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FXHW40 KWBC 171230
PMDHCO
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU JUL 17 2025
MONTHLY FORECAST DISCUSSION VALID AUGUST 2025
SEA-SURFACE TEMPERATURE (SST) ANOMALIES IN THE RANGE OF 0.0 TO +1.0 DEGREES
CELSIUS (C) WERE OBSERVED AROUND THE HAWAIIAN ISLANDS (KAUAI, OAHU, MAUI AND
THE BIG ISLAND) DURING THE PREVIOUS WEEK.
FROM JANUARY THROUGH JUNE 2025, RAINFALL TOTAL ACCUMULATIONS WERE:
LIHUE AIRPORT 10.19 INCHES (57 PERCENT OF AVERAGE)
HONOLULU AIRPORT 8.89 INCHES (108 PERCENT OF AVERAGE)
KAHULUI AIRPORT 6.44 INCHES (70 PERCENT OF AVERAGE)
HILO AIRPORT 30.14 INCHES (55 PERCENT OF AVERAGE)
MOST CLIMATE MODELS OF THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND THE
INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME/C3S) PREDICT ABOVE AVERAGE SSTS AROUND
KAUAI, OAHU, AND MAUI THROUGH AUGUST 2025 AND NEAR AVERAGE SSTS FOR THE BIG
ISLAND THROUGH AUGUST 2025. BASED PRIMARILY ON THESE SST FORECASTS, SURFACE
TEMPERATURES ARE ALSO FAVORED TO BE RELATIVELY WARM COMPARED TO NORMAL FOR
KAUAI, OAHU AND MAUI, WHILE EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL
TEMPERATURES ARE FORECAST FOR THE BIG ISLAND IN AUGUST 2025. FOR THE AUGUST
2025 PRECIPITATION OUTLOOK, BELOW NORMAL PRECIPITATION CHANCES ARE ELEVATED FOR
ALL OF THE ISLAND CHAIN, AS INDICATED BY MOST DYNAMICAL MODEL FORECASTS.
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
HILO EC 76.6 0.4 B55 7.6 8.4 10.3
KAHULUI A45 79.8 0.4 B50 0.3 0.5 0.6
HONOLULU A50 82.1 0.4 B45 0.1 0.2 0.4
LIHUE A50 79.7 0.4 B40 1.4 1.8 2.5
SEASONAL FORECAST DISCUSSION VALID ASO 2025 - ASO 2026
REFER TO THE PROGNOSTIC DISCUSSION OF THE LONG-LEAD SEASONAL OUTLOOKS FOR THE
CONTIGUOUS U.S. (CONUS) AND ALASKA FOR A DESCRIPTION OF THE EL NINO SOUTHERN
OSCILLATION (ENSO) OUTLOOK AND OTHER CLIMATE CONDITIONS RELEVANT TO THE
SEASONAL OUTLOOK. ENSO-NEUTRAL CONDITIONS ARE OBSERVED OVER THE TROPICAL
PACIFIC OCEAN. EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) ARE NEAR AVERAGE
ACROSS MOST OF THE PACIFIC OCEAN. OVER THE LAST COUPLE OF MONTHS, ABOVE-AVERAGE
SUBSURFACE TEMPERATURES HAVE EXTENDED ACROSS MOST OF THE EQUATORIAL PACIFIC
OCEAN. A SMALL REGION OF BELOW-AVERAGE SUBSURFACE TEMPERATURES HAS PERSISTED AT
DEPTH IN THE FAR EASTERN PACIFIC OCEAN. ENHANCED CONVECTION AND PRECIPITATION
WAS EVIDENT AROUND INDONESIA. LOW-LEVEL WIND ANOMALIES WERE EASTERLY OVER THE
EAST-CENTRAL AND EASTERN PACIFIC, WHILE UPPER-LEVEL WIND ANOMALIES WERE
WESTERLY OVER THE EASTERN EQUATORIAL PACIFIC. ENSO-NEUTRAL CONDITIONS ARE
FORECAST IN THE CPC ENSO OUTLOOK THROUGH THE LATE NORTHERN HEMISPHERE SUMMER
2025 WITH A 56% CHANCE IN AUGUST-OCTOBER. CHANCES OF LA NINA CONDITIONS
INCREASE INTO THE FALL AND WINTER 2025-26. DEVELOPMENT OF LA NINA WOULD ALTER
THE PROBABILITIES OF PRECIPITATION FOR THE HAWAIIAN ISLANDS, ESPECIALLY IN
BOREAL WINTER, BUT THE STATE OF ENSO AT LONGER LEAD TIMES IS SOMEWHAT UNCERTAIN
AS OF LATE SPRING 2025.
