US: Adverse weather forecast across much of Hawaii through at least Nov. 30

A low-pressure system is forecast to bring heavy rainfall across much of Hawaii through at least Nov. 30. Flash flooding and thunderstorms are possible across Kauai and Oahu Nov. 28 before expanding to Maui County and the Big Island Nov. 29-30. As of Nov. 28, the National Weather Service (NWS) has issued flash flood watches across Kauai, Oahu, and Niihau Nov. 28-30 and across all main Hawaiian islands early Nov. 29-30. Authorities will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed or a lack of stormwater drainage systems. Sites downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rain has saturated the soil. Disruptions to electricity and telecommunications services are possible where significant flooding, strong winds, or landslides impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather could also trigger flight delays and cancellations at airports in the affected regions. Flooding could block regional rail lines; passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities and some employees' inability to reach work sites.