871  
FXHW40 KWBC 181230  
PMDHCO  
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830AM EDT THU MAY 18 2017  
 
MONTHLY FORECAST DISCUSSION VALID JUNE 2017  
 
SEA SURFACE TEMPERATURE (SST) ANOMALIES SURROUNDING THE HAWAIIAN ISLANDS ARE  
CURRENTLY FROM POSITIVE ONE-HALF DEGREE TO TWO DEGREES.  
 
FOR JANUARY 2017 THROUGH THE END OF APRIL 2017, RAINFALL TOTAL ACCUMULATIONS  
WERE:  
 
- LIHUE AIRPORT 13.12 INCHES (95 PERCENT OF NORMAL)  
 
- HONOLULU AIRPORT 13.13 INCHES (189 PERCENT OF NORMAL)  
 
- KAHULUI AIRPORT 14.39 INCHES (164 PERCENT OF NORMAL)  
 
- HILO AIRPORT 26.97 INCHES (62 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) PREDICT ABOVE NORMAL SSTS  
AROUND THE HAWAIIAN ISLANDS. THIS ELEVATES THE CHANCES OF ABOVE-NORMAL MONTHLY  
MEAN AIR TEMPERATURES FOR THE HAWAIIAN ISLANDS IN JUNE 2017. EQUAL CHANCES (EC)  
FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION ARE ALSO INDICATED BY MOST  
DYNAMICAL MODEL FORECASTS FOR HAWAII DURING JUNE 2017.  
 
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
HILO A60 75.4 0.4 EC 5.3 6.3 8.7  
KAHULUI A60 78.0 0.5 EC 0.1 0.1 0.2  
HONOLULU A60 80.3 0.4 EC 0.1 0.2 0.3  
LIHUE A60 78.1 0.4 EC 1.1 1.3 1.6  
 
SEASONAL FORECAST DISCUSSION VALID JJA 2017 - JJA 2018  
 
REFER TO THE PROGNOSTIC DISCUSSION ON LONG-LEAD SEASONAL OUTLOOKS FOR THE CONUS  
AND ALASKA, AND DISCUSSION OF THE FORECASTS OF EQUATORIAL PACIFIC SSTS, FOR THE  
GENERAL BACKGROUND FOR THE SEASONAL FORECAST, INCLUDING DETAILS ON THE CURRENT  
STATE OF THE ATMOSPHERE AND OCEAN. ENSO-NEUTRAL CONDITIONS CURRENTLY ARE  
PRESENT ACROSS THE EQUATORIAL PACIFIC OCEAN. EQUATORIAL SEA SURFACE  
TEMPERATURES (SSTS) WERE NEAR AVERAGE NEAR THE INTERNATIONAL DATE LINE, WHILE  
ABOVE AVERAGE SSTS WERE MEASURED ACROSS THE EASTERN PACIFIC OCEAN. POSITIVE  
SUBSURFACE TEMPERATURE ANOMALIES STRENGTHENED IN THE WESTERN AND CENTRAL  
PACIFIC OCEAN AND WEAKENED IN THE EASTERN PACIFIC. ATMOSPHERIC CONVECTION  
ANOMALIES WERE WEAK OVER THE CENTRAL TROPICAL PACIFIC AND MARITIME CONTINENT,  
WHILE THE LOWER-LEVEL AND UPPER-LEVEL WINDS WERE NEAR AVERAGE OVER MOST OF THE  
TROPICAL PACIFIC. ENSO-NEUTRAL CONDITIONS ARE FAVORED TO CONTINUE THROUGH AT  
LEAST THE NORTHERN HEMISPHERE SPRING 2017, WITH INCREASING CHANCES FOR EL NINO  
DEVELOPMENT BY LATE SUMMER AND FALL.  
 
ENHANCED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR HAWAII  
FROM JJA 2017 TO OND 2017 DUE TO PREDICTED ANOMALOUSLY ABOVE-NORMAL SEA SURFACE  
TEMPERATURES ACROSS THE REGION, WHICH IS ALSO CONSISTENT WITH CPC'S STATISTICAL  
TOOL (CONSTRUCTED ANALOG). EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW NORMAL  
TEMPERATURES ARE ANTICIPATED AT ALL LOCATIONS FOR NDJ 2017 AND BEYOND.  
 
FOR JJA SEASON, THE NMME FAVORS ABOVE MEDIAN PRECIPITATION FOR HAWAII, WHILE  
THE CPC CONSTRUCTED ANALOG (CA) TOOL PREDICTS ABOVE MEDIAN PRECIPITATION FOR  
THE NORTHWESTERN ISLANDS AND BELOW MEDIAN PRECIPITATION FOR THE SOUTHEASTERN  
ISLANDS. HENCE ABOVE MEDIAN PREDICTION IS FORECAST FOR LIHUE AND HONOLULU,  
WHILE EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW NORMAL PRECIPITATION IS  
INDICATED AT HILO AND KAHULUI IN JJA 2017. THE CA ALSO FAVORS BELOW MEDIAN  
RAINFALL FOR THE INCOMING WINTER SEASON. MOST DYNAMICAL MODELS PREDICT A WARM  
EVENT (EL NINO) BY THE NORTHERN HEMISPHERE SUMMER. IF CORRECT, HISTORICAL EL  
NINO COMPOSITES FAVOR INCREASED ODDS FOR DRY CONDITIONS FOR HAWAII IN WINTER,  
WHICH IS CONSISTENT WITH THE FORECAST FROM THE CA TOOL. THERE IS HIGH  
UNCERTAINTY WITH THE PRECIPITATION FORECAST FOR THE REGION FROM JAS TO OND  
2017, AND IN MAM 2018 AND BEYOND.  
 
