Get ready Big Island: Forecast says another storm will bring heavy rain, strong winds Saturday night into Sunday

Updated: 5 p.m. Thursday

Itʻs now Tropical Depression Two-C, but by the time its expected track takes it south of the Big Island this weekend the system is forecast to be Tropical Storm Moke.

“This is not the same as Lala,” said John Bravender, warning coordination meteorologist at the Central Pacific Hurricane Center, during a press conference on Thursday. “Looks like the track is going to be a little further south and the wind field is not as large.”

But the message from Bravender and Hawaiʻi Gov. Josh Green is for the people of the Big island, especially those in the southern part, to prepare now.

The storm is expected to impact the same areas that were devastated less than a week ago by Hurricane Lala that damaged or destroyed a reported 263 homes and 18 businesses, and killed two people on Hawaiʻi Island.

The storm now has sustained winds of 35 mph and is about 815 miles east-southeast of Hilo, traveling north-northwest at 14 mph. It is expected to strengthen over the next two days, but only to a high-end tropical storm and not a hurricane (which requires sustained winds of 74 mph or more).

“So hopefully it won’t be as damaging,” Bravender said of this new storm. “However, there could be a lot of rain with that as well, especially for southeastern sections of the Big Island, the Kaʻū and Puna districts that already had the most rainfall during Hurricane Lala that could be impacted again.”

Bravender said even though the rainfall amounts aren’t expected to be as large, “given all the damage that we’ve had and the repairs that people are still trying to accomplish right now, we’re concerned about the extra damage potential from this.”

Grounds are porous. While they drain fast, they are still wet and still saturated.

“And with this rain, we could have more flooding damage and that’s what we’re focused on going forward,” Bravender said.

He also said there is concern that there can be strong gusty winds localized by the island terrain that can be very damaging.

“With this passing south of us, think of it like an enhanced trade wind type of pattern where you have strong gusty winds in those areas that typically see those strong winds,” Bravender said.

The greatest rainfall potential is on windward and southeast sections of Hawaiʻi Island, about 10 to 15 inches over the course of the weekend.

“It’s a ton of rain, and you can see flooding mudslides. We already have them,” Green said. “They’re going to continue to evolve and be a problem. Now, no one is in those houses, they’re already covered with mud. But we can’t say for sure it won’t affect the school again, or it won’t affect the (Kaʻū) hospital again. Though the hospital is open and functioning, we could lose power again for those who got restored.

“So that’s why we’re really posturing now to get ready for this.”

Bravender added: “We’re worried about people going through this again. And that’s the concern. Why we’re hitting this messaging hard with this type of cyclone. … Take action now just in case. Because we’ve seen what happened with Lala, and we’re worried about something similar. Because of the escape routes, egresses might be blocked or unavailable.”

Bravender said people should leave a flood prone area early, and stay with friends or family.

“Think about that now so you can get ready for that before the rain starts this weekend.”

Green said the hope is for the storm to go far south to be less of an impact to Hawaiʻi.

“But with this amount of water, because of this circumstance, we’re going to pre-position extra resources and we’re going to get some people out of the community,” Green said. “If you need support, you’re going to hear which philanthropic groups are helping us.

“But we will put you up in a hotel over in Hilo or perhaps Kona. We have some Airbnbs that have been donated just to help people because they may be without power and they may also worry more about the incoming changes again on the terrain.”

The Hawaiʻi County Civil Defense Agency said that due to this threat, the following should be done:

• Residents and businesses of Hawaii Island should expect and prepare for possible damaging winds, flooding rains, high surf, worsening of power outages, loss of communications and road closures.
• Please take this threat seriously and check your emergency kit for adequate food, water, medication, fuel, flashlights with working batteries, and emergency contact information.
• Secure all outdoor items that could become airborne or pose a threat to your property. 
• Boat owners and those with shoreline property, prepare for possible high surf impact.
• Please stay informed by signing up for Civil Defense alerts by texting HawaiiAlerts at 888777.

Avoid Travel to Kaʻū: Please continue to avoid any unnecessary travel into Ka‘ū District to help quicken emergency response.

Storm name

Because the system is expected to become a tropical storm in the Central Pacific, it will be named “Moke,” a commonly used direct equivalent to the name “Moses” in historical Hawaiian records and family genealogies.

Rainfall

Heavy rainfall associated with Tropical Depression Two-C is expected to impact the Big Island late Saturday night, spreading westward to the other Hawaiian Islands Sunday into Monday, according to the 5 a.m. Thursday advisory of the National Hurricane Center.

It is expected to produce rainfall totals of 5 to 10 inches with maximum amounts of 15 inches across the Big Island. Rainfall totals of 1 to 3 inches with maximum amounts of 5 inches are expected across the remainder of the Hawaiian Islands this weekend and early next week.

“This rainfall may produce life-threatening flooding and mudslides, especially in steep terrain and over areas that were recently affected by Lala,” the National Hurricane Center wrote.

Winds and surf

“There is a risk of wind and wave impacts in the Hawaiian Islands regardless of the exact track and intensity of the system. Watches may be required for portions of the Hawaiian Islands Thursday night or Friday.”

The cyclone is expected to be in a mostly favorable environment for the next couple of days, which should allow for gradual strengthening to a high-end tropical storm or a category one
hurricane as the system moves toward the Hawaiian Islands, the forecast said.

Swells generated by the depression are expected to affect portions of the Hawaiian Islands ths weekend, and could cause life-threatening surf and rip current conditions.

Second tropical disturbance

Disturbance 2 (in yellow on the map above) is a weak are of low presssure located several hundred miles south of the southern tip of the Baja California Peninsula. It is producing a large area of disorganized showers and thunderstorms.

Environmental conditions are forecast to be marginally favorable for development. It has a 40 percent chance of developing into a cyclone over the next seven days.

Disturbance 1 (in red on the map above) is a tropical wave located a few hundred miles south of the coast of southern Mexico. It is producing gusty winds and disorganized showers and thunderstorms.

Environmental conditions appear favorable for gradual development. A tropical depression is likely to form this weekend or early next week while the system moves west-northwest.