The threat of heavy rain continues even as a cold front moves east and weakens, National Weather Service forecasters said. A flood watch for Oahu and Maui County was extended to 6 a.m. Tuesday because of the continued threat of showers over areas already saturated by heavy rain Sunday and today.
“A weakening frontal boundary has stalled out across Molokai this morning,” forecasters said today. “Moderate to heavy showers and a slight chance for thunderstorms will persist for Oahu through Maui today, then slowly disperse through the middle of the week.
“Trade winds will build back in late Tuesday and focus remnant moisture over windward and mauka areas especially for Maui and Big Island.”
The storm system has been making its way down the island chain since early Sunday.
The cold front reached Kauai early Sunday, bringing with it bands of heavy showers. Poipu received 3.9 inches of rain in the 24-hour period ending at 8 p.m. Sunday.
Puu Opae and Lihue Airport also received about 2.4 inches of rain over the same period.
The front made its way to Oahu in the early Sunday afternoon, delivering showers to central Oahu and the North Shore through this morning. Punaluu recorded 7 inches of rain in a 24-hour period through 11 a.m. today. The Department of Emergency Management also noted heavy shower activity in Nanakuli, Mililani, Kailua, Laie and Kahuku.
Dillingham Airfield recorded almost 6.7 inches of rain. Wheeler Airfield got 4.4 inches and 3.7 inches fell at the Wilson Tunnel.
Weather radar showed a stationary area of very heavy rain along Kahekili Highway between Wailuku and Kahakuloa on Maui as of 9:24 a.m.
In anticipation of an incoming northwest swell, the weather service also issued a high-surf warning for the north- and west-facing shores of Kauai and Niihau and the north-facing shores of Oahu, Molokai and Maui through 6 a.m. Tuesday. Surf is expected to reach 20 to 25 feet in those areas.
Forecasters warn against water sweeping across portions of beaches, strong breaking waves, and strong longshore and rip currents. Breaking waves may also impact harbors, making navigating the harbor channel dangerous.