The National Weather Service moved up its warning of flash floods from the remains of Ida to Wednesday morning, saying heavy rains could start then and impact Long Island through Thursday afternoon.
"The remnants of Ida will track near the region Wednesday into Thursday, bringing heavy rain and potential flash flooding to the region," the weather service said in a Tuesday evening briefing.
"The flash flood watch is now in effect from 8 a.m. Wednesday through 2 p.m. Thursday. There is also a risk of an isolated tornado, mainly Wednesday night into Thursday morning."
Between 3 and 6 inches of rain could fall, forecasters said, though some areas could see more precipitation. The flooding risk also increases in areas already saturated from prior recent tropical storms like Fred and Henry.
The region could see rain fall at a rate of 1 to 2 inches per hour, the weather service said, lasting into Thursday afternoon. Winds, while nowhere near tropical storm force, will be gusty — up to about 30 mph at times.
The New York City Emergency Management issued a citywide travel advisory for Wednesday morning into Thursday morning.
"New Yorkers are advised to exercise caution when traveling, especially while driving, walking, or biking, and allow for additional travel time," the advisory said.
Thursday night, the system moves out but it will still be breezy and temperatures will fall to the high 50s before rebounding to the 70s Friday and Saturday with sunny skies.
Sunday and Monday, Labor Day, there is a 30% chance of showers, the weather service said.
Ida, now a tropical depression, devastated Louisiana Sunday as a hurricane. It left more than a million people without power, along with severe flooding, catastrophic structure damage and fatalities.
As of Tuesday evening, the weakened system was turning northeast and was over Tennessee, soaking areas of the southeast that had already been flooded by prior storms.
Ten to 18 inches fell in some parts of Mississippi and even up to 24 inches in some isolated areas, forecasters said. Kentucky, Ohio, West Virginia, Massachusetts and other states are all under a flash flood watch, the weather service said.