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 say.

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

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

Winds are expected to be relatively light out of the east in the morning, topping out at 10 mph, meaning the iconic balloons of the Macy's Thanksgiving Day Parade are expected to fly; the parade will go on as scheduled. 

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 Long Islanders, including fans of the Macy's Thanksgiving Day Parade, to Penn and Grand Central Madison stations on Thursday. Nine additional trains have been added to the afternoon ride home.

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.