU NOV 15 2018

SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS

THIS SECTION OF THE SEASONAL OUTLOOK MESSAGE SUMMARIZES THE FIRST FORECAST IN
THE SET, THE DECEMBER-FEBRUARY (DJF) 2018-2019 SEASONAL OUTLOOK. DESCRIPTION OF
THE SUBSEQUENT OUTLOOKS, CLIMATE FACTORS CONSIDERED, AND SPECIFIC FORECAST
RATIONALE FOR ALL OUTLOOKS ARE PROVIDED IN THE LAST TWO SECTIONS OF THE
MESSAGE.

THE DJF 2018-2019 TEMPERATURE OUTLOOK CONTINUES TO FAVOR ABOVE-NORMAL SEASONAL
MEAN TEMPERATURES FOR A GOOD PORTION OF THE FORECAST DOMAIN TO INCLUDE ALL OF
ALASKA AND MUCH OF THE WESTERN AND NORTHERN CONTIGUOUS U.S. THE GREATEST
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR THE PACIFIC
NORTHWEST AND THE ALASKA PANHANDLE. FOR SEASONAL TOTAL PRECIPITATION AMOUNTS
DURING DJF 2018-2019, THERE ARE MODESTLY ELEVATED CHANCES OF ABOVE-NORMAL
PRECIPITATION FOR MOST OF THE SOUTHERN TIER OF THE CONTIGUOUS U.S., THE CENTRAL
EASTERN SEABOARD, AND SOUTHERN ALASKA. BELOW-NORMAL PRECIPITATION IS MODESTLY
FAVORED OVER THE GREAT LAKES AND PARTS OF THE MIDWEST.

EQUAL CHANCES (EC) FOR ABOVE-, NEAR-, OR BELOW-NORMAL SEASONAL MEAN
TEMPERATURES OR SEASONAL TOTAL PRECIPITATION AMOUNTS ARE INDICATED IN AREAS
WHERE THE LIKELIHOOD OF THESE VARIABLES ARE FAVORED TO BE SIMILAR TO
CLIMATOLOGICAL PROBABILITIES. THE REASONS FOR THIS CAN BE A COMBINATION OF
WEAKLY DEFINED OR NON-RELIABLE CLIMATE FACTORS AS WELL AS CONSIDERABLE SPREAD
IN FORECAST TOOL SOLUTIONS.

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

STARTING WITH OCEAN CONDITIONS, WE ARE STILL OFFICIALLY IN ENSO-NEUTRAL
CONDITIONS THROUGH EARLY NOVEMBER AND THE EL NINO WATCH REMAINS IN PLACE. SEA
SURFACE TEMPERATURES (SSTS) ARE ABOVE-NORMAL ACROSS MOST OF THE EQUATORIAL
PACIFIC BASIN, GENERALLY RANGING FROM +0.5 - +1.0 DEGREES C. THE MOST RECENT
WEEKLY VALUES OF THE NINO4 AND NINO3.4 INDICES ARE NOW +0.9 AND +0.8 DEGREES C
RESPECTIVELY. SUBSEASONAL VARIABILITY OF EQUATORIAL SST ANOMALIES HAS BEEN
MODULATED BY MJO ACTIVITY OVER THE PAST SEVERAL WEEKS. A STRONG DOWNWELLING
OCEANIC KELVIN WAVE INITIATED AS A RESULT OF WESTERLY WIND BURST EVENTS
CONTINUES TO SHIFT EASTWARD ACROSS THE PACIFIC BASIN AT DEPTH. THE EQUATORIAL
UPPER-OCEAN HEAT CONTENT REMAINS ELEVATED AND FAVORS EL NINO CONDITIONS HEADING
INTO WINTER. SPECIFIC NINO3.4 SST FORECASTS ARE REVIEWED IN THE SECTION BELOW.