ENHANCED PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE INDICATED IN THE
OFFICIAL OUTLOOK FOR LIHUE, HONOLULU, AND KAHULUI FROM ASO
(AUGUST-SEPTEMBER-OCTOBER) 2025 THROUGH DECEMBER-JANUARY-FEBRUARY (DJF)
2025-26, FAVORED BY MOST NMME AND AVAILABLE C3S DYNAMICAL MODELS AND DECADAL
TEMPERATURE TRENDS. MOST MODEL GUIDANCE SUPPORTS EQUAL CHANCES (EC) OF ABOVE,
NEAR, AND BELOW NORMAL SEASONAL MEAN TEMPERATURES FOR THE BIG ISLAND THROUGH
SEPTEMBER-OCTOBER-NOVEMBER (SON) 2025, THOUGH A SUBSTANTIAL NUMBER OF MODELS
SUPPORT A WEAK TILT TOWARDS ABOVE NORMAL TEMPERATURES. BY
OCTOBER-NOVEMBER-DECEMBER (OND) 2025, THE TEMPERATURE OUTLOOK FOR ALL OF THE
ISLANDS IS FAVORED TO BE ABOVE NORMAL. THE FORECAST SIGNAL WEAKENS AT LONGER
LEADS, THEREFORE EC IS INDICATED FOR HAWAII BEGINNING IN JFM
(JANUARY-FEBRUARY-MARCH) 2026 AND EXTENDING THROUGH LONGER LEADS.
ENHANCED PROBABILITIES FOR BELOW NORMAL PRECIPITATION ARE INDICATED OVER THE
BIG ISLAND OF HAWAII, MAUI, AND OAHU FROM ASO THROUGH SON 2025, CONSISTENT WITH
MOST DYNAMICAL MODEL FORECASTS, AS WELL AS DECADAL TRENDS. FOR KAUAI, WEAK OR
CONFLICTING SIGNALS WARRANTS EC FOR ASO, FOLLOWED BY A SLIGHT TILT TOWARDS
BELOW NORMAL PRECIPITATION IN SON. FROM OND 2025 THROUGH DJF 2025-26, AN
ANOMALOUSLY WET PATTERN IS PREDICTED BY THE NMME AND ITS CONSTITUENT MODELS.
THIS IS CONSISTENT WITH AN EXPECTED ENSO-NEUTRAL BACKGROUND AND GENERALLY
NEAR-AVERAGE TRADE WINDS, WITH CONSIDERATION OF SIGNIFICANT PROBABILITIES FOR A
LA NIñA EVENT AS WELL. DUE TO CONSIDERABLE UNCERTAINTY IN THE PRECIPITATION
FORECASTS FROM DYNAMICAL AND STATISTICAL MODELS, EC IS INDICATED OVER THE
HAWAIIAN ISLANDS BEGINNING IN JFM 2026 THROUGH LONGER LEADS.
