UPDATE, MONDAY 5 A.M.
Although breezy to windy tradewinds are forecast for the islands today, deeper tropical moisture will continue to drift in from the east as the remnants of former tropical cyclone Barbara pass just south of the islands.
The remnant low, located about 300 nautical miles southeast of Hilo at 4 a.m., will increase clouds, showers and wind speeds statewide, the National Weather Service said today.
A flash flood watch for Hawaii island posted Sunday remains in effect through late tonight.
Drier weather is expected to return from Tuesday through Wednesday with easing tradewinds.
A high surf advisory remains in effect for all east-facing shores through 6 a.m. Tuesday.
The National Weather Service says the remnants of former tropical cyclone Barbara are expected to pass just south of the state, bringing an increase in shower activity through Tuesday, especially over the east end of the state.
The remnant low was around 350 nautical miles east-southeast of Hilo tonight and is expected to pass south of the Big Island on Monday and continue tracking south of the state through Tuesday.
The Weather Service has posted a flash flood watch for the Big Island through Monday night.
Forecasters are not sure how far north the moisture field will extend but do not expect flooding from rainfall on the other islands. They believe, however, that all islands are likely to see some locally heavy rainfall, especially windward areas.
Remnants of Barbara are also expected to continue to produce elevated surf along east-facing shores of most islands through Monday night. Forecasters say strong trade winds and elevated surf will produce very hazardous conditions along east-facing shores Monday into early Tuesday.
A flash flood watch is in effect for the Big Island from 10 p.m. tonight to late Monday night as the remnant of the former hurricane and tropical storm Barbara begins to reach the state.
Moisture will move in from the east and the initial threat of heavy rainfall will be over windward areas before spreading to leeward areas on Monday.
“The remnants of Barbara are forecast to pass through the area tonight through Tuesday with shower activity and winds increasing across most of the state,” the National Weather Service reported this afternoon.
Drier and more typical tradewind weather is expected Wednesday through Saturday.
Meanwhile, Cosme weakened to a tropical depression this afternoon in the eastern Pacific and is expected to become a remnant low overnight or early Monday.
Cosme is located about 670 miles west southwest of the southern tip of Baja California. It is expected to dissipate in two or three days.
The remnant of former hurricane and tropical storm Barbara will bring breezy trade winds, high surf, and possible flooding rains to Hawaii, with the Big Island expected to bear the brunt of the weather, forecasters said today.
Barbara, which once was a powerful Category 4 hurricane in the eastern Pacific, fell apart as it entered the Central Pacific Saturday, but what remains of the system was a few hundred miles east-southeast of the Big Island and moving west this morning.
The National Weather Service in Honolulu today issued a high surf advisory for all islands, a flash flood watch for Hawaii island, and a gale watch and small craft advisory for waters around the leeward and southeast side of the Big Island and for Alenuihaha Channel.
Forecasters said that breezy trade winds will bring a few showers, mainly to windward areas, to the islands today.
“Later tonight and Monday, deep moisture associated with the remnant of Barbara will move over the islands from the east, reaching windward Big Island as early as tonight,” forecasters said. “This increase in moisture will bring the potential for locally heavy rainfall, especially windward. Winds will also increase as the low passes, with locally windy conditions possible on Monday, especially on the Big Island.”
Barbara’s remnants are expected to pass just south of the Big Island on Monday before weakening Tuesday as it moves west of the islands, they said. Potentially heavy rain “is expected to begin moving over the Big Island tonight, then spread to at least some of the other islands through Monday.”
A flash flood watch has been issued for the Big Island from this evening through late Monday night. The weather service said the initial threat of heavy rain will be over windward areas, spreading to leeward areas on Monday.
“Although all islands are likely to see some locally heavy rainfall, especially windward … the potential for flooding rainfall away from the Big Island appears less likely at this time — but expansions to the flash flood advisory are definitely a possibility,” forecasters said this morning.
The high surf advisory is in effect through 6 a.m. Monday and calls for 6 to 9 feet waves through today for eastern shores of Molokai, Oahu and Kauai; 7 to 12 feet surf through tonight for eastern shores of the Big Island and Maui; and 5 to 8 feet waves through tonight for southern shores of all islands.
The weather service said drier and more typical trade-wind weather will gradually return to the islands Tuesday into Wednesday, and continue into next weekend.
The National Hurricane Center in Miami, meanwhile, is issuing advisories for Tropical Storm Cosme, far out in the eastern Pacific. Cosme was barely a tropical storm, with maximum sustained winds of 40 mph this morning, and was 655 miles west-southwest of the southern tip of Baja California. The hurricane center expects the storm to dissipate within four days and not threaten any land.