THE ATMOSPHERIC CONDITIONS ASSOCIATED WITH A DEVELOPING EL NINO EVENT REMAIN
MODEST AT BEST. THE PRESENCE OF WESTERLY WIND ANOMALIES HAS BEEN HIGHLY
DEPENDENT UPON THE PHASE OF THE SUBSEASONAL MJO SIGNAL. PERHAPS MORE CONCERNING
FROM THE PERSPECTIVE OF TROPICAL-EXTRATROPICAL TELECONNECTIONS IS THE ABSENCE
OF ANY PERSISTENT CONVECTIVE RESPONSE OVER THE CENTRAL EQUATORIAL PACIFIC TO
ABOVE-NORMAL SSTS. STANDARDIZED 200-HPA HEIGHT ANOMALY FORECASTS FROM THE
CFSV2, FOR EXAMPLE, SHOW A RELATIVE WEAKNESS IN POSITIVE HEIGHT ANOMALIES
SOUTHEAST OF HAWAII DURING DECEMBER, QUITE THE OPPOSITE OF THE EXPECTED EL NINO
SIGNAL.

TURNING TO CURRENT TERRESTRIAL CONDITIONS, WE NOTE MUCH ABOVE-NORMAL SOIL
MOISTURE ANOMALIES FROM TEXAS TO THE MIDWEST, EASTWARD TO THE GREAT LAKES,
MID-ATLANTIC AND PARTS OF THE NORTHEAST, WHILE DROUGHT CONDITIONS PERSIST
ACROSS MANY AREAS OF THE WEST. AS WE ARE ENTERING THE LATE AUTUMN AND WINTER
MONTHS, SOIL MOISTURE CONDITIONS, ALTHOUGH NEAR THE 99TH PERCENTILE IN MANY
AREAS, IS NOT EXPECTED TO CONTRIBUTE ANY SIGNIFICANT IMPACT TO THE CLIMATE
CONDITIONS OVER THE NEXT SEVERAL MONTHS SINCE INCIDENT SOLAR RADIATION IS NEAR
ITS MINIMUM IN THE ANNUAL CYCLE. SNOW COVER ANOMALIES HAVE BEEN POSITIVE OVER
MUCH OF THE NORTHERN CONUS AND SOUTHERN CANADA. IT IS NOT CLEAR, HOWEVER, THAT
THIS PLAYS A SUBSTANTIAL ROLE IN MODULATING THE CLIMATE IN THE COMING MONTHS.


PROGNOSTIC DISCUSSION OF SST FORECASTS

FORECASTS OF THE NINO3.4 SST ANOMALY REMAIN SIMILAR TO FORECASTS ISSUED LAST
MONTH. THE CPC CONSOLIDATION NINO3.4 SST ANOMALY FORECAST MAINTAINS ITS RECENT
PREDICTIONS OVER THE PAST SEVERAL MONTHS WITH A PEAK DURING NDJ 2018-2019 OF
JUST UNDER +1.0 DEGREE C AND THEN SLOWLY DECREASES OVER THE COURSE OF THE
WINTER AND SPRING MONTHS OF 2019. ONE TREND THAT HAS EMERGED THIS MONTH IS THAT
IN ADDITION TO THE CCA FORECAST, THE MARKOV MODEL AND TO SOME EXTENT THE
SST-CA, NOW FAVOR THE PERSISTENCE OR GROWTH OF POSITIVE NINO3.4 ANOMALIES
DURING 2019. THIS IS A TREND THAT WILL BE CLOSELY WATCHED OVER THE COMING
MONTHS. THE NMME NINO3.4 SST ANOMALY MODEL GUIDANCE ALSO HAS REMAINED
CONSISTENT OVER THE PAST FEW MONTHS AND CONTINUES TO INDICATE A SLIGHTLY
STRONGER EVENT (ENSEMBLE MEAN PEAKING AND PERSISTING BETWEEN +1.0 - +1.2
DEGREES C) DURING THE WINTER MONTHS. THE OFFICIAL CPC-IRI ENSO OUTLOOK FAVORS
EL NINO THIS WINTER AND SPRING AT A GREATER THAN 70% PROBABILITY THROUGH JFM
2019 AND THEN DECREASING TO NEAR 50% BY AMJ 2019.

