FXHW40 KWBC 151230
PMDHCO
Prognostic Discussion for Long-Lead Hawaiian Outlooks
NWS Climate Prediction Center College Park MD
830AM EDT Thu May 15 2025
MONTHLY FORECAST DISCUSSION VALID JUNE 2025
Sea-surface temperature (SST) anomalies in the range of +0.5 to +1.5 degrees
Celsius (C) were observed around the Hawaiian Islands (Kauai, Oahu, Maui and
the Big Island) during the previous week.
From January through April 2025, rainfall total accumulations were:
Lihue Airport 7.76 inches (55 percent of average)
Honolulu Airport 8.24 inches (119 percent of average)
Kahului Airport 6.39 inches (76 percent of average)
Hilo Airport 20.25 inches (50 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 June 2025. Some models predict weak or near zero
SST anomalies near the southeastern Hawaiian Islands in June 2025. Above normal
temperatures are favored for all of the Hawaiian Islands (Kauai, Oahu, Maui and
Hawaii or the Big Island) for June with lower probabilities indicated for the
southeastern islands of Maui (Kahului) and Hawaii (Hilo), based on model
forecasts.
For the June 2025 precipitation outlook, most models of the NMME and IMME
predict above normal precipitation across Kauai and Oahu. Most models of the
NMME and IMME also predict below normal precipitation for the Big Island of
Hawaii in June. Equal Chances (EC) for above, near or below normal
precipitation are indicated for Maui, where forecast models have mixed outcomes
and weak signals.
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
Hilo A60 75.4 0.4 B40 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 A40 0.1 0.2 0.3
Lihue A70 78.1 0.4 A45 1.1 1.3 1.6
SEASONAL FORECAST DISCUSSION VALID JJA 2025 - JJA 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 Niño Southern
Oscillation (ENSO) outlook and other climate conditions relevant to the
seasonal outlook. ENSO-neutral conditions continued over the Pacific Ocean
through April. Equatorial SST anomalies are near zero across much of the
Pacific Ocean. Weak negative SST anomalies are observed over parts of the
eastern equatorial Pacific Ocean, while weak positive SST anomalies are
observed over the far western Pacific Ocean near the Maritime Islands. Negative
subsurface temperature anomalies in the central Pacific Ocean have dissipated
in the last several weeks. Positive subsurface temperature anomalies persist at
depths of 50 to 300 meters in the western equatorial Pacific Ocean. Low-level
(850-hPa) wind anomalies are near zero across most of the equatorial Pacific
Ocean. Upper-level (200-hPa) wind anomalies are near zero across most of the
Pacific Ocean, while southerly cross-equatorial upper-level wind anomalies are
observed over the western Pacific Ocean. Suppressed convection and
precipitation were observed over the western and central Pacific Ocean to the
north of the equator, while enhanced convection and precipitation were observed
over parts of the Maritime Islands to the west.
Most dynamical and statistical models predict a continuation of ENSO-neutral
conditions into boreal summer. Some models, such as the CPC SST Canonical
Correlation Analysis (CCA) predict the development of a La Niña in autumn by
forecasts of negative Niño 3.4 region SST anomalies below the -0.5 C
threshold. ENSO-neutral conditions are forecast in the CPC ENSO Outlook with a
greater probability than La Niña through the December-January-February season,
although the probability of the development of La Niña increases through the
Northern Hemisphere autumn and winter, with some statistical tools indicating
La Niña is more likely. Development of La Niña 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 spring 2025.
Enhanced probabilities for above normal temperatures are indicated in the
official outlook for Lihue, Honolulu, Kahului and Hilo for JJA
(June-July-August) through October-November-December (OND) 2025, supported by
nearly all dynamical model forecasts from the NMME and C3S, as well as decadal
timescale temperature trends. Probabilities for above normal temperatures are
greater for northwestern islands of Hawaii, exceeding 70 percent in early
seasons, following calibrated model guidance from the NMME. Due to increasing
uncertainty in the state 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 NDJ (November-December-January) 2025 and
extending through longer leads.
Enhanced probabilities for above normal precipitation are forecast over the
northwestern Hawaiian Islands of Kauai and Oahu from JJA to
August-September-October (ASO) 2025, consistent with most dynamical model
forecasts, as well decadal trends. Dynamical model forecasts of positive SST
anomalies surrounding the northwestern Hawaiian Islands also support forecasts
of above normal precipitation. Enhanced probabilities for below normal
precipitation are forecast for the southeastern Big Island of Hawaii from JJA
to September-October-November (SON) 2025, consistent with most dynamical model
forecasts, as well decadal timescale precipitation trends. Equal Chances (EC)
for above, near or below normal precipitation are indicated for Maui (Kahului)
for all outlooks, with uncertainty in the transition from wetter conditions to
the northwest and drier conditions to the southeast. Beginning in OND 2025 for
the Big Island and SON 2025 for northwestern islands of Kauai and Oahu and
extending through longer leads, EC is indicated in the seasonal precipitation
outlook. Uncertainty in the state of ENSO beginning in OND 2025 results in
weaker signals and near climatological probabilities in the seasonal outlook.
Hilo
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
JJA 2025 A65 75.2 0.4 B40 19.4 27.2 31.4
JAS 2025 A65 76.1 0.4 B40 25.2 28.6 33.4
ASO 2025 A60 76.4 0.4 B40 26.1 28.8 33.3
SON 2025 A60 76.2 0.4 B40 24.3 30.2 40.8
OND 2025 A60 75.5 0.4 EC 28.3 34.5 42.0
NDJ 2025 EC 74.2 0.4 EC 26.4 36.6 43.0
DJF 2026 EC 72.8 0.4 EC 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
Kahului
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
JJA 2025 A70 77.7 0.4 EC 0.7 1.1 1.5
JAS 2025 A70 79.0 0.4 EC 0.8 1.1 1.6
ASO 2025 A70 79.4 0.4 EC 0.8 1.6 2.5
SON 2025 A65 79.1 0.4 EC 2.1 3.3 4.8
OND 2025 A60 77.8 0.4 EC 4.2 5.3 8.1
NDJ 2025 EC 75.9 0.4 EC 5.2 7.6 9.5
DJF 2026 EC 73.8 0.4 EC 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
Honolulu
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
JJA 2025 A70 79.9 0.4 A40 0.7 0.8 1.3
JAS 2025 A70 81.3 0.4 A40 1.0 1.4 1.7
ASO 2025 A70 81.7 0.4 A40 1.6 2.4 3.1
SON 2025 A65 81.4 0.4 EC 2.5 4.0 5.6
OND 2025 A60 80.0 0.4 EC 4.4 6.4 8.5
NDJ 2025 EC 77.7 0.5 EC 3.9 5.6 8.8
DJF 2026 EC 75.3 0.5 EC 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
Lihue
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
JJA 2025 A70 77.7 0.4 A40 4.4 5.3 6.9
JAS 2025 A70 79.0 0.3 A40 5.3 6.1 7.8
ASO 2025 A70 79.4 0.3 A40 6.2 7.9 8.4
SON 2025 A65 79.1 0.3 EC 9.2 10.0 11.2
OND 2025 A60 77.8 0.3 EC 9.2 11.7 15.6
NDJ 2025 EC 75.7 0.3 EC 8.6 12.1 16.9
DJF 2026 EC 73.6 0.4 EC 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
FORECASTER: Dan Collins
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 Jun 19, 2025.
$$