HILO
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
ASO 2025 EC 76.4 0.4 B50 26.1 28.8 33.3
SON 2025 EC 76.2 0.4 B40 24.3 30.2 40.8
OND 2025 A40 75.5 0.4 A40 28.3 34.5 42.0
NDJ 2025 A40 74.2 0.4 A40 26.4 36.6 43.0
DJF 2026 A40 72.8 0.4 A50 19.6 30.2 33.3
JFM 2026 EC 71.8 0.4 EC 22.0 32.0 44.5
FMA 2026 EC 71.7 0.4 EC 24.6 34.1 45.5
MAM 2026 EC 72.0 0.5 EC 22.5 28.4 34.0
AMJ 2026 EC 72.9 0.5 EC 21.4 23.7 29.0
MJJ 2026 EC 74.0 0.4 EC 20.2 27.5 29.1
JJA 2026 EC 75.2 0.4 EC 19.4 27.2 31.4
JAS 2026 EC 76.1 0.4 EC 25.2 28.6 33.4
ASO 2026 EC 76.4 0.4 EC 26.1 28.8 33.3
KAHULUI
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
ASO 2025 A40 79.4 0.4 B50 0.8 1.6 2.5
SON 2025 A45 79.1 0.4 B40 2.1 3.3 4.8
OND 2025 A45 77.8 0.4 A40 4.2 5.3 8.1
NDJ 2025 A45 75.9 0.4 A40 5.2 7.6 9.5
DJF 2026 A40 73.8 0.4 A50 4.6 6.9 8.7
JFM 2026 EC 72.5 0.4 EC 4.2 6.2 8.2
FMA 2026 EC 72.3 0.4 EC 3.2 4.1 6.4
MAM 2026 EC 73.0 0.4 EC 2.5 3.5 4.6
AMJ 2026 EC 74.3 0.5 EC 1.2 1.6 2.2
MJJ 2026 EC 76.0 0.5 EC 0.7 1.1 1.8
JJA 2026 EC 77.7 0.4 EC 0.7 1.1 1.5
JAS 2026 EC 79.0 0.4 EC 0.8 1.1 1.6
ASO 2026 EC 79.4 0.4 EC 0.8 1.6 2.5
HONOLULU
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
ASO 2025 A60 81.7 0.4 B45 1.6 2.4 3.1
SON 2025 A60 81.4 0.4 B40 2.5 4.0 5.6
OND 2025 A55 80.0 0.4 A40 4.4 6.4 8.5
NDJ 2025 A45 77.7 0.5 A40 3.9 5.6 8.8
DJF 2026 A40 75.3 0.5 A50 3.7 5.6 8.6
JFM 2026 EC 73.9 0.4 EC 2.1 4.6 7.8
FMA 2026 EC 73.8 0.4 EC 1.9 3.2 4.7
MAM 2026 EC 74.8 0.4 EC 1.8 2.6 3.0
AMJ 2026 EC 76.3 0.4 EC 1.2 1.6 1.8
MJJ 2026 EC 78.2 0.4 EC 0.8 1.4 1.6
JJA 2026 EC 79.9 0.4 EC 0.7 0.8 1.3
JAS 2026 EC 81.3 0.4 EC 1.0 1.4 1.7
ASO 2026 EC 81.7 0.4 EC 1.6 2.4 3.1
LIHUE
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
ASO 2025 A60 79.4 0.3 EC 6.2 7.9 8.4
SON 2025 A60 79.1 0.3 B40 9.2 10.0 11.2
OND 2025 A50 77.8 0.3 A40 9.2 11.7 15.6
NDJ 2025 A45 75.7 0.3 A40 8.6 12.1 16.9
DJF 2026 A40 73.6 0.4 A50 7.5 8.4 14.0
JFM 2026 EC 72.2 0.4 EC 6.5 8.8 13.8
FMA 2026 EC 72.1 0.5 EC 5.8 8.4 9.9
MAM 2026 EC 72.8 0.5 EC 5.3 6.6 8.0
AMJ 2026 EC 74.2 0.5 EC 4.7 5.5 6.0
MJJ 2026 EC 76.0 0.5 EC 4.9 5.4 5.9
JJA 2026 EC 77.7 0.4 EC 4.4 5.3 6.9
JAS 2026 EC 79.0 0.3 EC 5.3 6.1 7.8
ASO 2026 EC 79.4 0.3 EC 6.2 7.9 8.4
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 AUG 21, 2025.
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