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

THIS SET OF OUTLOOKS UTILIZED TYPICAL IMPACTS ASSOCIATED WITH EL NINO EVENTS,
ALBEIT WITH THE UNDERSTANDING THAT THIS MOST LIKELY WILL BE A WEAK OR
BORDERLINE MODERATE EVENT AND NOTING THE CONFIDENCE IN IMPACTS IN INTENSITY AND
LOCATION IS SOMEWHAT LOW. ADDITIONALLY, THE LACK OF A COHERENT CONVECTIVE
RESPONSE TO THIS POINT ADDS MORE UNCERTAINTY TO THE EQUATION: EVEN IF SSTS ARE
SUFFICIENTLY HIGH FOR THIS TO BE CONSIDERED AN EL NINO WINTER, THE
TROPICAL-EXTRATROPICAL TELECONNECTIONS MAY BE ESPECIALLY WEAK.  OTHER FACTORS
FROM BOTH THE TROPICS (E.G., MJO) AND HIGH/POLAR LATITUDES (E.G., AO/NAO, NPO,
ETC.) ARE LIKELY TO FAVOR HIGH VARIABILITY OVER THE WINTER AND EARLY SPRING
SEASONS AND LIKELY WILL EXPLAIN CONSIDERABLY MORE VARIANCE IN THE UPCOMING
SEASONAL MEANS IN TEMPERATURE AND PRECIPITATION.

LOCAL COASTAL SSTS AND CONSIDERATIONS OF AREAS OF ANOMALOUS SNOWFALL WERE
CONSIDERED IN MAKING THE OUTLOOKS DURING THE EARLIER LEADS.

CONTRIBUTIONS TO THE OUTLOOKS ALSO INCLUDED BIAS-CORRECTED AND CALIBRATED
DYNAMICAL MODEL GUIDANCE FROM THE NMME AND IMME ENSEMBLE SUITES (BOTH ENSEMBLE
MEAN AND THEIR PARTICIPANT MODELS) THROUGH AMJ 2019. DYNAMICAL MODEL GUIDANCE
FROM THE UKMET OFFICE, ESPECIALLY WITH RESPECT TO THE FORECAST SIGN OF THE NAO,
WAS ALSO CONSIDERED. EMPIRICAL AND STATISTICAL FORECAST MODELS ALSO PLAYED A
LARGE ROLE THROUGHOUT ALL FORECAST LEADS. THESE INCLUDED GUIDANCE FROM A
COMBINED ENSO-OCN TOOL, THE CCA, THE SST-CA, AND "BRIDGING" TECHNIQUES.
MOREOVER, CONSOLIDATION FORECAST GUIDANCE PRODUCTS FROM STATISTICAL ONLY,
DYNAMICAL MODEL ONLY, AND COMBINED STATISTICAL AND DYNAMICAL FORECAST TOOLS WAS
HEAVILY UTILIZED. OCN ALSO WAS UTILIZED OFTEN THROUGHOUT THE OUTLOOK LEADS FOR
BOTH TEMPERATURE AND PRECIPITATION.

PROGNOSTIC DISCUSSION OF OUTLOOKS - DJF 2018 TO DJF 2019

TEMPERATURE

IN REVIEWING THE FIRST FOUR FORECAST LEADS THROUGH THE WINTER 2018-2019 AND
EARLY SPRING MONTHS IN 2019, THE DJF-FMA 2018-2019 TEMPERATURE OUTLOOKS ARE
SIMILAR AND DEPICT ELEVATED ODDS OF ABOVE-NORMAL TEMPERATURES FOR ALASKA AND
MUCH OF THE WESTERN CONUS WITH EC NOTED FOR THE MUCH OF THE EASTERN CONUS. AS
WE PROGRESS THROUGH THE WINTER INTO THE EARLY SPRING, THE FORECAST SEQUENCE
DEPICTS A TENDENCY FOR THE ODDS OF ABOVE-NORMAL TEMPERATURES TO DECREASE ALONG
WITH FORECAST COVERAGE ACROSS THE NORTHERN TIER OF THE CONUS. AT THE SAME TIME,
THERE IS AN EASTWARD EXPANSION OF ENHANCED ODDS FOR ABOVE-NORMAL TEMPERATURES
ACROSS THE SOUTHERN TIER. FOR THESE LEADS, OTHER THAN AREAS IN ALASKA AND THE
PACIFIC NORTHWEST, THE PROBABILITIES ARE QUITE MODEST.

