408  
FXHW40 KWBC 201230  
PMDHCO  
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830AM EDT THU APR 20 2017  
 
MONTHLY FORECAST DISCUSSION VALID MAY 2017  
 
SEA SURFACE TEMPERATURE (SST) ANOMALIES SURROUNDING THE HAWAIIAN ISLANDS ARE  
CURRENTLY FROM POSITIVE ONE-HALF DEGREE TO TWO DEGREES. THIS IS WARMER THAN  
LAST MONTH.  
 
FOR JANUARY 2017 THROUGH THE END OF MARCH 2017, RAINFALL TOTAL ACCUMULATIONS  
WERE:  
 
- LIHUE AIRPORT 10.73 INCHES (93 PERCENT OF NORMAL)  
 
- HONOLULU AIRPORT 10.08 INCHES (159 PERCENT OF NORMAL)  
 
- KAHULUI AIRPORT 6.62 INCHES (92 PERCENT OF NORMAL)  
 
- HILO AIRPORT 21.89 INCHES (68 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 NEAR TO ABOVE NORMAL  
SSTS AROUND THE HAWAIIAN ISLANDS. THIS ELEVATES THE CHANCES OF ABOVE-NORMAL  
MONTHLY MEAN AIR TEMPERATURES FOR THE HAWAIIAN ISLANDS IN MAY 2017. EQUAL  
CHANCES (EC) FOR ABOVE, NEAR, OR BELOW MEDIAN PRECIPITATION ARE ALSO INDICATED  
BY MOST DYNAMICAL MODEL FORECASTS FOR HAWAII DURING MAY 2017.  
 
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
HILO A55 74.0 0.5 EC 4.1 7.4 8.7  
KAHULUI A55 75.8 0.6 EC 0.2 0.5 0.8  
HONOLULU A55 78.0 0.6 EC 0.2 0.4 0.8  
LIHUE A55 75.8 0.6 EC 1.3 1.5 2.3  
 
SEASONAL FORECAST DISCUSSION VALID MJJ 2017 - MJJ 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) ARE NEAR AVERAGE IN THE CENTRAL PACIFIC OCEAN, WHILE ABOVE  
AVERAGE SSTS ARE PRESENT IN THE EASTERN PACIFIC OCEAN AND ALONG 20N IN THE  
PACIFIC BASIN. SUBSURFACE (DOWN TO 150 METERS) TEMPERATURES HAVE DECREASED IN  
THE EAST-CENTRAL PACIFIC DURING RECENT WEEKS, WHILE INCREASING NEAR THE DATE  
LINE AND THE COAST OF SOUTH AMERICA. CONVECTION REMAINED ENHANCED OVER MOST OF  
THE MARITIME CONTINENT WHILE BEING SUPPRESSED OVER THE CENTRAL TROPICAL PACIFIC  
AND MUCH OF THE OFF-EQUATORIAL NORTHERN PACIFIC THAT LIES EAST OF THE DATE  
LINE. 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 MJJ 2017 TO ASO 2017 DUE TO PREDICTED ANOMALOUSLY ABOVE-NORMAL SEA SURFACE  
TEMPERATURES ACROSS THE REGION. THE CPC CONSTRUCTED ANALOG (CA) TOOL ALSO  
FAVORS NEAR TO ABOVE NORMAL TEMPERATURES, WITH ODDS INCREASING FROM SOUTH TO  
NORTH, AND ANOMALIES RATHER SMALL IN MAGNITUDE. EQUAL CHANCES (EC) FOR ABOVE,  
NEAR, OR BELOW NORMAL TEMPERATURES ARE ANTICIPATED AT ALL LOCATIONS FOR SON  
2017 AND BEYOND.  
 
THE NMME FAVORS ABOVE MEDIAN PRECIPITATION FOR MUCH THE BOREAL SUMMER. THE CPC  
CONSTRUCTED ANALOG (CA) TOOL FAVORS BELOW MEDIAN RAINFALL FOR EACH OF THE NEXT  
12 SEASONS. THE OUTLOOK FAVORS THE DYNAMICAL GUIDANCE FOR THE FIRST LEAD, IN  
THE REGIONS WHERE THE SIGNAL IS STRONGEST. SOME DYNAMICAL MODELS PREDICT A WARM  
EVENT (EL NINO) BY THE NORTHERN HEMISPHERE AUTUMN, CONTINUING INTO WINTER  
2017-18. 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. THE MIDDLE LEADS REFLECT THE UNCERTAINTY IMPLIED BY THE DISAGREEMENT  
IN THE DYNAMICAL MODELS AND THE CA TOOL. THE LATTER PORTIONS OF THE OUTLOOK  
REFLECT THE CONSISTENCY AMONG THE CA AND IMPLICATIONS OF DYNAMICAL MODEL  
OUTLOOKS FAVORING EL NINO.  
 
HILO  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
MJJ 2017 A60 74.0 0.4 EC 20.2 27.5 29.1  
JJA 2017 A0 75.2 0.4 EC 19.4 27.2 31.4  
JAS 2017 A45 76.1 0.4 EC 25.2 28.6 33.4  
ASO 2017 A45 76.4 0.4 EC 26.1 28.8 33.3  
SON 2017 EC 76.2 0.4 EC 24.3 30.2 40.8  
OND 2017 EC 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  
\N KAHULUI  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
MJJ 2017 A60 76.0 0.5 EC 0.7 1.1 1.8  
JJA 2017 A55 77.7 0.4 EC 0.7 1.1 1.5  
JAS 2017 A45 79.0 0.4 EC 0.8 1.1 1.6  
ASO 2017 A45 79.4 0.4 EC 0.8 1.6 2.5  
SON 2017 EC 79.1 0.4 EC 2.1 3.3 4.8  
OND 2017 EC 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  
\N HONOLULU  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
MJJ 2017 A60 78.2 0.4 A40 0.8 1.4 1.6  
JJA 2017 A55 79.9 0.4 EC 0.7 0.8 1.3  
JAS 2017 A50 81.3 0.4 EC 1.0 1.4 1.7  
ASO 2017 A45 81.7 0.4 EC 1.6 2.4 3.1  
SON 2017 EC 81.4 0.4 EC 2.5 4.0 5.6  
OND 2017 EC 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  
\N LIHUE  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
MJJ 2017 A60 76.0 0.5 A40 4.9 5.4 5.9  
JJA 2017 A60 77.7 0.4 EC 4.4 5.3 6.9  
JAS 2017 A50 79.0 0.3 EC 5.3 6.1 7.8  
ASO 2017 A50 79.4 0.3 EC 6.2 7.9 8.4  
SON 2017 EC 79.1 0.3 EC 9.2 10.0 11.2  
OND 2017 EC 77.8 0.3 EC 9.2 11.7 15.6  
NDJ 2017 EC 75.7 0.3 B4 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  
\NFORECASTER: MATTHEW ROSENCRANS  
 
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 MAY 18, 2017.  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page