Showers and thunderstorms streaming northward well ahead of approaching Hurricane Henri resulted in flash flooding across portions of New York City and Western Long Island. This rainfall developed in a moisture-rich environment, with the 8pm sounding from Upton, NY recording precipitable water values around 2.25 inches. Rainfall totals from this predecessor rainfall event ranged from 1-5 inches. The ASOS in Central Park recorded 4.45 inches of rain for August 21, a new record for the date, much of which fell within a three hour period from 9pm to midnight.

Flash Flood in KINGS, NEW YORK
From 21-AUG-21 21:00:00 to 22-AUG-21 01:09:00 (EST-5)
Location: BROOKLYN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A water rescue was reported at the intersection of 4th Avenue and Carroll Street in Park Slope, Brooklyn, due to flash flooding.

Flash Flood in KINGS, NEW YORK
From 21-AUG-21 21:00:00 to 22-AUG-21 01:09:00 (EST-5)
Location: CONEY IS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

A water rescue was reported on 3rd Avenue beneath the Gowanus Expressway in Bay Ridge, Brooklyn due to flash flooding.

Flash Flood in KINGS, NEW YORK
From 21-AUG-21 21:06:00 to 22-AUG-21 01:09:00 (EST-5)
Location: BROOKLYN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Vehicles were stranded due to flash flooding on 4th Avenue in Park Slope.

Flash Flood in KINGS, NEW YORK
From 21-AUG-21 21:21:00 to 22-AUG-21 01:09:00 (EST-5)
Location: NEW YORK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

All lanes were closed due to flooding on the northbound Brooklyn side of the Brooklyn Battery Tunnel in Carroll Gardens. The Clinton Street entrance to the tunnel was also closed.

Flash Flood in NASSAU, NEW YORK
From 21-AUG-21 21:50:00 to 22-AUG-21 01:09:00 (EST-5)
Location: NEW HYDE PARK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Multiple vehicles were stranded due to flooding at the intersection of Franklin Avenue and 2nd Street in Garden City.

Flash Flood in NASSAU, NEW YORK
From 21-AUG-21 21:55:00 to 22-AUG-21 01:09:00 (EST-5)
Location: FLORAL PARK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Multiple vehicles were stranded in flood waters at the intersection of Rockaway Avenue and Stewart Avenue in Garden City.

Flash Flood in BRONX, NEW YORK
From 21-AUG-21 22:20:00 to 21-AUG-21 22:50:00 (EST-5)
Location: THROGGS NECK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A video on social media showed cars stranded in standing water in the vicinity of the Throgs Neck Bridge in the Bronx.

Flash Flood in QUEENS, NEW YORK
From 21-AUG-21 22:29:00 to 22-AUG-21 01:09:00 (EST-5)
Location: (JFK)KENNEDY INL ARP
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

All lanes were closed due to flooding on the exit from I-678 northbound (Van Wyck Expressway) to Federal Circle near JFK Airport.

Flash Flood in NEW YORK, NEW YORK
From 21-AUG-21 23:05:00 to 21-AUG-21 23:35:00 (EST-5)
Location: CENTRAL PARK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The 3 train was suspended in both directions due to flooding between Harlem-148th Street and 34th Street-Penn Station in Manhattan.

Flash Flood in KINGS, NEW YORK
From 22-AUG-21 00:39:00 to 22-AUG-21 01:09:00 (EST-5)
Location: NEW YORK
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

All lanes of the Brooklyn Queens Expressway were closed due to flooding in both directions at Kane Street in Cobble Hill, Brooklyn.

Flash Flood in RICHMOND, NEW YORK
From 22-AUG-21 00:59:00 to 22-AUG-21 01:29:00 (EST-5)
Location: SOUTH BEACH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

St. Johns Avenue in Grasmere was flooded with water up to the hood of a car.