Update: High wind warning issued for Kaua‘i and Ni‘ihau

Update at 2:39 p.m. Jan. 29: A high wind warning will now go into effect from 6 p.m. today (Jan. 29) through 6 a.m. Friday (Jan. 31) for portions of Kaua‘i and Ni‘ihau, replacing a previous high wind watch.

The National Weather Service in Honolulu said southwest winds 20 to 30 mph, with localized gusts of more than 60 mph, are expected, with the highest risk for damaging winds over and to the east of mountains; although, other areas could see damaging gusts as well.

Winds are forecast to increase near Kaua‘i this evening into the night. Stronger winds will then spread to O‘ahu overnight into early Thursday.

Damaging winds can blow down trees and power lines, and damage roofs. Power outages are possible, and travel will be difficult, especially for some vehicles.

The public is advised to prepare for the possibility of property damage and power outages. Hazardous driving conditions because of powerful crosswinds will pose a serious risk for drivers, especially for lightweight and high-profile vehicles.

Loose outdoor items should be brought inside or secured properly.

A flood watch for the entire state, including Kaua‘i and Ni‘ihau, also goes into effect from 6 p.m. today through noon Friday.

National Weather Service forecast guidance remains in good agreement, depicting an active weather pattern unfolding beginning late tonight through early Friday, with models continuing to support a potential significant event evolving across the state as a major winter storm draws closer.

Impacts will range from flash flooding and strong to severe thunderstorms to damaging south to southwest winds, which will downslope into north and windward sections of the state.

Update at 8:22 a.m. Jan. 29: The National Weather Service forecast office in Honolulu has already extended a flood watch in effect for the entire state, including Kaua‘i and Ni‘ihau, as a major winter storm draws closer to the state.

The flood watch was originally set to run from 6 p.m. today (Jan. 29) through noon Friday (Jan. 31); however, it will now be in effect all day Friday, through 6 p.m.

Conditions will become increasingly favorable for the development of heavy showers and possibly thunderstorms over the western end of the state starting tonight, then progressing east on Thursday and continuing through Friday.

A high wind watch will also be in effect from 6 p.m. today through 4 a.m. Friday for lower elevations of all islands as southwest winds associated with the storm are forecast at 20 to 35 mph, with gusts up to 55 mph possible.

Forecasters in Honolulu expect cool and pleasant conditions to linger this morning before quickly transitioning through the day as winds shift out of the south-southeast ahead of the strengthening winter storm approaching from the northwest.

The low pressure system will pass just north of Kaua‘i on Thursday, with a cold front advancing down the island chain Thursday through Friday.

Guidance remains in good agreement and depicts an active weather pattern unfolding beginning late tonight through early Friday, with forecast models continuing to support a potential significant event evolving across the state.

Impacts will range from flash flooding and strong to severe thunderstorms to damaging south to southwest winds, which will downslope into north through windward sections of the state.

The area forecast discussion for the state from early this morning says conditions will fortunately improve quickly behind the front Friday night into the weekend, continuing through early next week.

Original post from 1 a.m. Jan. 29: National Weather Service forecasters in Honolulu have issued several watches in advance of a major winter storm expected to strike the state later this week.

A flash flood watch will be in effect from 6 p.m. Jan. 29 until noon Jan. 31 for all Hawaiian islands, including Kaua‘i and Ni‘ihau, because of the threat of flash flooding caused by excessive rainfall from the coming storm.

A strong winter low pressure system will develop Wednesday west of the state and pass by Thursday just north of Kaua‘i, with an associated cold front moving eastward across the state Thursday into Friday.

Conditions will become increasingly favorable for the development of heavy showers and possibly thunderstorms over the western end of the state starting Wednesday evening, then progressing east on Thursday and continuing through Friday morning.

Flood-prone roads and other low-lying areas could be closed because of elevated runoff and overflowing streams. Urban areas also might see more significant flooding and property damage because of rapid runoff.

The public should monitor later forecasts and be prepared to take action if flash flood warnings are issued.

A high wind watch will be in effect from 6 p.m. Jan. 29 through 4 a.m. Jan. 31 for lower elevations of all islands, as southwest winds associated with the storm are forecast at 20 to 35 mph, with gusts up to 55 mph possible.

Strongest winds will likely be across windward and mauka (toward the mountain) areas of O’ahu and Kaua’i. However, portions of Maui County and the Big Island could also see periods of strong winds.

Damaging winds could blow down trees and power lines, and widespread power outages are possible. Travel also could be difficult, especially for high-profile vehicles.

The public is advised to take precautions now to protect property, including tying down or moving loose objects to a sheltered location.

Big Island summits of Mauna Kea and Mauna Loa and the summit of Haleakalā on Maui also will be under a high wind watch during the same time period, as southwest winds of 40 to 50 mph are expected, with gusts up to 80 mph possible.

Winds this strong can make driving and even walking dangerous. They can even forcefully open doors and damage hinges or slam doors shut, possibly causing injuries.

All three summits will be under a winter weather watch from midnight Jan. 30 to noon Jan. 31.

Periods of snow and mixed precipitation are in the forecast atop the mountains, with snow accumulations up to 10 inches possible. A light glaze of ice is also possible on wet surfaces as temperatures drop below freezing.

Travel could be very difficult to impossible. Blowing snow will significantly reduce visibility at times, with periods of zero visibility.

Anyone planning travel to the summits, including hikers and campers, should monitor the latest forecasts and consider postponing their trip until weather improves.