311  
FXHW40 KWBC 211330  
PMDHCO  
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830AM EST THU DEC 21 2017  
 
MONTHLY FORECAST DISCUSSION VALID JANUARY 2018  
 
SEA SURFACE TEMPERATURE (SST) ANOMALIES ARE CURRENTLY AROUND ZERO TO NEGATIVE  
ONE DEGREE C OVER MOST OF THE NORTHWESTERN HAWAIIAN ISLANDS, AND ABOUT ZERO TO  
POSITIVE ONE-HALF DEGREE C OVER THE SOUTHEASTERN ISLANDS.  
 
FOR JANUARY 2017 THROUGH THE END OF NOVEMBER 2017, RAINFALL TOTAL ACCUMULATIONS  
WERE:  
 
- LIHUE AIRPORT 22.44 INCHES (70 PERCENT OF NORMAL)  
 
- HONOLULU AIRPORT 19.22 INCHES (139 PERCENT OF NORMAL)  
 
- KAHULUI AIRPORT 16.57 INCHES (114 PERCENT OF NORMAL)  
 
- HILO AIRPORT 95.25 INCHES (83 PERCENT OF NORMAL)  
 
THE NCEP CLIMATE FORECAST SYSTEM (CFS) AND OTHER CLIMATE MODELS RUN AS A PART  
OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) STILL PREDICT ABOVE NORMAL  
SSTS AROUND THE HAWAIIAN ISLANDS TO CONTINUE FOR JANUARY 2018. THIS ELEVATES  
THE CHANCES OF ABOVE NORMAL MONTHLY MEAN AIR TEMPERATURES FOR THE LIHUE,  
HONOLULU, KAHULUI AND HILO IN JANUARY 2018. RECENT CHANGES IN SST TEMPERATURES,  
SUCH AS THE COOLER SSTS BUILDING IN NEAR THE NORTHWESTERN ISLAND, MUTE THE  
FORECAST PROBABILITIES WHEN COMPARED TO THE DIRECT MODEL OUTPUT. MOST DYNAMICAL  
TOOLS ALSO FAVOR ABOVE NORMAL PRECIPITATION FOR HILO, KAHULUI, HONOLULU AND  
LIHUE DURING JANUARY 2018.  
 
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
HILO A40 71.6 0.5 A40 3.1 8.9 11.8  
KAHULUI A40 72.1 0.6 A40 1.2 2.3 2.8  
HONOLULU A40 73.3 0.5 A40 0.7 1.1 2.1  
LIHUE A40 71.8 0.7 A40 1.3 2.2 4.8  
 
SEASONAL FORECAST DISCUSSION VALID JFM 2018 - JFM 2019  
 
REFER TO THE PROGNOSTIC DISCUSSION ON LONG-LEAD SEASONAL OUTLOOKS FOR THE CONUS  
AND ALASKA FOR A DISCUSSION OF THE FORECASTS OF EQUATORIAL PACIFIC SSTS, AND  
FOR THE GENERAL BACKGROUND FOR THE SEASONAL FORECAST, INCLUDING DETAILS ON THE  
CURRENT STATE OF THE ATMOSPHERE AND OCEAN. LA NINA CONDITIONS CURRENTLY ARE  
PRESENT ACROSS THE EQUATORIAL PACIFIC OCEAN. EQUATORIAL SEA SURFACE  
TEMPERATURES (SSTS) ARE BELOW AVERAGE ACROSS THE CENTRAL AND EASTERN PACIFIC  
OCEAN, AND ABOVE AVERAGE IN THE WESTERN PACIFIC. POSITIVE ANOMALIES HAVE  
INCREASED IN THE WESTERN PACIFIC OCEAN, WHILE THE STRONGEST NEGATIVE ANOMALIES  
ARE BETWEEN 160W-80W. ATMOSPHERIC CONVECTION ANOMALIES WERE POSITIVE NEAR THE  
INTERNATIONAL DATE LINE, WHILE LOW-LEVEL TRADE WINDS WERE STRONGER THAN AVERAGE  
OVER THE WESTERN AND CENTRAL PACIFIC, WITH ANOMALOUS WESTERLY WINDS AT  
UPPER-LEVELS. THE NCEP CFS AND MOST OF THE DYNAMICAL MODELS FROM THE LATEST  
RUNS OF THE NMME FAVOR THE CONTINUATION OF LA NINA AT LEAST THROUGH THE  
NORTHERN HEMISPHERE WINTER 2017-18, WITH A TRANSITION TO ENSO-NEUTRAL MOST  
LIKELY DURING THE MID-TO-LATE SPRING. THE OFFICIAL CPC/IRI OUTLOOK FOR LA NINA  
INDICATES A GREATER THAN 80 PERCENT CHANCE OF LA NINA CONTINUING THROUGH JFM  
2018.  
 
