90 Day Narrative

267 
FXUS05 KWBC 151231
PMD90D
PROGNOSTIC DISCUSSION FOR LONG-LEAD SEASONAL OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830 AM EDT THU JUN 15 2017
SUMMARY OF THE OUTLOOK FOR NON-TECHNICAL USERS
THE JULY-AUGUST-SEPTEMBER (JAS) 2017 TEMPERATURE OUTLOOK FAVORS ABOVE-NORMAL 
TEMPERATURES ACROSS ALASKA AND MUCH OF THE CONTINENTAL U.S., ALTHOUGH 
PROBABILITIES ARE REDUCED ACROSS THE CENTRAL U.S. THE HIGHEST PROBABILITIES FOR 
ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE NORTHEAST, PARTS OF THE GULF 
COAST AND FLORIDA, THE SOUTHWEST, AND SOUTHWEST ALASKA AND THE ALEUTIANS. THE 
JAS 2017 PRECIPITATION OUTLOOK INDICATES A SLIGHT TILT IN THE ODDS FOR 
ABOVE-MEDIAN PRECIPITATION FOR THE NORTHERN GREAT PLAINS, WESTERN GULF COAST, 
SOUTHWEST ALASKA, AND THE ALEUTIANS.
DURING THE FALL AND WINTER 2017-18, CHANCES OF EL NINO DEVELOPMENT HAVE 
DECREASED COMPARED TO THE PREVIOUS MONTH. SINCE ENSO-NEUTRAL CONDITIONS ARE 
MOST LIKELY TO PERSIST, THE TEMPERATURE AND PRECIPITATION OUTLOOKS DURING THE 
COLD SEASON ARE BASED PRIMARILY ON DYNAMICAL MODEL GUIDANCE AND DECADAL TRENDS.
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 INDICATE 
ENSO-NEUTRAL CONDITIONS PERSIST, ALTHOUGH SEA SURFACE TEMPERATURES (SSTS) ARE 
ABOVE AVERAGE IN THE EAST-CENTRAL PACIFIC OCEAN. THE OBSERVED WEEKLY SSTS 
ACROSS THIS REGION, CENTERED ON JUNE 7, FEATURE SMALL POSITIVE SST ANOMALIES OF 
0.5 TO 1 DEGREE C FROM THE DATE LINE TO 130 DEGREES W. THE UPPER-OCEAN HEAT 
CONTENT ANOMALY FROM THE DATE LINE TO 100 DEGREES W REMAINS ABOVE AVERAGE BUT 
THE MAGNITUDE OF THIS ANOMALY DECREASED SINCE EARLY MAY.
DESPITE WARMER-THAN-AVERAGE OCEAN TEMPERATURES ACROSS THE CENTRAL AND EASTERN 
PACIFIC SINCE MARCH, ATMOSPHERIC CONVECTIVE ANOMALIES CONTINUE TO REMAIN NEAR 
AVERAGE OVER THE EASTERN TROPICAL PACIFIC AND SLIGHTLY SUPPRESSED TO THE WEST 
OF THE DATE LINE FROM MAY 13 TO JUNE 7. ENHANCED CONVECTION WAS OBSERVED ACROSS 
INDONESIA DURING THIS TIME PERIOD. THE WIND ANOMALIES AT THE LOWER AND 
UPPER-LEVELS WERE NEAR AVERAGE DURING THE PAST MONTH. THESE ATMOSPHERIC 
INDICATORS ARE CONSISTENT WITH ENSO NEUTRAL CONDITIONS.
PROGNOSTIC DISCUSSION OF SST FORECASTS
THE LATEST NCEP CFSV2 AND MOST OF THE MODELS OF THE NORTH AMERICAN MULTI-MODEL 
ENSEMBLE (NMME) ARE FAVORING A CONTINUATION OF ENSO-NEUTRAL CONDITIONS THROUGH 
THE FALL. THE CPC NINO 3.4 SST INDEX CONSOLIDATION FORECAST INDICATES A 
POSITIVE ANOMALY AT OR SLIGHTLY BELOW 0.5 DEGREES C THROUGH NDJ. DUE TO THESE 
LATEST MODEL PREDICTIONS ALONG WITH NEAR-AVERAGE ATMOSPHERIC CONDITIONS OVER 
THE PACIFIC, THE CPC/IRI CONSENSUS FORECAST INDICATES SLIGHTLY MORE CONFIDENCE 
(50 TO 55 PERCENT CHANCE) IN THE PERSISTENCE OF ENSO-NEUTRAL CONDITIONS THROUGH 
JFM 2018. THE CHANCES FOR EL NINO (AROUND 35 PERCENT) DURING THE UPCOMING FALL 
AND WINTER ARE SIMILAR TO THE CLIMATOLOGICAL PROBABILITY.
PROGNOSTIC TOOLS USED FOR U.S. TEMPERATURE AND PRECIPITATION OUTLOOKS
THE PRIMARY TOOLS USED FOR THE SEASONAL OUTLOOKS INCLUDED STATISTICAL AND 
DYNAMICAL MODEL FORECAST GUIDANCE, AND IN PARTICULAR AT LONGER LEADS, DECADAL 
TEMPERATURE AND PRECIPITATION TRENDS. THE CALIBRATED DYNAMICAL MODEL GUIDANCE 
FROM THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND, TO LESSER EXTENT, ITS 
INDIVIDUAL MODELS, INCLUDING THE NCEP CFS, WERE IMPORTANT CONTRIBUTORS TO THE 
OUTLOOKS THROUGH NDJ 2017. ANTECEDENT SOIL MOISTURE WAS CONSIDERED, ALTHOUGH IT 
WILL PLAY A DIMINISHING ROLE LATER IN THE UPCOMING SEASON OF JAS. THE 
DECREASING LIKELIHOOD OF EL NINO DEVELOPMENT, COMPARED TO PREVIOUS OUTLOOKS, 
WAS A FACTOR IN LATER LEADS. 
