According to the MTA, customers should allow for extra travel time, exercise caution.
Officials recommend travel only in emergencies.
The LIRR said in an earlier statement its goal is to "keep as much train service operating as possible on all branches. But to ensure customer and employee safety, service may be temporarily suspended if snow accumulations reach 10 to 13 inches."
Preparations for the storm began earlier Wednesday with "de-icer trains dispatched to prep rails," the railroad said.
"The LIRR had brought extra personnel on hand at Jamaica to ensure that switches there remain operational," and the railroad "is running anti-freeze trains throughout its electrified system to help reduce icing on the third rail."