Tropical Storm Darby could bring 2-4 inches of rain to windward Big Island, large swells

(Update 8 a.m. 7.16.22)

The National Weather Service says “locally strong trades will focus moisture associated with decaying Tropical Cyclone Darby over windward Big Island today, where periods of heavy rain can be expected. Elsewhere, fairly typical trade wind weather will prevail with passing windward showers and the occasional shower reaching leeward areas.”

In an updated weather synopsis issued at around 4 a.m. on Saturday, the NWS says conditions will improve over the Big Island this evening, with a fairly dry trade wind pattern then holding in place statewide through Tuesday. 

As of 5 a.m. on Saturday, Tropical Storm Darby was located: 190 miles SE of Hilo; 285 miles SE of Hāna; 310 miles SE of Kahului; 345 miles SE of Kaunakakai; 330 miles SE of Lānaʻi City; and 400 miles ESE of Honolulu.

The Central Pacific Hurricane center reports that Darby remains a weak tropical Storm SE of Hawaiʻi, with maximum sustained winds dropping to 45 mph. The system was moving toward the west at 22 mph.

According to the 5 a.m. forecast, “the forecast track will bring the center of Darby south of the Big Island later today.. Darby is expected to weaken into a post-tropical remnant low tonight before dissipating on Sunday.”

The CPHC says tropical-storm-force winds extend outward up to 60 miles from the center.

Rain:

The CPHC says, “Darby is expected to produce localized storm total rainfall of 2 to 4 inches along portions of mainly windward Big Island. These rains may cause minor flooding especially in low-lying and poor drainage areas.”

Parks:

On Maui, the state Department of Land and Natural Resources reports that Mākena State Park will be open on Saturday, and based on monitoring and discussion with Maui County Ocean Safety Officers, may close on Sunday.

This comes ahead of reports of a “historic” South Pacific swell bringing high surf and rough ocean conditions over the weekend. As a result, several State beach parks along south-facing shores will be closed.

Large swells:

On the water, large swells generated by Darby are expected to affect portions of the Hawaiian Islands over the weekend, with swells likely producing hazardous surf and dangerous rip currents.

This large south swell is expected to be the largest seen in Hawaiʻi over the last decade, according to a news release issued by DLNR. “Waves are forecast to peak in the 15-20 foot range on the south shores of each island, building all day Saturday to high surf warning levels Saturday night through Sunday night. Large wave run up and coastal impacts are expected, especially during the late afternoon high tides,” the release said.

Wind Advisory:

The National Weather Service issued a Wind Advisory for the Summit of Haleakalā on Maui and the summits of the Big Island until 6 p.m.

East to SE winds will increase to 35-45 mph with gusts up to 55 mph. Winds this strong can make driving and walking difficult, and can forcefully open doors and damage hinges or slam doors shut, possibly causing injuries. As a precaution, the public is asked to consider postponing travel to the summits until conditions improve. If you must travel to the summits, use extra caution walking and driving.