PROGNOSTIC DISCUSSION OF OUTLOOKS - JAS 2017 TO JAS 2018
TEMPERATURE
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS NEARLY ALL OF THE FORECAST DOMAIN 
FOR THE JAS OUTLOOK, AS THE TEMPERATURE TOOLS ARE IN GOOD AGREEMENT AND THE 
MOST RECENT NMME INCREASED COVERAGE OF ENHANCED ODDS FOR ABOVE-NORMAL 
TEMPERATURES. THE LOWEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE 
FORECAST ACROSS PARTS OF THE CENTRAL U.S. IN PART DUE TO INITIALLY HIGH SOIL 
MOISTURE ACROSS THE CENTRAL/SOUTHERN GREAT PLAINS AND UPPER MIDWEST, BUT THIS 
REDUCED AREA OF PROBABILITIES IS ALSO CONSISTENT WITH A CONSENSUS FROM THE 
VARIOUS TOOLS. EQUAL CHANCES OF BELOW-, NEAR-, OR ABOVE-NORMAL TEMPERATURES ARE 
LIMITED TO PARTS OF MONTANA BASED ON DYNAMICAL MODEL GUIDANCE AND THE CFS MODEL 
INDICATING A SMALL AREA OF BELOW-NORMAL TEMPERATURES.  PROBABILITIES FOR 
ABOVE-NORMAL TEMPERATURES DURING JAS ARE HIGHEST OVER THE NORTHEAST, PARTS OF 
THE GULF COAST AND FLORIDA, AND THE SOUTHWEST DUE TO DECADAL TRENDS AND 
CALIBRATED PROBABILITIES FROM THE NMME. THIS TOOL INDICATES INCREASED CHANCES 
FOR ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF ALASKA WITH THE HIGHEST CHANCES 
(50 AND ABOVE) OVER SOUTHWEST ALASKA AND THE ALEUTIANS. 
 
THE TEMPERATURE OUTLOOKS FROM ASO 2017 TO NDJ 2017-18 ARE BASED PRIMARILY ON 
THE NMME CALIBRATED PROBABILITIES SINCE THE MOST LIKELY OUTCOME IS FOR 
ENSO-NEUTRAL CONDITIONS DURING THESE SEASONAL PERIODS. AN EXPECTED LACK OF SEA 
ICE ELEVATES CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS NORTHERN ALASKA 
DURING THE FALL SEASON. DECADAL TRENDS ARE USED IN CREATING THE TEMPERATURE 
OUTLOOKS AT THE LONGER LEAD TIMES DURING THE SPRING AND SUMMER OF 2018. 
PRECIPITATION
ENHANCED ODDS FOR ABOVE-MEDIAN PRECIPITATION DURING JAS ARE MAINTAINED FROM ONE 
MONTH AGO ACROSS THE NORTH-CENTRAL U.S. AND PARTS OF ALASKA, BASED ON THE MOST 
RECENT DYNAMICAL MODEL GUIDANCE. PRECIPITATION TOOLS FEATURE A WET SIGNAL 
ACROSS THE WESTERN GULF COAST REGION AND INCREASED CHANCES FOR ABOVE-MEDIAN 
PRECIPITATION DURING JAS IS INTRODUCED TO THIS REGION. THE SIGNAL IS GENERALLY 
WEAK AMONG PRECIPITATION TOOLS WITH MONSOON RAINFALL ACROSS THE SOUTHWEST 
DURING JAS 2017. THEREFORE, EQUAL CHANCES OF BELOW-, NEAR-, OR ABOVE-MEDIAN 
PRECIPITATION ARE FORECAST FOR THE SOUTHWEST DURING JAS. 
SINCE THE PREVIOUS OUTLOOK, THE CHANCES FOR EL NINO DEVELOPMENT DURING THE NEXT 
SIX MONTHS HAVE DECREASED. GIVEN THE LATEST CPC/IRI CONSENSUS FORECAST FAVORING 
A CONTINUATION OF ENSO-NEUTRAL CONDITIONS THROUGH THE WINTER 2017-18, IT WAS 
NECESSARY TO REMOVE THE INCREASED CHANCES FOR ABOVE-MEDIAN PRECIPITATION OVER 
THE GULF COAST REGION AND SOUTHEAST DURING THE UPCOMING FALL AND WINTER. 
PRECIPITATION OUTLOOKS (THROUGH NDJ 2017-18) ARE BASED PRIMARILY ON GUIDANCE 
FROM THE CALIBRATED PROBABILITIES FROM THE NMME WHICH DEPICTS INCREASED CHANCES 
FOR ABOVE-MEDIAN PRECIPITATION FROM THE FOUR CORNERS REGION EXTENDING INTO THE 
NORTH-CENTRAL U.S.  PRECIPITATION OUTLOOKS AT LATER LEADS ARE BASED ON THE 
CONSOLIDATION AND DECADAL TRENDS.
FORECASTER: BRAD PUGH
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 JUL 20 2017
1981-2010 BASE PERIOD MEANS WERE IMPLEMENTED EFFECTIVE WITH THE MAY 19, 2011 
FORECAST RELEASE.
$$