240  
FXHW40 KWBC 201230  
PMDHCO  
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830AM EDT THU JUL 20 2017  
 
MONTHLY FORECAST DISCUSSION VALID AUGUST 2017  
 
SEA SURFACE TEMPERATURE (SST) ANOMALIES SURROUNDING THE HAWAIIAN ISLANDS ARE  
 
CURRENTLY BETWEEN ZERO DEGREE TO POSITIVE TWO DEGREE C, WITH HIGHER ANOMALIES  
NEAR THE NORTHWEST ISLANDS.  
 
FOR JANUARY 2017 THROUGH THE END OF JUNE 2017, RAINFALL TOTAL ACCUMULATIONS  
WERE:  
 
- LIHUE AIRPORT 15.45 INCHES (89 PERCENT OF NORMAL)  
 
- HONOLULU AIRPORT 14.02 INCHES (179 PERCENT OF NORMAL)  
 
- KAHULUI AIRPORT 14.59 INCHES (150 PERCENT OF NORMAL)  
 
- HILO AIRPORT 37.60 INCHES (63 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 AUGUST 2017. EQUAL CHANCES  
(EC) FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION ARE ALSO INDICATED BY MOST  
DYNAMICAL MODEL FORECASTS FOR HAWAII DURING AUGUST 2017.  
 
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
HILO A60 76.6 0.4 EC 7.6 8.4 10.3  
KAHULUI A60 79.8 0.4 EC 0.3 0.5 0.6  
HONOLULU A60 82.1 0.4 EC 0.1 0.2 0.4  
LIHUE A60 79.7 0.4 EC 1.4 1.8 2.5  
 
SEASONAL FORECAST DISCUSSION VALID ASO 2017 - ASO 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 ABOVE-AVERAGE ACROSS THE WESTERN TO EAST-CENTRAL  
PACIFIC, WHILE NEAR-AVERAGE SSTS WERE MEASURED IN THE EASTERN PACIFIC. POSITIVE  
SUBSURFACE TEMPERATURE ANOMALIES HAVE EXPANDED JUST BELOW THE SURFACE NEAR140 W  
AND CONTINUE TO PERSIST ACROSS MOST OF THE EQUATORIAL PACIFIC. ATMOSPHERIC  
CONVECTION ANOMALIES WERE SUPPRESSED OVER THE WEST-CENTRAL TROPICAL PACIFIC,  
WHILE THE LOWER-LEVEL AND UPPER-LEVEL WINDS WERE NEAR AVERAGE OVER MOST OF THE  
TROPICAL PACIFIC OCEAN. THE NCEP CFSV2 AND MOST OF THE MODELS FROM THE LATEST  
RUNS OF THE NMME ARE NOW FAVORING THE CONTINUATION OF ENSO-NEUTRAL THROUGH THE  
REMAINDER OF 2017. IN THE OFFICIAL OUTLOOK, ENSO-NEUTRAL IS FAVORED (ABOUT 50  
TO 55% CHANCE) THROUGH THE NORTHERN HEMISPHERE WINTER 2017-18.  
 
ENHANCED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INDICATED FOR HAWAII  
FROM ASO 2017 TO DJF 2018 DUE TO PREDICTED ANOMALOUSLY ABOVE-NORMAL SEA SURFACE  
TEMPERATURES ACROSS THE REGION. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW  
NORMAL TEMPERATURES ARE ANTICIPATED AT ALL LOCATIONS FOR JFM 2018 AND BEYOND.  
 
THERE IS HIGH UNCERTAINTY WITH THE PRECIPITATION FORECAST FOR HAWAII FROM ASO  
TO NDJ 2017. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION  
ARE INDICATED BY MOST DYNAMICAL MODEL FORECASTS AND NMME FOR HAWAII FROM ASO TO  
NDJ 2017. CPC CONSTRUCTED ANALOG (CA) TOOL FAVORS BELOW MEDIAN PRECIPITATION  
FOR LIHUE , HONOLULU, KAHULUI FOR THE INCOMING WINTER SEASONS FROM DJF TO JFM  
2018. EQUAL CHANCES (EC) FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION ARE  
FORECAST FOR HAWAII IN FMA 2018 AND LONGER LEADS.  
 
HILO  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
ASO 2017 A65 76.4 0.4 EC 26.1 28.8 33.3  
SON 2017 A60 76.2 0.4 EC 24.3 30.2 40.8  
OND 2017 A60 75.5 0.4 EC 28.3 34.5 42.0  
NDJ 2017 A55 74.2 0.4 EC 26.4 36.6 43.0  
DJF 2018 A45 72.8 0.4 EC 19.6 30.2 33.3  
JFM 2018 EC 71.8 0.4 EC 22.0 32.0 44.5  
FMA 2018 EC 71.7 0.4 EC 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  
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  
\N KAHULUI  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
ASO 2017 A65 79.4 0.4 EC 0.8 1.6 2.5  
SON 2017 A60 79.1 0.4 EC 2.1 3.3 4.8  
OND 2017 A60 77.8 0.4 EC 4.2 5.3 8.1  
NDJ 2017 A55 75.9 0.4 EC 5.2 7.6 9.5  
DJF 2018 A45 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 EC 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  
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  
\N HONOLULU  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
ASO 2017 A70 81.7 0.4 EC 1.6 2.4 3.1  
SON 2017 A65 81.4 0.4 EC 2.5 4.0 5.6  
OND 2017 A60 80.0 0.4 EC 4.4 6.4 8.5  
NDJ 2017 A55 77.7 0.5 EC 3.9 5.6 8.8  
DJF 2018 A45 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 EC 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  
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  
\N LIHUE  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
ASO 2017 A70 79.4 0.3 EC 6.2 7.9 8.4  
SON 2017 A65 79.1 0.3 EC 9.2 10.0 11.2  
OND 2017 A65 77.8 0.3 EC 9.2 11.7 15.6  
NDJ 2017 A60 75.7 0.3 EC 8.6 12.1 16.9  
DJF 2018 A50 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 EC 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  
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  
\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 AUG 17, 2017.  
 

 
 
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