Heavy showers and isolated thunder storms are forecast through tonight and more rain is likely to greet President Obama’s Christmas homecoming when Air Force One is expected to touch down at Joint Base Pearl Harbor-Hickam tomorrow night.

All islands remain under a flash flood watch through tonight.

"The greatest threat is the next 12 to 24 hours," said Derek Wroe, lead forecaster for the National Weather Service.

Tropical Storm Omeka, which had been sitting north of the main Hawaiian islands, was downgraded to a "remnant low" last night by the National Weather Service. 

But an even bigger system is unleashing rain today that will likely continue through Christmas, Wroe said.

"The front to the north will keep us under the threat of wet conditions pretty much through Christmas," he said. "It’s unlikely that we’ll have normal trade conditions until after Christmas."