Alert archive / New York / Flash Flood Warnings in 2021

Flash Flood Warning 24, NWS New York, NY

August 21, 20214 counties in New York

NWS New York, NY issued this flash flood warning at Aug 21, 2021, 10:47 PM EDT for 4 counties in New York. It was in force for 103 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 21, 2021, 10:47 PM EDT (02:47 UTC)
Expired
Aug 22, 2021, 12:30 AM EDT
In force
103 min
Issued by
NWS New York, NY
Area
Storm-based polygon
Flood severity
None

Counties Bronx County, NY, Nassau County, NY, New York County, NY, Queens County, NY

The radar

The Brookhaven radar (KOKX), 78 km from the middle of the area, began a volume at 02:48 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Aug 21, 10:50 PM EDTFLASH FLOOD1 Se Garden City, NYMULTIPLE VEHICLES STRANDED IN STREET FLOODING AT FRANKLIN AVE & 2 ST.
Aug 21, 10:55 PM EDTFLASH FLOODGarden City, NYMULTIPLE VEHICLES STRANDED IN STREET FLOODING AT ROCKAWAY AVE & STEWART AVE.
Aug 21, 11:20 PM EDTFLASH FLOOD1 Wnw Throgs Neck Bridg, NYVIDEO ON SOCIAL MEDIA OF CARS STRANDED IN STANDING WATER.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 2.8 hours before the alert went out and 78 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Brookhaven, NY at 00:00Z on 2021-08-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1163 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2021-08-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
1163 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
543 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
85 m²/s²
Significant tornado parameter
0.3
Supercell composite
1.7

Open this sounding in Storm Lab

The text

As transmitted.

037 
WGUS51 KOKX 220247
FFWOKX
NYC005-059-061-081-220445-
/O.NEW.KOKX.FF.W.0024.210822T0247Z-210822T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service New York NY
1047 PM EDT Sat Aug 21 2021

The National Weather Service in Upton has issued a

* Flash Flood Warning for...
  Bronx County in southeastern New York...
  Western Nassau County in southeastern New York...
  New York (Manhattan) County in southeastern New York...
  Queens County in southeastern New York...

* Until 1245 AM EDT.

* At 1047 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen. Additional rainfall amounts of 1 to 2 inches are 
  possible in the warned area. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Flash flooding caused by thunderstorms.

  SOURCE...Radar.

  IMPACT...Flash flooding of small creeks and streams, urban
           areas, highways, streets and underpasses as well as
           other poor drainage and low-lying areas.

* Some locations that will experience flash flooding include...
  Jamaica, Flushing, Mott Haven, East Tremont, Garden City, Mineola, 
  Great Neck, Throgs Neck Bridge, Laguardia Airport, RFK Bridge, 
  Jackson Heights, Astoria, Hempstead, Riverdale, Bayside, Co-op 
  City, Elmont, Whitestone, Baldwin and Port Washington.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4086 7395 4092 7392 4090 7386 4091 7385
      4089 7384 4088 7379 4089 7378 4089 7376
      4088 7375 4087 7375 4086 7375 4088 7373
      4088 7371 4085 7367 4072 7357 4066 7360
      4066 7369 4074 7385 4074 7395 4079 7392

FLASH FLOOD...RADAR INDICATED

$$

MW
2 follow-up statements
528 
WGUS71 KOKX 220310
FFSOKX

Flash Flood Statement
National Weather Service New York NY
1110 PM EDT Sat Aug 21 2021

NYC005-059-061-081-220445-
/O.CON.KOKX.FF.W.0024.000000T0000Z-210822T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bronx NY-Nassau NY-New York (Manhattan) NY-Queens NY-
1110 PM EDT Sat Aug 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1245 AM EDT SUNDAY 
FOR BRONX, WESTERN NASSAU, NEW YORK (MANHATTAN) AND QUEENS 
COUNTIES...

At 1110 PM EDT, Doppler radar indicated thunderstorms producing 
heavy rain. Between 1 and 3 inches of rain have fallen. Additional 
rainfall amounts of 1 to 2 inches are possible in the warned area. 
Flash flooding is already occurring.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Jamaica, Flushing, Mott Haven, East Tremont, Garden City, Mineola, 
  Great Neck, Throgs Neck Bridge, Laguardia Airport, RFK Bridge, 
  Jackson Heights, Astoria, Hempstead, Riverdale, Bayside, Co-op 
  City, Elmont, Whitestone, Baldwin and Port Washington.

At 10:50 PM, Emergency Management reported water rescues and 
stranded vehicles in Garden City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4086 7395 4092 7392 4090 7386 4091 7385
      4089 7384 4088 7379 4089 7378 4089 7376
      4088 7375 4087 7375 4086 7375 4088 7373
      4088 7371 4085 7367 4072 7357 4066 7360
      4066 7369 4074 7385 4074 7395 4079 7392

FLASH FLOOD...RADAR INDICATED

$$

MW
488 
WGUS71 KOKX 220430
FFSOKX

Flash Flood Statement
National Weather Service New York NY
1230 AM EDT Sun Aug 22 2021

NYC005-059-061-081-220440-
/O.CAN.KOKX.FF.W.0024.000000T0000Z-210822T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bronx NY-Nassau NY-New York (Manhattan) NY-Queens NY-
1230 AM EDT Sun Aug 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR BRONX, WESTERN NASSAU, NEW 
YORK (MANHATTAN) AND QUEENS COUNTIES...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 800 AM EDT Monday for portions 
of southern Connecticut, northeast New Jersey and southeast New York.

LAT...LON 4086 7395 4092 7392 4090 7386 4091 7385
      4089 7384 4088 7379 4089 7378 4089 7376
      4088 7375 4087 7375 4086 7375 4088 7373
      4088 7371 4085 7367 4072 7357 4066 7360
      4066 7369 4074 7385 4074 7395 4079 7392

$$

MW

The office that day

Everything else NWS New York, NY issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 21, 8:46 PM EDTFlash Flood WarningOKXKings, Queens5 hr
Aug 21, 9:03 PM EDTAreal Flood AdvisoryOKXBronx, Kings, Nassau, New York, Queens, Richmond and 1 more87 min
Aug 21, 10:18 PM EDTFlash Flood WarningOKXNew York4 hr
Aug 21, 10:37 PM EDTAreal Flood AdvisoryOKXBronx, Nassau, New York, Queens, Westchester83 min
Aug 22, 1:22 AM EDTFlash Flood WarningOKXRichmond117 min
Aug 22, 2:49 AM EDTAreal Flood AdvisoryOKXBronx, Kings, Nassau, New York, Queens86 min
Aug 22, 8:39 AM EDTAreal Flood AdvisoryOKXSuffolk4 hr
Aug 22, 1:32 PM EDTAreal Flood AdvisoryOKXKings, Nassau, Queens118 min
Aug 22, 2:44 PM EDTFlash Flood WarningOKXBronx, Kings, New York, Queens, Richmond, Rockland and 1 more3 hr
Aug 22, 3:17 PM EDTFlash Flood WarningOKXKings, Nassau, Queens2 hr
Aug 22, 4:32 PM EDTCoastal Flood StatementOKXNassau, Queens, Suffolk, Westchester10 hr
Aug 22, 4:51 PM EDTFlash Flood Warning Considerable damage threatOKXBronx, New York, Orange, Rockland, Westchester6 hr
Aug 22, 5:17 PM EDTSmall Craft AdvisoryOKX42 hr

Nearby

Flash Flood Warnings in New York, 2021Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.