Drivers face another treacherous commute Wednesday, with patches of black ice and dense fog after subfreezing temperatures overnight.
It warned that falling ice from trees, structures and utility wires poses "a significant hazard."
Today, forecasters expect sunny skies with a high temperature near 28 degrees and north winds ranging from 10 to 16 mph. Thursday night will be cold but clear, with a low of around 14 and west winds between 6 and 8 mph.
Standing water from snow that melted because of the above-freezing temperatures Wednesday could refreeze and produce black ice, the service said.
Forecasters said dense fog could also develop Thursday as milder air moves over snow.
The predictions follow a day when an ice storm that let loose sleet and freezing rain turned cars and trees into ice sculptures, and roads into hockey rinks.
The Long Island Power Authority said about 18,000 customers were without power at some point during the storm, but most outages had been restored by early last night. By 6 p.m., LIPA reported 600 customers without power.
Most outages were in Nassau County, said Vanessa Baird-Streeter, a LIPA spokeswoman.
"Outages were caused by downed wires, some downed poles and tree limbs" contacting power lines, Baird-Streeter said.
LIPA has shifted crews from the East End to help restore power in Nassau, Baird-Streeter said. To report an outage, call 800-490-0075.
With Zachary R. Dowdy
and Gary Dymski