243  
FXHW40 KWBC 211231  
PMDHCO  
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS  
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD  
830AM EDT THU MAY 21 2020  
 
MONTHLY FORECAST DISCUSSION VALID JUNE 2020  
 
POSITIVE SEA SURFACE TEMPERATURE (SST) ANOMALIES FROM ABOUT POSITIVE ONE HALF  
TO ONE DEGREE CELSIUS ARE SURROUNDING THE HAWAIIAN ISLANDS DURING THE PREVIOUS  
WEEK.  
 
FOR JANUARY THROUGH APRIL 2020, RAINFALL TOTAL ACCUMULATIONS WERE:  
 
- LIHUE AIRPORT 21.57 INCHES (157 PERCENT OF NORMAL)  
 
- HONOLULU AIRPORT 8.33 INCHES (120 PERCENT OF NORMAL)  
 
- KAHULUI AIRPORT 9.38 INCHES (107 PERCENT OF NORMAL)  
 
- HILO AIRPORT 57.21 INCHES (131 PERCENT OF NORMAL)  
 
THE NCEP CLIMATE FORECAST SYSTEM (CFS) AND OTHER CLIMATE MODELS OF THE NORTH  
AMERICAN MULTI-MODEL ENSEMBLE (NMME) PREDICT ABOVE NORMAL SSTS AROUND THE  
HAWAIIAN ISLANDS FOR JUNE 2020. THIS ELEVATES THE CHANCES OF ABOVE NORMAL  
MONTHLY MEAN AIR TEMPERATURES FOR HAWAII IN JUNE 2020. MOST DYNAMICAL MODELS  
FROM THE NMME INDICATE EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL  
PRECIPITATION OVER THE HAWAIIAN ISLANDS DURING JUNE 2020.  
 
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
HILO A60 75.4 0.4 EC 5.3 6.3 8.7  
KAHULUI A65 78.0 0.5 EC 0.1 0.1 0.2  
HONOLULU A70 80.3 0.4 EC 0.1 0.2 0.3  
LIHUE A70 78.1 0.4 EC 1.1 1.3 1.6  
 
SEASONAL FORECAST DISCUSSION VALID JJA 2020 - JJA 2021  
 
REFER TO THE PROGNOSTIC DISCUSSION OF THE LONG-LEAD SEASONAL OUTLOOKS FOR THE  
CONUS AND ALASKA FOR A DESCRIPTION OF THE ENSO OUTLOOK AND OTHER CLIMATE  
CONDITIONS RELEVANT TO THE SEASONAL OUTLOOK, 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 ABOVE AVERAGE ACROSS MOST OF THE WESTERN PACIFIC OCEAN  
AND NEAR AVERAGE ACROSS MOST OF THE EASTERN PACIFIC OCEAN. NEGATIVE SUBSURFACE  
TEMPERATURE ANOMALIES STRENGTHENED AND HAVE SHIFTED FROM THE WESTERN TO EASTERN  
PACIFIC OCEAN, WHILE POSITIVE SUBSURFACE TEMPERATURES ANOMALIES HAVE MOSTLY  
DISSIPATED. TROPICAL CONVECTION IS SUPPRESSED OVER THE DATE LINE AND AROUND  
INDONESIA. LOW-LEVEL WIND ANOMALIES WERE EASTERLY IN THE EAST-CENTRAL PACIFIC,  
AND UPPER-LEVEL WIND ANOMALIES WERE WESTERLY OVER THE CENTRAL AND EASTERN  
PORTIONS OF THE BASIN. THE TROPICAL ATMOSPHERIC CIRCULATION IS GENERALLY  
CONSISTENT WITH ENSO-NEUTRAL. ENSO-NEUTRAL IS LIKELY TO CONTINUE THROUGH  
NORTHERN HEMISPHERE SUMMER 2020 WITH PROBABILITIES ABOUT 65 PERCENT AND THROUGH  
AUTUMN 2020 WITH PROBABILITIES ABOUT 45 TO 50 PERCENT.  
 