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED FOR HAWAII  
FROM DJF 2017-2018 TO JJA 2018 DUE TO PREDICTED ABOVE NORMAL SEA SURFACE  
TEMPERATURES ACROSS THE REGION. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW  
NORMAL TEMPERATURES ARE INDICATED AT ALL LOCATIONS FOR JAS 2018 AND BEYOND.  
 
DYNAMICAL AND STATISTICAL TOOLS FAVOR ABOVE MEDIAN PRECIPITATION FOR HAWAII  
FROM JFM 2018 TO FMA 2018. THE CONSTRUCTED ANALOG (CA) AND CANONICAL  
CORRELATION ANALYSIS (CCA) TOOLS SHOW BELOW MEDIAN PRECIPITATION FOR HAWAII IN  
AMJ 2018 AND MJJ 2018. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW MEDIAN  
PRECIPITATION ARE INDICATED FOR HAWAII IN MAM 2018, JJA 2018 AND LONGER LEADS.  
 
HILO  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JFM 2018 A60 71.8 0.4 A50 22.0 32.0 44.5  
FMA 2018 A60 71.7 0.4 A40 24.6 34.1 45.5  
MAM 2018 A55 72.0 0.5 EC 22.5 28.4 34.0  
AMJ 2018 A50 72.9 0.5 B40 21.4 23.7 29.0  
MJJ 2018 A45 74.0 0.4 B40 20.2 27.5 29.1  
JJA 2018 A40 75.2 0.4 EC 19.4 27.2 31.4  
JAS 2018 EC 76.1 0.4 EC 25.2 28.6 33.4  
ASO 2018 EC 76.4 0.4 EC 26.1 28.8 33.3  
SON 2018 EC 76.2 0.4 EC 24.3 30.2 40.8  
OND 2018 EC 75.5 0.4 EC 28.3 34.5 42.0  
NDJ 2018 EC 74.2 0.4 EC 26.4 36.6 43.0  
DJF 2019 EC 72.8 0.4 EC 19.6 30.2 33.3  
JFM 2019 EC 71.8 0.4 EC 22.0 32.0 44.5  
\N KAHULUI  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JFM 2018 A60 72.5 0.4 A50 4.2 6.2 8.2  
FMA 2018 A60 72.3 0.4 A40 3.2 4.1 6.4  
MAM 2018 A55 73.0 0.4 EC 2.5 3.5 4.6  
AMJ 2018 A50 74.3 0.5 B40 1.2 1.6 2.2  
MJJ 2018 A45 76.0 0.5 B40 0.7 1.1 1.8  
JJA 2018 A40 77.7 0.4 EC 0.7 1.1 1.5  
JAS 2018 EC 79.0 0.4 EC 0.8 1.1 1.6  
ASO 2018 EC 79.4 0.4 EC 0.8 1.6 2.5  
SON 2018 EC 79.1 0.4 EC 2.1 3.3 4.8  
OND 2018 EC 77.8 0.4 EC 4.2 5.3 8.1  
NDJ 2018 EC 75.9 0.4 EC 5.2 7.6 9.5  
DJF 2019 EC 73.8 0.4 EC 4.6 6.9 8.7  
JFM 2019 EC 72.5 0.4 EC 4.2 6.2 8.2  
\N HONOLULU  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JFM 2018 A60 73.9 0.4 A50 2.1 4.6 7.8  
FMA 2018 A60 73.8 0.4 A40 1.9 3.2 4.7  
MAM 2018 A55 74.8 0.4 EC 1.8 2.6 3.0  
