Tropical Storm Niala turned west and away from the islands on Saturday, but high winds and locally heavy rains will persist through Monday, according to the National Weather Service.
At 5 p.m Saturday, Niala was 245 miles southeast of Hilo and 450 miles southeast of Honolulu, gathering strength as it moved westward at 8 mph.
Niala was carrying maximum sustained winds of 65 mph, just 10 mph shy of a Category 1 hurricane. Tropical storm-force winds extend outward up to 90 miles from the center.
Forecasters predict Niala will continue to move west through today before angling west-southwest on Monday. On its current track, Niala will pass 120 to 150 miles south of Hawaii island this afternoon.
Meanwhile, a tight pressure gradient between Niala and the islands will generate windy conditions along the smaller islands through tonight.
A tropical storm warning remains in effect for Hawaiian offshore waters beyond 46 miles out to 276 nautical miles, including the portion of the Papahanaumokuakea Marine National Monument east of French Frigate Shoals.
Hawaii island is under a flash-flood watch through Monday afternoon due to deep tropical moisture along the northern periphery of Niala that is lingering above the island. Heavy rain will favor east and south slopes but will reach all parts of the island.
In the 24-hour period ending Saturday at 5 p.m., rain gauges recorded heavy rainfall in Saddle Quarry (8.18 inches), Waiakea Uka (5.57), Kawainui Stream (5.30) and Honokaa (5.27).
The weather service also issued a tropical storm watch for Hawaii island, effective through tonight.
Meanwhile, a wind advisory is in effect for all islands except Hawaii island through 6 a.m. Monday. Winds will be especially strong in areas usually exposed to tradewinds, forecasters said.
Winds are expected to reach 25 to 35 mph, with gusts to 50 mph, forecasters said.
Forecasters say tradewinds will strengthen this weekend as Niala passes south of the smaller Hawaiian islands. The locally generated wind waves and easterly swell will produce advisory-level surf heights along east-facing shores through the weekend.
A high-surf advisory is in effect until 6 a.m. Monday. The advisory covers the east shores of Kauai, Oahu, Molokai and Maui.
Surf is expected to peak at 6 to 9 feet along east shores and 9 to 12 feet along southeast shores by this afternoon, then decline tonight and Monday.
Moderate to locally breezy tradewinds will prevail through the week and could become locally windy on Hawaii island over the weekend, forecasters said. Heavy showers and thunderstorms will be possible on Hawaii island late Saturday through Monday.