A powerful storm front is moving over the Hawaiian Islands, and the National Weather Service is warning residents that “gusty and erratic winds associated with strong thunderstorms may bring gusts near 50 mph, frequent lightning, visibility near zero in heavy rain, and the potential for small hail.”

A flood watch is in effect for Kauai, Niihau, Oahu, Maui, Lanai, Molokai and Kahoolawe through this afternoon. The Big Island is under a flood watch through this evening.

The weather service said the cold front, after bringing heavy rain and flooding to Kauai and Oahu on Tuesday evening, will do so for Maui County and Big Island today through Thursday.

“Drier weather and lighter winds will quickly fill in behind the front, with light and variable winds on Thursday,” officials said Tuesday evening. “Light to moderate east to southeast winds will develop on Friday and continue into the weekend, delivering just a few showers.”

Kauai County officials urge residents to be vigilant of potential severe weather conditions.

“With the forecast calling for gusty Kona winds, heavy rain, and possible strong thunderstorms, officials advise caution and avoiding non-essential travel and outdoor activities during inclement weather,” said Kauai Emergency Management Agency Administrator Elton Ushio. “In several recent Flash Flood Warning events, multiple residents and visitors had to be rescued after attempting to cross areas prone to flooding or flash flooding, such as roadways, rivers/streams and low-­lying areas.”

The NWS said there “will be favorable conditions for the development of heavy showers and thunderstorms” through tonight and that that the heaviest rain is expected over the slopes of the Kau and Puna districts. On Tuesday localized rain rates up to 2 inches per hour were observed.

Arrival of the front “will provide a source of deeper moisture and will potentially result in a period of prolonged heavy rainfall over the the Big Island’s southeast slopes” up to Thursday, forecasters said.

On Oahu the primary concern is for commuters between Kapolei and Honolulu, where there is potential for heavy rain this morning.

The weather service warns that “flood-prone roads and other low-lying areas may be closed due to elevated runoff and overflowing streams. Urban and leeward areas may receive more significant flooding and property damage due to rapid runoff.”