THIS DEPICTED EVOLUTION (VARIATION OF AREAS DENOTED AS EC) IN THE FORECAST OF
SEASONAL MEAN TEMPERATURES IS A RESULT OF CHANGING AREAS WITH THE GREATEST
UNCERTAINTY AND SO LOWER FORECAST CONFIDENCE. UNDERSTANDING THE WEAK NATURE OF
EL NINO ANTICIPATED THIS WINTER AND CONFRONTED BY CONSIDERABLE CONFLICTING
FORECAST TOOL INFORMATION IN THESE AREAS, EC IS FORECAST AT THIS TIME. DURING
DJF, JFM, AND FMA 2018-2019, DYNAMICAL MODEL GUIDANCE FROM THE NMME DEPICTS
CALIBRATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES NEARLY UNANIMOUSLY
ACROSS MUCH OF THE WESTERN CONUS AND NORTH-CENTRAL CONUS IN AGREEMENT WITH THE
AFOREMENTIONED STATISTICAL FORECAST TOOLS AND OBJECTIVE, SKILL WEIGHTED
CONSOLIDATION GUIDANCE PRODUCTS. HOWEVER, THE VARIOUS MODELS HAVE COME INTO
CONSENSUS ON A WEAKNESS EXTENDING FROM THE SOUTH-CENTRAL CONUS NORTHEASTWARD TO
PARTS OF NEW ENGLAND. IN ADDITION, THE UKMET GLOSEA5 FORECAST SYSTEM PREDICTS A
NEGATIVE NAO DIPOLE IN THE MEAN SEA LEVEL PRESSURE FIELD, CONSISTENT WITH A
WEAKNESS OVER THE SOUTHEASTERN THIRD OF THE CONUS. IN FACT, THERE WAS A LOT OF
INTERNAL DISCUSSION ABOUT THE INTRODUCTION OF PROBABILITIES FAVORING
BELOW-NORMAL TEMPERATURES SOMEWHERE OVER THE INTERIOR SOUTHEAST. HOWEVER, THERE
IS JUST NOT ENOUGH OBJECTIVE FORECAST GUIDANCE TO FAVOR SUCH A FORECAST. IN
THIS CASE A FORECAST OF EQUAL CHANCES IS ACTUALLY QUITE A BIT COOLER THAN THE
PREPONDERANCE OF OBJECTIVE DATA WOULD WARRANT. OUR FORECAST TEAM ERRED ON THAT
SIDE GIVEN THE COLDER DECEMBER OUTLOOK THAN SUGGESTED BY THE LOW-FREQUENCY
FORECAST GUIDANCE, AS WELL AS AN EXPECTATION OF A TENDENCY TOWARD A NEGATIVE
NAO AND ENHANCED MJO ACTIVITY BIASED TOWARD THE WEST-CENTRAL PACIFIC.

PROGRESSING INTO SPRING AND SUMMER, THE FORECAST TENDS TOWARD THE OBJECTIVE
MODEL GUIDANCE WITH INCREASING COVERAGE OF ABOVE-NORMAL TEMPERATURES OVER MUCH
OF THE EASTERN CONUS. THIS IS ALMOST UNANIMOUS AMONG THE VARIOUS FORECAST TOOLS
AND CONSISTENT WITH LONG-TERM TRENDS.

FOR ALASKA AND THE WESTERN CONUS, THERE IS LITTLE SUPPORT FOR ANY OTHER
FORECAST BESIDES ELEVATED ODDS FOR ABOVE-NORMAL TEMPERATURES FOR THIS PORTION
OF THE SET OF OUTLOOKS AS WELL AS THE REMAINING OUTLOOKS THROUGH DJF 2019-2020.
THE PRIMARY DRIVER FOR THE OUTLOOKS FROM MJJ 2019 THROUGH DJF 2019-2020 WERE
OCN, ENSO-OCN, AND STATISTICAL OBJECTIVE, SKILL WEIGHTED CONSOLIDATION FORECAST
TOOLS. BY FALL AND WINTER 2019-2020, THE FORECAST IS DAMPED RELATIVE TO THE
OBJECTIVE GUIDANCE - WHILE VERY HIGH OBJECTIVE PROBABILITIES COME FROM THE
AGREEMENT AMONG ALL THE EMPIRICAL FORECAST TOOLS, THE PHYSICAL UNDERPINNINGS OF
THE FORECAST SIGNAL ARE NOT READILY APPARENT.

