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FXHW40 KWBC 161231
PMDHCO
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU APR 16 2026
MONTHLY FORECAST DISCUSSION VALID MAY 2026
SEA SURFACE TEMPERATURE (SST) ANOMALIES IN THE RANGE OF -0.5 TO 0.5 DEGREES
CELSIUS (C) WERE OBSERVED AROUND THE HAWAIIAN ISLANDS (KAUAI, OAHU, MAUI AND
THE BIG ISLAND) DURING THE PREVIOUS WEEK.
FROM JANUARY THROUGH MARCH 2026, RAINFALL TOTAL ACCUMULATIONS WERE:
LIHUE AIRPORT 21.44 INCHES (178 PERCENT OF AVERAGE)
HONOLULU AIRPORT 17.32 INCHES (282 PERCENT OF AVERAGE)
KAHULUI AIRPORT 25.34 INCHES (359 PERCENT OF AVERAGE)
HILO AIRPORT 39.32 INCHES (128 PERCENT OF AVERAGE)
MOST CLIMATE MODELS OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND THE
INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME/C3S) PREDICT POSITIVE SST ANOMALIES
AROUND THE HAWAIIAN ISLANDS IN MAY 2026. BASED ON MODEL SST AND SURFACE AIR
TEMPERATURE FORECASTS, ABOVE NORMAL TEMPERATURES ARE FAVORED FOR KAUAI (LIHUE),
OAHU (HONOLULU), MAUI (KAHULUI), AND THE BIG ISLAND (HILO).
FOR THE MAY 2026 PRECIPITATION OUTLOOK, THE PROBABILITY OF ABOVE NORMAL
PRECIPITATION IS ELEVATED FOR ALL ISLANDS OF HAWAII. THE OUTLOOK IS CONSISTENT
WITH MOST MODELS OF THE NMME AND IMME, AS WELL AS STATISTICAL FORECASTS FROM
THE CONSTRUCTED ANALOG (CA).
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
HILO A50 74.0 0.5 A40 4.1 7.4 8.7
KAHULUI A50 75.8 0.6 A40 0.2 0.5 0.8
HONOLULU A50 78.0 0.6 A40 0.2 0.4 0.8
LIHUE A50 75.8 0.6 A40 1.3 1.5 2.3
SEASONAL FORECAST DISCUSSION VALID MJJ 2026 - MJJ 2027
REFER TO THE PROGNOSTIC DISCUSSION OF THE LONG-LEAD SEASONAL OUTLOOKS FOR THE
CONTIGUOUS U.S. (CONUS) AND ALASKA FOR FURTHER DESCRIPTION OF THE EL NIñO
SOUTHERN OSCILLATION (ENSO) OUTLOOK AND OTHER CLIMATE CONDITIONS RELEVANT TO
THE SEASONAL OUTLOOK. ENSO-NEUTRAL CONDITIONS ARE CURRENTLY PRESENT WITH
EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) NEAR-TO-BELOW AVERAGE IN THE
EAST-CENTRAL PACIFIC OCEAN RELATIVE TO AVERAGE TROPICAL SSTS, WHILE ABOVE
AVERAGE JUST WEST OF THE DATE LINE AND IN THE FAR EASTERN PACIFIC. ABOVE
