Forecasters: 100% chance of rain Thanksgiving Day; weekend to be crisp and clear

Long Islanders will awaken to a rainy Thanksgiving Day that will likely make local and regional travel difficult, forecasters said.

A low pressure system overnight is forecast to deliver a 100% chance of rain, beginning before sunrise Thursday and then lingering throughout the day, according to the National Weather Service. 

Long Island and the region are expected to get a half-inch of rain or more Thursday. 

Sustained winds should be relatively light, topping out at about 13 mph in Manhattan, meaning the iconic balloons of the Macy's Thanksgiving Day Parade are expected to fly.

Throngs of onlookers are expected to attend in person. The Long Island Rail Road has scheduled extra eastbound and westbound trains on multiple branches Thursday as transportation hubs across the nation anticipate record levels of holiday travel.

Six additional westbound trains split between the Babylon and Ronkonkoma branches will take riders, including fans of the parade, to Penn and Grand Central Madison stations on Thursday. Nine additional trains have been added for the afternoon ride home from those two stations, spread across the Babylon, Ronkonkoma and Port Jefferson branches.

Throughout the big travel weekend, the metropolitan airports are recommending extra early arrival times for outgoing flights.

For Long Island travelers heading north, a wintry mix is anticipated for the early morning hours Thursday that could leave up to 3 inches of snow in Orange County and more into the Catskills.

Thursday's rain on Long Island will taper off through the evening and overnight, leading to a prolonged period of sunny, dry conditions with daytime temperatures around 40 degrees, forecasters said.