NWS Issues Flood Watch for Kauai County Friday Through Early Saturday

The National Weather Service in Honolulu has issued a Flood Watch for Kauai County, and the HFO watch text also names Niihau, effective from 3 p.m. Friday through 6 a.m. Saturday, as a deep upper-level trough and an axis of deep moisture approach the islands. HFO forecasters warned the system will bring increasing moisture and instability late Friday into Saturday, elevating the chance for moderate to locally heavy rainfall and localized flooding.

The HFO forecast discussion, issued at 3:37 PM HST Thursday, states: "Looking ahead to the weekend, in addition to the moisture arriving on the trades, an axis of deep moisture will approach from the west as an upper-level trough swings overhead. The combination of increasing moisture and instability will bring the potential for localized flooding and isolated thunderstorms late Friday afternoon into Saturday, particularly across the western end of the state." The same HFO discussion adds that "confidence is increasing that Kauai could see periods of moderate to locally heavy rainfall capable of producing localized flooding."

Kauai County officials are already urging residents to limit travel and prioritize safety. County messaging posted by KauaiNowNews says, "County of Kauaʻi officials are still urging the public to stay home, avoid all unnecessary travel, and prioritize safety as severe weather continues today and into next week." KauaiNowNews and county briefings highlight the combined threat of wind and rain, noting "strong to damaging trade winds, with gusts up to 60 mph in exposed, leeward, and downslope areas," and warning that such winds "may bring down trees and power lines and increase the risk of hazardous travel, localized flooding, rapid runoff, and rising streams."

Media partners expanded the alert footprint for planning: HawaiiNewsNow's First Alert Weather Team is "declaring Friday and Saturday as First Alert Weather Days for parts of the state," with the First Alert starting Friday afternoon for Kauai and then expanding to Oahu and Maui County on Saturday. KITV chief meteorologist Pete Caggiano forecasted clouds and shower chances through the weekend, noting "On Aloha Friday, cloudy skies are expected with some passing light rain in the morning. Rain chances will be highest for windward and mountain areas. Scattered showers are expected in the afternoon."

Marine and surf conditions will be affected. HFO's watches and advisories list a High Surf Advisory for east-facing shores until 6 AM HST Friday and multiple Small Craft Advisories, some in effect until 6 AM HST Friday for Kauai leeward waters and others lasting until 6 PM HST Friday for channels and surrounding waters including the Alenuihaha Channel and Kauai Channel. KITV's surf outlook lists east-facing surf at 6-10 ft, north 2-4 ft, south 1-3 ft, and west 1-2 ft.

Near-surface trade winds are forecast at 10 to 20 mph from the east to northeast with overnight lows "near 70 degrees" and daytime highs "near 80 degrees," according to KITV. HFO noted it made "only minor tweaks" to the wind forecast to match the latest model guidance, while county messaging emphasizes current gust risk and a high wind warning in effect through 6 p.m. today in exposed areas. Residents are advised to monitor official NWS/HFO updates and county channels and to follow county guidance to avoid unnecessary travel as the system moves through; KauaiNowNews adds that conditions should "gradually improve starting Tuesday as the storm system moves away from the islands.