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED ACROSS THE  
HAWAIIAN ISLANDS IN THE OUTLOOK FROM JJA 2020 TO OND 2020, DUE TO PREDICTED  
PERSISTENCE OF ABOVE NORMAL SEA SURFACE TEMPERATURES IN THE NMME DYNAMICAL  
MODEL FORECASTS, AND SUPPORTED BY STATISTICAL MODELS INCLUDING THE CONSTRUCTED  
ANALOG (CA) AND OPTIMAL CLIMATE NORMALS (OCN) THROUGH NDJ 2020. THE SIGNAL  
WEAKENS AT LONGER LEADS, THEREFORE EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW  
NORMAL TEMPERATURES ARE INDICATED FOR HAWAII IN DJF 2021 AND THEREAFTER.  
 
NOW HAWAII IS INTO A DRY SEASON. THE NMME AND THE CONSOLIDATION OF DYNAMICAL  
AND STATISTICAL TOOLS ALSO FAVOR BELOW NORMAL PRECIPITATION FROM JJA 2020  
THROUGH SON 2020 OVER ALL HAWAIIAN ISLANDS, THOUGH SOME STATISTICAL TOOLS SUCH  
AS THE CA INDICATE ABOVE NORMAL IS MORE LIKELY FOR HAWAII DURING THIS PERIOD.  
THERE IS CONSIDERABLE UNCERTAINTY IN THE PRECIPITATION FORECASTS AMONG  
AVAILABLE DYNAMICAL AND STATISTICAL TOOLS OVER THE HAWAIIAN ISLANDS IN OND 2020  
AND LONGER LEADS, SO EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL  
PRECIPITATION ARE INDICATED.  
 