PRECIPITATION

THE OUTLOOKS FOR SEASONAL TOTAL PRECIPITATION AMOUNTS UTILIZED INFORMATION
CONSISTENT WITH AN ANTICIPATED (ALBEIT WEAK) EL NINO EVENT FROM DJF 2018-2019
THROUGH MAM 2019. DYNAMICAL MODEL GUIDANCE FROM THE NMME AND IMME CONTRIBUTED
TO THE OUTLOOKS AS WELL THROUGH AMJ 2019. GIVEN THE RANGE OF SOLUTIONS AND
GENERALLY WEAK INDICATORS FROM MANY OF THE FORECAST TOOLS, PROBABILITIES FOR
EITHER FORECAST CATEGORY (ABOVE- OR BELOW-NORMAL PRECIPITATION) ARE QUITE
MODEST. ABOVE-NORMAL PRECIPITATION IS FAVORED OVER THE SOUTHERN TIER OF THE
CONUS INCLUDING CALIFORNIA DURING DJF, BUT GRADUALLY CONTRACTING TO INCLUDE THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS BY MAM 2019. THE SLIGHT TILT TOWARD
ABOVE-NORMAL PRECIPITATION IN CALIFORNIA FOR DJF WAS BASED ON THE DYNAMICAL
MODEL CONSENSUS, INCLUDING INTERNATIONAL MODELS, ALONG WITH THE TILT TOWARD
ABOVE-NORMAL PRECIPITATION DEPICTED IN THE DECEMBER 2018 FORECAST.
PROBABILITIES FAVORING ABOVE-NORMAL PRECIPITATION GRADUALLY INCREASE IN
COVERAGE OVER THE CENTRAL CONUS, SHIFTING NORTHWARD WITH TIME.

BELOW-NORMAL PRECIPITATION IS NO LONGER FAVORED OVER THE NORTHERN HIGH PLAINS
AND NORTHERN ROCKIES DURING THE EARLY LEADS. THERE WAS A REMARKABLE LACK OF
SUPPORT AMONG THE VARIOUS FORECAST TOOLS FOR THIS SIGNAL. WHILE IT IS AMONG THE
ROBUST ENSO FOOTPRINTS, LONG TERM TRENDS AND THE CONSENSUS OF FORECAST TOOLS
LEAD TO EQUAL CHANCES BEING DEPICTED FOR THIS REGION THROUGH AMJ 2019.
BELOW-NORMAL PRECIPITATION IS FAVORED FOR PARTS OF THE GREAT LAKES AND THE OHIO
VALLEY FROM DJF 2018-2019 TO FMA 2019. EL NINO CONSIDERATIONS AND CONSISTENT
DYNAMICAL AND STATISTICAL MODEL GUIDANCE FAVORED ELEVATED ODDS OF ABOVE-NORMAL
PRECIPITATION FOR SOUTHERN ALASKA THROUGH FMA 2019.

FROM AMJ 2019 THROUGH NDJ 2019-2020, THE OUTLOOKS ARE BASED PREDOMINATELY ON
LONG TERM TRENDS AND MODEL GUIDANCE WHEN AVAILABLE. TO THIS END, THE MOST BROAD
AND CONSISTENT SIGNALS FOR THIS ARE ELEVATED ODDS FOR BELOW-NORMAL
PRECIPITATION IN THE NORTHERN ROCKIES FROM MJJ 2019 THROUGH JAS 2019 AND A
LARGER AREA FOR FAVORED ABOVE-NORMAL PRECIPITATION FOR PARTS OF THE PLAINS,
GREAT LAKES, NORTHEAST, OHIO VALLEY, AND MID-ATLANTIC FROM AMJ 2019 THROUGH SON
2019. LONG-TERM TRENDS FAVOR ABOVE-NORMAL PRECIPITATION FOR MUCH OF ALASKA
THROUGHOUT THE LONGER LEADS AS WELL.

FORECASTER: STEPHEN BAXTER

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 DEC 20 2018


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

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