Droughts have affected the islands throughout Hawaii’s recorded history. Drought forecasting is necessary to help prepare the state for potentially devastating drought events and forecasting tools have improved over the past few years. The National Oceanographic and Atmospheric Administration’s Climate Prediction Center and National Integrated Drought Information System have developed drought forecasting tools and long-lead rainfall outlooks. The El Nino phenomenon has a strong correlation to Hawaiian rainfall, where below-normal rainfall occurs frequently in the winter and spring season following an El Nino event.
The National Weather Service Climate Prediction Center’s (CPC) products are operational predictions of climate variability, real-time monitoring of climate and the required data bases, and assessments of the origins of major climate anomalies. The products cover time scales from a week to seasons, extending into the future as far as technically feasible, and cover the land, the ocean, and the atmosphere, extending into the stratosphere. The CPC’s U.S. Monthly Drought Outlook and the U.S. Seasonal Drought Outlook include the Hawaiian Islands.
El Niño events are closely linked to drought conditions in Hawaii. Records show that there is an approximately 70% chance of drought occurring in Hawaii during the wet season following an El Niño event. Many severe Hawaiian drought events are associated with the El Niño phenomenon. The National Weather Service Climate Prediction Center offers a monthly El Niño/Southern Oscillation (ENSO) Diagnostic Discussion and a Weekly ENSO Update.
The National Weather Service Climate Prediction Center produces a suite of short and long-range precipitation forecasts for Hawaii and the tropical Pacific islands, including maps showing estimates of rainfall anomalies.