Commuters Wednesday morning will likely be greeted with heavy rain, making for slick roads and lower visibility, forecasters said.
In all, 1 to 2 inches, with higher amounts locally, were forecast, with the heavier, steadier rain expected to end by midmorning Wednesday, said Joe Pollina, National Weather Service meteorologist based in Upton.
The weather service said there's a potential for additional heavy rain, with an increasing chance of minor coastal flooding Thursday and widespread minor to moderate coastal flooding Friday. This week's rainfall could total 4 to 8 inches, with locally higher amounts, the service said.
Forecasters' eyes are also trained on Tropical Storm Joaquin and its potential impact on Long Island.
As of 5 p.m. Tuesday, the storm was around 400 miles east of the northwest Bahamas, continuing to strengthen and expected to become a hurricane Wednesday, the National Hurricane Center said. Models were still diverging as to its track, though.
The heaviest rain will come Thursday morning, Friday and perhaps again on Sunday even if Joaquin stays off shore as expected, said News 12 Long Island meteorologist Bill Korbel.
"The forecast for Joaquin is still extremely uncertain, but it has intensified more rapidly than expected and is now a 65-mph tropical storm likely to become a hurricane" late Tuesday or Wednesday, Korbel said.
The area certainly can use rain, with Long Island MacArthur Airport registering a 9.3-inch precipitation deficit since Jan. 1, according to the Northeast Regional Climate Center.
This week's rainfall, as well as anything the tropical storm might bring, could "help eat away at the deficit," said Samantha Borisoff, climatologist with the center.
Still, the weather service said conditions also could bring an increased threat for coastal flooding, heavy surf and beach erosion later in the week.