HILO  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2020 A65 75.2 0.4 B60 19.4 27.2 31.4  
JAS 2020 A60 76.1 0.4 B50 25.2 28.6 33.4  
ASO 2020 A55 76.4 0.4 B45 26.1 28.8 33.3  
SON 2020 A50 76.2 0.4 B40 24.3 30.2 40.8  
OND 2020 A45 75.5 0.4 EC 28.3 34.5 42.0  
NDJ 2020 A40 74.2 0.4 EC 26.4 36.6 43.0  
DJF 2021 EC 72.8 0.4 EC 19.6 30.2 33.3  
JFM 2021 EC 71.8 0.4 EC 22.0 32.0 44.5  
FMA 2021 EC 71.7 0.4 EC 24.6 34.1 45.5  
MAM 2021 EC 72.0 0.5 EC 22.5 28.4 34.0  
AMJ 2021 EC 72.9 0.5 EC 21.4 23.7 29.0  
MJJ 2021 EC 74.0 0.4 EC 20.2 27.5 29.1  
JJA 2021 EC 75.2 0.4 EC 19.4 27.2 31.4  
KAHULUI  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2020 A65 77.7 0.4 B60 0.7 1.1 1.5  
JAS 2020 A60 79.0 0.4 B50 0.8 1.1 1.6  
ASO 2020 A55 79.4 0.4 B45 0.8 1.6 2.5  
SON 2020 A50 79.1 0.4 B40 2.1 3.3 4.8  
OND 2020 A45 77.8 0.4 EC 4.2 5.3 8.1  
NDJ 2020 A40 75.9 0.4 EC 5.2 7.6 9.5  
DJF 2021 EC 73.8 0.4 EC 4.6 6.9 8.7  
JFM 2021 EC 72.5 0.4 EC 4.2 6.2 8.2  
FMA 2021 EC 72.3 0.4 EC 3.2 4.1 6.4  
MAM 2021 EC 73.0 0.4 EC 2.5 3.5 4.6  
AMJ 2021 EC 74.3 0.5 EC 1.2 1.6 2.2  
MJJ 2021 EC 76.0 0.5 EC 0.7 1.1 1.8  
JJA 2021 EC 77.7 0.4 EC 0.7 1.1 1.5  
HONOLULU  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2020 A65 79.9 0.4 B60 0.7 0.8 1.3  
JAS 2020 A60 81.3 0.4 B50 1.0 1.4 1.7  
ASO 2020 A55 81.7 0.4 B45 1.6 2.4 3.1  
SON 2020 A50 81.4 0.4 B40 2.5 4.0 5.6  
OND 2020 A45 80.0 0.4 EC 4.4 6.4 8.5  
NDJ 2020 A40 77.7 0.5 EC 3.9 5.6 8.8  
DJF 2021 EC 75.3 0.5 EC 3.7 5.6 8.6  
JFM 2021 EC 73.9 0.4 EC 2.1 4.6 7.8  
FMA 2021 EC 73.8 0.4 EC 1.9 3.2 4.7  
MAM 2021 EC 74.8 0.4 EC 1.8 2.6 3.0  
AMJ 2021 EC 76.3 0.4 EC 1.2 1.6 1.8  
MJJ 2021 EC 78.2 0.4 EC 0.8 1.4 1.6  
JJA 2021 EC 79.9 0.4 EC 0.7 0.8 1.3  
LIHUE  
TEMPERATURE PRECIPITATION  
FCST AVE LIM FCST BLW MEDIAN ABV  
JJA 2020 A65 77.7 0.4 B60 4.4 5.3 6.9  
JAS 2020 A60 79.0 0.3 B50 5.3 6.1 7.8  
ASO 2020 A55 79.4 0.3 B45 6.2 7.9 8.4  
SON 2020 A50 79.1 0.3 B40 9.2 10.0 11.2  
OND 2020 A45 77.8 0.3 EC 9.2 11.7 15.6  
NDJ 2020 A40 75.7 0.3 EC 8.6 12.1 16.9  
DJF 2021 EC 73.6 0.4 EC 7.5 8.4 14.0  
JFM 2021 EC 72.2 0.4 EC 6.5 8.8 13.8  
FMA 2021 EC 72.1 0.5 EC 5.8 8.4 9.9  
MAM 2021 EC 72.8 0.5 EC 5.3 6.6 8.0  
AMJ 2021 EC 74.2 0.5 EC 4.7 5.5 6.0  
MJJ 2021 EC 76.0 0.5 EC 4.9 5.4 5.9  
JJA 2021 EC 77.7 0.4 EC 4.4 5.3 6.9  
FORECASTER: LUKE HE  
 
ANOMALIES ARE BASED ON THE 1981-2010 MEANS.  
 
CLARIFICATION: EC INDICATED EQUAL CHANCES THAT THE PREDICTED PARAMETER WILL  
FALL INTO ANY ONE OF THE THREE CATEGORIES, WHOSE BOUNDARIES ARE SPECIFIC IN THE  
TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULATE TILT  
OF THE ODDS TOWARD ABOVE NORMAL OR BELOW NORMAL CONDITIONS IN THE OUTLOOK. FOR  
EXAMPLE A40 MEANS A 40% CHANCE THAT THE AVERAGE TEMPERATURE OR TOTAL  
PRECIPITATION WILL BE IN THE ABOVE NORMAL CLASS, B40 MEANS A 40% CHANCE THAT  
THE AVERAGE TEMPERATURE OR TOTAL PRECIPITATION WILL BE IN THE BELOW NORMAL  
CLASS, AND N35 MEANS A 35% PROBABILITY THAT THE AVERAGE TEMPERATURE OR TOTAL  
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 THE VALID  
PERIODS. WITHIN ANY VALID PERIOD, OBSERVATIONS AND SHORTER RANGE FORECASTS  
SHOULD BE CONSULTED. ALSO, THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE  
ISSUANCES OF THE NEW SET NET MONTH, ON THU JUN 18, 2020.  
 

 
 
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