At the same time Iselle is wreaking havoc on the Hawaiian Islands, Hurricane Julio continues to churn in its wake, offering a real threat to deliver a rare double whammy of destruction on the state.

Julio strengthened to a Category 3 hurricane Thursday with 115 mph winds and traveling westerly at 16 mph more than 1,000 miles to the east of Hawaii.

It’s moving in roughly the same path as Iselle, although the projected track would take it just north of the islands and arriving near Hawaii island Sunday and the rest of the chain Monday.

"It’s still too far out to know what impacts it would have on the islands," said Chris Brenchley, National Weather Service meteorologist at the Central Pacific Hurricane Center in Hono­­lulu.

While Julio gained strength Thursday, forecasters said they expect it to maintain its power Friday before it starts to weaken slowly, and Julio may end up being demoted to tropical storm status before it reaches Hawaii.

But they also said that about Iselle, which regained some strength and approached the Big Island as a Category 1 hurricane with sustained 75 mph winds.

If Julio does strike Hawaii, officials warn it could exacerbate conditions left by Iselle, including the possibility of creating worsened flooding and new mudslide threats and dangerous blowing of newly loosened debris and tree branches, especially on the Big Island.

"It would be extremely rare" if Julio followed the exact path as Iselle, Brenchley said.

Julio’s maximum sustained winds were near 115 mph with higher gusts Thursday. Forecasters expect general westward to west-northwestward movement in the next day or so.

Gov. Neil Abercrombie said the state government is prepared to respond to not one, but two storms in short order.

"We’re ready for this," he declared, adding that responders are prepared whether Julio goes north of the islands or south. "Either way, whether it comes above us or below us, we have to be prepared for whatever the water, the wind, the rain or the consequences."