AVERAGE SUBSURFACE TEMPERATURES EXPANDED ACROSS THE EQUATORIAL PACIFIC OCEAN
AND HAVE REACHED THE SURFACE IN PARTS OF THE WESTERN AND EASTERN PACIFIC. BELOW
AVERAGE SUBSURFACE TEMPERATURES WEAKENED AND DISSIPATED IN THE EASTERN
EQUATORIAL PACIFIC OCEAN. LOW-LEVEL WIND ANOMALIES WERE WESTERLY OVER THE
WESTERN AND CENTRAL EQUATORIAL PACIFIC, AND WERE EASTERLY OVER THE EASTERN
PACIFIC. UPPER-LEVEL WIND ANOMALIES WERE WESTERLY OVER THE EAST-CENTRAL AND
EASTERN PACIFIC. ENHANCED CONVECTION AND PRECIPITATION WERE EVIDENT EAST OF
PAPUA NEW GUINEA, WHILE SUPPRESSED CONVECTION AND PRECIPITATION WERE OBSERVED
OVER WESTERN INDONESIA, THE PHILIPPINES, AND EAST OF THE DATE LINE ALONG THE
EQUATORIAL PACIFIC. ENSO-NEUTRAL CONDITIONS ARE FAVORED WITH A 80% CHANCE
THROUGH APRIL-MAY-JUNE 2026. EL NINO IS LIKELY TO EMERGE IN THE
JUNE-JULY-AUGUST (JJA) SEASON WITH A 62% CHANCE AND PERSIST THROUGH AT LEAST
THE END OF 2026. HISTORICALLY, EL NIñO CONDITIONS FAVOR ABOVE NORMAL
PRECIPITATION FOR HAWAII IN THE BOREAL SUMMER AND EARLY AUTUMN. THE HAWAII
SEASONAL OUTLOOK FOR TEMPERATURE AND PRECIPITATION IS BASED PRIMARILY ON
DYNAMICAL MODEL FORECASTS FROM THE NMME AND STATISTICAL FORECASTS (CCA, CA,
ENSO-OCN, AND OCN). THE IMPACTS OF THE ENSO ON THE TEMPERATURE AND
PRECIPITATION FOR HAWAII WEAKEN IN BOREAL AUTUMN, LEADING TO INCREASED
UNCERTAINTY IN THE HAWAII SEASONAL OUTLOOK FOR TEMPERATURE AND PRECIPITATION IN
THESE SEASONS.
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE PREDICTED IN THE
OUTLOOK FOR LIHUE, HONOLULU, KAHULUI AND HILO BEGINNING IN MAY-JUNE-JULY (MJJ)
AND CONTINUING THROUGH SEPTEMBER-OCTOBER-NOVEMBER (SON) 2026, SUPPORTED BY
NEARLY ALL DYNAMICAL MODEL FORECASTS FROM THE NMME AND C3S, THE CA STATISTICAL
MODEL, AND CONSISTENT WITH DECADAL TIMESCALE TEMPERATURE TRENDS FOR THE REGION.
DUE TO INCREASING UNCERTAINTY IN THE IMPACTS OF ENSO AND WEAKENING SIGNALS IN
FORECAST GUIDANCE AT LONGER LEADS, EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW
NORMAL TEMPERATURES ARE INDICATED FOR HAWAII BEGINNING IN
OCTOBER-NOVEMBER-DECEMBER (OND) 2026 AND EXTENDING THROUGH LONGER LEADS.
