A large and slow moving low pressure developed along the Middle Atlantic coast on Wednesday, March 21st and moved slowly north and east along the coast through Thursday, March 22nd. Moderate to heavy snow bands moved across Long Island and New York City with lighter snow across the Lower Hudson Valley. The heaviest snow occurred in New York City and Long Island Wednesday night into early Thursday morning. The highest snowfall rates occurred on Long Island with generally 2 to 4 inches per hour at times. The NWS official observation at the Islip Airport indicated a snowfall rate of 5 inches per hour between 9pm and 10pm on March 21st with around 9 inches of snow falling from 8pm to 10pm. Within these heavier bands, near-blizzard conditions occurred with visibilities one quarter mile or less and winds gusting 30 to 35 mph.

Winter Storm in SOUTHWEST SUFFOLK, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Official NWS Observation at Islip Airport was 18.4 inches of snow. The FAA Contract Observer at the Airport reported snowfall rates 2 to 4 inches per hour during the night of March 21st with a one hour rate of 5 inches. NWS Employees reported similar snowfall rates in Ronkonkoma, Patchogue, and Sayville. Snowfall amounts ranged from 9 to 20 inches across Southwest Suffolk as reported by NWS Employees, trained spotters, social media, and the public. Near-blizzard conditions occurred with visibility falling below one quarter mile at times and winds gusting 30 to 35 mph during the highest snowfall rates.

Heavy Snow in SOUTHERN QUEENS, NEW YORK
From 21-MAR-18 06:00:00 to 22-MAR-18 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters, social media, and the FAA Contract Observer at John F. Kennedy Airport reported 8 to 15 inches of snow.

Winter Weather in NORTHERN WESTCHESTER, NEW YORK
From 21-MAR-18 07:00:00 to 22-MAR-18 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters, social media, and the public reported 2 to 8 inches of snow. These totals were reached in more than 12 hours and did not meet NWS criteria for warning level snow.

Heavy Snow in RICHMOND (STATEN IS.), NEW YORK
From 21-MAR-18 06:00:00 to 22-MAR-18 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Social Media and the public reported 7 to 14 inches of snow.

Heavy Snow in KINGS (BROOKLYN), NEW YORK
From 21-MAR-18 06:00:00 to 22-MAR-18 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Social Media and trained spotters reported 7 to 13 inches of snow.

Winter Storm in NORTHWEST SUFFOLK, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters, social media, broadcast media, and the public reported 10 to 20 inches of snowfall. Near-blizzard conditions occurred at times during the evening of March 21st with visibility falling below one quarter of a mile at times and winds gusting 25 to 30 mph.

Heavy Snow in NEW YORK (MANHATTAN), NEW YORK
From 21-MAR-18 06:00:00 to 22-MAR-18 04:30:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Official NWS Observation at Central Park reported 8.4 inches of snow. Law enforcement in Gramercy Park reported 10.0 inches of snow.

Heavy Snow in BRONX, NEW YORK
From 21-MAR-18 05:00:00 to 22-MAR-18 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Park/Forest Service

The Bronx Zoo reported 8.1 inches of snow and the public reported 8.5 inches of snow in Morris Park.

Winter Weather in SOUTHERN WESTCHESTER, NEW YORK
From 21-MAR-18 07:00:00 to 22-MAR-18 06:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters reported 6 to 8 inches of snowfall. These amounts were reached in more than 12 hours and did not meet NWS criteria for warning level snowfall.

Winter Storm in NORTHERN NASSAU, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters, Fire Department/Rescue,  social media, and the public reported 10 to 15 inches of snow. Near-blizzard conditions occurred at times during the evening of March 21st with visibility falling below one quarter of a mile at times and winds gusting 25 to 30 mph.

Winter Storm in SOUTHERN NASSAU, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 07:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

NWS Employees in East Meadow and Farmingdale reported 14.5 and 13.1 inches of snowfall respectively. Snowfall amounts across southern Nassau ranged from 7 to 16 inches as reported by trained spotters, social media, and CoCoRaHS and the public.
Near-blizzard conditions occurred at times during the evening of March 21st with visibility falling below one quarter of a mile at times and winds gusting 25 to 30 mph.

Winter Weather in ORANGE, NEW YORK
From 21-MAR-18 15:00:00 to 22-MAR-18 02:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters generally reported 3 to 5 inches of snow across the eastern half of the county with an isolated report of 7 inches in Monroe. The western half of the county saw 0.5 to 3 inches of snow.

Winter Weather in ROCKLAND, NEW YORK
From 21-MAR-18 07:00:00 to 22-MAR-18 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters reported 3 to 6 inches of snow with the highest amounts across the southern tier of the county in Sloatsburg.

Winter Weather in PUTNAM, NEW YORK
From 21-MAR-18 10:00:00 to 22-MAR-18 04:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A COOP observer and trained spotters reported 3 to 5 inches of snow.

Winter Weather in SOUTHEAST SUFFOLK, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

A COOP Observer and trained spotters reported 3 to 5 inches of snow.

Winter Weather in NORTHEAST SUFFOLK, NEW YORK
From 21-MAR-18 08:00:00 to 22-MAR-18 09:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters reported 3 to 7 inches of snow.

Heavy Snow in NORTHERN QUEENS, NEW YORK
From 21-MAR-18 05:00:00 to 22-MAR-18 05:00:00 (EST-5)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Trained spotters, social media, and the FAA Contract Observer at La Guardia Airport reported 9 to 14 inches of snow.