HILO  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2017 A70 75.2 0.4 EC 19.4 27.2 31.4  
JAS 2017 A65 76.1 0.4 EC 25.2 28.6 33.4  
ASO 2017 A60 76.4 0.4 EC 26.1 28.8 33.3  
SON 2017 A55 76.2 0.4 EC 24.3 30.2 40.8  
OND 2017 A45 75.5 0.4 EC 28.3 34.5 42.0  
NDJ 2017 EC 74.2 0.4 B40 26.4 36.6 43.0  
DJF 2018 EC 72.8 0.4 B40 19.6 30.2 33.3  
JFM 2018 EC 71.8 0.4 B40 22.0 32.0 44.5  
FMA 2018 EC 71.7 0.4 B40 24.6 34.1 45.5  
MAM 2018 EC 72.0 0.5 EC 22.5 28.4 34.0  
AMJ 2018 EC 72.9 0.5 EC 21.4 23.7 29.0  
MJJ 2018 EC 74.0 0.4 EC 20.2 27.5 29.1  
JJA 2018 EC 75.2 0.4 EC 19.4 27.2 31.4  
\N KAHULUI  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2017 A70 77.7 0.4 EC 0.7 1.1 1.5  
JAS 2017 A65 79.0 0.4 EC 0.8 1.1 1.6  
ASO 2017 A60 79.4 0.4 EC 0.8 1.6 2.5  
SON 2017 A55 79.1 0.4 EC 2.1 3.3 4.8  
OND 2017 A45 77.8 0.4 EC 4.2 5.3 8.1  
NDJ 2017 EC 75.9 0.4 B40 5.2 7.6 9.5  
DJF 2018 EC 73.8 0.4 B40 4.6 6.9 8.7  
JFM 2018 EC 72.5 0.4 B40 4.2 6.2 8.2  
FMA 2018 EC 72.3 0.4 B40 3.2 4.1 6.4  
MAM 2018 EC 73.0 0.4 EC 2.5 3.5 4.6  
AMJ 2018 EC 74.3 0.5 EC 1.2 1.6 2.2  
MJJ 2018 EC 76.0 0.5 EC 0.7 1.1 1.8  
JJA 2018 EC 77.7 0.4 EC 0.7 1.1 1.5  
\N HONOLULU  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2017 A70 79.9 0.4 A50 0.7 0.8 1.3  
JAS 2017 A65 81.3 0.4 EC 1.0 1.4 1.7  
ASO 2017 A60 81.7 0.4 EC 1.6 2.4 3.1  
SON 2017 A55 81.4 0.4 EC 2.5 4.0 5.6  
OND 2017 A45 80.0 0.4 EC 4.4 6.4 8.5  
NDJ 2017 EC 77.7 0.5 B40 3.9 5.6 8.8  
DJF 2018 EC 75.3 0.5 B40 3.7 5.6 8.6  
JFM 2018 EC 73.9 0.4 B40 2.1 4.6 7.8  
FMA 2018 EC 73.8 0.4 B40 1.9 3.2 4.7  
MAM 2018 EC 74.8 0.4 EC 1.8 2.6 3.0  
AMJ 2018 EC 76.3 0.4 EC 1.2 1.6 1.8  
MJJ 2018 EC 78.2 0.4 EC 0.8 1.4 1.6  
JJA 2018 EC 79.9 0.4 EC 0.7 0.8 1.3  
\N LIHUE  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2017 A70 77.7 0.4 A50 4.4 5.3 6.9  
JAS 2017 A70 79.0 0.3 EC 5.3 6.1 7.8  
ASO 2017 A65 79.4 0.3 EC 6.2 7.9 8.4  
SON 2017 A60 79.1 0.3 EC 9.2 10.0 11.2  
OND 2017 A50 77.8 0.3 EC 9.2 11.7 15.6  
NDJ 2017 EC 75.7 0.3 B40 8.6 12.1 16.9  
DJF 2018 EC 73.6 0.4 B40 7.5 8.4 14.0  
JFM 2018 EC 72.2 0.4 B40 6.5 8.8 13.8  
FMA 2018 EC 72.1 0.5 B40 5.8 8.4 9.9  
MAM 2018 EC 72.8 0.5 EC 5.3 6.6 8.0  
AMJ 2018 EC 74.2 0.5 EC 4.7 5.5 6.0  
MJJ 2018 EC 76.0 0.5 EC 4.9 5.4 5.9  
JJA 2018 EC 77.7 0.4 EC 4.4 5.3 6.9  
\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 JUN 15, 2017.  
 

 
 
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