ENHANCED PROBABILITIES FOR ABOVE NORMAL PRECIPITATION ARE FORECAST OVER ALL
HAWAIIAN ISLANDS, KAUAI, OAHU, MAUI AND THE BIG ISLAND, FROM JUNE-JULY-AUGUST
(JJA) 2026 TO AUGUST-SEPTEMBER-OCTOBER (ASO) 2026, CONSISTENT WITH MOST
DYNAMICAL MODEL FORECASTS FROM THE NMME AND STATISTICAL FORECASTS, INCLUDING
CCA, CA, ENSO-OCN, AND NMME CONSOLIDATION. DUE TO CONSIDERABLE UNCERTAINTY IN
THE PRECIPITATION FORECASTS FROM DYNAMICAL AND STATISTICAL MODELS AND THE
DECREASE IN FORECAST SIGNAL, EC IS INDICATED OVER THE HAWAIIAN ISLANDS IN MJJ
2026 AND BEGINNING IN SON 2026 AND EXTENDING THROUGH LONGER LEADS.
HILO
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
MJJ 2026 A50 74.0 0.4 EC 20.2 27.5 29.1
JJA 2026 A60 75.2 0.4 A40 19.4 27.2 31.4
JAS 2026 A60 76.1 0.4 A50 25.2 28.6 33.4
ASO 2026 A70 76.4 0.4 A40 26.1 28.8 33.3
SON 2026 A60 76.2 0.4 EC 24.3 30.2 40.8
OND 2026 EC 75.5 0.4 EC 28.3 34.5 42.0
NDJ 2026 EC 74.2 0.4 EC 26.4 36.6 43.0
DJF 2027 EC 72.8 0.4 EC 19.6 30.2 33.3
JFM 2027 EC 71.8 0.4 EC 22.0 32.0 44.5
FMA 2027 EC 71.7 0.4 EC 24.6 34.1 45.5
MAM 2027 EC 72.0 0.5 EC 22.5 28.4 34.0
AMJ 2027 EC 72.9 0.5 EC 21.4 23.7 29.0
MJJ 2027 EC 74.0 0.4 EC 20.2 27.5 29.1
KAHULUI
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
MJJ 2026 A50 76.0 0.5 EC 0.7 1.1 1.8
JJA 2026 A60 77.7 0.4 A40 0.7 1.1 1.5
JAS 2026 A60 79.0 0.4 A50 0.8 1.1 1.6
ASO 2026 A70 79.4 0.4 A40 0.8 1.6 2.5
SON 2026 A60 79.1 0.4 EC 2.1 3.3 4.8
OND 2026 EC 77.8 0.4 EC 4.2 5.3 8.1
NDJ 2026 EC 75.9 0.4 EC 5.2 7.6 9.5
DJF 2027 EC 73.8 0.4 EC 4.6 6.9 8.7
JFM 2027 EC 72.5 0.4 EC 4.2 6.2 8.2
FMA 2027 EC 72.3 0.4 EC 3.2 4.1 6.4
MAM 2027 EC 73.0 0.4 EC 2.5 3.5 4.6
AMJ 2027 EC 74.3 0.5 EC 1.2 1.6 2.2
MJJ 2027 EC 76.0 0.5 EC 0.7 1.1 1.8
HONOLULU
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
MJJ 2026 A50 78.2 0.4 EC 0.8 1.4 1.6
JJA 2026 A60 79.9 0.4 A40 0.7 0.8 1.3
JAS 2026 A60 81.3 0.4 A50 1.0 1.4 1.7
ASO 2026 A70 81.7 0.4 A40 1.6 2.4 3.1
SON 2026 A60 81.4 0.4 EC 2.5 4.0 5.6
OND 2026 EC 80.0 0.4 EC 4.4 6.4 8.5
NDJ 2026 EC 77.7 0.5 EC 3.9 5.6 8.8
DJF 2027 EC 75.3 0.5 EC 3.7 5.6 8.6
JFM 2027 EC 73.9 0.4 EC 2.1 4.6 7.8
FMA 2027 EC 73.8 0.4 EC 1.9 3.2 4.7
MAM 2027 EC 74.8 0.4 EC 1.8 2.6 3.0
AMJ 2027 EC 76.3 0.4 EC 1.2 1.6 1.8
MJJ 2027 EC 78.2 0.4 EC 0.8 1.4 1.6
LIHUE
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
MJJ 2026 A50 76.0 0.5 EC 4.9 5.4 5.9
JJA 2026 A60 77.7 0.4 A40 4.4 5.3 6.9
JAS 2026 A60 79.0 0.3 A50 5.3 6.1 7.8
ASO 2026 A70 79.4 0.3 A40 6.2 7.9 8.4
SON 2026 A60 79.1 0.3 EC 9.2 10.0 11.2
OND 2026 EC 77.8 0.3 EC 9.2 11.7 15.6
NDJ 2026 EC 75.7 0.3 EC 8.6 12.1 16.9
DJF 2027 EC 73.6 0.4 EC 7.5 8.4 14.0
JFM 2027 EC 72.2 0.4 EC 6.5 8.8 13.8
FMA 2027 EC 72.1 0.5 EC 5.8 8.4 9.9
MAM 2027 EC 72.8 0.5 EC 5.3 6.6 8.0
AMJ 2027 EC 74.2 0.5 EC 4.7 5.5 6.0
MJJ 2027 EC 76.0 0.5 EC 4.9 5.4 5.9
FORECASTER: LUKE HE
ANOMALIES ARE BASED ON THE 1991-2020 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 MAY 21, 2026.
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