Prognostic Meteorological Discussion
Issued by NWS
Issued by NWS
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FXHW40 KWBC 201331
PMDHCO
Prognostic Discussion for Long-Lead Hawaiian Outlooks
NWS Climate Prediction Center College Park MD
830AM EDT Thu Nov 20 2025
MONTHLY FORECAST DISCUSSION VALID DECEMBER 2025
Sea-surface temperature (SST) anomalies in the range of +0.0 to +1.0 degree
Celsius (C) were observed around the Hawaiian Islands (Kauai, Oahu, Maui and
the Big Island) during the previous week, with the warmest anomalies around
Kauai.
From January through October 2025, rainfall total accumulations were:
Lihue Airport 18.50 inches (67 percent of average)
Honolulu Airport 9.87 inches (82 percent of average)
Kahului Airport 6.80 inches (59 percent of average)
Hilo Airport 46.57 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 most of the Hawaiian Islands in December 2025. 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 of Hawaii
(Hilo), with greater probabilities for the northwestern islands of Oahu and
Kauai. For the December 2025 precipitation outlook, above 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 A40 72.5 0.4 A45 6.8 10.2 13.6
Kahului A45 73.5 0.5 A45 1.9 2.7 3.4
Honolulu A55 74.9 0.6 A45 0.8 1.3 3.8
Lihue A60 73.3 0.5 A45 1.8 3.2 5.5
SEASONAL FORECAST DISCUSSION VALID DJF 2025 - DJF 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.
La Nia conditions are observed over the tropical Pacific Ocean. Equatorial sea
surface temperatures (SSTs) are below average across the central and east
central Pacific Ocean. Over the last couple of months, below average subsurface
temperatures persisted across the central and eastern Pacific. Above average
subsurface temperatures were observed in the western half of the Pacific.
Enhanced convection and precipitation was evident over Indonesia, southeastern
Asia, the Philippines, and northern Australia. Suppressed convection and
precipitation was observed near the Date Line. Low level wind anomalies were
easterly from the western to the east central equatorial Pacific Ocean, while
upper level wind anomalies were westerly over most of the equatorial Pacific.
The CPC ENSO Outlook forecasts La Nia to continue through
December-January-February (DJF) 2025-26, with a transition to ENSO-neutral most
likely in January-February-March (JFM) 2026 (61% chance).
Enhanced probabilities for above normal temperatures are predicted in the
outlook for Kauai, Oahu, Maui, and the Big Island from DJF 2026 through
April-May-June (AMJ) 2026, supported by dynamical model forecasts from the NMME
and C3S. Probabilities for above normal temperatures are greater for
northwestern islands of Hawaii, following calibrated model guidance from the
NMME and C3S. 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
May-June-July (MJJ) 2026 and extending through longer leads.
Enhanced probabilities for above normal precipitation are forecast over the
island chain from DJF 2026 through AMJ 2026, supported by most of the dynamical
model forecast tools. This is often (but not always) the case during a cold
season La Nia, and is related to the tendency of the jet to bifurcate
upstream. On occasion, a robust subtropical cyclone, often referred to as a
kona low, travels with the southern branch of the split jet, and approaches the
Hawaiian Islands from the northwest. The Hawaiian word, kona, means leeward and
is used to describe winds with a southerly component that replace the usually
persistent trade wind regime. Historically, kona lows have produced a variety
of weather-related hazards, most notably heavy rain, floods, and high winds
(Morrison and Businger, 2001, Weather and Forecasting). Similar to the
temperature outlooks, the greatest probabilities favoring positive anomalies
are for the northwestern islands, with reduced odds over the southeastern
islands. Equal chances (EC) for above, near or below normal precipitation are
indicated for the islands of Kauai, Oahu, Maui, and the Big Island starting in
MJJ 2026 and continuing through longer leads.
Hilo
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
DJF 2026 A40 72.8 0.4 A40 19.6 30.2 33.3
JFM 2026 A40 71.8 0.4 A40 22.0 32.0 44.5
FMA 2026 A40 71.7 0.4 A40 24.6 34.1 45.5
MAM 2026 A40 72.0 0.5 A40 22.5 28.4 34.0
AMJ 2026 A40 72.9 0.5 A40 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
SON 2026 EC 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
Kahului
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
DJF 2026 A50 73.8 0.4 A45 4.6 6.9 8.7
JFM 2026 A45 72.5 0.4 A45 4.2 6.2 8.2
FMA 2026 A45 72.3 0.4 A40 3.2 4.1 6.4
MAM 2026 A40 73.0 0.4 A40 2.5 3.5 4.6
AMJ 2026 A40 74.3 0.5 A40 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
SON 2026 EC 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
Honolulu
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
DJF 2026 A60 75.3 0.5 A55 3.7 5.6 8.6
JFM 2026 A55 73.9 0.4 A50 2.1 4.6 7.8
FMA 2026 A45 73.8 0.4 A50 1.9 3.2 4.7
MAM 2026 A40 74.8 0.4 A45 1.8 2.6 3.0
AMJ 2026 A40 76.3 0.4 A40 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
SON 2026 EC 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
Lihue
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
DJF 2026 A65 73.6 0.4 A60 7.5 8.4 14.0
JFM 2026 A60 72.2 0.4 A55 6.5 8.8 13.8
FMA 2026 A50 72.1 0.5 A50 5.8 8.4 9.9
MAM 2026 A45 72.8 0.5 A50 5.3 6.6 8.0
AMJ 2026 A40 74.2 0.5 A45 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
SON 2026 EC 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
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 December 18, 2025.
$$