AMJ 2018 A50 76.3 0.4 B40 1.2 1.6 1.8  
MJJ 2018 A45 78.2 0.4 B40 0.8 1.4 1.6  
JJA 2018 A40 79.9 0.4 EC 0.7 0.8 1.3  
JAS 2018 EC 81.3 0.4 EC 1.0 1.4 1.7  
ASO 2018 EC 81.7 0.4 EC 1.6 2.4 3.1  
SON 2018 EC 81.4 0.4 EC 2.5 4.0 5.6  
OND 2018 EC 80.0 0.4 EC 4.4 6.4 8.5  
NDJ 2018 EC 77.7 0.5 EC 3.9 5.6 8.8  
DJF 2019 EC 75.3 0.5 EC 3.7 5.6 8.6  
JFM 2019 EC 73.9 0.4 EC 2.1 4.6 7.8  
\N LIHUE  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JFM 2018 A60 72.2 0.4 A50 6.5 8.8 13.8  
FMA 2018 A60 72.1 0.5 A40 5.8 8.4 9.9  
MAM 2018 A55 72.8 0.5 EC 5.3 6.6 8.0  
AMJ 2018 A50 74.2 0.5 B40 4.7 5.5 6.0  
MJJ 2018 A45 76.0 0.5 B40 4.9 5.4 5.9  
JJA 2018 A40 77.7 0.4 EC 4.4 5.3 6.9  
JAS 2018 EC 79.0 0.3 EC 5.3 6.1 7.8  
ASO 2018 EC 79.4 0.3 EC 6.2 7.9 8.4  
SON 2018 EC 79.1 0.3 EC 9.2 10.0 11.2  
OND 2018 EC 77.8 0.3 EC 9.2 11.7 15.6  
NDJ 2018 EC 75.7 0.3 EC 8.6 12.1 16.9  
DJF 2019 EC 73.6 0.4 EC 7.5 8.4 14.0  
JFM 2019 EC 72.2 0.4 EC 6.5 8.8 13.8  
\NFORECASTER: LUKE HE  
 
ANOMALIES BASED ON 1981-2010 MEANS  
CLARIFICATION: EC INDICATES EQUAL CHANCES THAT THE CLIMATE WILL FALL INTO ANY  
ONE OF THE THREE RANGES OR CATEGORIES WHOSE BOUNDARIES ARE SPECIFIED IN THE  
TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULAR TILT  
OF THE ODDS TOWARD ABOVE-NORMAL OR BELOW-NORMAL CONDITIONS IN THE OUTLOOK. FOR  
EXAMPLE A40 MEANS A 40% CHANCE THAT TEMPERATURE OR PRECIPITATION WILL BE IN THE  
ABOVE CLASS, B40 MEANS A 40% PROBABILITY THAT TEMPERATURE OR PRECIPITATION WILL  
BE IN THE BELOW CLASS, AND N35 MEANS A 35% PROBABILITY THAT TEMPERATURE OR  
PRECIPITATION WILL BE IN THE NEAR-NORMAL CLASS. WHEN EC IS SPECIFIED, ALL  
CATEGORIES ARE EQUALLY LIKELY.  
NOTE - THESE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THEIR VALID  
PERIODS. WITHIN ANY VALID PERIOD OBSERVATIONS AND SHORTER RANGE FORECASTS  
SHOULD BE CONSULTED. ALSO - THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE  
ISSUANCE OF THE NEW SET NEXT MONTH ON THU JAN 18, 2018.  
 

 
 
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