FXHW40 KWBC 191230 PMDHCO Prognostic Discussion for Long-Lead Hawaiian Outlooks NWS Climate Prediction Center College Park MD 830AM EST Thu Mar 19 2026 MONTHLY FORECAST DISCUSSION VALID APRIL 2026 Sea surface temperature (SST) anomalies in the range of 0 to +1 degrees Celsius (C) were observed around the Hawaiian Islands (Kauai, Oahu, Maui and the Big Island) during the previous week with warmer anomalies near Kauai and weaker anomalies near the Big Island of Hawaii. From January through February 2026, rainfall total accumulations were: Lihue Airport 7.09 inches (111 percent of average) Honolulu Airport 3.71 inches (98 percent of average) Kahului Airport 4.23 inches (96 percent of average) Hilo Airport 25.96 inches (144 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 April 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 April 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 72.6 0.7 A45 7.4 8.9 11.2 Kahului A50 74.1 0.6 A45 0.5 0.9 1.3 Honolulu A50 76.3 0.5 A45 0.3 0.5 0.7 Lihue A50 74.0 0.6 A45 1.6 1.9 2.8 SEASONAL FORECAST DISCUSSION VALID AMJ 2026 - AMJ 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 Niņo Southern Oscillation (ENSO) outlook and other climate conditions relevant to the seasonal outlook. La Niņa conditions continued into March 2026. SST anomalies are negative over the east-central equatorial Pacific. SST anomalies were positive over the western tropical Pacific Ocean and the equatorial Pacific to the east of about 120 degrees west longitude. Average relative SST anomalies for the Niņo 3.4 region are currently about -0.5 degrees C, the threshold between La Niņa and ENSO-neutral conditions, where relative SST anomalies subtract the average global tropical SST anomaly between 20 degrees S and 20 degrees N latitude. The most recent 3-month Relative Ocean Niņo Index (RONI) is -0.9 C for the December through February period, indicating a relatively stronger La Niņa during winter that is currently weakening. Positive SST anomalies are observed across most of the tropical Pacific Ocean to the north of 10 degrees N latitude. Above-average subsurface ocean temperatures have expanded across the entire equatorial Pacific Ocean at depths greater than 200 meters in the western Pacific and 150 meters in the eastern Pacific, and extending to the surface in the far eastern equatorial Pacific. Above-average outgoing longwave radiation (OLR), associated with suppressed convection and precipitation, is observed around the Date Line in the equatorial Pacific Ocean, while below-average OLR, associated with enhanced convection and precipitation, is observed over much of the Maritime Continent and northern Australia. Easterly low-level (850-hPa) wind anomalies are enhanced over the central equatorial Pacific, while upper-level (200-hPa) wind anomalies are westerly over the east-central equatorial Pacific. The Madden Julian Oscillation (MJO) has circled the globe in recent weeks but has shown signs of interference with other tropical variability, remaining relatively weak. The real-time multivariate MJO (RMM) index has recently strengthened in Phase 7 in the western Pacific Ocean. Models predict eastward propagation in the next week. However dynamical model forecasts diverge and indicate significant uncertainty in the MJO in the following weeks, with some model realizations predicting a strong MJO to propagate across the Western Hemisphere into the Indian Ocean, while other solutions predict the MJO signal to quickly weaken. MJO activity may enhance precipitation over the central Pacific and Hawaii in the next two to three weeks, at the end of March and the beginning of April. The impacts of the MJO for Hawaii are uncertain for the remainder of April. Dynamical and statistical models predict a transition from La Niņa to ENSO-neutral conditions in the next month. Some models, such as the NCEP Climate Forecast System (CFSv2) and the CPC SST Constructed Analog (CA) predict a rapid increase in sea surface temperatures, with the potential for development of El Niņo conditions, with Niņo 3.4 anomalies exceeding +0.5 degrees C, by the end of boreal spring (June). While the CPC SST Canonical Correlation Analysis (CCA) predicts ENSO-neutral conditions and a weaker positive Niņo 3.4 anomaly to emerge in spring, the CCA favors ENSO-neutral conditions to persist through summer. The CPC ENSO Outlook forecasts ENSO-neutral conditions with greater than a 90% chance in the three-month March-April-May (MAM) season. However, El Niņo conditions are more likely than ENSO-neutral in summer and autumn 2026. ENSO-neutral conditions are expected to be in place for the Hawaii Outlook for April and the next three month season, while potential El Niņo conditions impact the outlooks in summer and early autumn. Historically, El Niņo 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, including the CA. 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 April-May-June (AMJ) and continuing through August-September-October (ASO) 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 September-October-November (SON) 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, for AMJ and May-June-July (MJJ) 2026, associated in part with predicted positive SST anomalies near the islands, as predicted ENSO-neutral conditions emerge. In June-July-August (JJA) 2026, EC is indicated in the seasonal precipitation outlook, due to uncertainty in the state of ENSO and weaker signals in forecast tools. Above normal precipitation is more likely to occur in the July-August-September (JAS) and ASO seasons, supported by the NMME and CA forecasts and possibly linked to an emerging El Niņo. In SON 2026 through longer leads, EC is indicated in the seasonal precipitation outlook, as the impact of El Niņo on the climate of Hawaii weakens in autumn. If an El Niņo event emerges by boreal autumn, it will likely persist into winter. Historically, El Niņo conditions lead to below-average precipitation for the Hawaiian Islands in boreal winter. However, due to uncertainty in model forecasts for longer leads, EC is indicated for the precipitation outlook. Hilo TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV AMJ 2026 A55 72.9 0.5 A45 21.4 23.7 29.0 MJJ 2026 A50 74.0 0.4 A40 20.2 27.5 29.1 JJA 2026 A50 75.2 0.4 EC 19.4 27.2 31.4 JAS 2026 A45 76.1 0.4 A40 25.2 28.6 33.4 ASO 2026 A40 76.4 0.4 A45 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 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 Kahului TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV AMJ 2026 A55 74.3 0.5 A45 1.2 1.6 2.2 MJJ 2026 A50 76.0 0.5 A40 0.7 1.1 1.8 JJA 2026 A50 77.7 0.4 EC 0.7 1.1 1.5 JAS 2026 A45 79.0 0.4 A40 0.8 1.1 1.6 ASO 2026 A40 79.4 0.4 A45 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 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 Honolulu TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV AMJ 2026 A55 76.3 0.4 A45 1.2 1.6 1.8 MJJ 2026 A50 78.2 0.4 A40 0.8 1.4 1.6 JJA 2026 A50 79.9 0.4 EC 0.7 0.8 1.3 JAS 2026 A45 81.3 0.4 A40 1.0 1.4 1.7 ASO 2026 A40 81.7 0.4 A45 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 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 Lihue TEMPERATURE PRECIPITATION FCST AVE LIM FCST BLW MEDIAN ABV AMJ 2026 A55 74.2 0.5 A45 4.7 5.5 6.0 MJJ 2026 A50 76.0 0.5 A40 4.9 5.4 5.9 JJA 2026 A50 77.7 0.4 EC 4.4 5.3 6.9 JAS 2026 A45 79.0 0.3 A40 5.3 6.1 7.8 ASO 2026 A40 79.4 0.3 A45 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 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 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 Apr 16, 2026. $$