As the Big Island continues to reel from the devastation wrought over the weekend by Hurricane Lala, another potential threat looms to the southeast of Hawaii.

Dubbed EP90 by the National Hurricane Center in Miami, the tropical rainstorm — which was on the verge Wednesday of crossing from the Eastern Pacific into the Central Pacific — is producing showers and thundershowers and is showing signs of organizing into a tropical cyclone.

“Environmental conditions appear favorable for further development of this system, and a tropical depression is likely to form during the next day or so as the system moves westward to west-northwestward at 10 to 15 mph and crosses into the Central Pacific. Interests in the Hawaiian Islands should closely monitor the progress of this system,” wrote NHC forecaster Larry Kelly in an update today.

The probability that the low-pressure system will form into a cyclone within the next 48 hours is 90%, according to Kelly.

AccuWeather forecasters say the current track based on computer forecast models could have the storm passing within 100 miles south of Hawaii Island as a hurricane on Sunday — just a week after Hurricane Lala passed 30 miles south of the island, causing significant damage and apparently at least two deaths.

“The Big Island will be especially sensitive to flooding after Lala already caused significant flooding and mudslides last weekend,” said AccuWeather lead hurricane expert Alex DaSilva. “The rainfall amounts and location of the rain is going to be largely dependent on the storm track, which could move farther south and largely miss the islands.

“That doesn’t mean there wouldn’t be significant impacts to land, though.”

Widespread rainfall amounts of 4-8 inches are expected across the island, with a potential for 24 inches in some areas. Flooding and gusty winds could occur, forecasters say, with the highest risk for impacts to lives and property expected to be across the higher elevations and windward side of the island.

Hawaii County Civil Defense said Wednesday it is closely monitoring the tropical disturbance, urging Big Island residents and visitors to prepare for the potential arrival of another cyclone.

“We’ve been watching that area of interest, as they call it, since it first popped up … right around the time of Lala approaching us,” Acting Civil Defense Administrator Darryl Oliveira said Wednesday. “So, going forward, we have a daily briefing every day with a detailed update from the weather service specifically on that area of interest and the conditions that are developing. The weather service said (Wednesday) morning that the system could develop into some sort of tropical cyclone — that’s a tropical depression, a tropical storm or a hurricane — with some indication of what that might look like.”

Oliveira said the agency is “always prepping and planning for the worst” — whether or not the worst-case situation arises.

“One aspect of our preparation is sheltering,” he said. “Given that the community is just getting out of the post-impact phase of Lala, especially down south, I can see maybe more residents taking advantage of sheltering opportunities rather than riding it out because they don’t have the infrastructure, personally, to stay in place. So, a key consideration is expecting a higher shelter count.

“Yes, we’re all going through the recovery from Lala, but we have another system of concern, and we want everybody to be prepared.”

Email John Burnett at john.burnett@hawaiitribune-herald.com.