Heavy rains in the forecast for Big Island late Sunday and Monday according to the National Weather Service


“Barbara has lost all her deep convection. So it’s still an area of low pressure but no longer has tropical characteristics,” Jon Jelsema, senior forecaster for the National Weather Service, said.

Just a few days ago Barbara was a category four hurricane. The fact that she is continuing to weaken is good news.

But even though she will pack less of a punch as she gets closer to Hawaii, she is still expected to drench portions of the islands starting as early as Sunday night.

But just how much will it rain?

“Even though this system has lost its thunderstorm activity, it still has very, very humid conditions that are moving towards the islands. So that’s going to be with the trade winds moving over the mountain to really bring some heavy torrential rainfall to Windward areas,” Jelsema explained.

Torrential rains could equal flash flooding.

“Any vulnerable locations low-lying areas that typically flood in heavy rainfall patterns for Windward areas, they should be prepared.”

The winds will also increase according to Jelsema.

“It’s going to be some noticeably stronger winds than we’ve seen over the past month or two.”

Those winds expected to be 20-30 mph. So it’s a good idea to tie down loose items around your home.

Hawaii County Mayor Harry Kim said they are remaining vigilant. He even met with other county officials Friday to prepare just in case.

“Nature will play its own game, its own forecast game and we’re not smart enough to know what it is. Our job is to prepare for all scenarios ….As far as the government sectors, our responsibility is to do as much as we can. Check all drainage canals and flood canals and make sure they are as cleared of debris as possible to make sure that all the areas that are at risk or in case that are a potential threat are clear.”

Kim said that if the weather gets too bad they would take acton to notify those in Waipio Valley and Waimano of the dangers.

“If things increase and further action is needed, we have to be timely in that presentation to the public on what to do or what not to do,” Kim said.

Maui and Oahu may possibly see heavy downpours on Monday. But some wonder if there’s could be a repeat of the torrential rains that flooded areas of Honolulu on June 25, 2019.

“They are two totally different types of systems. This one is going to be a trade wind pattern, where the other one was almost like a Kona wind type pattern where we had winds from the south. In Kona wind type patterns, we tend to get heavy rainfall in Leeward areas versus trade wind patterns we have heavy rainfall in Windward areas,” Jelsema explained.

KHON: “So it’s not necessarily going to be less rain it’s just going to be hitting a different side of the island?”

“That’s exactly right. The Windward areas are going to be the main targets from this event,” Jelsema said.

Jelsema also said that the rain could possibly help relieve some of the drought conditions being felt on Hawaii and Maui if they are on the issues are on Windward side of the islands.

KHON: “Is there any chance Barbara could strengthen as she gets closer to the islands?”

“Right now luckily for us is experiencing a tremendous amount of wind shear, which is strong winds above the surface. That’s what’s wiped out all of the thunderstorm activity with the system. It’s also moving over very cool water, which is unfavorable for any potential intensification. And it is surrounded by a lot of dry air. Three factors are going to make it impossible for the system to redevelop,” Jelsema said.

The only downside is that it is just the beginning of hurricane season in Hawaii.

“Hurricane season runs right through November 30, so we still have a long way to go.”

And the peak season starts mid July through August.

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