Long Island weather forecast: Heavy rain, high wind gusts as autumn begins

Fall won't be the only thing nipping the air this weekend.

The arrival of the autumn equinox at 2:50 a.m. Saturday will be accompanied by heavy rains and gusty winds that will washout many outdoor plans for the weekend, the National Weather Service said.

Thursday afternoon Gov. Kathy Hochul issued a statement calling on New Yorkers to prepare for heavy rainfall that could start Friday evening. She said the system could impact communities as far north as the Capital Region, but the system effects should be especially felt in Long Island and New York City.

"I urge all New Yorkers to monitor the weather forecast closely and prepare to act, if necessary, to protect yourself and others,” she said.

Hochul encouraged state residents to sign up for NY Alert, the state's free emergency alert system, at  alert.ny.gov.

The National Weather Service said an area of low pressure has developed along the eastern coast of the United States and will move toward Long Island through Friday and into Saturday. The system is associated with a broad area of low pressure northeast of the Bahamas that will probably become a tropical storm late Friday and early Saturday as it approaches the Carolinas. 

Although Thursday will be sunny and seasonable, the associated warm front has the potential to bring soaking rain, gusty winds, coastal flooding, beach erosion and dangerous rip currents to the area this weekend, and possibly into early next week, according to the weather service forecast.

The low-pressure system is expected to weaken and drift out to sea Sunday into Monday, forecasters said.

Total rainfall between 2 a.m. Saturday and 8 p.m. Sunday on Long Island is expected to range from about 2.3 inches and 2.5 inches, according to a weather service forecast issued Thursday afternoon.

There will be a sharp gradient between heavier rainfall to the south of the forecast area, meaning Long Island, and less to the north, including Westchester and Southern Connecticut, the weather service said.

Fall's entrance will also be windy: Stiff wind gusts out of the east-north-east could peak at 30 mph to 40 mph at the coast and will probably bring gales over the ocean waters, the weather service said.

Coastal flooding is possible beginning with Saturday afternoon's high tide and possibly continuing into Sunday, the weather service said.

Rough surf, dangerous rip currents and ocean beach erosion/flooding issues are all possible beach worries beginning Thursday through this weekend and possibly lasting into next week.

The arrival of fall is measured by the arrival of the equinox, derived from the Latin words "aequus" and "nox," meaning "equal night." Saturday's event is one of only two times of the year (spring is the other) when the Earth's axis is tilted neither toward nor away from the sun. That position results in almost equal amounts of daylight and darkness at all latitudes, the weather service said.

There are slight variations in the sunlight times, depending on how far you are from the equator, the weather service said.

New York City, positioned at 40.71° latitude and considerably north of the equator, will see sunrise Saturday at 6:42 a.m. and sunset at 6:55 p.m., according to the web site timeanddate.

That would be 12 hours, 13 minutes of daylight, largely obscured by the expected thick clouds and driving rain.

And, of course, the days grow shorter and colder as we advance through autumn toward the winter solstice, the longest night of the year, Thursday, Dec. 21. at 10:27 p.m.

Check back for updates on this developing story.